Academic literature on the topic 'Silver nitrate'

Mestrado em Toxicologia e Ecotoxicologia
Production and utilization of silver nanoparticles (AgNPs) for various applications is growing rapidly, mainly due to their antibacterial activity. Their inclusion in many consumer products led to an increased release of AgNPs in the environment, especially in aquatic ecosystems. AgNPs reach both freshwater and marine environments from the effluents of the wastewater treatment plants, presenting differentiated behavior in these two environments potentially influencing its toxicity. The study of AgNPs toxicity to marine organisms is extremely important to the assessment of the potential risk of AgNPs in the environment. The toxicity of AgNPs on the living organisms is dependent on various environmental conditions. Regarding the toxicity of AgNPs in the marine environment, there is a lack of information on the toxic effects at different salinities. This study upsurges to fill this gap, being the first report on the effects of AgNPs on marine gastropods, using Nassarius reticulatus as a case study. N. reticulatus adults were collected from a reference population in Ria de Aveiro (NW Portugal, 40° 38' 33.24"N | 8° 44' 06.69’’W). Specimens were transported to the laboratory in local seawater and kept in aquaria to spawn. Egg capsules were maintained until veliger larva were noticed, which enclosure was induced by cesarean. These recently hatched larvae were then exposed to nominal concentrations of AgNPs and Ag+ (0.1, 1, 10, 100 μg Ag/L) for up to 96 h, either in the presence or absence of food. Larval mortality and swimming behavior –namely the velum beating arrest–were determined for each treatment. The median lethal concentration (LC50) of AgNPs was higher to that of ionic Ag (AgNO3). Results also revealed that the negative impact of AgNPs on N. reticulatus veligers swimming ability is higher when compared with the effect of ionic Ag (EC50-96 h 1.044 μg Ag/L). However, although the velum arrests have significantly decreased under Ag+ exposure, AgNPs did not show any effects. Additionally, the presence of the food proved to be an effective factor that can cause a significant drop in the mortality of the N. reticulatus larvae exposed to AgNPs.
A produção e utilização de nanopartículas de prata (AgNPs) em diversas aplicações têm crescido rapidamente, principalmente devido à sua atividade antibacteriana. A inclusão de AgNPs em muitos produtos de consumo conduziu a um aumento da sua libertação no meio ambiente, especialmente nos ecossistemas aquáticos. As AgNPs atingem tanto o ambiente marinho como o de água doce a partir da descarga de efluentes de estações de tratamento de águas residuais, apresentando comportamento diferenciado nestes dois meios, potencialmente influenciando a sua toxicidade. O estudo da toxicidade das AgNPs em organismos marinhos é extremamente importante na avaliação do potencial risco da presença de AgNPs no ambiente. A toxicidade de AgNPs emorganismos vivos é dependente de várias condições ambientais. No que se refere à toxicidade das AgNPs em ambiente marinho, verifica-se uma lacuna de informação relativamente aos efeitos tóxicos a diferentes salinidades. Este trabalho surge para preencher esta lacuna, sendo o primeiro relato do efeito de AgNPs em larvas de gastrópodes marinhos, usando Nassarius reticulatus como caso de estudo. Foram colhidos adultos de N. reticulatus de uma população de referência da Ria de Aveiro (NW Portugal, 40° 38' 33.24"N | 8° 44' 06.69’’W). Os espécimes foram transportados para o laboratório em água do local e aí mantidos em aquário até à postura de cápsulas ovígeras. As cápsulas foram mantidas até à observação de larvas velígeras no seu interior, cuja eclosão foi induzida por cesariana. Estas larvas recém-eclodidas foram então expostas a concentrações nominais de AgNPs e Ag+ (0,1, 1, 10, 100 ug de Ag / L), durante 96 h, na presença ou ausência de alimento. A mortalidade larvar e o comportamento de natação, nomeadamente a inibição do batimento do velum, foram determinados para cada um dos tratamentos. A concentração letal média (CL50) das AgNPs revelou-se superior à da Ag iónica (AgNO3). Os resultados também revelaram que o impacto negativo das AgNPs na natação das velígeras de N. reticulatus é superior (EC50-96 h 0.044 μg Ag/L) quando comparado com o efeito da Ag iónica (EC50-96 h 1.044 μg Ag/L). Contudo, embora a inibição da movimentação do velum das larvas ter diminuido significativamente na presença de Ag+, as AgNPs não mostraram quaisquer efeitos na inibição do batimento do velum. Adicionalmente, a presença de alimento revelou ser um fator importante, podendo causar uma redução significativa na mortalidade das larvas de N. reticulatus expostas a AgNPs.

L’objet de ce travail est de développer des nouveaux catalyseurs pour réduire les ions nitrites (NO2- /HNO2) et nitrates (NO3-) dans l’eau en étudiant les facteurs qui vont influencer leurs réductions catalytiques. On a montré que la présence de polyoxométallates (POMs) permet d’améliorer les propriétés catalytiques de l’électrode de Cu et d’Ag pour la réduction de ions nitrate et nitrite avec des conditions adaptées. Par la suite, des nanoparticules du cuivre (Cu@POM) ou d’argent (Ag@POM) ont été préparées par électroréduction of CuPOM in situ ou photocatalyse en présence d’ions POMs et Ag(I) respectivement. Leurs propriétés électrocatalytiques ont été étudiées. Six différents polyoxométallates substitués par des atomes de Cu(II) (CuPOMs) ont montré de bonnes activités pour la réduction de nitrite à pH 1 et à pH 5. Deux activités sont observées : au potentiel de la réduction de CuII et au potentiel de réduction des W(VI) du POM. Quant à la réduction du nitrate, [Cu4(H2O)2(P2W15O56)2]16- et [(A-β-SiW9O34)Cu4(OH)3(H2O)(H3N(CH2)3COO)2]3 5- peuvent catalyser la réduction du nitrate à un potentiel au-delà de la réduction du Cu(II) à la réduction des W(VI). Par contre, dans le cas de [(SbW9O33)2{Cu(H2O)}3]12– aucune électrocatalyse n’est observée. Cela indique que le type de POM influence les propriétés catalytiques des nanoparticules. Pour le système Ag@POM photoréduit, un catalyseur hétérogène est préparé et stabilisé par une couche de Nafion. Les nanoparticules Ag@POM sont actives pour la réduction du nitrite et du nitrate et possèdent une activité meilleure que celle mesurée pour l’électrode d’Ag seule. Dans la dernière partie, une étude préliminaire de polyoxométallates encapsulés dans les ‘Metal-Organic Framworks’ (MOFs) e st présentée. L’entité POM conserve ses propriétés électrochimiques et électrocatalytiques pour la réduction de nitrite après immobilisation dans la cage MOF
The object of this work is to develop new catalysts to reduce nitrite ions (NO2- / HNO2) and nitrate ions(NO3-) in water and also tried to understand the factors that will influence catalytic reductions. It has been shown that the presence of polyoxometalates makes it possible to improve the catalytic properties of the Cu and Ag bulk electrodes for the reduction of nitrate and nitrite ions under suitable conditions. Then, the copper or silver nanoparticles decorated with POMs, Cu@POM or Ag@POM), are formed with two different methods: electroreduction in situ of CuPOM or photocatalysis in the presence of POM and Ag(I) ions respectively). Their electrocatalytic properties are presented. Six different Cusubstituted polyoxometalates (CuPOMs) are active for nitrite reduction at pH 1 and pH 5. Two activities are observed at the potential of CuII reduction and at the potential of WVI reduction in POM. [Cu4(H2O)2(P2W15O56)2]16- and [(A-β-SiW9O34)Cu4(OH)3(H2O)(H3N(CH2)3COO)2]3 5- catalyse the nitrate reduction at the potential beyond the reduction of CuII and at the reduction of WVI. On the other hand, no catalysis efficiency was observed with [(SbW9O33)2{Cu(H2O)}3]12-. This indicates the type of POM will influence the catalytic properties of nanoparticles. With the photoreduced Ag@POM nanoparticles, a heterogeneous catalyst is prepared and stabilized by a Nafion layer. Ag@POM nanoparticles are active for the reduction of nitrite and nitrate and have an activity better than the Ag electrode alone. In the last part, a preliminary study of polyoxometalates encapsulated in Metal-Organic Framworks (MOFs) is presented. POM retains its electrochemical and electrocatalytic properties toward the reduction of nitrite after immobilized in the cage of MOF

