Academic literature on the topic 'Surface water quality processes and contaminated sediment assessment'

Can Gio mangrove forest (CGM) is located downstream of Ho Chi Minh City (HCMC), situated between an estuarine system of Dong Nai - Sai Gon river and a part of Vam Co river. The CGM is the largest restored mangrove forest in Vietnam and the UNESCO’s Mangrove Biosphere Reserve. The CGM has been gradually facing to numeric challenges of global climate change, environmental degradation and socio-economic development for the last decades. To evaluate sediment quality in the CGM, we collected 13 cores to analyze for sediment grain size, organic matter content, and trace element concentration of Cd, Cr, Cu, Ni, Pb, Zn. Results showed that trace element concentrations ranged from uncontaminated (Cd, Cu, and Zn) to very minor contaminated (Cr, Ni, and Pb). The concentrations were gradually influenced by suspended particle size and the mangrove plants.ReferencesAnh M.T., Chi D.H., Vinh N.N., Loan T.T., Triet L.M., Slootenb K.B.-V., Tarradellas J., 2003. Micropollutants in the sediment of Sai Gon – Dong Nai rivers: Situation and ecological risks. Chimia International Journal for Chemistry, 57, 09(0009–4293), 537–541.Baruddin N.A., Shazili N.A., Pradit S., 2017. Sequential extraction analysis of heavy metals in relation to bioaccumulation in mangroves, Rhizophora mucronata from Kelantan delta, Malaysia. AACL Bioflux, 10(2), 172-181. Retrieved from www.bioflux.com/aacl.Bravard J.-P., Goichot M., Tronchere H., 2014. An assessment of sediment transport processes in the lower Mekong river based on deposit grain size, the CM technique and flow energy data. Geomorphology, 207, 174-189.Cang L.T., Thanh N.C. 2008. Importing and exporting sediment to and from mangrove forest at Dong Trang estuary, Can Gio district, Ho Chi Minh city. Science & Technology Development, 11(04), 12-18.Carignan J., Hild P., Mevelle G., Morel J., Yeghicheyan D., 2001. Routine analyses of trace elements in geological samples using flow injection and low-pressure on-line liquid chromatography coupled to ICP-MS: A study of geochemical reference materials BR, DR-N, UB-N, AN-G and GH. The Journal of Geo standard and Geoanalysis, 187-198.Carlson P.R., Yarbro L.A., Zimmermann C.F., Montgomery J.R., 1983. Pore water chemistry of an overwash mangrove island. Academy Symposium: Future of the Indian River System, 46(3/4), 239-249. https://www.jstor.org/stable/24320336.Chatterjee M., Canário J., Sarkar S.K., Branco V., Godhantaraman N., Bhattacharya B.D., Bhattacharya A., 2012. Biogeochemistry of mercury and methylmercury in sediment cores from Sundarban mangrove wetland, India—a UNESCO World Heritage Site. Environ Monit Assess, 184, 5239–5254.Claudia R., Huy N.V., 2004. Water allocation policies for the Dong Nai river basin in Viet Nam: An integrated perspective. EPTD Discussion Paper, 127, 01-52.Folk R.L., Ward W.C., 1957. Brazos River bar: A study in the significance of grain size parameters. Journal of Sedimentary Petrology, 27(1), 3-26.Furukawaa K., Wolanski E., Mueller H., 1997. Currents and sediment transport in mangrove forests. Estuarine, Coastal and Shelf Science, 44, 301-310.Hai H.Q., Tuyen N.N., 2011. Coastal Erosion of Can Gio district Ho Chi Minh City due to the global climate change. The journal of development of technology and science, 14, 17-28.HCM SO S.O., 2015. Annual statistic data in 2015 for HCM city. Ho Chi Minh city: Statistic office of HCM city.HCMC, 2017. Decision No. 3901 on approving the areas of forest and land in HCM city in 2016. Ho Chi Minh: The people's committee of HCM city.Herut B., Sandler A., 2006. Normalization methods for pollutants in marine sediments: review and recommendations for the Mediterranean. Haifa 31080: Israel Oceanographic & Limnological Research: IOLR Report H18/2006.Hong P.N., San H.T., 1993. Mangroves of Vietnam: Chapter VI Human impacts on the mangrove ecosystem. Bangkok 10501: IUCN - The International Union for Conservation of Nature, ISBN: 2-8317-0166-x.Hubner R., Astin K.B., Herbert R.J., 2009. Comparison of sediment quality guidelines (SQGs) for the assessment of metal contamination in marine and estuarine environments. Journal of Environmental Monitoring, 11, 713–722.IAEA, 2003. Collection and preparation of bottom sediment samples for analysis of radionuclides and trace elements. Vienna, Austria: International Atomic Energy Agency, IAEA-TECDOC-1360, ISBN 92–0–109003–X.Jingchun L., Chongling Y., Ruifeng Z., Haoliang L., Guangqiu Q., 2008. Speciation changes of Cd in mangrove (Kandelia Candel L.) rhizosphere sediments. Bull Environ Contam Toxicol, 231-236. Doi:10.1007/s00128-007-9351-z.Kalaivanan R., Jayaprakash M., Nethaji S., Arya V., Giridharan L., 2017. Geochemistry of Core Sediments from Tropical Mangrove Region of Tamil Nadu: Implications on Trace Metals. Journal of Earth Science & Climatic Change, ISSN: 2157-7617., 8(1.1000385), 1-10. Doi:10.4172/2157-7617.1000385.Kathiresan K., Saravanakumar K., Mullai P., 2014. Bioaccumulation of trace elements by Avicennia marina. Journal of Coastal Life Medicine, 2(11), 888-894.Kitazawa T., Nakagawa T., Hashimoto T., Tateishi M., 2006. Stratigraphy and optically stimulated luminescence (OSL) dating of a Quaternary sequence along the Dong Nai River, southern Vietnam. Journal of Asian Earth Sciences, 27, 788–804.Lacerda L.D., 1998. Trace metals of biogeochemistry and diffuse pollution in mangrove (M. Vannucci, Ed.) Mangrove ecosystem occassional papers (ISSN: 0919-1348), 2, 1-72.Laura H., Probsta A., Probsta J.L., Ulrich E., 2003. Heavy metal distribution in some French forest soils: evidence for atmospheric contamination. The Science of Total Environment, 195-210.Li R., Li R., Chai M., Shen X., Xu H., Qiu G., 2015. Heavy metal contamination and ecological risk in Futian mangrove forest sediment in Shenzhen Bay, South China. Marine Pollution Bulletin, 101, 448–456.Long E., Morgan L.G., 1990. The potential for biological effects of sediment-sorted contaminants tested in the national status and trends program. Seattle, Washington: NOAA Technical Memorandum NOS OMA 52.Long E.R., Field L.J., MacDonald D.D., 1998. Predicting toxicity in marine sediments with numerical sediment quality guidelines. Environmental Toxicology and Chemistry, 17, 714–727. http://onlinelibrary.wiley.com/doi/10.1002/etc.5620170428/abstract;jsessionid=C5264A1AD0.7ACCA9B4EF9A088BE2EDE9.f04t04Long E.R., MacDonald D.D., Smith