Journal articles on the topic 'SYNTHETIC POLLUTION INDEX (SPI)'
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Grema, H. M., H. Hamidu, A. Suleiman, A. I. Kankara, A. O. Umaru, and N. F. Abdulmalik. "Cadmium geochemistry and groundwater pollution status evaluation using indexing and spatial analysis for Keffe community and Environs Sokoto Basin, North Western Nigeria." Nigerian Journal of Basic and Applied Sciences 30, no. 1 (August 24, 2022): 05–23. http://dx.doi.org/10.4314/njbas.v30i1.2.
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Representative groundwater samples were collected from the Kaffe community and environs to evaluate the concentrations and geochemical constraints for mobilizing cadmium (Cd) and selected heavy metals. Field-based in-situ measurements of physicochemical parameters were combined with Atomic Absorption Spectrophotometer analysis of dissolved elemental concentrations. Pollution indices (i.e. heavy metal pollution index; HPI, heavy metal evaluation index; HEI, contamination degree; Cd, metal index; MI, synthetic pollution index; SPI, ecological risk index; ERI and Nemerow index; NI) evaluations highlighted the levels of heavy metals in the groundwater. Cadmium and iron (Fe) concentrations exceeded the recommended limits in 97% of the analysed samples, with an average pH of 6.3. Strong positive correlations were observed between cadmium and the computed pollution indices (p 0.774 to p 0.100), suggesting significant Cd pollution of the groundwater. Components analysis grouped Cd, Fe, and the pollution indices in the first PC. This was favourably compared to the correlation analysis result. Cluster analysis categorized Cd, Zn and pH in the first cluster consistent with the suggested dissolution and enrichment of Cd and Zn in the groundwater under similar geochemical conditions. The study area is medium and moderately polluted based on HPI, HEI, Cd, and NI.
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Hui, Tian, Jizhong Du, Qifa Sun, Qiang Liu, Zhuang Kang, and Hongtao Jin. "Using the Water Quality Index (WQI), and the Synthetic Pollution Index (SPI) to Evaluate the Groundwater Quality for Drinking Purpose in Hailun, China." Sains Malaysiana 49, no. 10 (October 31, 2020): 2383–401. http://dx.doi.org/10.17576/jsm-2020-4910-05.
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Solangi, Ghulam Shabir, Altaf Ali Siyal, Muhammad Munir Babar, and Pirah Siyal. "Evaluation of drinking water quality using the water quality index (WQI), the synthetic pollution index (SPI) and geospatial tools in Thatta district, Pakistan." DESALINATION AND WATER TREATMENT 160 (2019): 202–13. http://dx.doi.org/10.5004/dwt.2019.24241.
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Hui, Tian, Liang Xiujuan, Sun Qifa, Liu Qiang, Kang Zhuang, and Gong Yan. "Evaluation of Drinking Water Quality Using the Water Quality Index (WQI), the Synthetic Pollution Index (SPI) and Geospatial Tools in Lianhuashan District, China." Polish Journal of Environmental Studies 30, no. 1 (October 5, 2020): 141–53. http://dx.doi.org/10.15244/pjoes/120765.
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Solangi, Ghulam Shabir, Altaf Ali Siyal, Muhammad Munir Babar, and Pirah Siyal. "Groundwater quality evaluation using the water quality index (WQI), the synthetic pollution index (SPI), and geospatial tools: a case study of Sujawal district, Pakistan." Human and Ecological Risk Assessment: An International Journal 26, no. 6 (April 7, 2019): 1529–49. http://dx.doi.org/10.1080/10807039.2019.1588099.
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Solangi, Ghulam Shabir, Altaf Ali Siyal, Muhammad Munir Babar, and Pirah Siyal. "Evaluation of surface water quality using the water quality index (WQI) and the synthetic pollution index (SPI): a case study of Indus Delta region of Pakistan." DESALINATION AND WATER TREATMENT 118 (2018): 39–48. http://dx.doi.org/10.5004/dwt.2018.22407.
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Nhu Tam, Doan Ngoc. "APPLICATION OF PRINCIPLE COMPONENT ANALYSIS TO BUILD PROVINCIAL ECO-EFFICIENCY INDEX FOR BINH DUONG PROVINCE FROM 2001-2012." Vietnam Journal of Science and Technology 54, no. 2A (March 19, 2018): 251. http://dx.doi.org/10.15625/2525-2518/54/2a/11938.
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Based on a proposed concept of Regional Eco-Efficiency of Zhou Zhenfeng, a set of indicators for assessing, eco-efficiency of provincial level has been conducted. Set of indicators included 26 indicators, and was divided into 3 groups: Socio-Economic Development Index (SDI) (9 indicators); Resources Consumption Index (RCI) (7 indicators) and Environmental Pressure index (EPrI) (10 indicators). Principle component analysis (PCA) was used to assess Eco-efficiency Synthetic Index (ESI) of Binh Duong province in the 2001-2012. Results shown that the ESI of Binh Duong province has been clearly improving from 2001-2012. RCI and EPrI respectively had a significant correlation with SDI. Results also have been shown that the industrialization generated waste and if the pollution control solution is not effectively so environmental pressure is continuously increase and degrade the environment.
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Bedolla-Rivera, Héctor Iván, Eloy Conde-Barajas, Sandra Lizeth Galván-Díaz, Francisco Paúl Gámez-Vázquez, Dioselina Álvarez-Bernal, and María de la Luz Xochilt Negrete-Rodríguez. "Compost Quality Indexes (CQIs) of Biosolids Using Physicochemical, Biological and Ecophysiological Indicators: C and N Mineralization Dynamics." Agronomy 12, no. 10 (September 24, 2022): 2290. http://dx.doi.org/10.3390/agronomy12102290.
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The increasing production of biosolids (BS) as a result of urban wastewater treatment generates pollution problems in their management and final disposal, and a better management is needed for their disposal. The composting of BS is an alternative process for obtaining a product with potential application as an organic amendment in the recovery of agricultural soils. As a biotechnological contribution, this study analyzed a composting process with BS, bovine manure (BM) and rice husks using four treatments T1 (C/N = 24); T2 (C/N = 34); T3 (C/N = 44); T4 (C/N = 54) for 120 days, in order to develop compost quality indexes (CQIs) through the analysis of 18 physicochemical, biological and ecophysiological indicators. Subsequently, three methodologies—successfully used on soils—were implemented for the development of the CQIs called “unified”, “additive” and “nemoro”. The indicators that comprised the CQIs were nitrification index (NI) and synthetic enzymatic index (SEI). The CQIs made it possible to differentiate the quality of the compost according to the treatments applied. The treatments used resulted in composts considered phytonutritious whose average quality value depending on the CQI developed was considered high (CQIw = 0.62), moderate (CQIa = 0.56) and low (CQIn = 0.30). The developed CQIs can be applied to determine the quality of BS composting systems reducing the cost of monitoring.
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Sur, Chanyang, Dongkyun Kim, Joo-Heon Lee, Muhammad Mazhar Iqbal, and Minha Choi. "Hydrological Drought Assessment of Energy-Based Water Deficit Index (EWDI) at Different Geographical Regions." Advances in Meteorology 2019 (May 29, 2019): 1–11. http://dx.doi.org/10.1155/2019/8512727.
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This study applied the remote sensing-based drought index, namely, the Energy-Based Water Deficit Index (EWDI), across Mongolia, Australia, and Korean Peninsula for the period between 2000 and 2010. The EWDI is estimated based on the hydrometeorological variables such as evapotranspiration, soil moisture, solar radiation, and vegetation activity which are derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) imageries. The estimated EWDI was compared with the Evaporative Stress Index (ESI), the Vegetation Condition Index (VCI), and the Standardized Precipitation Index (SPI). The correlation coefficients between the drought indices are as follows: 0.73–0.76 (EWDI vs ESI), 0.64–0.71 (EWDI vs VCI), 0.54–0.64 (EWDI vs SPI-3), 0.69–0.71 (ESI vs VCI), 0.55–0.62 (ESI vs SPI-3), and 0.53–0.57 (VCI vs SPI-3). The drought prediction accuracy of each index according to error matrix analysis is as follows: 83.33–94.17% (EWDI), 70.00–91.67% (ESI), 47.50–85.00% (VCI), and 61.67–88.33% (SPI-3). Based on the results, the EWDI and ESI were found to be more accurate in capturing moderate drought conditions than the SPI at different geographical regions.
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Kim, Young-Sik, Gi-Sun Kim, and Mi-Ra Song. "A Study on SPI(soil pollution index) in City Land." Korean Journal of Environmental Health Sciences 33, no. 6 (December 31, 2007): 502–5. http://dx.doi.org/10.5668/jehs.2007.33.6.502.
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Abeysingha, N. S., and U. R. L. N. Rajapaksha. "SPI-Based Spatiotemporal Drought over Sri Lanka." Advances in Meteorology 2020 (January 21, 2020): 1–10. http://dx.doi.org/10.1155/2020/9753279.