Mestrado em Toxicologia e Ecotoxicologia
Atualmente, as nanopartículas de prata (AgNP) são bastante utilizadas em vários produtos devido às suas propriedades únicas e excecionais, nomeadamente a sua potente atividade antibacteriana. Algumas das suas aplicações comuns são em têxteis, produtos cosméticos e tintas. Deste modo, é esperada a presença de AgNP nos sistemas aquáticos. Tendo isto em consideração, o objetivo deste trabalho é descrever os efeitos tóxicos de AgNP de diferentes tamanhos, e comparar estes efeitos com os induzidos pela exposição a AgNO3 usando as características comportamentais das planárias da espécie Dugesia tigrina. Foram efetuados testes de exposição aguda (96 h) e testes de exposição crónica (8 dias) onde foram avaliados parâmetros como a sobrevivência, a locomoção, alimentação e regeneração cefálica. Foram selecionadas AgNP de diferentes tamanhos (AgNP de 10-25 nm e AgNP 3-8 nm) e comparados os efeitos com os da exposição a AgNO3, de modo a analisar se a toxicidade tem origem na libertação de iões Ag ou se é devida às propriedades das diferentes nanopartículas. Os resultados mostraram que os valores de LC50 para as 24, 48, 72 e 96 h não variaram ao longo do tempo para AgNP (10-25 nm) (76.62 μg L-1) e para AgNO3 (109.1 μg L-1). As planárias experienciaram nas primeiras 24 h várias alterações morfológicas na zona da cabeça como aurículas suprimidas e principalmente dissolução da cabeça. Estes efeitos notaram-se principalmente na AgNP (10-25 nm) e AgNO3. Em relação à exposição crónica, as planárias apresentaram uma redução significativa na locomoção e na alimentação na exposição a todas as nanopartículas estudadas, sendo estes parâmetros os mais sensíveis para D. tigrina. Relativamente à capacidade de regeneração não houve efeitos significativos à exposição a Ag. A fonte de toxicidade pode estar relacionada com as propriedades das AgNP que interferem com o sistema nervoso das planárias, causando a sua morte. Este estudo demonstrou que as planárias são um organismo adequado para estudos ecotoxicológicos comportamentais e devem ser considerados em metodologias de avaliação de risco ambiental.
Currently, silver nanoparticles (AgNP) are widely used in several products because of their unique and exceptional properties, particularly its potent antibacterial activity. Thus, AgNP are very often applied in textiles, cosmetics and paints. Under those circumstances, AgNP is expected to be present in aquatic systems. Taking this into consideration, the objective of the present work is to describe the toxicity of AgNP of different sizes and compare to the toxicity from AgNO3 exposure using behavioral endpoints of the planarian Dugesia tigrina. Acute exposure tests (96 h) and chronic exposure tests (8 days) were performed, in which parameters such as survival, locomotion, feeding and regeneration were evaluated. Therefore, AgNP of different sizes were selected (AgNP of 10-25 nm and AgNP 3-8 nm) and effects from exposure were compared to those from AgNO3, in order to analyze whether the source of toxicity was originated by release the ionic form of Ag or related to the inherent properties of nanoparticles. The results showed that LC50 values at 24, 48, 72 and 96 h were equal over time for AgNP (10-25 nm) (76.62 μg L-1) and for AgNO3 (109.1 μg L -1). In the first 24 h, planarians experienced several morphological alterations at the head region such as suppressed auricles and mainly head dissolution. These effects were noted mainly in AgNP (10-25 nm) and AgNO3 exposures. Regarding chronic exposure, planarians presented a significant reduction in locomotion and feeding activity upon both AgNP exposures. These endpoints revealed to be the most sensitive to D. tigrina. There were no significant effects on the regeneration test. The source of toxicity may be related to the properties of AgNP that interfere with nervous system of planarians consequently causing their death. This study demonstrated that planarians are an adequate organism for behavioural ecotoxicological studies and should be considered in environmental risk assessment methodologies.

Silver nanoparticles (NPs) were synthesized and stabilized by a simple method in aqueous solution, by the reduction of silver nitrate with stannous chloride (SnCl2.2H2O) and cetyl trimethyl ammonium bromide (CTAB)through day light irradiation. Thereby, the silver nanoparticles were colloidally stabilized by CTAB as a surfactant. The synthesis of silver NPs with different size were possible by changing the reaction conditions such as reagent ratio. The silver NPs were characterized by Dynamic Light Scattering (DLS) and UV-visible spectroscopy. A very strong plasmon resonance peak at 400-500 nm in the UV-visible spectra is a clear consequence of the silver NPs production. The synthesized silver NPs showed good stability by using CTAB. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20633

Thesis (M.S.)--West Virginia University, 2006.
Title from document title page. Document formatted into pages; contains xiii, 104 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 70-73).

