The provision of goods and services by aquatic ecosystems plays an important role in socio-economic development and livelihoods in the southern African region. Water resource management in South Africa developed from an agrarian and pastoral focus up to 1956 to also supporting mining and industrial activities. This led to the introduction of the resource water quality objectives and pollution prevention approaches, which balanced the needs for development and protection. Prior to 1994, access to water resources was limited to riparian property owners and a minority of the population who controlled industrial and mining activities. The establishment of a democratic government amplified the need for accelerated socio-economic development, with equity, efficiency and sustainability being the principles of such development. New approaches were needed, which could achieve these development objectives and secure the resource base for future generations. An overview of the scientific process highlighted a risk based approach as potentially supporting the much needed balance between development and protection. The aims of this thesis is to develop a framework and process for the application of ecological risk assessment to water resource management in South Africa, to use case studies to draft guidelines for ecological risk assessment and to assess the degree to which ecological risk assessment can contribute to effective water resource management in South Africa. The United States Environmental Protection Agency’s guidelines for ecological risk assessment were identified amongst international best practice as meeting the requirements for local application. A framework was drafted for ecological risk assessment in South Africa, with the main phases being to agree on objectives, formulate the analysis plan, analyse information, characterise risk and manage risk. Modifications from the Environmental Protection Agency’s process include the order of activities in the first phase, the explicit testing of hypotheses and clarification of the evaluation of existing data or collection of new data. An industrial effluent case study was used to assess the applicability of the proposed framework. The case study dealt specifically with the assessment of risks posed by current conditions and long term licence conditions. The framework was found to be useful to identify weaknesses in the established monitoring programme and to evaluate lines of evidence to assess the degree to which the stated conditions would have unacceptable consequences. The study highlighted several weaknesses in the suggested framework, of which the most critical is the interpretation of the risk hypothesis as a testable null hypothesis. It became clear that cause-effect relationships should be stated as the risk hypothesis, whereas the assessment should evaluate expressed or expected conditions against a risk profile for a given stressor to benefit fully from the risk assessment approach. Changes to the framework terminology were suggested as well as nested feedback loops to allow for iterative processes where new information becomes available. The proposed guidelines incorporate the learning from the case study application as well as feedback from a peer review process. The guidelines incorporate the suggested actions under each phase as well as notes providing the rationale for each step. Three case study outlines were provided to assist users with the interpretation of the guidelines in different applications. The proposed guidelines are applied in an ecological Reserve determination case study, which specified the ecological water quality requirements. The study found that a risk-based approach was followed in the development of the water resource management policy, but the Reserve determination method is generally hazard based, with site specific modifications of the target values being allowed on a conservative basis. The case study highlighted a lack of readiness of water resource managers to accommodate scientific results expressed as probability distributions in support of management decisions. The thesis is concluded with a discussion of the key learning points of the ecological risk assessment development process. The evaluation highlights the move from stating and testing a null hypothesis to stating the risk hypothesis and evaluating the stated conditions against a risk profile. Several implementation challenges are highlighted, with specific recommendations made for adopting the proposed guidelines.