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Drought is one of the most significant hazards in Sri Lanka. Status of drought in Sri Lanka was assessed using Standardized Precipitation Index (SPI) at 3, 6, and 12 months’ time scales using monthly rainfall (1970 to 2017) data of 54 weather stations. The frequency of drought events was evaluated using SPI, and trend of SPI was also detected using the Mann–Kendall (MK) test and Sen’s slope estimator. The result based on SPI identified hydrological years 1975-76, 1982-83, 1986-87, 1988-89, 2000-01, 2001-02, 2013-14, and 2016-17 as drought years for 52, 32, 35, 33, 33, 31, 31, and 31% of tested stations (54), respectively, at annual time scale. Comparison of the SPI at different time scales revealed that more drought events (SPI ≤ −1) occurred during Yala season than Maha cropping season. Considering the Thiessen polygon average rainfall, more frequent drought events occurred in the dry zone (57%) than the wet (49%) and intermediate zone (47%) at the annual time scale. SPI trend results showed greater increase in drought (59% of stations) during Yala seasons as compared to the Maha cropping season (15% of stations) in Sri Lanka.
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C., Kougblenou, Atinkpahoun C., Saizonou M., Youssao A., and Soclo H. "STUDY OF CONTAMINATION BY METALLIC ELEMENTS IN COASTAL SEDIMENTS: CASE OF THE COTONOU CHANNEL." International Journal Of Advanced Research 10, no. 04 (April 28, 2022): 157–67. http://dx.doi.org/10.21474/ijar01/14529.
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Coastal aquatic ecosystems are environments increasingly affected by human activities due to urban discharges and their use as dumps. The objective of this study is to determine the profiles of metallic elements concentration (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb) of Cotonou channel sediments and to evaluate their quality. For this, surface sediments (0-5cm) were sampled at 13 sites along the channel. Thus,Geoaccumulation Index (Igeo), Enrichment Factor (EF) and Sediment Pollution Index (SPI) were calculated to assess the chemical quality of these sediments. The metal contents of the sediments follow the following order of abundance: Fe >Al>Mn> Zn >Cr>Cu > Co> Ni >Pb> As> Cd. The Igeo geo-accumulation index and the Enrichment Factor FE reveal moderate polymetallic contamination by several elements. The results show Fe, Co, and Ni being the most concerning. As for the Sediment Pollution Index (SPI), it reports low, moderate and high pollution of sediments.
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Penconek, Agata, Dorota Kasak, and Arkadiusz Moskal. "Soy Protein Nanofibers Obtained by Solution Blow Spinning." Processes 11, no. 8 (August 1, 2023): 2310. http://dx.doi.org/10.3390/pr11082310.
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The climate crisis, growing pollution of the environment with waste, and ubiquitous microplastics have encouraged the search for new methods and new opportunities to use natural materials in the least harmful processes. Replacing synthetic materials with raw materials is not only a matter of “fashion”, but also a necessity. Therefore, this study aimed to produce fibers from an aqueous solution containing the highest possible concentration of soy protein isolate (SPI) through solution-blowing. As the aqueous solution of SPI has no fiber-forming potential, polyethylene oxide (PEO) was used as the carrier/matrix. The rheology of the aqueous PEO solution and PEO/SPI blends (flow curves, loss modulus, and storage modulus) was then analyzed. The proportions of the PEO/SPI mixtures and the process parameters were determined on this basis. As a result of the conducted research, nanofibers were produced from water solutions of PEO/SPI with a soy protein content of up to 7.88%, with a PEO share of 1.25%. The average diameter of the obtained fibers was 225–495 nm, depending on the process parameters and SPI content—as the SPI content in the PEO/SPI mixture increased, the average fiber diameter decreased. The production of nanofibers with a high soy protein content increases their application possibilities. Firstly, due to a much larger surface area, and secondly, due to the presence of numerous functional groups in the protein structure, which can be a place of attachment for additional compounds that give the obtained nanofibers the desired properties.
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Addi, Martin, Kofi Asare, Samuel Kofi Fosuhene, Theophilus Ansah-Narh, Kenneth Aidoo, and Comfort Gyasiwaa Botchway. "Impact of Large-Scale Climate Indices on Meteorological Drought of Coastal Ghana." Advances in Meteorology 2021 (February 3, 2021): 1–17. http://dx.doi.org/10.1155/2021/8899645.
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The devastating effects of drought on agriculture, water resources, and other socioeconomic activities have severe consequences on food security and water resource management. Understanding the mechanism that drives drought and predicting its variability is important for enhancing early warning and disaster risk management. In this study, meteorological droughts over six coastal synoptic stations were investigated using three-month Standardized Precipitation Index (SPI). The dry seasons of November-December-January (NDJ), December-January-February (DJF), and January-February-March (JFM) were the focal seasons for the study. Trends of dry seasons SPIs were evaluated using seasonal Mann–Kendall test. The relationship between drought SPI and ocean-atmosphere climate indices and their predictive ability were assessed using Pearson correlation and Akaike Information Criterion (AIC) stepwise regression method to select best climate indices at lagged timestep that fit the SPI. The SPI exhibited moderate to severe drought during the dry seasons. Accra exhibited a significant increasing SPI trend in JFM, NDJ, and DJF seasons. Besides, Saltpond during DJF, Tema, and Axim in NDJ season showed significant increasing trend of SPI. In recent years, SPIs in dry seasons are increasing, an indication of weak drought intensity, and the catchment areas are becoming wetter in the traditional dry seasons. Direct (inverse) relationship was established between dry seasons SPIs and Atlantic (equatorial Pacific) ocean's climate indices. The significant climate indices modulating drought SPIs at different time lags are a combination of either Nino 3.4, Nino 4, Nino 3, Nino 1 + 2, TNA, TSA, AMM, or AMO for a given station. The AIC stepwise regression model explained up to 48% of the variance in the drought SPI and indicates Nino 3.4, Nino 4, Nino 3, Nino 1 + 2, TNA, TSA, AMM, and AMO have great potential for seasonal drought prediction over Coastal Ghana.
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Makumbura, Randika K., and Upaka Rathnayake. "Variation of Leaf Area Index (LAI) under Changing Climate: Kadolkele Mangrove Forest, Sri Lanka." Advances in Meteorology 2022 (October 10, 2022): 1–10. http://dx.doi.org/10.1155/2022/9693303.
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Mangroves are an essential plant community in coastal ecosystems. While the importance of mangrove ecosystems is well acknowledged, climate change is expected to have a considerable negative impact on them, especially in terms of temperature, precipitation, sea level rise (SLR), ocean currents, and increasing storminess. Sri Lanka ranks near the bottom of the list of countries researching this problem, even though the scientific community's interest in examining the variation in mangrove health in response to climate change has gained significant attention. Consequently, this study illustrates how the leaf area index, a measure of mangrove health, fluctuates in response to varying precipitation, particularly during droughts in Sri Lanka's Kadolkele mangrove forest. The measurements of the normalized difference vegetation index (NDVI) were used to produce the leaf area index (LAI), which was then combined with the standard precipitation index (SPI) to estimate the health of the mangroves. The climate scenario, RCP8.5, was used to forecast future SPI (2021–2100), and LAI was modeled under the observed (1991–2019) and expected (2021–2100) drought events. The study reveals that the forecasted drought intensities modeled using the RCP8.5 scenario have no significant variations on LAI, even though some severe and extreme drought conditions exist. Nevertheless, the health of the mangrove ecosystem is predicted to deteriorate under drought conditions and rebound when drought intensity decreases. The extreme drought state (-2.05) was identified in 2064; therefore, LAI has showcased its lowest (0.04). LAI and SPI are projected to gradually increase from 2064 to 2100, while high fluctuations are observed from 2021 to 2064. Limited availability of LAI values with required details (measured date, time, and sample locations) and cloud-free Landsat images have affected the study results. This research presents a comprehensive understanding of Kadolkele mangrove forest under future droughts; thus, alarming relevant authorities to develop management plans to safeguard these critical ecosystems.
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Zhong, Fanglei, Qingping Cheng, and Ping Wang. "Meteorological Drought, Hydrological Drought, and NDVI in the Heihe River Basin, Northwest China: Evolution and Propagation." Advances in Meteorology 2020 (June 9, 2020): 1–26. http://dx.doi.org/10.1155/2020/2409068.
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Understanding the evolution and propagation of different drought types is crucial to reduce drought hazards in arid and semiarid regions. Here, Standardized Precipitation Index (SPI), Streamflow Drought Index (SDI), and Vegetation Condition Index (VCI) were used to investigate the spatiotemporal variation of different drought types and correlations between Pre (Pre-R)/post (Pos-R)-reservoir. Results showed that the average peak/intensity/duration/severity of meteorological droughts (MD) were greater in the Pre-R than in the Pos-R period in the upstream Heihe River Basin (UHRB), while there was little change between the Pre-R and Pos-R periods in the midstream Heihe River Basin (MHRB). The average peak/intensity/duration/severity of hydrological drought (HD) decreased in the mainstream for Yingluoxia (Ylx) but increased for Zhengyixia (Zyx) station in the Pos-R period. Propagation time decreased by 3 months (negative effect) in Ylx and increased by 8 months (positive effect) in Zyx compared with the Pre-R period. In the Pos-R period, propagation time increased (1–3 months) for tributaries (positive effect). Propagation times for the mainstream and tributaries varied for different seasons and time periods. Pearson’s correlation coefficient values were lower at short timescales (1–3 months) but higher at long timescales for the Pos-R period in Ylx and Zyx for SDI-1 with different timescales of SPI. The SDI and SPI had no lag in the UHRB and MHRB. However, VCI with SPI had a significant lag correlation at short timescales in the UHRB (lag 6 months) and MHRB (lag 4 months), and the VCI with SDI had a significant lag correlation for 1 month in the MHRB. The propagation time from MD to HD has been reduced for Pos-R in the UHRB. There was a positive effect (prolonged MD propagation HD time) in Pos-R but still faces serious drought stress in the MHRB.