A COMPARISON OF THE ANTIMICROBIAL EFFICACY OF SILVER DIAMINE FLUORIDE AND SILVER NITRATE: AN IN VITRO STUDY By: Nicholas L Luke, D.D.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University. Virginia Commonwealth University, May 2018 Thesis Advisor: William O. Dahlke Jr., D.M.D. Pediatric Dentistry, Department Chair Purpose: To determine the antimicrobial efficacy of SDF and SN/NaF. Methods: Three bacterial species were combined to create an in vitro biofilm. Treatment was completed with SN, SN/NaF, SDF, SDF½ or untreated (control). Results: The untreated group demonstrated significantly higher growth than all other treatment groups across the study. On the BHI-plates (1-day), there were significant differences between all treatments except SDF and SDF½. On the BHI-plates (3-days), SN/NaF was not significantly different from SDF or SDF½. On the L-MRS-plates (1-day), both SN treatment groups yielded significantly higher growth than the SDF groups. On the L-MRS-plates (3-days), SN yielded significantly higher growth than SN/NaF, SDF, and SDF½. Conclusion: SDF is more effective than SN/NaF, with the exception of BHI-plates (3-days) only and SN/NaF is more effective than SN on primarily S. mutans and L. acidophilus. There is evidence of a possible antimicrobial tolerance of oral bacteria to silver.

A comparison of the antimicrobial efficacy of silver diamine fluoride and silver nitrate on various cariogenic bacteria: an ex vivo study By: Reham AlNajjar, D.D.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University. Virginia Commonwealth University, 2019 Thesis Advisor: William Dahlke, D.M.D., Associate Professor and Chair of Pediatric Dentistry, School of Dentistry Purpose: The use of silver-based antimicrobials is an emerging method for the treatment of dental caries. In this study, the authors compare the efficacy of the two most prominent silver- based therapeutics, silver diamine fluoride (SDF) and silver nitrate (AgNO3), on cariogenic and non-cariogenic multispecies biofilms. Currently there is a lack of studies comparing the efficacy of SDF to AgNO3. Methods: Plaque samples from anterior and posterior tooth sites from children presenting both with early childhood caries and caries-free children were collected, pooled, and utilized to create four ex vivo biofilm systems in artificial saliva. SDF and AgNO3 were administered to these biofilms and bacterial survival was quantified and compared to untreated controls. Results: Each of the four pooled sample types was applied to plates coated in artificial saliva + 1% sucrose. Both SDF and AgNO3 were very effective against plaque derived biofilms when compared to untreated biofilms (P0.05) in the potency of each compound. Conclusions: SDF and AgNO3 significantly inhibit ex vivo cariogenic and non-cariogenic biofilms at similar levels.

Orientador: Mario Fernando de Goes
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo foi avaliar a resistência da união e qualidade de camada híbrida de acordo com o modo de interação de diferentes sistemas adesivos com a dentina. Para a avaliação da resistência da união à tração foram utilizados sete terceiros molares humanos hígidos, os quais foram submetidos cortes perpendiculares ao longo eixo do dente para obtenção de superfícies planas de dentina média. Estas foram secionadas em quatro partes iguais, por dois cortes perpendiculares entre si. Os sistemas de ¿passo único¿ Adper Prompt (ADP) e Xeno III (XE); de ¿dois passos¿ Clearfil SE Bond (SE) e Adhe SE (ADSE); e o Single Bond (SB) foram aplicados sobre as superfícies dentinárias seguindo as instruções dos fabricantes. Sobre a dentina tratada foi construído um bloco de resina composta (Filtek Z250, 3M/ESPE) com 5 mm de altura. Após 24 h, cada espécime foi secionado de modo a obter espécimes com formato de ¿palito¿ com área média de 1mm2 para a realização do teste de tração. Os padrões de fratura foram examinados em microscopia eletrônica de varredura (MEV). Os valores foram submetidos à análise da variância e ao teste Tukey (p<0,05). Para a avaliação da qualidade de camada híbrida foram utilizados 15 terceiros molares, dos quais, através de cortes perpendiculares ao longo eixo, foram obtidas duas superfícies planas e adjacentes de dentina média por dente. Sobre estas duas superfícies adjacentes, foi aplicado o mesmo sistema adesivo. A seguir, entre as superfícies hibridizadas foi aplicada uma resina de baixa viscosidade de modo a uni-las formando um bloco composto por dentina-resina-dentina após a polimerização. Decorridas 24h cada bloco foi cortado no sentido mésio-distal criando 12 interfaces por adesivo; 4 interfaces foram submetidas à técnica de pigmentação com nitrato de prata amoniacal; 4 à técnica de pigmentação com metenamina de prata; e 2 serviram de controle. Todas as interfaces foram observadas sob MEV. As médias de resistência de união, em MPa, foram: SE (51,48 ± 15,24); ADSE (37,08 ± 12,55); XE (36,24 ± 11,95); SB (26,20 ± 4,39) e ADP (24,92 ± 6,17). Houve predominância de fraturas do tipo mista entre adesivo e camada híbrida para SB, ADSE e XE; e fratura coesiva na camada de adesivo para SE e ADP. Em relação à qualidade de camada híbrida, SB mostrou maior intensidade na deposição de grãos de prata metálica na camada híbrida quando comparado aos outros sistemas. SE e ADSE apresentaram deposições de grãos de prata metálica semelhantes entre si e em menor intensidade comparada com os demais grupos. XE e ADP mostraram quantias moderadas de grãos prata metálica na camada híbrida e, diferentemente dos demais, dentro da camada de adesivo. Áreas de nanoinfiltração no interior da interface de união puderam ser identificadas tanto pela solução de nitrato de prata amoniacal como também pela solução de metenamina de prata. De acordo com o modo de interação dos sistemas adesivos com a dentina há formação de diferentes padrões de camada híbrida que, provavelmente, infuenciou nos valores de resistência de união
Abstract: This study evaluated the bond strength and hybrid layer formation between different adhesive systems and dentine. To evaluate the bond strength, seven molars fresh extracted were sectioned in multiple parallel layers. The middle dentine layers were selected and sectioned into four equal pieces perpendicular to the previous sections. The ¿one step¿ self-etching adhesive systems Adper Prompt (ADP) and XENO III (XE); the ¿two steps¿ self-etching adhesive systems Clearfil SE Bond (SE) and Adhe SE (ADSE) and the ¿total-etch¿ adhesive Single Bond (SB) were applied on dentine surfaces according to the manufactures¿ instructions. A block of resin (Filtek Z250, 3M/ESPE) of 5 mm height was built in three increments, each one light cured for 20 seconds, on the treated dentine. The specimens were stored in 37°C distilled water for 24h and then sectioned in X and Y directions to obtain 1 mm2 area sticks. The sticks were submitted to a microtensile bond strength test in a universal testing machine (Instron 4411) at a crosshead speed of 0.5mm/min. The results were submitted to one-way analysis of variance and Tukey¿s test at a 5% level of significance. To evaluate the hybrid layer, 15 third molars were used. Two adjacent flat surfaces of middle dentine were obtained for each tooth. The same adhesive system was applied on these two adjacent surfaces, which were applied according to manufacturers' instructions. A resin ¿sandwich¿ block of dentine/resin/dentine was made filling the two adjacent slices with a low viscosity resin, which was polymerized for 20s. After 24 h, each block was mesio-distally sectioned producing 12 interfaces per adhesive. Four interfaces were stained with ammoniacal silver nitrate solution and 4 with silver methenamine solution. The other four were kept without stain and used as a control group. All the interfaces were observed under SEM. The bond strength means, in MPa, were: SE (51.48 ± 15.24); ADSE (37.08 ± 12.55); XE (36.24 ± 11.95); SB (26.20 ± 4.39) and ADP (24.92 ± 6.17). There was prevalence of mixed failure between adhesive and hybrid layer for SB, ADSE and XE; and prevalence of cohesive failure in the adhesive layer for SE and ADP. According to the hybrid layer, SB showed a greater intensity of silver grains deposition than the other systems. SE and ADSE presented similar silver grains depositions but in a small quantity. XE and ADP differing from the others, not only showed moderate amounts of silver grains in the hybrid layer, but also inside the adhesive layer. It was possible to identify nanoleakage inside the bond interface with both used stains. According to the interactions of the adhesive systems with dentine, there were different hybrid layer patterns, which may influence the bond strength
Doutorado
Materiais Dentarios
Doutor em Materiais Dentários