Os estudos de análise de risco ecológico consistem em avaliar as alterações ecológicas ocasionadas pelas diversas atividades antropogênicas a um determinado sistema, tais como aquelas decorrentes da lixiviação de áreas contaminadas, das emissões de efluentes urbanos, industriais e do runoff de áreas agrícolas, entre outras, por meio da integração das informações físicas, químicas e biológicas. A partir dessa análise, o objetivo geral desse estudo foi avaliar as implicações dos impactos antrópicos relacionados com os diferentes usos e ocupações da bacia hidrográfica do Lobo (municípios de Itirapina e Brotas, estado de São Paulo, Brasil) na dinâmica ecológica dos ecossistemas aquáticos lóticos e lênticos, utilizando para tal finalidade a caracterização limnológica dos corpos hídricos e o reconhecimento dos potenciais impactos existentes, para posterior aplicação de uma análise de risco ecológico, com base nas linhas de evidência química, ecotoxicológica e ecológica. Para tanto, foram realizadas coletas em quatro períodos distintos (chuvoso, seco e intermediários), em 14 estações de amostragem (tributários e reservatório), incluindo variáveis bióticas e abióticas, cujos resultados foram avaliados temporal e sazonalmente, permitindo uma abordagem integrada do sistema. Os resultados obtidos no diagnóstico ambiental indicam que as alterações registradas se relacionam com os usos antrópicos da bacia hidrográfica, incluindo a emissão de efluentes domésticos da cidade de Itirapina (SP) e as fontes difusas associadas ao aporte de sedimentos e agroquímicos utilizados nas diferentes culturas estabelecidas na região. Ao analisar os dados da tríade (químicos, ecotoxicológicos e ecológicos) de forma conjunta e quantitativa, os resultados mostraram que na linha de evidência química os riscos foram maiores no reservatório em relação aos tributários, nos quais os riscos foram considerados como baixo e moderado no período seco, em algumas estações de amostragem. Riscos ecotoxicológicos não foram identificados na maioria dos locais amostrados, porém situação inversa foi registrada para os riscos ecológicos em função da influência das variáveis limnológicas. A integração das linhas de evidência mostra diferença sazonal em relação aos períodos seco e chuvoso, com valores de risco mais elevados no período seco, além da associação do risco com a degradação ambiental de cada sistema avaliado. Assim a partir dos resultados obtidos, verifica-se que os impactos na bacia hidrográfica do Lobo são relevantes, necessitando de medidas emergenciais de recuperação e manejo integrado dos ecossistemas terrestres e aquáticos, promovendo a minimização dos efeitos e recuperação das funções ambientais ou serviços ecossistêmicos em curto, médio e longo prazo. / Ecological risk assessment studies are important to assess environmental changes that have been caused by various anthropogenic activities, such as leaching of contaminated areas, input of domestic and industrial sewage, runoff of agricultural areas and other impacts, which are responsible for physical, chemical and biological alterations. In this context, the aim of this study was to evaluate the impact of the anthropogenic activities developed in the Lobo Hydrographic Basin (Itirapina and Brotas, state of São Paulo, Brazil) on the ecological dynamics of lotic and lentic aquatic ecosystems. To attempt it, limnological studies and the evaluation of the potential impacts were carried out before the subsequent application of an ecological risk analysis, which were based on chemical, ecotoxicological and ecological evidence lines. For this purpose, samples were taken in different periods (rainy, dry and intermediate seasons), in 14 sampling stations (tributaries and reservoir), including biotic and abiotic variables in relation to water and sediment, and the results were analyzed space and seasonally. The results obtained suggest that domestic sewage from Itirapina city (São Paulo State), deforestation and diffuse pollution (associated with the accumulation of sediments and agrochemicals used in different cultures established in the region) were the main impacts in the Lobo watershed. The Triad Analysis (based on chemical, ecotoxicological and ecological measures), in addition of the quantitative results from chemical evidence line, indicated that risks were higher in the reservoir in comparison with the tributaries, where the risks were considered low or moderate in dry season in some sampling stations. Ecotoxicological risks were not identified at most of sampled sites, but the inverse situation was registered for ecological risks due to the influence of limnological variables. Seasonal differences between dry and rainy seasons were observed after the integration of all evidence lines, with higher risk values occurring during dry season, in addition to the risk associated with environmental degradation of each ecosystem. From the results, it is possible to conclude that the activities developed in the Lobo Hydrographic Basin have been responsible for several ecological impacts in this system, beside some alterations promoted by climatological events. Also, to prevent more social, economic and ecological negative consequences, some efforts need to be allocated to minimize the impacts, promoting recovery of the environmental functions and ecosystem services in short, medium and long term.