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Zhao, Xiao Qing, Hong Hui Yang, and Jian Chen. "Evaluation on Characteristics of Heavy Metal Spatial Pollution in Farmland Soils along the Bijiang River." Applied Mechanics and Materials 295-298 (February 2013): 1586–93. http://dx.doi.org/10.4028/www.scientific.net/amm.295-298.1586.
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Based on the farmland soils along the Bijiang River, a main tributary of the international Lantsang-Mekong River flowing through the Jinding Lead-Zinc Deposit, this dissertation makes analyses on the pollution characteristics of spatial variation in farmland soils by adopting the soil sampling and testing analysis and applying single-factor pollution index (SPI) evaluation and Nemerow composite pollution index (NCPI) evaluation. The results indicate that: (1) In accordance with Environmental Quality Standard for Soils (II), the content of Cd contained in the farmland soils has severely exceeded the standard in a large scale, followed by Pb and Zn. However, the content of As is maintained within the specified standard; (2)The SPI values of soils are in the following sequence: Cd＞Zn＞Pb＞As. The pollution level caused by the heavy metal “Cd” to the farmland soils is extremely heavy in a wide range, and a majority of the farmlands are heavily polluted by Zn. The farmlands with moderate pollution by Pb are centered at Plot 2 in the deposit, and only a few farmland soils are moderately polluted by As at Plot 2 in the deposit;(3) Based on the NCPI, the results indicate that the NCPI of the farmland soils has reached to the degree of heavy pollution; (4) It is indicated based on the RPI evaluation that the RPI values of As, Cd, Pb and Zn contained in the farmland soils have exceeded the standard in the following sequence: Pb＞Zn＞Cd＞As, which illustrates that during the development of Jinding Lead-Zinc Deposit in Lanping County, the heavy metals imposing the most profound influence on the soil pollution are Pb and Zn. The heavy metal pollution in the farmland soils from the upper reaches to the lower reaches of the Bijiang River is not only caused by the development of Jinding Lead-Zinc Deposit in Lanping County, but is also associated with its high soil background value;(5) There is a remarkable spatial variation of heavy metal pollution in farmland soils from the upper reaches to the lower reaches of the Bijiang River. Both the SPI and the NCPI values of heavy metals in the soils within the deposit at the upper reaches of the Bijiang River are the lowest; the pollution index of the soils closest to the deposit are the highest, and the pollution index of the soils with a certain distance from the deposit drops swiftly; the pollution index of Plot 4 rises to a certain degree at the middle reaches, and gradually ascends near the Yunlong County seat at Plot 5, however, with a comparatively small growth rates.
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Abera Tareke, Kassa, and Admasu Gebeyehu Awoke. "Hydrological and Meteorological Drought Monitoring and Trend Analysis in Abbay River Basin, Ethiopia." Advances in Meteorology 2022 (November 28, 2022): 1–18. http://dx.doi.org/10.1155/2022/2048077.
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The definition of drought is very controversial due to its multi-dimensional impact and slow propagation in onset and end. Predicting the accurate occurrence of drought remains a challenging task for researchers. The study focused on hydrological and meteorological drought monitoring and trend analysis in the Abbay river basin, using the streamflow drought index (SDI), standardized precipitation index (SPI), and reconnaissance drought index (RDI), respectively, to fill this research gap. The study also looked into the interrelationships between the two drought indicators. The SDI, SPI, and RDI were calculated using long-term streamflow, precipitation, and temperature data collected from 1973 to 2014. The data were collected from eight streamflow stations and fifteen meteorological gauge stations. DrinC software (Drought Indices Calculator) was used to calculate the SDI, SPI, and RDI values. The result from meteorological drought using SPI12 and RDI12 shows that 1975, 1981, 1984, 1986, 1991, 1994, and 2010 were extreme drought years, whereas 1983, 1984, 2001, and 2010 were the most extreme hydrological drought years based on the SDI12 result. Except for Bahir Dar and Gondar, a severe drought occurs at least once a decade in all stations considered in this study. In general, the SPI, RDI, and SDI results indicated that the study area was exposed to the most prolonged severe and extreme drought from 1981 to 1991. The findings of this study also demonstrated that the occurrence of hydrometeorological droughts in the Abbay river basin has a positive correlation at long time scales of 6 and 12 months. The trend analysis using the Mann–Kendall test implied that there was a significant meteorological drought trend in two stations (Debre Berhan and Fiche) at SPI12 and RDI12 time scale, but for the remaining thirteen stations, there is no trend in all time scales. The hydrological drought trend analysis in the basin on a seasonal (SDI3) and yearly (SDI12) time scale also revealed that three streamflow stations have a positive trend (Kessie, Gummera, and Border). This implies that water resource management is still a vital tool for the sustainable development of the Abbay river basin in the future.
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Sabau, Nicu Cornel, Teodor Eugen Man, Andrei Armas, Ciprian Balaj, and Mariana Giru. "CHARACTERIZATION OF AGRICULTURAL DROUGHTS USING STANDARDIZED PRECIPITATION INDEX (SPI) AND BHALME-MOOLEY DROUGHT INDEX (BDMI)." Environmental Engineering and Management Journal 14, no. 6 (2015): 1441–54. http://dx.doi.org/10.30638/eemj.2015.156.
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Xie, Jian Jun, Na Li, and Nian Zeng. "Preparation and its Properties of the Urea Modified Soy Protein Isolate Adhesives." Advanced Materials Research 580 (October 2012): 481–84. http://dx.doi.org/10.4028/www.scientific.net/amr.580.481.
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Soy proteins have shown great potential for use as renewable and environmentally friendly adhesives. The orthogonal experiments are designed for the urea-modified soy protein isolate(SPI) adhesives and the optimum formula is obtained. The mass concentrations of SPI and urea are 14% and 8%(relative to the total mass of SPI and water), the reaction temperature and time are 35°C and 60 min, respectively. Some basic and adhesion properties and its structure of the modified SPI adhesive for the optimum formula are measured. The viscosity is 43Pa.s, and the dry- and wet-state adhesion strengths of the urea-modified SPI optimum formula are 0.96MPa and 0.78MPa(>0.72MPa), respectively according to GB/T10724-2006, which satisfied with the requirement of the II-type plywood. Its surface hydrophobicity is improved and the thermal properties is slightly improved after 200°C. Recently, some concerns about environmental pollution, resource scarcity, and related health issues have pushed scientists to replace the petrochemicals-based synthetic polymers, which are used extensively in construction, packaging, glue and plywood industries, with the bio-based adhesives. SPI adhesives have shown great potential for use as environmentally friendly adhesives in plywood since 1930s when it’s first be developed. And it has been modified by chemical alkali[1], sodium dodecyl sulfate(SDS)[2,3], and urea[2], guanidine hydrochloride[4], etc. However, most of these modifications can not very well improve the water resistance and the bonding strength separately. Poor water resistance is a fatal weakness which seriously restricts the application in the industry. Many studies[5~8] have shown that the adhesives with some enhanced performances, for example, adhesion strength and water-resistant, can be obtained by unloading SPI molecular chain with the hydrophobic group using urea, SDS, other surfactant and guanidine hydrochloride, etc. And the unloading mechanism of the SPI molecular chain with the hydrophobic group is proclaimed. The optimum concentration of urea is 1mol/L for the water-resistant. The aim of this research was to improve the tacky strength and the water resistance[9] by using urea to modify SPI and evaluate the resulting adhesive’s potential for use in the plywood.
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Shalishe, Amba, Anirudh Bhowmick, and Kumneger Elias. "Meteorological Drought Monitoring Based on Satellite CHIRPS Product over Gamo Zone, Southern Ethiopia." Advances in Meteorology 2022 (June 28, 2022): 1–13. http://dx.doi.org/10.1155/2022/9323263.
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Drought is a frequent occurrence in semidesert areas of southern Ethiopia that significantly affect regional, social, economic, and environmental conditions. Lack of rainfall monitoring network, instrument measurement, and failure are major bottlenecks for agro-and hydroclimate research in developing countries. The objectives of this study were to evaluate the performance of CHIRPS rainfall product and to assess meteorological drought using SPI for the period 2000 to 2020 over Gamo Zone, southern Ethiopia. The performance of CHIRPS v2 was assessed and compared to station observations (2000–2020) in the study domain to derive SPI on a three-month timescale. The Pearson correlation coefficient (R), bias, probability of bias (PBias), mean error (ME), mean absolute error (MAE), root mean square error (RMSE), and Nash simulation efficiency (NSE) values across the zone for CHIRPS v2 were found to be 0.88, 1.02, 2.56, 0.25, 22.41, 33.14, and 0.77, respectively. The results indicate that CHIRPS performed good ability to analyze the drought characteristics in the Gamo Zone. The spatial and temporal distribution method of meteorological drought has been evaluated using the Climate Data Tool (CDT). The Standardized Precipitation Index (SPI) was computed using the gamma distribution method. The magnitude of (SPI-3) of monthly and seasonal (MAM) meteorological drought in the zone from 2000 to 2020. The result shows that the known historic drought years (2014, 2015, 2010, 2009, and 2008) were indicated very well. Furthermore, sever and extreme droughts were observed in 2008 and 2009 with drought duration of 6.7 and 6.3, respectively, in most areas of the zone. Hence, this study revealed that CHIRPS can be a useful supplement for measuring rainfall data to estimate rainfall and drought monitoring in this region.