Soluções de nitrato de prata são freqüentemente usadas em testes de micro e nanoinfiltração, apesar de nem todas as suas características estarem definidas claramente na literatura. Neste estudo foram avaliadas soluções aquosas de nitrato de prata quanto ao pH e à quantidade de prata iônica (ppm) em várias concentrações, bem como o desempenho dessas soluções em testes de microinfiltração realizados em dentes decíduos e permanentes. Numa primeira fase foi analisado o pH (pHmetro digital) de solução a 50% (p/v), tendo como variáveis a pureza da água, a marca comercial do sal, a cor do frasco, e a idade pós-preparo. Posteriormente, avaliou-se a quantidade de prata iônica, por espectrometria de emissão atômica, presente nas soluções (1%, 5%, 25% e 50%) ao longo de 168 horas de armazenagem. Em cavidades de classe V, confeccionadas nas faces vestibular e lingual/palatina de molares, foram aplicados dois sistemas adesivos (OptiBond FL ou OptiBond Solo Plus SE). Após a restauração (Filtek Z-250) foi determinado o valor médio de microinfiltração (mm) para diversas concentrações e idade pós-preparo das soluções. Os dados obtidos foram tratados por análise de variância e teste de Tukey (a=0,05). As soluções analisadas na primeira etapa apresentaram pH médio entre 7,9±2,2 a 11,8±0,9, e houve diferenças significativas para todas as variáveis. O teor médio de prata iônica apresentou diferenças significativas para o fator Concentração (4,75±0,5 a 1% e 293±15,3ppm a 50%); porém, não houve diferença para o fator Idade. Nos testes de microinfiltração houve diferença significante apenas para o fator Adesivo (p<0,01); os demais fatores e as interações não apresentaram diferenças significativas. Com base nos resultados obtidos neste estudo pode-se concluir que: 1) o pH de soluções aquosas de nitrato de prata varia de neutro a alcalino; 2) a quantidade de prata iônica e o pH se mantêm estáveis por até 168h; 3) a concentração e a idade pós-preparo das soluções não interferiram nos valores médios de microinfiltração; 4) o sistema adesivo OptiBond FL apresentou menores valores de microinfiltração, em dentes permanentes e decíduos
Silver nitrate solutions are frequently used in micro and nanoleakage tests, although not all of their characteristics are clearly defined in the literature. In this study an assessment was made of aqueous silver nitrate solutions as regards pH and the amount of ionic silver (ppm) in various concentrations, as well as the performance of these solutions in microleakage tests performed in primary and permanent teeth. In the first phase the pH (digital pH meter) of a 50% (w/v) solution was analyzed, having water purity, commercial brand of the salt, the color of the flask, and the storage time as variables. Afterwards, the amount of ionic silver present in the solutions (1%, 5%, 25% and 50%) was evaluated by atomic emission spectrometry, throughout 168 hours of storage. In Class V cavities made on the vestibular and lingual/palatal faces of molars, two adhesive systems were applied (OptiBond FL or OptiBond Solo Plus SE). After restoration (Filtek Z-250) the mean microleakage value (mm) was determined for the various concentrations and post-preparation time of the solutions. The data obtained were submitted to analysis of variance and the Tukey test (a=0.05). The solutions analyzed in the first stage had a mean pH ranging between 7.9±2.2 and 11.8±0.9, and there were significant differences for all the variables. The mean ionic silver content presented with significant differences for the factor Concentration (4.75±0.5 at 1% and 293±15.3 ppm at 50%); but there was no difference for the factor Time. In the microleakage tests there was significant difference only for the factor Adhesive (p<0.01); the other factors and the interactions did not present with any significant differences. Based on the results obtained in this study, it may be concluded that: 1) the pH of aqueous silver nitrate solutions varies from neutral to alkaline; 2) the amount of ionic silver and pH remained stable for up to 168h; 3) the concentration and the post-preparation time of the solutions did not interfere with the mean microleakage values; 4) the adhesive system OptiBond FL presented with the lowest microleakage values in both permanent and primary teeth