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-08-05T15:07:47Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 20160404 Tese final Duarte catalogada formato digital.pdf: 4026733 bytes, checksum: d6ac5259ffcea51116ee53e1ba8c164a (MD5) / Made available in DSpace on 2016-08-05T15:07:47Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 20160404 Tese final Duarte catalogada formato digital.pdf: 4026733 bytes, checksum: d6ac5259ffcea51116ee53e1ba8c164a (MD5) Previous issue date: 2016-03-18 / CNPq / The environment is a complex system where human, ecological environment (e.g., plants, animals, microbes), materials (eg, pollutants, medical), and meteorological/oceanographic conditions interact. The human impact has potential to cause significant damage to the ecological environment (e.g., potential oil spills on the coast cause risk to coastal ecosystems, tuna industrial fishing cause risk to sharks that are bycaught). Similarly, the human impact may turn against the human itself by favoring the growth of populations of unwanted species (e.g., poor sanitation favors the growth of microbial populations that cause risk of an excessive proportion of sick humans). Therefore, it has been demanded an efficient method of quantifying the risks in systems where plant, animals or microbes populations are involved in order to give support to risk management in environmental issues, fisheries management and public health. First, this paper proposes a methodology capable of quantifying ecological risks (i.e., likelihood of adverse effects on the ecosystem, in the long term, due to exposure to stressors such as chemical, fishing, etc.) or microbial risks (i.e., likelihood of adverse effects in humans, in the long term, due to exposure to microbial pathogens). It uses population modeling to simulate future changes in populations of ecologically important species (e.g., fish, corals, sharks), or undesirable (e.g., parasites), under conditional scenarios simulating the influence humans impacting and/or managing the risks. The risk is calculated in terms of probability of extinction or decline, explosion or growth of these populations over time. Second, the methodology is applied to four case studies in Brazil. Each of them have their specific conclusions, as follows. (1) Ecological Risk Assessment caused by potential maritime accidents in the transportation of oil to the port of Suape. Conclusion: low but significant ecological risk. (2) Ecological Risk Assessment caused by potential maritime accidents in the passage of oil tankers nearby Fernando de Noronha. Conclusion: negligible ecological risk, although a more detailed analysis is required due to limited data. (3) Microbial Risk Assessment to Porto de Galinhas community inherent to sanitation and medical treatment program. Conclusion: high microbial risk, the current sanitation level is not enough to contain the spread of schistosomiasis disease, and periodic treatment of patients is not efficient to reduce risks significantly. (4) Ecological Risk Assessment of tuna industrial fishing in Brazilian waters. Conclusion: industrial tuna fishing does not cause significant risks to the population of Mako sharks in the South Atlantic Ocean. In each case study, several conditional scenarios were simulated for the next 100 years, including adverse scenarios and scenarios with risk control measures. Thus, it was possible to quantify the added risk caused by each adverse condition as well as the reduced risk caused by each control measure. In this way, the manager has objective information to prioritize scenarios and evaluate the cost-effectiveness of control measures. The general conclusion of this work is that the proposed methodology has proven to be practicable, useful and efficient. / O meio-ambiente é um sistema complexo onde interagem humanos, meio ecológico (e.g., plantas, animais, micróbios), materiais (e.g., poluentes, medicinais) e condições meteorológicas/oceanográficas. O impacto humano tem potencial para causar danos significativos ao meio ecológico (e.g., potenciais vazamentos de petróleo na costa causam risco ao ecossistema costeiro, pesca industrial de atum causa risco aos tubarões que são pescados por acidente). Similarmente, o impacto humano pode se voltar contra o próprio humano ao favorecer o crescimento de populações de espécies indesejáveis (e.g., saneamento básico precário favorece o crescimento de populações de micróbios que causam risco de haver uma excessiva parcela de humanos doentes). Portanto, tem sido demandado um método eficiente de quantificar os riscos inerentes a sistemas onde populações de plantas, animais ou micróbios estejam envolvidas, de forma a dar suporte para o gerenciamento dos