S.L., Calder F.D., 1995. Incidence of adverse biological effects within ranges of chemical concentration in marine and estuarine sediments. Environmental management, 19, 81-97.Maiti S.K., Chowdhury A., 2013. Effects of Anthropogenic Pollution on Mangrove Biodiversity: A Review. Journal of Environmental Protection, 4, 1428-1434.Marchand C., Allenbach M., Lallier-Verges E., 2011. Relation between heavy metal distribution and organic matter cycling in mangrove sediments (Conception Bay, New Caledonia). Geoderma, Elsevier, 160 (3-4), 444-456.Mohd F.N., Nor R.H., 2010. Heavy metal concentrations in an important mangrove species, Sonneratia caseolaris, in Peninsular Malaysia. Environment Asia, 3, 50-53.Muller G., 1979. Schwermetalle in den Sedimenten des Rheins - Veränderungen seit 1971. Umschau, 778-783.Nam V.N., 2007. Restoration of Can Gio mangrove forest: Its structure and function in comparison between the ecosytems of plantion and nature mangrove forest. Workshop on the thesis between Germany and Vietnam.Nickerson N.H., Thibodeau F.R., 1985. Association between pore water sulfide concentrations and the distribution of mangroves. Biogeochemistry, 1, 183-192.Ong Che R.G., 1999. Concentration of 7 Heavy Metals in Sediments and Mangrove Root Samples from Mai Po, Hong Kong. Marine Pollution Bulletin, 39, 269-279.Passega R., 1957. Texture as characteristics of clastic deposition. Publisher: American Association of Petroleum Geologists.Passega R., 1964. Grain size representation by CM patterns as a geological tool. J Sediment Petrol, 34, 830–847.Phuoc V.L., An D.T., Cang L.T., Chung B.N., Tien N.V., 2010. Study the sediment dynamics in Can Gio mangrove forest (Nang Hai site, Ho Chi Minh city). Ho Chi Minh city: The final report of National University Ho Chi Minh city, No. B2009-18-36.Pumijumnong N., Danpradit S., 2016. Heavy metal accumulation in sediments and mangrove forest stems from Surat Thani province, Thailand. The Malaysian forester, 79(1&2), 212-228.QCVN43:2012/BTNMT, 2012. QCVN43:2012/BTNMT: National technical regulation on the sediment quality, Ha Noi: Ministry of natural resources and environment of Vietnam.Qiao S., Shi X., Fang X., Liu S., Kornkanitnan N., Gao J., Yu Y., 2015. Heavy metal and clay mineral analyses in the sediments of Upper Gulf of Thailand and their implications on sedimentary provenance and dispersion pattern. Journal of Asian Earth Sciences, 114, 488–496.Rollinson H. R., 1993. Using geochemical data for evaluation, presentation and interpretation. UK: Longman Group UK Limited ISBN-0-582-06701-4.Spalding M., Blasco F., Field C., 2010. World atlas of mangrove. Cambridge: Earthscan in UK and US, ISBN: 978-1-84407-657-4.Strady E., Dang V.B., Némery J., Guédron S., Dinh Q.T., Denis H., Nguyen P.D., 2016. Baseline seasonal investigation of nutrients and trace metals in surface waters and sediments along the Saigon River basin impacted by the megacity of HCM, Viet Nam. Environ Sci Pollut Res, 1-18. doi:10.1007/s11356-016-7660-7.Tam N.F., Wong Y.S., 1996. Retention and distribution of heavy metals in mangrove soils receiving wastewater. Environment pollution, 94(5), 283-291.Thomas N., Lucas R., Bunting P., Hardy A., Rosenqvist A., Simard M., 2017. Distribution and drivers of global mangrove forest change, 1996– 2010. PLoS ONE, 12(6): e0179302, 1-14. Doi:10.1371/journal.pone.0179302.Thuy H.T., Loan T.T., Vy N.N., 2007. Study on environmental geochemistry of heavy metals in urban canal sediments of Ho Chi Minh city. Science and Technology Development, 10(01), 1-9.Toan T.T., Bay N.T., 2006. A study on the tendency of accretion and erosion in Can Gio coastal zone. Vietnam-Japan estuary workshop, 184-194.Tri N.H., Hong P.N., Cuc L.T., 2000. Can Gio Mangrove Biosphere Reserve Ho Chi Minh city, Ha Noi, Viet Nam. Ha Noi: Hanoi University Publisher.Truong T.V., 2007. Planning for water source of Dong Nai river basin. Retrieved from Water Resources Planning: http://siwrp.org.vn/tin-tuc/quy-hoach-tai-nguyen-nuoc-luu-vuc-song-dong-nai_143.html.Tuan L.D., Oanh T.T., Thanh C.V., Quy N.D., 2002. Can Gio mangrove biosphere reserve. HCM city, Vietnam: Agriculture Publisher.Tue N.T., Quy T.D., Amono A., 2012. Historical profiles of trace element concentrations in Mangrove sediments from the Ba Lat estuary, Red river, Vietnam. Water, Air & Soil Pollution, ISSN 0049-6979, 223(3), 1315-1330.Twilley R., Chen R., Hargis T., 1992. Carbon sinks in mangroves and their implications to carbon budget of tropical coastal ecosystems. Water, Air & Soil pollution, Netherland, 64, 265-288.UN Environment Program, 2006. Methods for sediment sampling and analysis. Palermo (Sicily), Italy: United Nation Environment Program.UNESCO, 2000. List of Biosphere reserves approved by MAB committee belonging to UNESCO. Retrieved from United Nations, Educational, Scientific, Cultural Organization (UNESCO): http://www.unesco.org/new/en/natural-sciences/environment/ecological-sciences/biosphere-reserves/asia-and-the-pacific.Vandenberghe N., 1975. An evaluation of CM patterns for grain size studies of fine grained sediments. Sedimentology, 22, 615-622.Vinh B.T., Ichiro D., 2012. Erosion mechanism of cohesive river bank and bed of Soai Rap river (Ho Chi Minh city). J. Sci. of the Earth, 34(2), 153-161.Wang J., Du H., Xu Y., Chen K., Liang J., Ke H., Cai M., 2016. Environmental and Ecological Risk Assessment of Trace Metal Contamination in Mangrove Ecosystems. BioMed Research International, Article ID 2167053, 1-14. Doi:10.1155/2016/2167053.Wedepohl K.H., 1995. The composition of the continental crust. Geochimica et Cosmochimica Acta, 59(7), 1217-1232.Woodroffe C., Rogers K., McKee K., Lovelock C., Mendelssohn I., Saintilan N., 2016. Mangrove sedimentation and response to relative sea level rise. The Annual Review of Marine Science, 8, 243-266.Zhang J., Liu C.L., 2002. Riverine Composition and Estuarine Geochemistry of Particulate Metals in China-Weathering Features, Anthropogenic Impact and Chemical Fluxes. Estuarine, Coastal and Shelf Science, 54(6), 1051-1070.Zhang W., Feng H., Chang J., Qu J., Xie H., Yu L., 2009. Heavy metal contamination in surface sediments of Yangtze River intertidal zone: An assessment from different indexes. Environmental Pollution, 157, 1533-1543.Zheng W.-j., Xiao-yong C., Peng L., 1997. Accumulation and biological cycling of heavy metal elements in Rhizophora stylosa mangroves in Yingluo Bay, China. Marine ecology progress series, 159, 293-301.