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O processo Sol-Gel tem permido preparar materiais vítreos ou vítro-cerâmicos com novas composições com alto grau de pureza, homogêneos, materiais híbridos orgânicos e inorgânicos (OIHM) e até materiais impossíveis de serem preparados por processos convencionais. Um dos melhores sistemas para obtenção dos OIHM de sílica (ORMOSIL – Silicato Organicamente Modificado) é a reação combinada com alcoóxidos de Silício como o TEOS (Tetraetilortosilicato) e alcoóxidos funcionalizados como o GPTS (3-Glicidoxipropil-trimetoxisilano). A Prata, é aplicada em diversas áreas como por exemplo, em pinturas a base de Prata (utilizados para circuitos impressos), em filmes fotográficos, películas de vidros dentre várias outras aplicações. Dois efeitos encontrados quando uma amostra GTD-Ag (Amostra com a dopagem de AgNO3), irradiada por uma lâmpada UV e tratada a temperatura (acima de 80 °C), são os efeitos fotocrômicos e termocrômicos. Para o efeito fotocrômico, a irradiação por lâmpada UV, produz partículas de prata oxidadas (Ag+) que transformam-se em partículas de prata reduzidas (Ago), ocorrendo-se assim, o escurecimento dos filmes (redução). O clareamento das amostras GTD-Ag (oxidação), foi obtido através de um agente oxidante, o H2O2. Para observar o efeito termocrômico, as amostras GTD-Ag, são tratadas em forno convencional em temperaturas de 80 °C à 550 °C em atmosferas de N2 e ambiente. No tratamento térmico em atmosfera de N2, foi possível observar o escurecimento (redução) da amostra, a partir da temperatura de 80 °C, e em tratamento térmico à atmosfera ambiente, observamos um clareamento da amostra (oxidação), a partir da temperatura de 200 °C. Utilizando a técnica de análise térmica diferencial (DTA), foi possível verificar a óxido-redução da amostra GTD-Ag, quando tratada em atmosfera ambiente, em temperaturas superiores a 150 °C. Comportamento semelhante é observado para as amostras GTD (Amostra sem dopagem de AgNO3), em temperaturas acima de 200 °C, ocorrendo um efeito conhecido por pirólise, que no nosso caso é a degradação do grupo epóxi.
The sol-gel process has allowed prepare vitreous or vitro-ceramic materials with novel compositions with high purity, homogeneous, organic and inorganic hybrid materials (OIHM) and impossible materials to be prepared by conventional methods. One of the better systems for obtaining OIHM silica (ORMOSIL - Silicate Organically Modified), is the combined reaction of silicon alkoxides such as TEOS (Tetraethylorthosilicate), and functionalised alkoxides such as GPTS (3- Glycidoxypropyl-trimethoxysilane). The Silver is applied in various areas such as Silver paintings (used for printed circuits) on photographic films, glass films among many other applications. Two effects found when a GTD-Ag sample (Sample with AgNO3 doping) irradiated by a UV lamp and treated at temperatures (above 80 °C), are photochromic and thermochromic effects. For the photochromic effect, the UV irradiation lamp produces oxidized silver particles (Ag+) which becomes reduced particles silver (Agº), occurring to thereby darkening of the films (reduction). The samples of the bleaching GTD-Ag (oxidation) were obtained by an oxidizing agent H2O2. To observe the thermochromic effect, the GTD-Ag samples are treated in a conventional oven at temperatures of 80 °C to 550 °C in N2 atmosphere and ambient. In the heat treatment in N 2 atmosphere, was observed to darkening (reduction) of the sample from the 80 °C temperature and treatments to the ambient atmosphere, we observed a whitening of the sample (oxidation) at low temperature 200 °C. Using the differential thermal analysis (DTA), we found the redox sample GTD-Ag, when treated in atmosphere ambient at temperatures above 150 °C. Similar behavior is observed for the GTD samples (Sample undoped AgNO3) at temperatures above 200 °C, occurring an effect known by pyrolysis which in our case is the degradation of the epoxy group.

AbstractThe synthesis of silver nanoparticles using plant extract as a capping agent has been very easy, economical and environment friendly method. The Madhuca longifolia is one of the well-known trees for its various benefits from food industry to its medicinal applications. It is indigenous to India, Nepal, Sri Lanka and Myanmar. In the present aqueous extract was used from leaves of M. lngifolia has been used as a capping agent to form AgNPs by reducingsilver nitrate with the help of green synthesis route. UV-visible spectroscopicy gave maximaat 420 nmconfirmed the synthesis of M. longifolia AgNPs. Characterization was done by TEM, SEM, XRD and FTIR techniques. FTIR confirmed the presence of various phytochemicals and formation of nanoparticles. XRD confirmed the formation of crystalline structure of synthesized silver nanoparticles. The shape of silver nanoparticles was irregular and spherical. The reaction solution turned brown which is the primary indication of formation of AgNPs. Crystalline size was calculated and found to be 10–25 nm; and TEM showed the size of nanoparticles around 5–40 nm. The M. longifolia based Silver nanoparticles were evaluated for their antibacterial and antibiofilm activity on Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative) by disc diffusion and percentage inhibition methods was confirmed.

Alloy 22 (UNS N60622) is a nickel-based alloy, which is extensively used in aggressive industrial applications, especially due to its resistance to localized corrosion and stress corrosion cracking in high chloride environments. The purpose of this work was to characterize the anodic behavior of Alloy 22 in concentrated calcium chloride (CaCl2) brines and to evaluate the inhibitive effect of nitrate, especially to localized corrosion. Standard electrochemical tests such as polarization resistance and cyclic polarization were used. Results show that the corrosion potential of Alloy 22 was approximately −360 mV in the silver-silver chloride (SSC) scale and independent of the tested temperature. Cyclic polarization tests showed that Alloy 22 was mainly susceptible to localized attack in 5 M CaCl2 at 75°C and higher temperatures. The addition of nitrate in a molar ratio of chloride to nitrate equal to 10 increased the onset of localized corrosion to approximately 105°C. The addition of nitrate to the solution also decreased the uniform corrosion rate and the passive current of the alloy.

In this study, the femtosecond laser ablation technique was engaged to fabricate silver-doped titanium dioxide nanoparticles. Further, these NPs were employed in surface-enhanced Raman scattering-based sensing of RDX and ammonium nitrate traces.

Bubble printing of Ga-In liquid metal nanoparticles was demonstrated. Fine line patterns with line width of several µm were formed. The conductivity of the resultant line patterns was improved by galvanic replacement using silver nitrate.

Alloy 22 (N06022) may be susceptible to crevice corrosion in chloride solutions. Nitrate acts as an inhibitor to crevice corrosion. Several papers have been published regarding the effect of nitrate on the corrosion resistance of Alloy 22 at temperatures 100°C and lower. However, very little is known about the behavior of this alloy in highly concentrated brines at temperatures above 100°C. In the current work, electrochemical tests have been carried out to explore the anodic behavior of Alloy 22 in high chloride high nitrate electrolytes at temperatures as high as 160°C at ambient atmospheres. Even though Alloy 22 may adopt corrosion potentials in the order of +0.5 V (in the saturated silver chloride scale), it does not suffer crevice corrosion if there is high nitrate in the solution. That is, the inhibitive effect of nitrate on crevice corrosion is active for temperatures higher than 100°C.

Corning Polarcor glasses contain submicron-size silver particles embedded in a soda-lime glass host. The elongated silver particles have their major axes oriented in a common direction. The glasses polarize light by selective absorption. The absorption is from surface plasmon excitation in the silver particles. Planar waveguides were fabricated by a K-Na ion exchange process. Singlemode guides at 836 nm were obtained from a potassium nitrate melt at 340 C with an exchange time of 31 h. TE and TM pass polarizers had measured extinction ratios >39 dB/mm at 836 nm with <1.5 dB/mm propagation loss for the pass axis. Using the bulk values for the dielectric response of silver, the effective dielectric tensor for the composite is calculated and the extinction ratio is determined.