riscos em problemas de gestão ambiental, gestão pesqueira e saúde pública. Em primeiro lugar, este trabalho propõe uma metodologia capaz de quantificar riscos ecológicos (i.e., probabilidade de ocorrência de efeitos adversos no ecossistema, no longo prazo, devido à exposição a estressores como químicos, pesca, entre outros) ou microbianos (i.e., probabilidade de ocorrência de efeitos adversos em humanos, no longo prazo, devido à exposição a patógenos microbianos). Utilizase a modelagem populacional para simular futuras mudanças nas populações de espécies ecologicamente importantes (e.g., peixes, corais), ou indesejáveis (e.g., parasitas), quando condicionadas a cenários que simulam a influência do humano causando impacto e/ou gerindo os riscos. O risco é calculado em termos de probabilidade de extinção ou declínio, explosão ou crescimento, dessas populações ao longo do tempo. Em segundo lugar, aplica-se a metodologia para avaliar o risco inerente a quatro estudos de caso no Brasil. Cada um deles tem sua conclusão específica, como segue. (1) Análise de Risco Ecológico causado por potenciais acidentes marítimos no transporte de petróleo para o porto de Suape. Conclusão: baixo risco ecológico, porém significativo. (2) Análise de Risco Ecológico causado por potenciais acidentes marítimos na passagem de navios petroleiros ao largo de Fernando de Noronha. Conclusão: risco ecológico negligenciável, mas uma análise mais detalhada é necessária devido à escassez de dados. (3) Análise de Risco Microbiano à comunidade de Porto de Galinhas inerentes ao sistema de saneamento básico e programa de tratamento medicinal. Conclusão: alto risco microbiano, o nível de saneamento básico atual não é suficiente para conter a proliferação da doença esquistossomose, e o tratamento periódico de doentes não é eficiente para reduzir os riscos significativamente. (4) Análise de Risco Ecológico causado pela pesca industrial de atum em águas brasileiras. Conclusão: a pesca industrial de atuns não causa riscos significativos à população de tubarões Mako no oceano Atlântico Sul. Em cada estudo de caso, foram simulados diversos cenários condicionais para os próximos 100 anos, incluindo cenários adversos e cenários com medidas de controle dos riscos. Assim, foi possível quantificar a adição do risco causada por cada cenário adverso e a redução do risco causada por cada medida de controle. Desta forma, o gestor tem informação objetiva para priorizar cenários e avaliar o custo-benefício das medidas de controle. A principal conclusão deste trabalho é que a metodologia proposta provou-se ser praticável, útil e eficiente.

A prospective ecological risk assessment method was developed evaluating the cumulative probabilistic impact of chemical stressors to aquatic organisms. This method was developed in response to the need to evaluate the magnitude, duration and episodic nature of chemical stressors on aquatic communities under environmental exposure scenarios. The method generates a probabilistic expression of the percent of an ecosystem's species at risk from a designated chemical exposure scenario.

Pesticide use in rice farming is a common practice in the Mekong Delta and poses ecological risks to aquatic organisms, the environment, and human health. This study focused on the ecological risk assessment of pesticide use in rice farming using the PRIMET model as a decision support tool to evaluate the risks of pesticide exposure, ecotoxicity, and risk characterization, as well as employing the species sensitivity distribution (SSD) assessment model to calculate the potentially affected fraction (PAF) of species based on the computed predicted environmental concentrations (PECs) from PRIMET. The study involved collating and analyzing data on pesticide inventories and the application of 138 farmers, which formed the basis for pesticide use, farming practices,environmental variables, and ecological indicators from two provinces in the Mekong Delta: Dong Thap and Hau Giang. This study showed that pesticide use was high with a wide range of pesticide types. The ecotoxicity assessment indicated that some pesticides pose a potential acute and chronic risk to non-target organisms. The active ingredient identified as posing acute toxicity risk with an ETR >100 is the insecticide indoxacarb, which belongs to the chemical class of oxadiazine of which Arthropods were seen to be highly sensitive to when exposed making them more at risk even at very low concentrations. In contrast, fish generally exhibit moderate tolerance and are sensitive to certain chemicals. The risk characterization revealed that the ecological risks of pesticide use were higher in Dong Thap than in Hau Giang due to differences in ecological conditions, pesticide practices, and farming systems. Overall, this study highlights the need for improved pesticide management practices in rice farming in the Mekong Delta region to reduce ecological risks and protect the environment and human health. The practical and theoretical implications of this study are discussed.

