Although many commercial chemicals can dissociate, the study of the biological and environmental fate of ionogenic organic chemicals (IOCs) is still in its infancy. Uptake of the veterinary drug diclofenac in vultures and cattle was successfully simulated with a newly developed physiologically-based pharmacokinetic model for IOCs, lending credence to diclofenac’s proposed role in South Asian vulture population declines. Proteins and phospholipids rather than total lipids control the tissue distribution of diclofenac. A method was developed to simultaneously extract neutral and acidic pesticides and benzotriazoles from water samples with recoveries ranging 70-100%. This method was applied to samples from a laboratory calibration experiment of the Polar Organic Chemical Integrative Sampler. The sampler had higher uptake for neutral and acidic pesticides when filled with triphasic sorbent admixture and OASIS MAS sorbent, respectively. While either sorbent can also be applied for methylated benzotriazoles, neither is capable of quantitatively sampling all three compound groups.

This research focuses on the development, evaluation, and application of a mercury (Hg) mass balance model for predicting the accumulation of Hg in fish. This model requires accurate estimates of Hg elimination rate by fish and feeding rates to adequately predict Hg concentration in fish. An empirical model was developed to estimate Hg elimination by fish using data obtained from published experiments. This analysis showed that Hg elimination rate was overestimated in short-term experiments, positively correlated to water temperature, negatively correlated to body size, and that the elimination rate of inorganic Hg was faster than that of methylmercury. This empirical model was then incorporated in a Hg mass balance model to predict the concentration of Hg in fish. The Hg mass balance model accurately predicted Hg concentration in fish when it was combined with food consumption rates that were determined using a radioisotopic method. This analysis suggested that the parameters of the Hg mass balance model were adequate for predicting Hg concentration in fish. I also showed that Hg concentration tended to be underestimated by the Hg mass balance model when it was combined with feeding rates determined with a laboratory-derived bioenergetic model, probably because activity costs derived in the laboratory do not reflect activity costs of fish in the field. Beside predicting Hg concentration in fish, I showed that this mass balance model could also be used to estimate feeding rates of fish in the field by measuring the concentration of Hg in fish. This approach was validated using data obtained from a published experiment. It was also successfully tested using independent estimates of feeding rates obtained with a radioisotopic method. I applied this Hg mass balance model to compare the energy budget of sympatric populations of dwarf and normal whitefish (Coregonus clupeaformis). This analysis showed that dwarf whitefish consumed 40--50% more food than normal whitefi

Thèse (D. en sciences de l'environnement)--Université du Québec à Montréal, 2005. / En tête du titre: Université du Québec à Montréal. Comprend des réf. bibliogr. Publié aussi en version électronique.