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Lyon, Bradfield, Michael A. Bell, Michael K. Tippett, Arun Kumar, Martin P. Hoerling, Xiao-Wei Quan, and Hui Wang. "Baseline Probabilities for the Seasonal Prediction of Meteorological Drought." Journal of Applied Meteorology and Climatology 51, no. 7 (July 2012): 1222–37. http://dx.doi.org/10.1175/jamc-d-11-0132.1.
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AbstractThe inherent persistence characteristics of various drought indicators are quantified to extract predictive information that can improve drought early warning. Predictive skill is evaluated as a function of the seasonal cycle for regions within North America. The study serves to establish a set of baseline probabilities for drought across multiple indicators amenable to direct comparison with drought indicator forecast probabilities obtained when incorporating dynamical climate model forecasts. The emphasis is on the standardized precipitation index (SPI), but the method can easily be applied to any other meteorological drought indicator, and some additional examples are provided. Monte Carlo resampling of observational data generates two sets of synthetic time series of monthly precipitation that include, and exclude, the annual cycle while removing serial correlation. For the case of no seasonality, the autocorrelation (AC) of the SPI (and seasonal precipitation percentiles, moving monthly averages of precipitation) decays linearly with increasing lag. It is shown that seasonality in the variance of accumulated precipitation serves to enhance or diminish the persistence characteristics (AC) of the SPI and related drought indicators, and the seasonal cycle can thereby provide an appreciable source of drought predictability at regional scales. The AC is used to obtain a parametric probability density function of the future state of the SPI that is based solely on its inherent persistence characteristics. In addition, a method is presented for determining the optimal persistence of the SPI for the case of no serial correlation in precipitation (again, the baseline case). The optimized, baseline probabilities are being incorporated into Internet-based tools for the display of current and forecast drought conditions in near–real time.
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Chen, Rui, Lei Han, Zhao Liu, Yonghua Zhao, Risheng Li, Longfei Xia, and Yamin Fan. "Assessment of Soil-Heavy Metal Pollution and the Health Risks in a Mining Area from Southern Shaanxi Province, China." Toxics 10, no. 7 (July 11, 2022): 385. http://dx.doi.org/10.3390/toxics10070385.
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Soil-heavy metal pollution in mining areas is one of the problems in the comprehensive treatment of soil environmental pollution. To explore the degree of soil-heavy metal pollution and the human health risk in mining areas, the contents of soil As, Cd, Cu, Cr, Hg, Ni, Pb, and Cr(VI) in an abandoned gold mining area were determined. The geoaccumulation index (Igeo), single-factor pollution index (SPI), Nemerow comprehensive pollution index (NCPI), potential ecological risk index (PERI), and the human health risk assessment model were used to assess the pollution degree and the risk of soil-heavy metal pollution. Finally, the assessment results were used to provide remediation guidance. The results showed that (1) the average contents of As, Cd, Cr, Cu, Hg, and Ni in the mining area exceeded the background values of the soil elements. (2) The mining area was polluted by heavy metals to different degrees and had strong potential ecological hazards. (3) The total carcinogenic risk of heavy metals exceeded the health risk standard. The main components of pollution in the mining area were As, Cd, Cr, and Hg. Results from this study are expected to play a positive role in pollution treatment and the balance between humans and ecology.
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Abed, Mahmood F., Ghazi Atiya Zarraq, and Salwa H. Ahmed. "Assessment of Groundwater Pollution using Aqueous Geo-Environmental Indices, Baiji Province, Salah Al-Din, Iraq." Iraqi Geological Journal 55, no. 1B (February 28, 2022): 94–104. http://dx.doi.org/10.46717/igj.55.1b.9ms-2022-02-25.
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The study area is located in Baiji province characterized by anthropogenic activities which may affect the groundwater quality. Therefore, the present work was intended for assessing groundwater quality and its suitability for drinking. Groundwater samples were collected from 33 different well, then analyzed to determine 20 parameter which are TDS, Ca, Mg, Na, K, Cl, SO4, NO3, Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, As, B and Se. Nemerow Pollution Index Synthetic Pollution Index, and Pollution Index of Groundwater were used for determining groundwater suitability for human consumption. Nemerow Pollution Index values indicate that groundwater pollution is ranged from seriously to moderately polluted. According to Synthetic Pollution Index results, the water samples were moderately polluted to unsuitable for drinking. Depending on the rating of Pollution Index of Groundwater values, groundwater was polluted.
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Sepulcre-Canto, G., S. Horion, A. Singleton, H. Carrao, and J. Vogt. "Development of a Combined Drought Indicator to detect agricultural drought in Europe." Natural Hazards and Earth System Sciences 12, no. 11 (November 29, 2012): 3519–31. http://dx.doi.org/10.5194/nhess-12-3519-2012.
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Abstract. This study proposes a drought indicator that combines the Standardized Precipitation Index (SPI), the anomalies of soil moisture and the anomalies of the fraction of Absorbed Photosynthetically Active Radiation (fAPAR). Computed at the European level, the Combined Drought Indicator (CDI) gives a synthetic and synoptic overview of the drought situation using a classification scheme. Derived from the integration of the three individual indices, this classification scheme is composed of three warning levels: "watch" when a relevant precipitation shortage is observed, "warning" when this precipitation shortage translates into a soil moisture anomaly, and "alert" when these two conditions are accompanied by an anomaly in the vegetation condition. The design of the CDI includes the study of the relationship between the three individual indices. To achieve this, the SPI-3 (3-month SPI) was computed using the precipitation data obtained from a set of weather stations located in different agricultural areas of Europe, while the soil moisture and fAPAR data were extracted from the pixels of the respective grids surrounding these stations. The CDI is assessed for the main drought episodes of Europe between 2000 and 2011, using reported data from different sources, such as the EM-DAT Emergency Events Database and Eurostat annual yield estimates. The capability of the CDI to serve for drought early warning is evaluated as well as its robustness against false alarms. The indicator has been spatially implemented for the entire continent using different information layers of the European Drought Observatory. These layers correspond to SPI-3 grids derived from interpolated weather station precipitation data, anomalies of fAPAR from the MERIS Global Vegetation Index and anomalies of soil moisture obtained using the LISFLOOD distributed hydrological model. Maps of the CDI obtained for the European drought event in spring 2011 are shown and discussed, evaluating its operational applicability. To conclude, the main limitations of the indicator are presented and possible avenues for improvement are discussed.
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Hinis, Mehmet Ali, and Mehmet Selim Geyikli. "Accuracy Evaluation of Standardized Precipitation Index (SPI) Estimation under Conventional Assumption in Yeşilırmak, Kızılırmak, and Konya Closed Basins, Turkey." Advances in Meteorology 2023 (April 17, 2023): 1–13. http://dx.doi.org/10.1155/2023/5142965.
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The doubt in the calculation algorithm of the standardized precipitation index (SPI), which is widely preferred in the evaluation and monitoring of drought, still remains up-to-date because its calculation process is performed in the form of standardization or normalization with a default probability distribution. Therefore, the success of this index is directly affected by the choice of the probability distribution model. This study is based on the effect of three different parameter estimation methods on the calculation process, as well as the comparison of the SPI results calculated based on the default Gamma distribution and the distribution with the best ability to represent the 3-and 12-month consecutive summed rainfall data among the 15 candidate distributions namely Gamma (GAM), Generalized Extreme Value (GEV), Pearson Type III (P III), Log Pearson Type III (LP III), two-parameter Lognormal (LN2), three-parameter Lognormal (LN3), Generalized Logistic (GLOG), Extreme Value Type I (EVI), Generalized Pareto (GPAR), Weilbul (W), Normal (N), Exponential (EXP), Logistic (LOG), four-parameter Wakeby (WK4), and five-parameter Wakeby (WK5) distributions. Approximately 68.4% and 18.4% of the 3-month data considered had the best fit to the Weibull and Pearson III distribution, while approximately 24% and 18% of the 12-month data had the best fit to the Weibull and Logistic distribution. On the other hand, it was found that the default Gamma distribution calculated the extreme drought categories significantly more than the best-fit distribution model. In terms of parameter estimation methods, L-moments for 3-month series and maximum likelihood approaches for 12-month series were most dominant.
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Zhang, Yuhu, Wanyuan Cai, Qiuhua Chen, Yunjun Yao, and Kaili Liu. "Analysis of Changes in Precipitation and Drought in Aksu River Basin, Northwest China." Advances in Meteorology 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/215840.