Abstract Since the beginning of North America's industrialization, the Great Lakes have been negatively impacted by the discharge of industrial, agricultural and municipal pollutants. The governments of Canada and the United States have recognized that the accumulation of pollutants within the bottom sediment and the water column has had a detrimental effect on the Great Lakes ecosystem. In 1972, Canada and the United States signed the Great Lakes Water Quality Agreement, which established common water quality objectives and commitments to programs and other measures to achieve these objectives. This included measures for the abatement and control of pollution from dredging activities. By 1985, the International Joint Commission, a body established by the two countries to provide advice on boundary water issues, identified 43 Areas of Concern where impaired water quality prevented full beneficial use of rivers, bays, harbours and ports. The Great Lakes Water Quality Agreement, amended in 1987, committed both countries to concentrate remediation efforts in these 43 Areas of Concern. This led to the development of Remedial Action Plans to assess and remediate contamination problems. Contaminated sediment was identified in all of these Areas of Concern. In 1989, the Canadian government created the 5-year $125-million Great Lakes Action Plan in support of the Great Lakes Water Quality Agreement. Of this, $55 million was allocated to the Great Lakes 2000 Cleanup Fund for the 17 Canadian Areas of Concern. A portion of the Cleanup Fund was designated for the development and demonstration of technologies for assessment, removal and treatment of contaminated sediment. Since its creation, the Remediation Technologies Program, established under the Cleanup Fund, has successfully performed 3 full-scale remediation projects, 11 pilot-scale technology demonstrations and 29 bench-scale tests. In addition to these projects, the program also evaluated existing sediment management practices and processes.