<p> Globally, millions of people rely upon plumbing to help store and deliver safe water to building inhabitants. This water is used for drinking, cooking, washing, appliances, and other activities to protect public health and support economic activity. Water softeners are common devices used to remove minerals from water to limit scale formation in plumbing thereby protecting appliances and improving drinking water taste. Despite tens of millions of these devices in U.S. homes, little is known about how these devices impact chemical drinking water quality. Further, many homes that have softeners have been impacted by disasters such as chemical spills and wildfires and encountered hydrocarbon contaminated drinking water. At present, no information is available about hydrocarbon fate in softeners and how to decontaminate these devices. The objectives of the first chapter were to (1) determine how bench-scale and full-scale water softeners impact drinking water organic carbon, chlorine disinfectant, total cell count, and sulfur concentrations, and (2) assess the softener’s ability to be decontaminated by water flushing after hydrocarbon contamination. The objectives of the second chapter were to (1) better understand the effect wildfires have on private drinking water well infrastructure, water quality, and (2) identify practical research needs. Chapter 1 experiments revealed that both new and aged softener resins leached organic carbon compounds into drinking water, and this prompted notable reductions of drinking water free chlorine disinfectant levels. Newly installed water softeners caused first flushed water to have high levels of organic carbon (934 mg/L) with about 40% particulate organic carbon. Total sulfur concentration was also elevated. After 1 week of use, water softeners caused drinking water to have 4-8 mg/L organic carbon levels. When exposed to hydrocarbon contaminated drinking water, resins absorbed and leached benzene, toluene, ethylbenzene, and total xylenes (BTEX) for more than 2 weeks. Chapter 2 results revealed that for the private drinking water wells sampled after the 2021 Marshall Fire, semi-volatile organic compound (SVOC); No SVOCs exceeded health-based drinking water limits. No volatile organic compounds were found in either shallow or deep wells or within homeowner plumbing. Heavy metals (Li and V) were found in several wells, but these contaminants were not associated with the fire. A private well water system serving 8 properties was damaged, lost pressure, and had not been flushed or repaired 7 months after the fire due to financial and technical challenges. Thesis results provide new knowledge for utilities, health officials, and building owners who desire to better understand commercially available softeners and wildfire damage considerations for private drinking water wells. Results described here can be used to inform communications with homeowners, public health recommendations regarding plumbing safety and water use decisions following suspected or confirmed building chemical contamination and wildfires. </p>

Uncertainty is pervasive in risk assessment. In ecotoxicological risk assessments, it arises from such sources as a lack of data, the simplification and abstraction of complex situations, and ambiguities in assessment endpoints (Burgman 2005; Suter 1993). When evaluating and managing risks, uncertainty needs to be explicitly considered in order to avoid erroneous decisions and to be able to make statements about the confidence that we can place in risk estimates. Although informative, previous approaches to dealing with uncertainty in ecotoxicological modelling have been found to be limited, inconsistent and often based on assumptions that may be false (Ferson & Ginzburg 1996; Suter 1998; Suter et al. 2002; van der Hoeven 2004; van Straalen 2002a; Verdonck et al. 2003a). In this thesis a Generalised Linear Modelling approach is proposed as an alternative, congruous framework for the analysis and prediction of a wide range of ecotoxicological effects. This approach was used to investigate the results of toxicity experiments on the effect of 2,4-Dichlorophenoxyacetic Acid (2,4-D) formulations and 4-Chlorophenol (4-CP, an associated breakdown product) on Daphnia carinata. Differences between frequentist Maximum Likelihood (ML) and Bayesian Markov-Chain Monte-Carlo (MCMC) approaches to statistical reasoning and model estimation were also investigated. These approaches are inferentially disparate and place different emphasis on aleatory and epistemic uncertainty (O'Hagan 2004). Bayesian MCMC and Probability Bounds Analysis methods for propagating uncertainty