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The analysis of the spatiotemporal trends of precipitation and drought is relevant for the future development and sustainable management of water resources in a given region. In this study, precipitation and Standardized Precipitation Index (SPI) trends were analyzed through applying linear regression, Mann–Kendall, and Spearman’s Rho tests at the 5% significance level. For this goal, meteorological data from 9 meteorological stations in and around Aksu Basin during the period 1960–2010 was used, and two main annual drought periods were detected (1978-1979 and 1983–1986), while the extremely dry years were recorded in 1975 and 1985 at almost all of the stations. The monthly analysis of precipitation series indicates that all stations had increasing trend in July, October, and December, while both increasing and decreasing trends were found in other months. For the seasonal scale, precipitation series had increasing trends in summer and winter. 33% of the stations had the decreasing trend on precipitation in the spring series, and it was 11% in the autumn. At the same time, the SPI-12 values of all stations had the increasing trend. The significant trends were detected at Aheqi, Baicheng, Keping, and Kuche stations.
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Sahli, Leila, Fatima-Zohra Afri-Mehennaoui, Mohamed El Hadef El Okki, Jean François Férard, and Smail Mehennaoui. "Assessment of sediment quality and pore water ecotoxicity in Kebir Rhumel basin (NE-Algeria): a combined approach." Water Science and Technology 65, no. 2 (January 1, 2012): 393–401. http://dx.doi.org/10.2166/wst.2012.802.
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The objectives of this study are to use different approaches to assess the current pollution status in the wadis of the Kebir Rhumel basin. First, sediment trace metal contents were measured by flame atomic absorption spectroscopy. Then, sediment quality was assessed on the basis of contamination assessment indexes such as: Geoaccumulation Index (Igeo), Contamination factor (Cf), Contamination degree (Cd), Sediment Pollution Index (SPI) and SEQ guidelines (Consensus Sediment Quality Guidelines). In addition, several toxicity tests (Daphnia magna mobility inhibition acute test-48 h, Aliivibrio fischeri luminescence inhibition acute test – 15/30 mn and Pseudokirchneriella subcapitata growth inhibition chronic test – 72 h) were conducted to assess sediment pore water ecotoxicity. Trace metal concentrations followed the order: Mn > Zn > Pb > Cr > Cu > Ni > Co > Cd. Indexes used indicate varying degrees of sediment quality. Igeo, Cf, Cd and SPI reveal a polymetallic contamination dominated by two or more elements in which Cd, Cu and Pb are of greatest concern. SEQ guidelines showed that biological effects on fauna would likely be observed occasionally and/or frequently for Cd, Cr, Cu, Pb and Zn contents. Test organisms exposed to sediment pore water showed that the algal P. subcapitata test was more sensitive than the D. magna and A. fischeri tests. Hence, algal growth inhibition proved to be the most sensitive response to contaminants present in sediment extracts but a significant relationship with trace metal contents was not demonstrated.
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Won, Jeongeun, Jeonghyeon Choi, Okjeong Lee, and Sangdan Kim. "Copula-based Joint Drought Index using SPI and EDDI and its application to climate change." Science of The Total Environment 744 (November 2020): 140701. http://dx.doi.org/10.1016/j.scitotenv.2020.140701.
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Ye, Xu-chun, Yun-liang Li, Xiang-hu Li, Chong-yu Xu, and Qi Zhang. "Investigation of the Variability and Implications of Meteorological Dry/Wet Conditions in the Poyang Lake Catchment, China, during the Period 1960–2010." Advances in Meteorology 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/928534.
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This paper presents a quantitative investigation of the variability of meteorological dry/wet conditions of the Poyang Lake catchment during 1960–2010 by using the standardized precipitation-evapotranspiration index (SPEI) based on daily observations of 14 meteorological stations across the catchment. Extending from previous studies, the background of the encounter and overlap of multitimescales of meteorological dry/wet episodes for several severe drought and flood events were discussed. In addition, the possible impacts of temperature changes on dry/wet variability were also examined by the comparison of SPEI and standardized precipitation index (SPI) variations at multitimescales during the study period. Major results show that the occurrence of dry/wet condition has become increasingly frequent in the recent two decades, especially the extreme wet episodes in 1990s and the extreme dry episodes in 2000s. Historically, the encounter and overlap of multitimescales of meteorological dry/wet episodes plays an important role in the occurrence of several severe drought and flood events. The study concluded that the impact of temperature anomaly to the dry/wet variability cannot be neglected.
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Shin, Ji Yae, Muhammad Ajmal, Jiyoung Yoo, and Tae-Woong Kim. "A Bayesian Network-Based Probabilistic Framework for Drought Forecasting and Outlook." Advances in Meteorology 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/9472605.
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Reliable drought forecasting is necessary to develop mitigation plans to cope with severe drought. This study developed a probabilistic scheme for drought forecasting and outlook combined with quantification of the prediction uncertainties. The Bayesian network was mainly employed as a statistical scheme for probabilistic forecasting that can represent the cause-effect relationships between the variables. The structure of the Bayesian network-based drought forecasting (BNDF) model was designed using the past, current, and forecasted drought condition. In this study, the drought conditions were represented by the standardized precipitation index (SPI). The accuracy of forecasted SPIs was assessed by comparing the observed SPIs and confidence intervals (CIs), exhibiting the associated uncertainty. Then, this study suggested the drought outlook framework based on probabilistic drought forecasting results. The overall results provided sufficient agreement between the observed and forecasted drought conditions in the outlook framework.
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Wang, Shi Xu, Zu Lu Zhang, and Xue Wang. "Heavy Metal Environmental Assessment of Surface Soil in Rizhao Tea-Planting Areas." Advanced Materials Research 807-809 (September 2013): 1397–401. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.1397.
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Analysis about contents and distributions of heavy metal elements in soil is one of the primary matters in surveying geochemical environmental quality in Rizhao tea-planting areas. By using 1km×1km sampling data of surface soil in Rizhao tea-planting areas, Geostatistics method is adopted to analyze spatial distribution of heavy metal elements, and nemerow synthetic index method is adopted to assess environmental qualities of heavy metals and show the result out by Kriging interpolation. The assessment results are as follows: the distribution of all the heavy metals besides Cd, Pb is comparatively uniformity; From the result of the single pollution index, the gross part of research areas is clean, only Cd, Ni pollution existed in finitude areas; From the spatial distribution of nemerow synthetic pollution index, 88.41% of the research areas soil belongs to level I, and 6.44% belongs to level II, and 5.14% level III, while no area belongs to level IV and level V.
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Nour, Hamdy E., Fatma Ramadan, Nouf El Shammari, and Mohamed Tawfik. "Status and contamination assessment of heavy metals pollution in coastal sediments, southern Kuwait." AIMS Environmental Science 9, no. 4 (2022): 538–52. http://dx.doi.org/10.3934/environsci.2022032.
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<abstract> <p>To assess the heavy metals concentration in the coastal sediments of the southern Kuwait coast, Fe, Mn, Cu, Pb, Ni, Co, Cd and Cr were measured by inductively coupled plasma mass spectroscopy. Whereas, the south of Kuwait coast is characterized by the presence of tourist resorts, and commercial and oil exports harbors. Moreover, environmental indicators were used to help in evaluating the degree and the intensity of pollutants in these sediments. Geoaccumulation index (Igeo) revealed that the sediments of hard all Hamara and Al-Khiran coasts are moderately polluted by Cu, while Ras Al-Zour and Ras Al-Jula'ia coasts are moderately polluted by Cd. Moreover, the enrichment factor (EF) indicated that the sediments of Hadd Al-Hamara coast are severely enriched with Ni, Cr and Pb, while the Al-Khiran coast is moderate severely enriched with the same metals. Ras Al-Zour and Ras Al-Jula'ia coasts are severely enriched with Ni and very severely enriched with Pb. Simultaneously, all studied sites are extremely severely enriched with Cu and Cd. These results were confirmed by the results of the contamination factor (CF) and the soil pollution index (SPI) indicated that Hadd Al-Hamara and Al-Khiran coasts are highly contaminated with Cu and Cd, while Ras Al-Zour and Ras Al-Jula'ia coasts are highly contaminated with Cd. Generally, the pollution load index showed that the sediments of all studied sites are no heavy metal pollution (PLI < 1). Pollutants might be originated from commercial wastes and construction activities.</p> </abstract>
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Wendleder, Anna, Peter Friedl, and Christoph Mayer. "Impacts of Climate and Supraglacial Lakes on the Surface Velocity of Baltoro Glacier from 1992 to 2017." Remote Sensing 10, no. 11 (October 24, 2018): 1681. http://dx.doi.org/10.3390/rs10111681.