The environmental risk assessment of Holmen, a former naval base, included characterisation of the sediments with regard to pollution with xenobiotics, heavy metals, nutrients and bacteria, and ecotoxicity. A simple hydraulic model was established, and the release of substances from the sediment to the water was assessed. Sediment biotests with Corophium volutator and porewater biotests with Skeletonema costatum and Acartia tonsa were conducted. The sediment was characterised as strongly contaminated in the major parts of the investigated area. Based on the application of the acid volatile sulfide method it was concluded that practically none of the heavy metals were bioavailable. Both the sediment and the porewater from a number of stations were toxic. The toxicity did not appear to be attributable to the content of heavy metals, more likely to other contaminants. Furthermore, the sediment, which has served as a sink for accumulation of contaminants over a period of many years, also may constitute a source of contamination due to potential release of heavy metals and xenobiotics from the sediment to the water in some areas. The release appears to give rise to concentrations above the EU Water Quality Objectives at some stations.

Abstract Purpose The purpose of the study was to determine the levels of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F), two types of persistent organic pollutant (POP), in an urban retention reservoir located in an industrial zone within a coal-mining region. It also assesses the potential ecological risk of the PCDDs/Fs present in bottom sediments and the relationship between their content and the fraction of organic matter. Materials and methods The sediment samples were collected from Rybnik Reservoir, located in the centre of the Rybnik Coal Region, Silesia, one of Poland’s major industrial centres. Seventeen PCDD/F congeners in the surface of the sediments were analysed using high-resolution gas chromatography and high-resolution mass spectrometry (HRGC/HRMS). Results and discussion The toxic equivalency (TEQ) of the PCDDs/Fs in the sediments ranged from 1.65 to 32.68 pg TEQ g−1. PCDDs constituted 59–78% of the total PCDDs/Fs, while the PCDFs accounted for 22–41%. The pattern of PCDD/F congeners in the sediments was dominated by OCDD. However, the second-most prevalent constituents were OCDF and ∑HpCDFs in the low TOC sediment (< 10 g TOC kg−1), but HpCDD in the rich TOC samples (> 10 g TOC kg−1). PCDD/F concentrations in the sediment samples were 2- to 38-fold higher than the sediment quality guidelines limit, indicating high ecological risk potential. Although a considerable proportion of PCDDs/Fs in the bottom sediments from the Rybnik Reservoir were derived from combustion processes, they were also obtained via transport, wastewater discharge, high-temperature processes and thermal electricity generation. The PCDD/F concentrations were significantly correlated with all fractions of organic matter; however, the strongest correlation coefficients were found between PCDDs/Fs and humic substances. Besides organic matter, the proportions of silt/clay fractions within sediments played an important role in the transport of PCDDs/Fs in bottom sediments. Conclusions The silt/clay fraction of the bottom sediments plays a dominant role in the movement of PCDDs/Fs, while the organic matter fraction affects their sorption. The results indicate that the environmental behaviour of PCDDs/Fs is affected by the quantity and quality of organic matter and the texture of sediments.