in risk models are also compared for the first time. For simple models, Bayesian and frequentist approaches to Generalised Linear Model (GLM) estimation were found to produce very similar results when non-informative prior distributions were used for the Bayesian models. Potency estimates and regression parameters were found to be similar for identical models, signifying that Bayesian MCMC techniques are at least a suitable and objective replacement for frequentist ML for the analysis of exposureresponse data. Applications of these techniques demonstrated that Amicide formulations of 2,4-D are more toxic to Daphnia than their unformulated, Technical Acid parent. Different results were obtained from Bayesian MCMC and ML methods when more complex models and data structures were considered. In the analysis of 4-CP toxicity, the treatment of 2 different factors as fixed or random in standard and Mixed-Effect models was found to affect variance estimates to the degree that different conclusions would be drawn from the same model, fit to the same data. Associated discrepancies in the treatment of overdispersion between ML and Bayesian MCMC analyses were also found to affect results. Bayesian MCMC techniques were found to be superior to the ML ones employed for the analysis of complex models because they enabled the correct formulation of hierarchical (nested) datastructures within a binomial logistic GLM. Application of these techniques to the analysis of results from 4-CP toxicity testing on two strains of Daphnia carinata found that between-experiment variability was greater than that within-experiments or between-strains. Perhaps surprisingly, this indicated that long-term laboratory culture had not significantly affected the sensitivity of one strain when compared to cultures of another strain that had recently been established from field populations. The results from this analysis highlighted the need for repetition of experiments, proper model formulation in complex analyses and careful consideration of the effects of pooling data on characterising variability and uncertainty. The GLM framework was used to develop three dimensional surface models of the effects of different length pulse exposures, and subsequent delayed toxicity, of 4-CP on Daphnia. These models described the relationship between exposure duration and intensity (concentration) on toxicity, and were constructed for both pulse and delayed effects. Statistical analysis of these models found that significant delayed effects occurred following the full range of pulse exposure durations, and that both exposure duration and intensity interacted significantly and concurrently with the delayed effect. These results indicated that failure to consider delayed toxicity could lead to significant underestimation of the effects of pulse exposure, and therefore increase uncertainty in risk assessments. A number of new approaches to modelling ecotoxicological risk and to propagating uncertainty were also developed and applied in this thesis. In the first of these, a method for describing and propagating uncertainty in conventional Species Sensitivity Distribution (SSD) models was described. This utilised Probability Bounds Analysis to construct a nonparametric 'probability box' on an SSD based on EC05 estimates and their confidence intervals. Predictions from this uncertain SSD and the confidence interval extrapolation methods described by Aldenberg and colleagues (2000; 2002a) were compared. It was found that the extrapolation techniques underestimated the width of uncertainty (confidence) intervals by 63% and the upper bound by 65%, when compared to the Probability Bounds (P3 Bounds) approach, which was based on actual confidence estimates derived from the original data. An alternative approach to formulating ecotoxicological risk modelling was also proposed and was based on a Binomial GLM. In this formulation, the model is first fit to the available data in order to derive mean and uncertainty estimates for the parameters. This 'uncertain' GLM model is then used to predict the risk of effect from possible or observed exposure distributions. This risk is described as a whole distribution, with a central tendency and uncertainty bounds derived from the original data and the exposure distribution (if this is also 'uncertain'). Bayesian and P-Bounds approaches to propagating uncertainty in this model were compared using an example of the risk of exposure to a hypothetical (uncertain) distribution of 4-CP for the two Daphnia strains studied. This comparison found that the Bayesian and P-Bounds approaches produced very similar mean and uncertainty