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The Baltoro Glacier is one of the largest glaciers in the Karakoram mountain range. Long-term monitoring of glacier dynamics provides key information on glacier evolution in a changing climate, which is essential for regional water resource and natural hazard management. On large glaciers, detailed field based mass balance is not feasible. Ice dynamic variations quantify changes in mass transport and possibly the influence of environmental parameters on the evolution of the glacier. Although velocity variations of Baltoro Glacier during winter and summer are linked to seasonally enhanced basal sliding, little is known about differences in timing and magnitude of (intra-)seasonal velocity variations and their determining mechanisms. We present time series of annual, seasonal, and intra-seasonal glacier surface velocities by means of intensity offset tracking applied on multi-mission Synthetic Aperture Radar (SAR) data for a period of 25 years from 1992 to 2017. Supraglacial lakes forming on the downstream glacier surface in summer were mapped from 1991 to 2017 based on the Normalized Difference Water Index (NDWI), calculated from multi-spectral Landsat and ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) imagery. Additionally, precipitation data of the Tropical Rainfall Measurement Mission (TRMM) and temperature data of ERA-Interim were used to derive the Standardized Precipitation Index (SPI) and Standardized Temperature Index (STI) from 1998 to 2017. Linking surface velocities to the SPI confirmed a strong correlation between heavy precipitation events in winter and the magnitude and the timing of glacier acceleration in summer. Downstream extensions of summer acceleration that have been found since 2015 may be explained by additional water draining from an increased number of supraglacial lakes through crevasses that have been formed in consequence of higher initial velocities, evoked by strong winter precipitation. The warmer melt seasons observed in the years 2015 to 2017 additionally affects the formation of a supraglacial lake, so stronger summer acceleration events in recent years may be indirectly related to global warming.
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Huang, Wenjun, Jianjun Yang, Yang Liu, and Entao Yu. "Spatiotemporal Variations of Drought in the Arid Region of Northwestern China during 1950–2012." Advances in Meteorology 2021 (April 3, 2021): 1–12. http://dx.doi.org/10.1155/2021/6680067.
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There are water resource shortages and frequent drought disasters in the arid region of northwestern China (ARNC). The purpose of this study is to understand the spatiotemporal variations of the droughts in this region and to further estimate future changes. Multiple drought indexes such as the standardized precipitation index (SPI), the standardized precipitation evapotranspiration index (SPEI), and the self-calibrated Palmer drought severity index (SC-PDSI) are used to investigate the temporal and spatial characteristics of the ARNC drought from 1950 to 2012. Our results indicate the following: (1) The drought indexes exhibit significant increasing trends, and the highest drought frequency occurred in the 1960s, followed by a decreasing trend during the next few decades. All four seasons exhibit a wet trend, with a higher drought frequency in summer than in the other seasons. (2) The changes of the drought indexes in the ARNC also exhibit distinct spatial variations, with a wet trend in the subregions of North Xinjiang (NXJ), the Tianshan Mountains (TS), South Xinjiang (SXJ), and the Qilian Mountains (QL), but with a dry trend in the subregions of the Hexi Corridor (HX) and the western part of Inner Mongolia (WIM). (3) There was a major climate variability in the ARNC that occurred in the 1980s, and there were dry and wet climate oscillation periods of 8a, 17a, and >20a.
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Rivera, Juan A., Sofía Hinrichs, and Georgina Marianetti. "Using CHIRPS Dataset to Assess Wet and Dry Conditions along the Semiarid Central-Western Argentina." Advances in Meteorology 2019 (April 4, 2019): 1–18. http://dx.doi.org/10.1155/2019/8413964.
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The Climate Hazards group Infrared Precipitation with Stations (CHIRPS) dataset was conceived as a tool for monitoring drought and environmental change over land. Recent validation efforts along South America have assessed its suitability for reproducing the main spatial and temporal features of precipitation. Nevertheless, little has been done regarding the ability of CHIRPS for the assessment of wet and dry conditions, particularly in areas where in situ precipitation records are scarce. In this paper, we investigated the performance of CHIRPS for monitoring wet and dry events along the semiarid Central-Western Argentina. Using the Standardized Precipitation Index (SPI), we compared the CHIRPS database with records from 49 meteorological stations along the study area for the period 1987–2016. Results indicate that the CHIRPS dataset adequately reproduced the temporal variability of SPI on multiple timescales (1 month, 3 months, and 6 months), particularly in the region dominated by warm season precipitation. The large overestimation of the seasonal precipitation in the region dominated by cold season precipitation can introduce errors that are reflected in the performance of CHIRPS over the western portion of the domain. The frequency of wet and dry classes was accurately reproduced by CHIRPS on timescales larger than 1 month (SPI1), given the existence of a wet bias that produces an underestimation of the frequency of zero values. This bias is further translated to the evaluation of the SPI1 during the spatial and temporal assessment of historical dry (1998) and wet (2016) events, especially for the classification of extreme dry/wet months. The results from the evaluation indicate that CHIRPS is a suitable tool for assessing dry and wet conditions for timescales longer than 1 month and can support decision-making process within the hydrometeorological agencies over the region.
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Nawrot, Nicole, Ewa Wojciechowska, Muhammad Mohsin, Suvi Kuittinen, Ari Pappinen, and Shahabaldin Rezania. "Trace Metal Contamination of Bottom Sediments: A Review of Assessment Measures and Geochemical Background Determination Methods." Minerals 11, no. 8 (August 12, 2021): 872. http://dx.doi.org/10.3390/min11080872.
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This paper provides an overview of different methods of assessing the trace metal (TM) contamination status of sediments affected by anthropogenic interference. The geochemical background determination methods are also described. A total of 25 papers covering rivers, lakes, and retention tanks sediments in areas subjected to anthropogenic pressure from the last three years (2019, 2020, and 2021) were analysed to support our examination of the assessment measures. Geochemical and ecotoxicological classifications are presented that may prove useful for sediment evaluation. Among the geochemical indices, several individual pollution indices (CF, Igeo, EF, Pi (SPI), PTT), complex pollution indices (PLI, Cdeg, mCdeg, Pisum, PIAvg, PIaAvg, PIN, PIProd, PIapProd, PIvectorM, PINemerow, IntPI, MPI), and geochemical classifications are compared. The ecotoxicological assessment includes an overview of Sediment Quality Guidelines (SQG) and classifications introduced nationally (as LAWA or modified LAWA). The ecotoxicological indices presented in this review cover individual (ERi) and complex indices (CSI, SPI, RAC, PERI, MERMQ). Biomonitoring of contaminated sites based on plant bioindicators is extensively explored as an indirect method for evaluating pollution sites. The most commonly used indices in the reviewed papers were Igeo, EF, and CF. Many authors referred to ecotoxicological assessment via SQG. Moreover, PERI, which includes the toxic response index, was just as popular. The most recognised bioindicators include the Phragmites and Salix species. Phragmites can be considered for Fe, Cu, Cd, and Ni bioindication in sites, while Salix hybrid cultivars such as Klara may be considered for phytostabilisation and rhizofiltration due to higher Cu, Zn, and Ni accumulation in roots. Vetiveria zizanoides demonstrated resistance to As stress and feasibility for the remediation of As. Moreover, bioindicators offer a feasible tool for recovering valuable elements for the development of a circular economy (e.g., rare earth elements).
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Pei, Jia Pei, Zhang Tai, Shi Xiao Shuang, Xia Bin Yu, and Liu Ran. "Soil Heavy Metal Pollution Analysis of City Surface Based on Neural Network." Applied Mechanics and Materials 340 (July 2013): 947–51. http://dx.doi.org/10.4028/www.scientific.net/amm.340.947.
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Identified the urban soil has heavy metal pollution degree and the cause of the contamination of the overall analysis system. Through the mat lab software to realize pollution degree distribution visualization, use numerous evaluation pollution degree synthetic index methods, and then the reference neural network building the knowledge about the cause of the contamination analysis to determine the mechanism of the main causes of the pollution.
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Boudad, B., H. Sahbi, and I. Mansouri. "Analysis of meteorological and hydrological drought based in SPI and SDI index in the Inaouen Basin (Northern Morocco)." Journal of Materials and Environmental Sciences 9, no. 1 (January 1, 2018): 219–27. http://dx.doi.org/10.26872/jmes.2018.9.1.25.
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Halecki, Wiktor, and Sławomir Klatka. "Aplication of Soil Productivity Index after Eight Years of Soil Reclamation with Sewage Sludge Amendments." Environmental Management 67, no. 5 (January 18, 2021): 822–32. http://dx.doi.org/10.1007/s00267-020-01422-1.
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AbstractRemediation methods are gaining acceptance as effective and inexpensive techniques used in the reclamation of degraded areas. The reclamation of post-mining sites has become important for the conservation of soil and vegetation. An assessment of potential productivity of plants based on the depth of their root zone is crucial for the validation of properties of post-mining soils. Our aim was to present soil productivity parameters that would facilitate assessment of various post-mining objects. Soil productivity index (SPI) was calculated to assess soil quality, mainly in areas degraded by hard coal mining. It is based on an equation determining the relationship between the productivity index and the physical, chemical, and hydrological properties of soil. Our study demonstrated the positive effects of enriched sewage sludge with amendments on newly formed soil and plants. The soil productivity index was 0.81, demonstrating the suitable condition of the initial soil resulting from reclamation. This parameter might be important for post-industrial reclamation, such as wasteland intended to be transformed into woodland. Considering the composition of sewage sludge amendments, it can be successfully used as an effective method of restoring and improving both the physical and chemical properties of soils, thus effectively replacing mineral fertilisers. The use of sewage sludge in soil reclamation will be an important method of managing this waste material in post-mining areas.
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Loto, O. O., and A. O. Ajibare. "Pollution Assessment of the Physico-Chemical Properties of the Lagos Lagoon." Nigerian Journal of Technological Research 16, no. 3 (September 28, 2021): 1–7. http://dx.doi.org/10.4314/njtr.v16i3.1.