Abstract In this study, metal concentrations in the water column and surface sediment of the Sabalan Dam Reservoir (SDR) were determined. Moreover, heavy metal pollution index (HPI), contamination index (CI), heavy metal evaluation index (HEI), enrichment factor (EF), geo-accumulation index (Igeo), sediment quality guidelines (SQGs), consensus-based SQGs (C-BSQGs), and mean probable effect concentration quotients (mPECQs) were evaluated for water and sediments of SDR. It was observed that metal concentrations in river entry sediment were lower, but those in river entry water were higher than corresponding values in the vicinity of the dam structure. The HPI values of water samples taken from 10 m depth in the center of SDR exceeded the critical limit, due to high concentrations of arsenic. However, according to CI, the reservoir water was not contaminated. The HEI values indicated contamination of SDR water with metals at 10 m depth. A comparison of water quality indices revealed that HEI was the most reliable index in water quality assessment, while CI and HPI were not sufficiently accurate. For SQGs, As and Cu concentrations in sediments were high, but mPECQ, Igeo, and EF revealed some degree of sediment pollution in SDR. The calculated EF values suggested minor anthropogenic enrichment of sediment with Fe, Co, V, and Ni; moderate anthropogenic enrichment with As and Mn; and moderate to severe anthropogenic enrichment with Cu. A comparison of SQG values revealed that the threshold effect and probable effect levels were the most reliable metrics in the assessment of sediment toxicity. Statistical analysis indicated similarities between metal concentrations in the center of the reservoir and near to the dam structure, as a result of similar sediment deposition behavior at these points, while higher flow velocity at the river entry point limited deposition of fine particles and associated metals.

Abstract Purpose Numerous sites contaminated with fiber emissions from pulp and paper industries are found in coastal areas of the Baltic Sea, but there is limited knowledge about the magnitude of dispersal of persistent organic pollutants (POPs) from these anthropogenic, organic-rich sediments called fiberbanks. The aim of this study was to quantify and compare different POP dispersal pathways from such fiberbanks. Dispersal mechanisms studied included abiotic and biotic routes (dissolved in water, particle-bound, and bioaccumulation). Materials and methods Contaminated fibrous sediments located in Ångermanälven River estuary in north-eastern Sweden were studied in sediment types representing different fiber content (i.e., fiberbanks, fiber-rich sediments, and less fiber impacted sediments). Sediment-to-water fluxes of dissolved contaminants (polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and dichlorodiphenyltrichloroethane (DDT)) were measured in situ using benthic flux chambers. Particle resuspension was measured by sampling bottom water, before and after disturbing the sediment surface. Benthic biota was collected to determine the body burden of contaminants and to determine biota-pore water accumulation factors (BAFPW) and biota-sediment accumulation factors (BSAFs). In addition, concentrations of dissolved POPs in the water column were measured in field using passive samplers. Instrumental analysis was performed using gas chromatography coupled to a triple quadrupole mass spectrometer (GC-MS/MS). Results and discussion The flux of dissolved Σ20PCBs was approximately two times higher from one of the investigated fiberbanks (3.4 ng m− 2 day− 1) compared to the other. The average particle burden of PCBs was also higher at this fiberbank after artificial disturbance (15 ng g−1 particle), which indicates that larger amounts of contaminants are likely to disperse via particle resuspension from this site compared to the other fiberbank (4.8 ng g− 1 particle). The difference might be associated with a layer of recently settled minerogenic material that covers one of the fiberbanks, which probably functions as a protective barrier. The lack of benthic biota implies that contaminant release by bioturbation is negligible in the studied fiberbanks. However, benthic biota from fiber-rich sediment showed bioaccumulation and biomagnification of contaminants. Conclusions The importance of diffusive flux from fiberbanks under undisturbed conditions became apparent when the different dispersal pathways were quantified. However, no dispersal pathway could be judged as irrelevant, since even under undisturbed conditions, advective particle transport was significant. Additionally, the uptake by biota and trophic transfer can be considerable. Quantification of dispersal routes and understanding of the relative importance of various pathways is critical for proper risk assessment and management of contaminated sediments.

Abstract Purpose The main objective of the study was the determination of the Cd, Cr, Cu, Pb, and Zn distribution in Wigry Lake sediments, as well as the contamination and ecotoxicological risk assessment on the basis of a large data set. Materials and methods Select metal concentrations were determined via AAS or ICP-MS. Contamination assessment was achieved via the implementation of different geochemical background values, selected pollution indices, and by way of comparison with the limit values of the sediment quality guidelines and supported by cartographic methods. Results and discussion Metal concentrations presented in the paper were associated with a specific type of sediment and sedimentation environment. The highest concentrations of metals were found in the fluvial-lacustrine sediment covering the bottom of the bay of eutrophic character. The lowest amounts were found in the lacustrine chalk and clastic sediment present in the littoral parts of the lake, while profundal sediments were more enriched with metals. Studies revealed that the examined metals have mostly natural, but also anthropogenic origin. The assessment of lake sediments, with the use of geochemical background values and different indices, yielded highly diversified results associated with the variability of background values applied in the study. However, ultimately, the Wigry Lake sediments were found to be only slightly contaminated with Cd, Cr, Cu, and Zn, while Pb concentrations were considered to be more disturbing. The potential ecotoxicological risk was assessed as low. Conclusions Particular attention in this study was paid to the significance of the geochemical background values adopted for calculations, which, in the case of Wigry Lake, gave very divergent results. A uniquely large data set facilitated the performance of a thorough analysis of metal distributions in recent lacustrine sediments and highlighted the necessity of using integrated approaches in aquatic ecosystem studies.