Although nitrate fertilizers are critical for enhancing crop production, excess application of nitrate fertilizer can result in ground water contamination leading to the so called "nitrate problem". Health and environmental problems related to this "nitrate problem" have led to serious concerns in many parts of the world including the United States and Israel. These concerns have resulted in legislation limiting the amount of nitrate N in drinking water to 10mg/g. Development of a fast, reliable, nitrate sensor for in-situ application can be extremely useful in dynamic monitoring of environmentally sensitive locations and applying site-specific amounts of nitrate fertilizer in a precision farming system. The long range objective of this study is to develop a fast, reliable, real-time nitrate sensor. The specific objective of this one year feasibility study was to explore the possible use of nitrate sensor based on mid-IR spectroscopy developed at UCD along with the silver halide fiber ATR (i.e. attenuated total internal reflection) sensor developed at TAU to detect nitrate content in solution and soil paste in the presence of interfering compounds. Experiments conducted at Technion and UCD clearly demonstrate the feasibility of detecting nitrate content in solutions as well as soil pastes using mid-IR spectroscopy and an ATR technique. When interfering compounds such as carbonates, bicarbonates, organic matter etc. are present special data analysis technique such as singular value decomposition (SYD) or cross correlation was necessary to detect nitrate concentrations successfully. Experiments conducted in Israel show that silver halide ATR fiber based FEWS, particularly flat FEWS, resulted in low standard error and high coefficient of determination (i.e. R² values) indicating the potential of the flat Fiberoptic Evanescent Wave Spectroscopy (FEWS) for direct determinations of nitrate. Moreover, they found that it was possible to detect nitrate and other anion concentrations using anion exchange membranes and M1R spectroscopy. The combination of the ion-exchange membranes with fiberoptices offers one more option to direct determination of nitrate in environmental systems.

In this 1-year feasibility study, we tried polymerization of several different monomers, commercial as well as novel, specially designed and synthesized for this project in the presence of the nitrate ion to produce imprinted conductive polymers. Polymers 1 and 2 (shown below) produced a response to nitrate, but one inferior to that produced by a polypyrrole (Ppy)-based sensor (which we demonstrated prior to this study). Thus, we elected to proceed with improving the stability of the Ppy-based sensor. In order to improve stability of the Ppy-based sensor, we created a two-layer design which includes nitrate-doped Ppy as an inner layer, and nitrate-doped PEDOT as the outer layer. PEDOT is known for its high environmental stability and conductivity. This design has demonstrated promise, but is still undergoing optimization and stability testing. Previously we had failed to create nitrate-doped PEDOT in the absence of a Ppy layer. Nitrate-doped PEDOT should be very promising for sensor applications due to its high stability and exceptional sensing properties as we showed previously for sensing of perchlorate ions (by perchlorate-doped PEDOT). During this year, we have succeeded in preparing nitrate-doped PEDOT (4 below) by designing a new starting monomer (compound 3 below) for polymerization. We are currently testing this design for nitrate sensing. In parallel with the fabrication design studies, we fabricated and tested nitrate-doped Ppy sensors in a series of flow studies under laboratory and field conditions. Nitrate-doped Ppy sensors are less stable than is desirable but provide excellent nitrate sensing characteristics for the short-term experiments focusing on packaging and deployment strategies. The fabricated sensors were successfully interfaced with a commercial battery-powered self-logging (Onset Computer Hobo Datalogger) and a wireless data acquisition and transmission system (Crossbow Technologies MDA300 sensor interface and Mica2 wireless mote). In a series of flow-through experiments with water, the nitrate-doped Ppy sensors were exposed to pulses of dissolved nitrate and compared favorably with an expensive commercial sensor. In 24-hour field tests in both Merced and in Palmdale, CA agricultural soils, the sensors responded to introduced nitrate pulses, but with different dynamics relative to the larger commercial sensors. These experiments are on-going but suggest a form factor (size, shape) effect of the sensor when deployed in a porous medium such as soil. To fill the need for a miniature reference electrode, we identified and tested one commercial version (Cypress Systems, ESA Mini-reference electrode) which works well but is expensive ($190). To create an inexpensive miniature reference electrode, we are exploring the use of AgCl-coated silver wire. This electrode is not a “true” reference electrode; however, it can calibrated once versus a commercial reference electrode at the time of deployment in soil. Thus, only one commercial reference electrode would suffice to support a multiple sensor deployment.