Submitted by RUTH HELENA GIANSANTE null (ruthhgster@gmail.com) on 2018-04-03T13:04:19Z No. of bitstreams: 1 RUTH_GIANSANTE_DISS_versão final (20DEZ2017) (5)6.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-04-03T18:23:48Z (GMT) No. of bitstreams: 1 giansante_rh_me_jabo.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5) / Made available in DSpace on 2018-04-03T18:23:48Z (GMT). No. of bitstreams: 1 giansante_rh_me_jabo.pdf: 858614 bytes, checksum: 2838c4b704bfcc265b052ef9b29dcb67 (MD5) Previous issue date: 2017-11-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Rizobactérias são excelentes candidatas à aplicação em processos de bioacumulação de elementos potencialmente tóxicos, pois desenvolveram mecanismos para a incorporação intracelular de uma ampla gama de íons. A sensibilidade e a capacidade de remoção de cádmio (Cd2+) de duas espécies de rizobactérias: Rizobium tropici (LBMP-C01) e Ensifer meliloti (LBMPC02), foram estudadas. A concentração mínima inibitória (CMI) das bactérias foi determinada pelo cultivo em meio contendo CdCl2.2H2O (0,025 a 4 mmol L-1). Foram realizados testes de viabilidade das células das duas estirpes na CMI e ensaios de bioacumulação com suspensões de células bacterianas nas doses de 10, 20 e 30 %(v/v) em solução contendo 100 mg L-1 de Cd2+. As estirpes LBMP-C01 e LBMP-C02 foram sensíveis a concentrações de Cd2+ superiores a 1,0 e 0,05 mmol L-1, respectivamente. As células de LBMP-C01 e LBMP-C02 apresentaram-se viáveis nas CMI 1,0 e 0,05 mmol L-1 Cd2+, respectivamente. A estirpe LBMP-C01 não removeu Cd2+ nos ensaios de bioacumulação e a estirpe LBMP-C02 foi capaz de remover 80 % deste íon em solução contendo 100 mg L-1 Cd2+, após 72 h de contato e 30 %(v/v) do bioacumulador. Os espectros de absorção molecular na região do infravermelho, de ambas as espécies estudadas praticamente não indicaram diferenças nos grupos funcionais presentes nas moléculas da biomassa celular. A observação por microscopia eletrônica de transmissão mostrou a presença de maior número de grânulos eletrodensos no citoplasma da estirpe de LBMP-C02 em relação à LBMP-C01 quando estas foram cultivadas com Cd2+. A estirpe LBMP-C02 foi a mais eficiente na remoção de Cd2+. A resistência a metais dessas duas bactérias envolve mecanismos diferentes. / Rhizobacteria are excellent candidates for use in the processes of bioaccumulation of potentially toxic elements because they have developed mechanisms for the intracellular uptake of a wide range of ions. Here, the sensitivity and capacity to remove cadmium (Cd2+) of two species of rhizobacteria, Rhizobium tropici (LBMP-C01) and Ensifer meliloti (LBMP-C02), were studied. The minimum inhibitory concentration (MIC) of the bacteria was determined by culturing them in medium containing CdCl2·2H2O (0.025 to 4 mmol L-1 ). Cell viability tests of the two strains were performed at MIC, and bioaccumulation assays were performed with 10, 20, and 30 %(v/v) bacterial cell suspensions in a Cd2+ solution 100 mg L-1 . Strains LBMP-C01 and LBMP-C02 were sensitive to Cd2+ concentrations above 1.0 and 0.05 mmol L-1 , respectively. LBMP-C01 and LBMP-C02 cells were viable at the MICs of Cd2+ solution 1.0 and 0.05 mmol L-1 , respectively. LBMP-C01 did not remove Cd2+ in the bioaccumulation assays, whereas LBMP-C02 removed 80 % of this ion in Cd2+ solution 100 mg L-1 , after 72 h of contact and 30 %(v/v) of the bioaccumulator. The infrared absorption spectra of both species did not indicate differences in the functional groups present in the molecules of the cell biomass. Transmission electron microscopy showed the presence of a larger number of electron-dense granules in the cytoplasm of LBMP-C02 compared to LBMP-C01 when they were cultured with Cd2+. The LBMP-C02 strain was the most efficient in the Cd2+ removal. The metal resistance of these two bacteria involves different mechanisms.