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Lagos lagoon has received wastewater discharged from different anthropogenic sources. Therefore, this study determined the water quality and identified its pollution status. Water quality index (WQI), several heavy metal pollution indices as well as single factor and comprehensive pollution indices were applied. The obtained data revealed that physicochemical parameter varied between 24.00±1.41 and 27.00±0.71°C for temperature; 2.50±2.83 and 10.50±0.71‰ for salinity; 3.90±0.99 and 4.60±0.85 mg/l for dissolved oxygen; 7.26±0.25 and 8.38±0.66 for pH; 3.50±0.71 and 10.00±7.07mg/l for BOD. The results also revealed that sulphate, phosphate and nitrate had means of 10.00±10.45mg/l, 0.85±1.04mg/l and 11.11±17.88 mg/l respectively while Pb, Zn, Cu and Hg had means of 0.25±0.49mg/l, 25.49±44.27mg/l, 1.88±2.94mg/l and 0.00±0.00mg/l respectively. SPI classified pH, BOD, Cu and Zn within the ‘medium pollution’ category while nitrate and phosphate indicated heavy pollution of the lagoon. The PI revealed that Cu and Zn had moderate and slight effect on the aquatic environment respectively while Pb and Hg had no effect on the ecosystem. The mean WQI revealed that the lagoon was classified to be good for aquatic biota despite that HEI and Cd revealed that there was high pollution of heavy metals in the lagoon. The CPI described the lagoon as slightly polluted.
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Asamoah, Yaw, and Kow Ansah-Mensah. "Temporal Description of Annual Temperature and Rainfall in the Bawku Area of Ghana." Advances in Meteorology 2020 (April 1, 2020): 1–18. http://dx.doi.org/10.1155/2020/3402178.
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With varied implications, Ghana’s temperature and rainfall are projected to rise and decline, respectively. A study exposing specific areas of concern for appropriate responses in this regard is a welcome one. This study sought to describe the temporal variations in temperature and rainfall in the Bawku Area of Ghana. A forty-year (1976–2015) daily climate data was collected on three meteorological stations from the Ghana Meteorological Agency. Normality test, homogeneity test, Standardised Precipitation Index (SPI) analysis, Mann–Kendall trend test, and One-way post hoc ANOVA were performed using XLSTAT and DrinC. Over the period under study, the mean annual rainfall pattern was generally erratic, fluctuating between 669.8 mm and 1339.4.6 mm with an annual average of 935.3 mm. The long-term (40-year period) average temperature of the three stations, on the other hand, was 28.7°C, varying between 26.9°C and 29.9°C annually. Whereas the SPI value of 2006 was ≥2.0, indicating extremely wet year with 2.3% probability of recurring once every 50 years, 1988 was the hottest year with temperature anomaly value of 1.2°C, while coolest years were 1979 (−1.8°C) and 1976 (−1.0°C). The Mann–Kendall trend test showed a rise in rainfall in Binduri, Garu-Tempane, and Manga, yet none of the rainfall changes were statistically significant (P>0.05). Mean temperature on the other hand experienced a significant rise (P<0.05). With an R-square of 34.7%, the rise in temperature in Manga witnessed the most significant change in annual temperature changes. There were statistically significant (P<0.05) differences in the interdecadal temperature over the 40-year period. Generally, it can be stated that both temperature and rainfall vary in the study area with various degrees of disparities, but temperature assumes an upward trend at a faster rate. We therefore recommend that stakeholders resort to the construction of dams and boreholes to ensure regular availability of water for both domestic and agricultural uses.
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Zhu, Xiaoping, Wenlong Chen, Jianguo Wang, Wei Guo, Liehui Lei, Yisi Liu, Weicong Ye, and Xiaoxuan Chen. "Synthetic Evaluation on the Potential Ecological Risks of Heavy Metal Pollution in Sediments in the Sea near Bohe Port of Maoming." Journal of Physics: Conference Series 2224, no. 1 (April 1, 2022): 012069. http://dx.doi.org/10.1088/1742-6596/2224/1/012069.
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Abstract The pollution index method and Hakanson potential ecological risk index method were used to study and analyze the pollution factors (Hg, Cu, Pb, Zn, Cd, As, Cr) in surface sediments of the sea near Bohe Port of Maoming. The results show that the overall contamination level and potential ecological risk of typical pollutants are at the low level in this sea area. The sequence of the pollution degree of heavy metals in surface sediments is As> Cr >Zn> Hg>Cu>Pb>Cd; and the potential ecological risk sequence is Hg>As>Cd>Cu>Pb>Cr >Zn. Hg is the major factor of potential ecological risk in surface sediments of this sea area.
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Farshbaf Zinati, F., J. D. D. Jansen, and S. M. M. Luthi. "Estimating the Specific Productivity Index in Horizontal Wells From Distributed-Pressure Measurements Using an Adjoint-Based Minimization Algorithm." SPE Journal 17, no. 03 (May 24, 2012): 742–51. http://dx.doi.org/10.2118/135223-pa.
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Summary Recent developments in the deployment of distributed-pressure-measurement devices in horizontal wells promise to lead to a new, low-cost, and reliable method of monitoring production and reservoir performance. Practical applicability of distributed-pressure sensing for quantitative-inflow detection will strongly depend on the specifications of the sensors, details of which were not publicly available at the time of publication. Therefore, we theoretically examined the possibility of identifying reservoir inflow from distributed-pressure measurements in the well. The wellbore and nearwellbore region were described by semianalytical steady-state models, and a gradient-based inversion method was applied to estimate the specific productivity index (SPI) as a function of along-well position. We employed the adjoint method to obtain the gradients, which resulted in a computationally efficient inversion scheme. With the aid of two numerical experiments (one of which was based on a real well and reservoir), we investigated the effects of well and reservoir parameters, sensor spacing, sensor resolution, and measurement noise on the quality of the inversion results. In both experiments, we generated synthetic measurements with the aid of a high-resolution reservoir-simulation model and used these to test the semianalytical inversion algorithm. In the first experiment, we considered a 2000-m horizontal well passing through two 300-m high-permeability streaks in a background with a permeability that was 10 times lower. The location of the streaks and the SPIs along the well were detected with fair accuracy using 20 unknown parameters (SPI values) and 20 pressure measurements. Decreasing the number of measurements resulted in a poorer detection of the streaks and their SPIs. The detection performance also decreased for increasing noise levels and deteriorated sensor resolution, though the negative effect of random measurement noise was cancelled out primarily by stacking multiple measurements. The detrimental effects of measurement noise and low sensor resolution were strongest in areas where the inflow was lowest (usually close to the toe). The second experiment concerned a high-rate near-horizontal well with slightly varying inclination that intersected a dipping package of formations with strongly variable permeabilities. Additionally, a satisfactory detection of SPIs was obtained even though the heterogeneities were no longer perpendicular to the well as in the first experiment. As a result of using the simple semianalytical forward model and the adjoint method, the inversions typically required less than 90 seconds on a standard laptop. This offered the opportunity to extend the algorithm to multiphase flow and dynamic applications (pressure-transient testing), while still maintaining sufficient computational speed to perform the inversion in real time.
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Darma, Aminu Inuwa, Sani Ibrahim, and Ali Sani. "The impact of gold ore mining on total lead (Pb) concentration in some mining and residential communities in Zamfara State, Nigeria." Dutse Journal of Pure and Applied Sciences 8, no. 2b (June 26, 2022): 43–52. http://dx.doi.org/10.4314/dujopas.v8i2b.5.
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Illegitimate artisanal gold mining quite often results in elevated lead (Pb) concentrations in mining and residential areas close to ore mining sites, which exposes the communities to varying degrees of health and environmental challenges.Here,mining and residential soils from Abare, Dareta and Bagega, Anka local government,Zamfara state's exposed communities, were examined for total Pb concentration.Three replicates of soil from four different soil fields in mining and residential areas were carefully selected for sampling from the surface layer 0 to 21 cm.All thesoil samples were digested and analysed using flame atomic absorption spectrophotometry (Varian model-AA240FS). The total Pb concentration in the mining areas ranges from 466.01-729.13 mg/kg (Abare), 151.34-168.21 mg/kg (Bagega) and 108.89-258.88 mg/kg (Dareta), while those from the residential areas ranges from 326.28-391.38mg/kg (Abare), 67.74-79.44 mg/kg (Bagega) and 17.58-43.40mg/kg (Dareta).This study revealed that the Pb concentration in all mining areas exceeded the standard ofthe department of petroleum resources of Nigeria's 85 mg/kg threshold (DPR).According to the study, the only residential communities with Pb concentrations above the DPR threshold are those in Abare.Based on the computed degree of contamination indices in those areas using the single pollution index (SPI) and Nemerow composite pollution index (NCPI), the study revealed the residential sites are within the safety limit, whereas the mining sites are slightly contaminated. Nevertheless, more studies are needed to determine the Pb speciation in those areas.