8+fjordar-området är topografiskt väldigt varierande. Vattenutbytet är långsamt och tillförseln av näringsämnen stor. Största delen av näringsämnen stannar kvar i fjordarna. Mest i Havstens- och Hakefjordar där 40-50 % av den lokala näringstillförseln stannar kvar. Utsläppen från jordbruk och skogsbruk är stora i 8+fjordar-området. T.ex. står dessa för 62 % av kvävetillförseln och 69 % av fosfortillförseln till Byfjorden. Men utsläpp från punktkällor direkt till havet är också betydande (21 % av kvävetillförseln och 19 % av fosfortillförseln till Byfjorden). Man har genom en mängd olika tilltag de senaste decennierna försökt sänka utsläppen av kväve och fosfor och även om koncentrationerna av kväve och fosfor fortsatt är höga har halterna av främst kväve sjunkit i 8+fjordar-området. De stora utsläppen av näringsämnen ökar växtplanktonproduktionen och när denna sjunker till botten och bryts ner av bakterier orsakar det syrebrist och höga koncentrationer av giftigt svavelväte i de djupare delarna av fjordarna. I de grundare delarna av fjordsystemet finns grunda vikar med ålgräsängar, blåmusselbankar och klippkuster med tångskogar. Dessa biotoper har förändrats under de senaste decennierna med en ökande påväxt av fintrådiga alger. Den pelagiska miljön (de fria vattenmassorna) är främst påverkad av avrinning av sötvatten från älvar och åar och av inflöde av salthaltigt vatten från Skagerrak genom Marstrandsfjorden och norrut i fjordsystemet. Närsaltkoncentrationen är hög i hela vattenpelaren vilket ses speciellt för nitrat. Detta ger förhöjda klorofyllkoncentrationer även om dessa alltså har minskat betydligt under de senaste decennierna. 8+fjordar-området har länge haft höga koncentrationer av giftiga dinoflagellater, men de senaste decennierna har giftalgsblomningarna minskat betydligt. De flesta områden uppnår nu minst god ekologisk status avseende vinterkoncentrationer av totalt kväve med undantag för By-, Havstens-, Askerö- och Älgöfjordar. Status för växtplankton klassas som hög i nästan hela området. År 2006 kom den amerikanska kammaneten Mnemiopsis leidyi till svenska västkusten. Den är en effektiv predator på djurplankton och kan vissa år minska djurplanktonbiomassan avsevärt under hösten. Detta kan ha allvarliga konsekvenser för överlevnad av fisk och fisklarver som livnär sig på djurplankton. De allra flesta fiskarter livnär sig på djurplankton i larvstadiet. Den bentiska miljön innefattar livsmiljön från de djupa mjukbottnarna till tångskogarnas och ålgräsängarnas topp. 8+fjordar-områdets bentiska miljö kännetecknas av klippstränder med hårdbottnar beväxta med bland annat snärjtång, blåstång, sågtång, sockertång och fintrådiga alger, där blåmusslor och andra evertebrater lever och de djupare delarna täcks av fastsittande bentiska evertebrater som till exempel havsanemoner och havsnejlikor. De djupare sedimentbottnarna hyser grävande evertebrater som livnär sig på den biomassa som sjunker ner från pelagialen. Här dominerar havsborstmasken Scalibregma inflatum, slätbukig Sammanfattning trådormstjärna och pepparmussla. Vatten från Skagerrak strömmar in i 8+fjordarområdet söderifrån och de södra bassängerna inklusive Hake- och Askeröfjordar är normalt syresatta under hela året även i sina djupaste delar, medan de djupa delarna av de nordligare Kalvö-, Borgile-, Koljö- och Byfjordar samt även Havstensfjorden ofta präglas av långvarig syrebrist. I dessa områden försvinner bottenfaunan ofta helt eller befinner sig i någon fas av återkolonisering efter vattenutbyten. Den bentiska miljön hade bättre ekologisk status under 1980- och 90-talet än under det tidiga 2000-talet. De flesta åren därefter visar måttlig status i Hake-, Halse- och Havstensfjordar. I de grunda vikarna har mängden fintrådiga alger ökat betydligt sedan slutet på 1990-talet. Dessa alger bildar påväxt på ålgräs och tång och täta mattor av ruttnande alger på botten vilket försvagar ålgräs och tång och orsaker lokal syrebrist i ängarna. Dessa alger har ökat i biomassa delvis på grund av avsaknaden av betande evertebrater (t.ex. märlkräftor) som i sin tur har minskat i antal eftersom mesopredatorer som t.ex. strandkrabba och läppfiskar har ökat när deras predatorer, som t.ex. torsk, har fiskats bort. Utbredningen av ålgräs i 8+fjordar-området har minskat ganska dramatiskt de senaste decennier, speciellt kring Kungälv och Uddevalla där 80–85% av arean har försvunnit. Status för ålgräs och tång är otillfredsställande eller måttlig i nästan hela 8+fjordar-området. Fiskbestånden i 8+fjordar-området har varit överfiskade under lång tid och liksom i Västerhavets övriga kuststområden är förekomsten av större bottenlevande fisk, främst torskfiskar, mycket reducerad i 8+fjordar-området. Det fanns ett betydande fiske av torsk, näbbgädda, rödspotta, sill och skarpsill i området på 1960- talet men 2004–2008 hade de flesta fisken kollapsat med undantag av fisket på sill och skarpsill som fortfarande fiskas även on mängden landad sill har minskat betydligt från 2014 till 2021. Av alla fångster av sill och skarpsill fiskades i genomsnitt 14 % av sillen och 87 % av skarpsillen med lysfiske. SLU:s undersökningar visar dessvärre inte på någon återhämtning av fiskbestånden under de senaste 20 åren, trots att det riktade fisket efter flera av dessa arter stoppats och det införts ett fiskefritt område i Havstensfjorden. Genetiska studier visar dock att det fortfarande finns ett lokalt lekande bestånd av torsk i området och det har observerats bättre rekryteringar 2016 och 2019. Sportfisket efter havsöring är betydande, men störst är fisket efter makrill både med spö och med dörj. Det finns ingen officiell statistik på landningar men i Fiskeriverkets rapport från 1999 angavs att fritidsfiskets sammanlagda fångster översteg yrkesfiskets för lax och havsöring och vissa arter av plattfisk. Det finns en del vattenbruk i 8+fjordar-området. Företaget Scanfjord är störst, med blåmusselodlingar i yttre Stigfjorden, Havstensfjorden och Koljöfjorden. En rad andra aktörer har odlingar främst i norra delen av 8+fjordar-området och företaget Marine Taste odlar sjöpungar nära Stenungsund. Sjöfåglar är viktiga länkar mellan näringsvävar i havet och på land och de kan vara bra indikatorer på förändringar i de marina ekosystemen. Efter mitten av 1990- talet har ejderpopulationen minskat till hälften och arten är numera (2020) rödlistad som ”starkt hotad” (EN) i både Sverige och Europa. Strandskatan har minskat med omkring 40 % i Sverige de senaste 30 åren och är sedan 2020 rödlistad som "nära hotad" (NT). Troliga faktorer för dessa två arters minskning är minskad mängd och/eller kvalitet, inklusive vitaminbrist, på bytesdjur, ökad utbredning av syrefria bottnar, klimatförändringar, predation och sjukdom. Stora förändringar har också ägt rum hos många måsfågelbestånd de senaste 20–30 åren. Fisktärna och silltrut (på västkusten) har klarat sig bra, medan övriga måsfåglar minskat så kraftigt att de blivit rödlistade. Bestånden av grågås, kanadagås och vitkindad gås har ökat kraftigt de senaste 30 åren. Tillgången på höst- och vintergröna grödor har ökat genom ändrat jordbruk och varmare och snöfattigare vintrar vilket har gynnat gässen. Storskarven var tidigare utdöd i Sverige men under 1980- och 1990-talet spred sig skarven längs den svenska kusten och i 8+fjordar-området etablerades de första kolonier i början av 2000-talet. Det finns ingen regelbunden inventering av storskarv i Sverige men år 2021 räknades 1300 bon i 7 kolonier från Nordre Älvs mynning i söder till Havstensfjord i norr, absoluta majoriteten väster om OrustTjörn. I 8+fjordar-området är storskarvens vanligaste byten smörbult och plattfisk, men även andelen torskfisk och sötvattensfisk är betydande. Knubbsäl, gråsäl och tumlare förekommer i 8+fjordar-området. Knubbsäl och tumlare är de överlägset vanligaste marina däggdjuren medan antalet gråsälar är betydligt färre. Efter att jakten förbjöds och sälarna skyddades, samtidigt som mängden miljögifter minskade, började sälpopulationen