Sediments containing high concentrations of heavy metals in reservoirs, lakes and rivers, can resuspend into aquatic environments and negatively impact water quality. The concentrations of 10 elements were studied in surface sediments and water from the Aguada Blanca Reservoir, Peru, an important water source to 1,080,000 people in the arid province of Arequipa. Sediment and water samples were collected from nine points in 2019. The enrichment, accumulation, ecological risk and distribution of metals in sediment were determined, and the information on heavy metals in water was used to assess the quality of the aquatic system. Spatially, heavy metals showed variations throughout the study area, with an increase for most elements near the deepest part of the reservoir. The average concentration of Cd in sediment was 4 times higher than the natural background. In water, As was the only element that exceeded Peruvian regulations (As > 10 μg L-1). The Enrichment Factor (EF) and Geoaccumulation Index (Igeo) of metals in sediment presented the following order: Cd> As> Pb> Zn> Cu> Ni> Cr, with Ni and Cr being the only elements that did not present enrichment. The most considerable Igeo was Cd (1.21 ± 1.45), presenting a classification of moderately to heavily contaminated. The integrated potential ecological risk (RI) of Cd presented high values in 5 points of the reservoir. The information developed will assist in establishing effective control strategies for the quality of the aquatic system. Keywords: heavy metals, reservoir, sediments, water quality.

Thriving of the society in Zhengzhou city and development of its economy needs scientific and practical solutions of two main problems; natural water shortage and pollution. It is essential to assess the groundwater quality in order to confirm public safety in Zhengzhou and to reduce contamination in there. Fuzzy Synthetic evaluation was applied to delineate the extent of groundwater contamination in Zhengzhou. Assessment of shallow groundwater results concluded that the first three grades of Chinese water quality standards are 91%, whereas the fourth and fifth grades constitute 9% of it. For the deep water quality, the first two grades are 94% and 6%. It is deduced that part of the shallow groundwater quality is effectively contaminated. Contamination disappears going downward into the deep water. Cluster analysis show exactly same deduction. Fuzzy synthetic evaluation results (using Geographic Information System) were employed to assess the groundwater flow direction around the surveyed wells. It is concluded that infiltration of upstream industrial groundwater is probable into the deep confined groundwater

Abstract. Landslides of contaminated soil into surface water represent an overlooked exposure pathway that has not been addressed properly in existing risk analysis for landslide hazard, contaminated land, or river basin management. A landslide of contaminated soil into surface water implies an instantaneous exposure of the water to the contaminated soil, dramatically changing the prerequisites for the mobilisation and transport of pollutants. In this study, an analytical approach is taken to simulate the transport of suspended matter released in connection with landslides into rivers. Different analytical solutions to the advection-dispersion equation (ADE) were tested against the measured data from the shallow rotational, retrogressive landslide in clayey sediments that took place in 1993 on the Göta River, SW Sweden. The landslide encompassed three distinct events, namely an initial submerged slide, followed by a main slide, and a retrogressive slide. These slides generated three distinct and non-Gaussian peaks in the online turbidity recordings at the freshwater intake downstream the slide area. To our knowledge, this registration of the impact in a river of the sediment release from a landslide is one of the few of its kind in the world, and unique for Sweden considering the low frequency of landslide events, making it highly useful for evaluating how appropriate the ADE is to describe a landslide into surface water. The results yielded realistic predictions of the measured concentration variation, after proper calibration. For the three individual slides it was estimated that a total of about 0.6% (515 000 kg) of the total landslide mass went into suspension/was suspended and was transported downstream. This release corresponds to about 1 to 2% of the annual suspended sediment delivery for that river stretch. The studied landslide partly involved an industrial area and by applying the analytical solution for the transport of metals in the sediments it was found that landslides have the possibility to release a significant amount of pollutants if large contaminated areas are involved. However, further studies are needed to develop more detailed descriptions of the transport processes. There is also a need to increase the knowledge on possible environmental consequences in the near and far field, in a short and long-time perspective. Finally, the risk for the release of pollutants should not be neglected in landslide hazard and risk assessment.

Urban development is becoming increasingly common along landward margins of mangroves and results in increased impervious surfaces which collect and facilitate discharge of storm-water at point locations into the mangrove swamp. In contrast, natural storm-water inputs into mangroves are largely diffuse flows. Along the central Queensland coast Neosarmatium trispinosum and Parasesarma erythrodactyla are the most abundant species of sesarmid crabs occuring within these mangroves. Following a trial that found burrow counts were the most reliable estimate of relative crab abundance, comparisons were made between mangroves receiving storm-water input and control sites that were not affected.