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Nhu, Viet-Ha, Ayub Mohammadi, Himan Shahabi, Baharin Bin Ahmad, Nadhir Al-Ansari, Ataollah Shirzadi, Marten Geertsema, et al. "Landslide Detection and Susceptibility Modeling on Cameron Highlands (Malaysia): A Comparison between Random Forest, Logistic Regression and Logistic Model Tree Algorithms." Forests 11, no. 8 (July 30, 2020): 830. http://dx.doi.org/10.3390/f11080830.
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We used remote sensing techniques and machine learning to detect and map landslides, and landslide susceptibility in the Cameron Highlands, Malaysia. We located 152 landslides using a combination of interferometry synthetic aperture radar (InSAR), Google Earth (GE), and field surveys. Of the total slide locations, 80% (122 landslides) were utilized for training the selected algorithms, and the remaining 20% (30 landslides) were applied for validation purposes. We employed 17 conditioning factors, including slope angle, aspect, elevation, curvature, profile curvature, stream power index (SPI), topographic wetness index (TWI), lithology, soil type, land cover, normalized difference vegetation index (NDVI), distance to river, distance to fault, distance to road, river density, fault density, and road density, which were produced from satellite imageries, geological map, soil maps, and a digital elevation model (DEM). We used these factors to produce landslide susceptibility maps using logistic regression (LR), logistic model tree (LMT), and random forest (RF) models. To assess prediction accuracy of the models we employed the following statistical measures: negative predictive value (NPV), sensitivity, positive predictive value (PPV), specificity, root-mean-squared error (RMSE), accuracy, and area under the receiver operating characteristic (ROC) curve (AUC). Our results indicated that the AUC was 92%, 90%, and 88% for the LMT, LR, and RF algorithms, respectively. To assess model performance, we also applied non-parametric statistical tests of Friedman and Wilcoxon, where the results revealed that there were no practical differences among the used models in the study area. While landslide mapping in tropical environment such as Cameron Highlands remains difficult, the remote sensing (RS) along with machine learning techniques, such as the LMT model, show promise for landslide susceptibility mapping in the study area.
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Zhang, Hanwen, Yuee Huang, Shu Zhou, Liangchen Wei, Zhiyuan Guo, and Jinchun Li. "Pollution level and risk assessment of heavy metals in sewage sludge from eight wastewater treatment plants in Wuhu City, China." Spanish Journal of Agricultural Research 18, no. 2 (May 26, 2020): e1103. http://dx.doi.org/10.5424/sjar/2020182-15796.
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Aim of study: To investigate the content, contamination levels and potential sources of five heavy metals (Hg, Pb, Cd, Cr, As) in sewage sludge from eight wastewater treatment plants (W1 to W8).Area of study: Wuhu, located in southeastern Anhui Province, southeastern China.Material and methods: The sewage sludge pollution assessment employed the single-factor pollution index, Nemerow’s synthetic pollution index, monomial potential ecological risk coefficient and potential ecological risk index. The potential sources among the five heavy metals were determined using the Pearson’s correlation analysis and principal component analysis (PCA).Main results: The mean concentrations of the heavy metals were 0.27 mg/kg (Hg), 70.78 mg/kg (Pb), 3.48 mg/kg (Cd), 143.65 mg/kg (Cr) and 22.17 mg/kg (As). W1, W5 and W6 sewage sludge samples showed the highest levels of heavy metal contamination, and cadmium had the highest contamination level in the study area. Pearson’s correlation analysis and PCA revealed that Pb and Cd mainly derived from traffic emissions and the manufacturing industry and that As and Cr originated from agricultural discharges.Research highlights: The pollution of cadmium in Wuhu should be controlled preferentially. The heavy metal pollution of W1, W5 and W6 sewage treatment plants is relatively high, they should be key prevention targets.
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Manik, Tumiar Katarina, Paul B. Timotiwu, and Mua’ddin Mua’ddin. "Shallot growth and yield supported by irrigation and nitrogen application in utilizing dry land area in Mesuji, Lampung Province, Indonesia." SAINS TANAH - Journal of Soil Science and Agroclimatology 20, no. 1 (June 30, 2023): 100. http://dx.doi.org/10.20961/stjssa.v20i1.70711.
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Lampung Province, Indonesia local government intended to extend shallot cultivation in Mesuji Regency, Lampung (-3.86, 105.43). Mesuji has 21,863.5 ha dry land area, with unproductive land of 10,325.6 ha which could be potential for growing <em>shallot</em>. However, horticulture crops such as shallot often face obstacles in dry land since dry land characterized with poor soil nutrient and limited water. The objective of this research are to analyze the effects of nitrogen fertilizer and different irrigation volumes on shallot growth and production, investigate shallot suitability to Mesuji agro-climate, and estimate shallot yield potential in Mesuji. The treatments on factorial split block were: without N, 80 kg N ha<sup>-1</sup> , 160 kg N ha<sup>-1</sup>, and 240 kg N ha<sup>-1</sup> and the irrigation levels: 25, 50, 75 and 100% of ETc; ETc is crops evapotranspiration. The Mesuji agro-climate was evaluated using standardized precipitation index (SPI) and the yield was simulated by Aquacrop model. The results showed that the effort of shallots production with a high fresh weight of bulbs and biomass in the Mesuji area requested water at least 75% ETc and N fertilizer doses of 160 kg N ha<sup>-1</sup>. The SPI indicated near normal condition was more than 65%, and drought existed in a small percentage in both places (a total of 16.9% for Brebes the centre of shallot production and 19.43% for Mesuji). The AquaCrop simulation gave a good yield estimation (simulated 19.451 ton ha<sup>-1</sup> and observed 17.351 ton ha<sup>-1</sup>). There is a possibility that shallot will grow well in the Mesuji area even though the quality of the shallot should be further tested.
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Zhuang, Sukai, and Xinwei Lu. "Environmental Risk Evaluation and Source Identification of Heavy Metal(loid)s in Agricultural Soil of Shangdan Valley, Northwest China." Sustainability 12, no. 14 (July 19, 2020): 5806. http://dx.doi.org/10.3390/su12145806.
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To understand the environmental quality and heavy metal(loid) pollution of farmlands in Shangdan Valley, the contents of macroelements (Na, K, Si, Mg, Ca, Al, Fe, Ti, P, S, Cl, Br) and heavy metal(loid)s (Cu, Pb, Zn, Mn, Ni, V, Co, Cr, As) were surveyed by the X-ray fluorescence method. The pollution degree and ecological risk of the heavy metal(loid)s were judged by the Nemerow synthetic pollution index, geo-accumulation index, and potential ecological risk index, and their sources were identified by the multivariate statistic method. The mean contents of nine heavy metal(loid)s in Shangdan Valley farmland soil exceeded their corresponding reference values. Soils were not contaminated with As, Cr, Mn, and Ni but were slightly contaminated with Co, Cu, Pb, V, and Zn. Their comprehensive pollution levels were moderate to serious. The ecological risk index of single heavy metal(loid) decreased in the sequence As > Pb > Co > Cu > Ni > V > Zn > Cr > Mn. The source analysis results indicated that Cu, Pb, Zn, and As were highly affected by anthropogenic inputs, e.g., metal smelting and agricultural activities, while Mn, Ni, Cr, and V were principally derived from a natural source. As for Co, it was affected by a mixture source of nature, fossil fuel combustion, and fertilizer.
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Askar, Shavan, Sajjad Zeraat Peyma, Mohanad Mohsen Yousef, Natalia Alekseevna Prodanova, Iskandar Muda, Mohamed Elsahabi, and Javad Hatamiafkoueieh. "Flood Susceptibility Mapping Using Remote Sensing and Integration of Decision Table Classifier and Metaheuristic Algorithms." Water 14, no. 19 (September 28, 2022): 3062. http://dx.doi.org/10.3390/w14193062.
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Flooding is one of the most prevalent types of natural catastrophes, and it can cause extensive damage to infrastructure and the natural environment. The primary method of flood risk management is flood susceptibility mapping (FSM), which provides a quantitative assessment of a region’s vulnerability to flooding. The objective of this study is to develop new ensemble models for FSM by integrating metaheuristic algorithms, such as genetic algorithms (GA), particle swarm optimization (PSO), and harmony search (HS), with the decision table classifier (DTB). The proposed algorithms were applied in the province of Sulaymaniyah, Iraq. Sentinel-1 synthetic aperture radar (SAR) data satellite images were used for flood monitoring (on 27 July 2019), and 160 flood occurrence locations were prepared for modeling. For the training and validation datasets, flood occurrence data were coupled to 1 flood-influencing parameters (slope, altitude, aspect, plan curvature, distance from rivers, land cover, geology, topographic wetness index (TWI), stream power index (SPI), rainfall, and normalized difference vegetation index (NDVI)). The certainty factor (CF) approach was used to determine the spatial association between the effective parameters and the occurrence of floods, and the resulting weights were employed as modeling inputs. According to the pairwise consistency technique, the NDVI and altitude are the most significant factors in flood modeling. The area under the receiver operating characteristic (AUROC) curve was used to evaluate the accuracy and effectiveness of ensemble models. The DTB-GA model was found to be the most accurate (AUC = 0.889), followed by the DTB-PSO model (AUC = 0.844) and the DTB-HS model (AUC = 0.812). This research’s hybrid models provide a reliable estimate of flood risk, and the risk maps are reliable for flood early-warning and control systems.