estimates, with the P-bounds intervals always being wider than the Bayesian ones. This difference is due to the different methods for dealing with dependencies between model parameters by the two approaches, and is confirmation that the P-bounds approach is better suited to situations where data and knowledge are scarce. The advantages of the Bayesian risk assessment and uncertainty propagation method developed are that it allows calculation of the likelihood of any effect occurring, not just the (probability)bounds, and that the same software (WinBugs) and model construction may be used to fit regression models and predict risks simultaneously. The GLM risk modelling approaches developed here are able to explain a wide range of response shapes (including hormesis) and underlying (non-normal) distributions, and do not involve expression of the exposure-response as a probability distribution, hence solving a number of problems found with previous formulations of ecotoxicological risk. The approaches developed can also be easily extended to describe communities, include modifying factors, mixed-effects, population growth, carrying capacity and a range of other variables of interest in ecotoxicological risk assessments. While the lack of data on the toxicological effects of chemicals is the most significant source of uncertainty in ecotoxicological risk assessments today, methods such as those described here can assist by quantifying that uncertainty so that it can be communicated to stakeholders and decision makers. As new information becomes available, these techniques can be used to develop more complex models that will help to bridge the gap between the bioassay and the ecosystem.

The aim of this study was to understand the contribution of Linear Alkylbenzene Sulfonates (LAS) to the decline of Mediterranean coastal forest exposed to marine aerosols. LAS are a group of synthetic anionic surfactants widely used in the composition of household or industrial detergents and agrochemicals. This study was part of a large project (RISICO) aiming the assessment of the environmental impact of the LAS at multiple levels: biodegradation in the coastal waters, sorption – desorption processes in the sediments, toxicity to the aquatic life and toxicity to the coastal forest (by aerosolisation of the sea water). <p>Previous studies pointed out this group of surfactants as the main cause of the coastal forest decline. However, the quantification of this surfactant in the environmental samples (mainly sea water and foliar deposition) was done using non-specific analytical methods as methylene blue active substances (MBAS), leading to overestimation of the environmental concentrations of LAS. <p>The work hypothesis was that at actual environmental concentrations, the LAS does not play a key role in the foliar uptake of the sea salt deposited on the coastal vegetation by the marine aerosols, therefore the LAS may not be the main cause of the coastal forest decline. <p>The research involved both greenhouse experiments and field measurements. The experimental work was conducted on young Mediterranean trees (Laurus nobilis L. Quercus ilex L. and Pinus halepensis P. Mill.) and investigated the synergistic toxic effects of exposure to simulated marine aerosol contaminated with surfactants. An array of endpoints was used including photosynthetic activity, relative water content, foliar deposition and uptake of salt and LAS, and pigments analysis. The results of those experiments revealed that LAS itself did not have phytotoxic effects. Nevertheless, the surfactant was shown to enhance the foliar uptake of the salt in the tested species, especially in Pinus halepensis, confirming the conclusions of previous studies regarding the sensitivity of this species to polluted marine aerosols. <p>The field work was conducted in San Rossore National Park (Italy) and Porquerolles Island (France) and was focused on evaluating the health status of the Mediterranean forest (Quercus ilex L. Pinus halepensis Mill. and Pinus pinaster Aiton.) and also on quantification of LAS in coastal aerosols using highly specific analytical methods, like the mass spectrometry (MS). The frequencies and extent of injuries in the coastal trees were found to be correlated to the salt but not with the LAS content of the leaves. The concentrations of LAS in the Pinus and Quercus leaves were comparable in the two studied sites but the concentrations of salt were extremely high in San Rossore, suggesting that other factors may determine the excessive salt foliar uptake. The parallel MS and MBAS carried out in the same set of aerosol samples revealed that MBAS measurements were not relevant for LAS concentrations in the marine aerosols. Projecting the experimental results to the real LAS and salt exposure of the coastal forest, we concluded that LAS may play a marginal role in coastal vegetation decline. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Surfactants are used in a wide assortment of "down-the-drain" consumer products, yet they are often discharged in wastewater treatment plant effluent into receiving water, potentially causing environmental harm. The objective of this project was to predict surfactant toxic units and in-stream nutrients in the upper Trinity River watershed. Surface and pore water samples were collected in late summer 2005. General chemistries and surfactant toxic units were calculated. GIS models of anthropogenic and natural factors were collected and analyzed according to subwatersheds. Multiple regression analyses using the Maximum R2 improvement method were performed to predict surfactant toxic units and in-stream nutrients using GIS and in-stream values. Both geospatial and in-stream parameters generated multiple regression models for surfactant surface and pore water toxic units, as well as in-stream nutrients, with high R2 values. Thus, GIS and in-stream parameter modeling have the potential to be reliable and inexpensive method of predicting surfactant toxic units and nutrient loading in the upper Trinity River watershed.

Studies in the USA have reported that species of meiobenthic copepods can be used as bioindicators of sediment-associated contaminants. The main objective of this research project was to develop and validate methods to assess the effects of estuarine pollution, using the marine benthic copepod Robertsonia propinqua as a bioindicator of environmental health in New Zealand intertidal / estuarine areas. Cultures of R. propinqua were set up and maintained in the laboratory and individuals used in 96h acute and full life-cycle chronic bioassays using the pre-selected contaminants atrazine and zinc sulphate. From the 96h acute experiments it was found that the lethal doses at which 50% mortality occurred (LC50) for exposed nauplii and adult individuals were 7.5 mg/L and 31.8 mg/L, respectively for atrazine and 1.7 mg/L and 2.7 mg/L, respectively for zinc sulphate. This indicated that the nauplii life stage was more sensitive than were the adult life stages for exposure to both contaminants. Based on the 'trigger' values reported (atrazine = 0.013 mg/L, zinc = 0.015 mg/L) in the Australian and New Zealand guidelines for fresh and marine water quality, which provide values at which concentrations of contaminants can occur in the environment before they begin causing effects on aquatic fauna, it is unlikely that the calculated LC50s in the current research will induce biological effects in exposed copepods in the short-term. The calculated LC50 results were then used to further investigate the effects of chronic exposure of sediment-associated contaminants on the complete life-cycle (egg-reproductive adult) of R. propinqua. In a laboratory-based full life-cycle toxicity test, field-collected sediments from polluted sites in the Auckland and Bay of Plenty regions reduced reproductive output (nauplii and copepodite production) of R. propinqua individuals, but the number of males and females, gravid females, clutch size per female and the number of eggs produced were not affected by either the polluted or non-polluted (reference) sediment samples from both field regions. Field investigations of meiofauna community composition in polluted and non-polluted field sites were carried out in 2004 in the Auckland and Bay of Plenty field regions in New Zealand. Greater sediment organic content and a correspondingly deeper redox potential discontinuity layer occurred in all polluted field sites compared with the non-polluted sites. However, species composition could not be used to characterise polluted and non-polluted sites, as there were no dominant taxa which were representative of these sites. The results presented in this thesis indicate that R. propinqua has strong potential to be a good candidate species as a bioindicator of environmental contamination. Furthermore, the full life-cycle toxicity test could be used as a rapid test to detect immediate changes in individual reproduction and development as well as long-term population effects. The technologies developed as part of this research may eventually provide additional tools for commercial environmental consultancies and may compliment existing standard operating procedures for environmental assessments involving pollution of estuarine ecosystems.