Project develops a stochastic dynamic programming technique for the optimal operation of a reservoir, to control salinity in the reservoir and thereby also in releases. These procedures are to meet irrigation and municipal demands.. A stochastic dynamic programming technique for the optimal operation of a reservoir to control salinity in the reservoir and thereby also in the releases, and to meet irrigation and municipal demands is developed. The technique defines the optimal policy for releases to meet salinity and irrigation water supply requirements. The problem for which the approach was specifically developed is characterised by the presence of a strongly stratified, essentially two-layer, condition in a reservoir used to supply irrigation water. The two-layer condtion exists over the winter months when cold and heavy saline flows enter the reservoir and flow to the bottom of the reservoir. The two-layer condition continues until mixing of the reservoir occurs in early summer. While the reservoir is stratified, it is possible to flush the saline water out of the reservoir by low level intakes. This flushing reduces the overall salinity level in the reservoir when mixing occurs at end of winter, and thereby reduces the salinity of reservoir summer. However, removing the saline bottom layer also reduces the volume of water available for irrigation. Hence there are limitations on the amount that can be withdrawn to reduce the salinity. The technique is an approach to optimising the performance of the reservoir to meet irrigation demands, while minimising salt concentration in the irrigation water. Stochastic dynamic programming is used to reflect the uncertainty in the inflows while chance-constraints are reservoir beginning of the irrigation season. Three different probabilistic nature of the salt inflows to the reservoir: 1) salt load is directly related to the volume of inflow, 2) salt load is independent of the volume of the inflow, and 3) salt load is conditioned on the volume of inflow. The model is demonstrated by application to the Wellington Reservoir in Western Australia for the case in which the salt load is conditioned on the inflow. The results of the application of the model for a range of different combinations of maximum allowable saltconcentration and probability of exceeding that are compared to each other and to the release policy generated in an earlier simulation analysis undertaken to manage the salinity question.

Coal seam gas (CSG) is obtained by pumping water from the saturated coal seam to reduce the pressure allowing the methane gas to desorb. The co-produced water from the gas extraction process has a geochemical signature mainly determined by the moderate levels of salinity, sodicity and dissolved trace elements. Typically, CSG co-produced water requires treatment to be suitable for beneficial re-use, since untreated co-produced water can cause soil infiltration damage and nutritional imbalance for crops and livestock. CSG water from the Bowen Basin (Queensland) was used in this study and has a typical ionic composition of Na+-Cl--HCO3-. In this study, two natural ion exchange materials, zeolite and scoria, were used for the removal of Na+, Sr2+ and Ba2+ from CSG co-produced water. Following XRD analysis, the mineral composition of the zeolite material was found to be consistent of clinoptilolite (41%) and mordenite (29%), while the scoria material presented as diopside (35%), forsterite (33%) and anorthite (29%) characteristic. The real exchange capacity exhibited by the zeolite material was 75 meq/100 g, while the real exchange capacity determined for the scoria was 28 meq/100 g. Adsorption capacity and kinetic rates for Na+ ions were favoured by the use of small fraction sizes of natural forms of the zeolite and scoria material, which increased the accessibility of available adsorption sites on the material for cation interaction, consequently, an optimised fraction size of 0.6 – 0.3 mm was used in all studies. Equilibrium studies used a ratio of 20:1 for solution and material (50 mL : 2.5 g) for 72 h showing that the scoria and zeolite material treated with NH4+ exhibited greater adsorption capacities for Na+, Sr2+ and Ba2+ than the natural form. The maximum Na+ adsorption observed in the scoria and zeolite materials enriched with NH4+ was 17 and 45 meq/100 g, which corresponds to 61% and 60% of the measured real exchange capacity, respectively. The scoria and zeolite materials enriched with NH4+ for Sr2+ adsorption were 4.5 and 8 meq/100 g (44 and 80% removal of the initial Sr2+ concentration). The maximum Ba2+ adsorption achieved using the scoria and zeolite in NH4+ form was 5.8 and 10.6 meq/100 g (40 and 94% removal of the initial Ba2+ concentration). Competitive uptake studies were undertaken to determine selectivity isotherms and coefficients that showed the scoria material’s selectivity series was Ba2+ >Sr2+ >> Ca2+ > K+ > Na+, while, the zeolite material exhibited selectivity for K+ >Ba2+> Sr2+ >> Ca2+ > Na+. Other cations present in CSG water compete with Na+ for adsorption sites, reducing its adsorption capacity to 10 and 38 meq/100 g for scoria and zeolite. The adsorption and desorption of Na+ ions studied in batch mode showed that the ability of scoria and zeolite to adsorb cations decreased with the number of regeneration cycles. The effect of the flow rate on the removal of Na+ by the scoria and the zeolite material in a fixed bed column experiment was relatively small (5% reduction when using flow rates of up 10 BV/h). Columns packed with the scoria and the zeolite material exhibited a larger Na+ dynamic adsorption capacity (breakthrough capacity) when treated with NH4+ as well as larger desorption capacities than the same materials in K+ form. Nonetheless, the adsorption capacity exhibited for both materials was approximately 50% of the real exchange capacity. The maximum bed volumes obtained before the breakpoint (C/C0 = 0.3, output concentration) with a flow rate of 5 BV/h for the scoria material in NH4+ form using CSG water was 1.5 BV, while zeolite in NH4+ form exhibited 4.5 BV. These results showed that in using any natural and pre-treated ion exchange material as a CSG water treatment technology, allow the adsorption of Na+ ions with evident improvement for pre-treated materials. Batch and column type experiments showed that chemical conditioning increased the zeolite and scoria ion selectivity towards cations such as Ba2+, Sr2+ and Na+ present in high concentrations in CSG water. Ion selectivity was found to be correlated to the incoming hydrated cation size and its energy of hydration. The outcomes obtained from the experimentation indicates that natural ion exchangers are suitable for the removal of cations present in CSG water through ion exchange. Nonetheless, limitations to the use of natural and pre-treated ion exchange materials were identified. The high salinity characteristic of CSG water needs to be corrected with other treatment methods or mixed with low salinity water, before the CSG water can be beneficially re-used. The use of natural ion exchange material for the treatment of CSG water may consist of a multi-column arrangement with several trains operating in parallel allowing continuous treatment and facilitate the regeneration of the column without the need to stop the treatment.