längs västkusten återhämta sig under 1980-talet. Knubbsälpopulationen har ökat sedan dess även om virussjukdom (Phocine Distemper Virus, PDV) reducerade antalet betydligt år 1988 och 2002. Under 2010-talets senare hälft uppskattades antalet knubbsälar i Västerhavet till över 20 000 djur. I 8+fjordar-området vistas de flesta sälar på utsidan Orust och Tjörn med mycket färre sälar i själva 8+fjordar-området. Prover insamlade 2015-2016 visade att knubbsälens födoval är helt dominerat av plattfisk (viktandel >70 %) följt av sill, rötsimpa och vitling. Miljögifter finns i stora koncentrationer i vissa delar av 8+fjordar-området, främst i Byfjorden där föroreningar från hamnen länge har varit stora och kring Stenungsund där utsläpp från den kemiska industrin dominerar. Men inom 8+fjordar-området finns även ett stort antal mindre båtvarv och marinor som genom åren har bidragit till giftiga utsläpp främst från båtbottenfärg. I Byfjorden har bottensedimenten höga eller mycket höga koncentrationer av olja, polycykliska aromatiska kolväten (PAH) och PCB. Där är koncentrationerna av TBT, som tidigare användes i båtbottenfärg, och dess två nerbrytningsprodukter DBT och MBT mycket höga. Flera metaller så som zink, kadmium, koppar och nickel finns också i höga koncentrationer. Kvicksilver- och PBDE-halten i blåmusslor överskrider Vattendirektivets gränsvärde för fisk. Dessa föroreningar finns också i Havstensfjorden och Halsefjorden men i lägre koncentrationer. Kring Stenungsund är bottensedimentens halter av hexaklorbensen (HCB) höga eller mycket höga men det avspeglas dock inte i förhöjda HCB-halter i blåmusslor från samma område. Halterna av DBT och MBT är också höga här, medan halterna av TBT inte är förhöjda. Kopparhalten i sediment från Stenungsundsområdet är förhöjda och på en lokal är de långt över Vattendirektivets gränsvärde. Även koncentrationen av PBDE i blåmussla överstiger vattendirektivets gränsvärde. Blåstång från en lokal vid nordvästra Stenungsön har höga eller mycket höga koncentrationer av kadmium, arsenik och koppar. I syrefria bottnar förekommer ingen omblandning av sedimentet av infauna såsom havsborstmaskar vilket gör att lagrade ämnen inte i så hög utsträckning frigörs till vattnet och miljögifter koncentreras som mest i dessa områden. Nedbrytningshastigheten av organiska miljögifter är också betydligt långsammare i en syrefattig miljö än i en syrerik och det kan ta många decennier att bryta ned gifterna. Om syrefria bottnar innehållande miljögifter åter syresätts och omblandningen sätts igång, är det därför risk för kontaminering av kringliggande vatten. Mikroplast som härstammar från den lokala plastindustrin finns i större mängder i bottensedimenten kring Stenungsund. En studie visade att minst 3 miljoner och i värsta fall 36 miljoner polyetylenpellets större än 2 mm, motsvarande 73–730 kg, släpps ut via Stenunge å årligen. När mindre fraktioner ner till 300 µm inkluderades i mätningarna var det totala partikelantalet hundrafaldigt högre. Dessa partiklar har direkt effekt på djur och växter i fjorden. Elfiskeundersökningar visade att 62 % av öring fångade i Stenunge å hade plastpartiklar i magen. Flera invasiva arter har etablerat sig i 8+fjordar-området de senaste decennierna. Den amerikanska kammaneten Mnemiopsis leidyi finns i stora mängder sensommar och höst under de flesta år. Under år med dessa maneter kan de äta upp största delen av djurplanktonbiomassan vilket skapar problem för fisklarver som livnär sig på detta plankton. Stillahavsostronet eller det japanska jätteostronet har observerats på stränder i hela 8+fjordar-området. Dessa ostron kan tränga undan blåmussla när det bildas stora ostronbankar och de europeiska ostronen kan smittas av nya typer av parasiter. Ostronens skal är också vassa och kan orsaka skador på människor som går på bottnen i grunda områden. Mellan 20 och 40 % av 8+fjordar-områdets kustlinje är bebyggd inom 100 meters avstånd till vattenlinjen. I Kungälv och på Tjörn och Orust har bebyggd kustlinje fördubblats på bara 10 år trots förbud mot uppförande av nya byggnader närmre än 100 meter från strandlinjen enligt strandskyddslagstiftningen. 20–25 % av kusten i dessa kommuner är nu bebyggd. Friluftslivet till sjöss har också ökat kraftigt under senare år. Intervjuundersökningar visar att det under 2004 uppskattningsvis fanns totalt 26 600 båtar på svenska västkusten men att antalet har fyrdubblats fram till 2010. Denna ökning av mänsklig närvaro stör på många olika sätt. Pirar eller bryggor kan störa djurs naturliga migrationsrutter längs kusten, speciellt i topografiskt komplexa områden som 8+fjordar-området och större strukturer som t.ex. brofästen eller bortsprängningar och utgrävningar kan ändra vattengenomströmningen. I 8+fjordar-området kan det ha extra stor effekt eftersom vattenutbytet är naturligt långsamt. Fåglar störs kraftigt av snabbgående båtar. Många fåglar undviker ofta platser med mycket trafik under ruggningen och på rastoch övervintringslokaler kan störningar från båtar leda till att de oftare tar till flykt med energiförluster som följd. Marint skräp är ett särskilt stort problem i Bohuslän där stora mängder makroskräp driver i land på grund av havsströmmarna (Jutska strömmen). Detta är faktiskt ett av Europas mest nedskräpade marina områden. 96 % av det marina skräpet längs stränderna i Bohuslän utgörs av plastartiklar, och det vanligaste är snören och linor som till allra största del kommer från fisket. Effekter av skräp på det marina djurlivet är väldokumenterade, t ex insnärjning av marina djur och intag av skräpföremål av fåglar, fiskar och evertebrater. Förlorade tinor, garn och ryssjor utgör också en betydande del av skräpet. Efter intervjuundersökningar uppskattades antalet förlorade hummertinor till 3900 per år på västkusten bara från fritidsfisket. Förlorade fiskredskap fiskar vidare och studier har visat att så mycket som 163 800 humrar och krabbtaskor fångas per år på västkusten i detta spökfiske. Klimatförändringarna leder till att haven runt Sverige blir allt varmare, att kustnära vatten utsötas när nederbörden ändras och att haven försuras när ökade mängder koldioxid tas upp i havet. Varmare vatten tar upp mer plats så havsnivån stiger med stigande temperatur och detta förvärras när polernas fastlandsisar smälter. I 8+fjordar-området ökar ytvattentemperaturen fyra gångar så snabbt som den globala medeluppvärmningen och enligt SMHI har temperaturen ökat med 3,5 °C sedan 1960. Salthalt och skiktning förändras i kustnära miljöer när nederbörden varierar. I svenska kustnära marina miljöer har saliniteten minskat under perioden från 1992, då mätningarna började, fram till ca 2010, men under de senare åren har den ökat så mycket att den nu är tillbaka på samma nivå som 1990. En tredjedel av den koldioxid som släpps ut absorberas av världens hav där den bildar kolsyra. Under industrialiseringen har det globala medel-pH minskat från cirka 8,11 till 8,06, en minskning som motsvarar en ökning i surhet med 30 %. Det finns ingen marin övervakning av pH i 8+fjordar-området men data från danska fjordar visar en försurning som är dubbel så snabb som globala medelvärdet. Av alla belastningar relaterade till klimatförändringarna är det temperaturökningen som har störst effekt på djur och växter i havet. Först och främst förflyttas utbredningsområden för djur och växter mot norr. Torsken i Skagerrak/Kattegatt föredrar temperaturer som är låga jämfört med de medeltemperaturer de upplever i området i dag och den temperaturökningen vi ser i 8+fjordar-området minskar därför torskens lekmöjlighet i området. Ålgräs påverkas också av ökande temperaturer och studier visar att en 5 °C ökning minskar ålgräsets skottäthet. Havsförsurning påverkar främst bottnens kalcifierande arter som kräftdjur, blötdjur och tagghudingar. Till exempel har det visat sig att sjöborrelarvers utveckling försämras av även mycket små minskningar i pH och bottensamhällen påverkas så att både artrikedom och antal individer minskar under försurning.