Study examines issues associated with the design and operation of water quality monitoring networks where one or more monitoring stations have been discontinued. A methodology has been developed for prediction of these water quality values at discontinued stations in Queensland.. This study examines an issue associated with the design and operation of water quality monitoring networks, namely, the situation, where, because of reductions in the budget allocated to water quality monitoring, or because the budget allocated to water quality monitoring is not increasing at the same rate at which the cost of operation of the network is increasing, or the need for a monitoring station is more acute in another location, one or more existing monitoring stations have to be discontinued. The particular question addressed in relation to this scenario is the development of an improved metho-dology for the prediction of water quality values at the discontinued stations. The methodology proposed for the improved prediction of these water quality is derived from the information theory interpretation of the entropy principle, as formulated in terms of the Principle of Maximum Entropy (POME) and the Minimum Discrimination Information (MDI). The methodology itself is a nonlinear optimisation model in which an entropy function of the form Pi ln Pi where Pi represents the probability of event xi, is maximised subject to a series of constraints on the form and statistics of the probability function from which the Pi values are derived. An important feature of the probability distribution predictions provided by the model is that they are the 'most likely' distributions and therefore are un-biased, being affected only by the information which the user chooses to include in the constraints imposed on the optimisation, and on the historical values of the probability distributions which are incorporated into the non-linear objective function. The approach is demonstrated by application to a series of water quality monitoring networks in Queensland, Australia. The model was evaluated on the basis of these cases in a verification step involving a comparison of the accuracy of the predictions provided by the entropy technique with the accuracy of the predictions available from a traditional regression based approach. The predictions from the entropy based approach were on average more accurate then those obtained from the regression approach 61% of the time. The performance of the approach in terms of the accuracy of its predictions, the unbiased nature of those predictions, and the fact that it requires the same type and amount of data as traditional regression techniques, indicates that the technique represents a significant advance in the prediction of water quality values at dis-continued water quality monitoring stations.

Project investigates a neural network approach to reservoir operations.. The techniques traditionally used to generate optimal or near optimal operating policies for reservoirs fall into two general categories, optimisation and simulation. These techniques have, to date, been unable to satisfactorily address the complete range of issues which must be considered in the development of optimal reservoir operating policies. Neural networks appear to have the potential to address some of the problems associated with the use of optimisation and simulation to define the wide range of issues involved in optimal decision for operations of reservoirs. A neural network approach to reservoir operations is investigated in this thesis. In particular, the sensitivity of the performance of the neural network to variations in the key parameters of; normalisation method, number of training patterns, number of hidden neurons, learning rate, momentum coefficient, number of training iterations, and starting connection weights is examined. The approach utilises historical patterns of inflow, storage, and demand for a reservoir to predict the quantity of water to be released from the reservoir. Based on the analysis in this study, it was determined that relatively few rules exist for selection of the values of the parameters of the neural network. In general, where rules do exist, they tend to be in the form of guidelines or principles rather than explicit rules. Despite this lack of explicit rules, the neural network used in this study was able to perform reasonably well in predicting the quantity of water to be released. Overall, the concept of neural networks appear to have considerable potential to provide an alternative method for use in optimising reservoir performance, compared to the more conventional methods of optimisation or simulation.