Bitumen extraction in the Athabasca oil sands in Alberta releases metals to the region. In this study, I performed an uptake-elimination experiment with wood frog tadpoles (Lithobates sylvaticus) to determine the bioaccumulation potential of metals from exposure to MacKay River sediment, an area affected by oil sands contamination, and to uncontaminated reference sediment. Wood frog tadpoles, Gosner stages 28-32, were exposed to two sediments: (1) MacKay River sediment that is enriched in petrogenic hydrocarbons from natural and anthropogenic sources; and (2) an uncontaminated reference sediment. Tadpole exposures to sediments lasted 4 days, followed by a depuration phase for an additional 4 days where tadpoles were allowed to eliminate excess metals from their bodies. The metal concentrations at various time points during the uptake and elimination phases were determined in order to define toxicokinetic parameters, such as uptake and elimination first order rate constants, accumulation by ingestion, and assimilation efficiencies for specific metals. It was determined that tadpoles exposed to the MacKay sediment had higher concentrations of Al, Co, Cu, Cr, Mg, Ni, Pb, V, and Zn throughout the uptake phase of the study compared to tadpoles exposed to reference sediment. We also observed little to no decrease in concentrations of Al, Co, Cu, Cr, Mg, Ni, Pb, V, and Zn throughout the elimination phase of the study. In addition, biota-sediment accumulation factors (BSAF) revealed that Cu, Zn, Cr, and V had among the highest bioaccumulation potential in our trials. The experiment was subsequently repeated by preventing direct contact of the tadpoles to sediment with a screen, exposing tadpoles only to metals in water. By comparing tadpole exposures to metals from ‘aqueous’ and ‘aqueous +sediment’ in separate trials, and by tracking sediment ingestion rates, I am able to show that sediment ingestion constitutes the primary source of metal bioaccumulation by tadpoles. Not only were metal concentrations higher in tadpoles that were ingesting sediment, but they also had greater metal uptake rates compared to tadpoles that were only exposed to contaminated water. It was also determined that assimilation efficiencies were higher in tadpoles exposed to reference sediment compared to ones exposed to MacKay River sediment. Using toxicokinetic parameters defined by the uptake-elimination experiment, I developed a computational model using STELLATM system dynamics software to accurately estimate first order uptake and depuration rate constants for metals in exposed aquatic animals. The model estimated metal uptake and depuration kinetics with a mean relative error of 2.25 ± 0.93 % (±SE, n=9) for the uptake study and 2.53 ± 2.61 % (±SE, n=9) for the depuration study. With increased oil-sands production anticipated, we recommend continued monitoring of contaminants from oil-sands for the purpose of understanding the potential risks they may have on northern Alberta’s ecosystems.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2011. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-12-15T09:45:05Z No. of bitstreams: 1 Janice Goris Garcia.pdf: 702089 bytes, checksum: 1220229f5c1f2087c00596bdbd146af8 (MD5) / Approved for entry into archive by cristiane soares (krikasoares@live.com) on 2013-12-18T17:44:26Z (GMT) No. of bitstreams: 1 Janice Goris Garcia.pdf: 702089 bytes, checksum: 1220229f5c1f2087c00596bdbd146af8 (MD5) / Made available in DSpace on 2013-12-18T17:44:26Z (GMT). No. of bitstreams: 1 Janice Goris Garcia.pdf: 702089 bytes, checksum: 1220229f5c1f2087c00596bdbd146af8 (MD5) Previous issue date: 2011 / Neste trabalho teores de elementos traço As, Cd, Cu, Cr, Fe, Mn, Pb, Ni e Zn foram determinados no camarão-rosa Farfantepenaeus paulensis, no cirripédio Balanus improvisus e no mexilhão Perna perna, coletados entre os anos de 2006 e 2010 no estuário da Lagoa dos Patos. Os resultados foram avaliados em função das variações hidrológicas interanuais ocorridas neste estuário e da comparação com resultados anteriores de trabalhos desenvolvidos com estas espécies neste estuário. As cracas inteiras analisadas mostraram-se adequadas ao monitoramento de As, Cd, Pb e Mn, cujos teores relacionaram-se positivamente às concentrações da água estuarina e inversamente à salinidade. Da mesma forma, os mexilhões juvenis apresentaram maiores concentrações de As, Cd, Cr, Pb, Mn e Zn quando o estuário apresentava-se sob condições menos salinas, exibindo o mesmo comportamento destes metais na água. Já os teores de cobre nesses organismos estiveram associados de forma direta à salinidade do estuário. As maiores concentrações de alguns metais nos mexilhões e cracas amostrados no Farol da Conceição, local sem aporte antrópico direto, com relação à região portuária, podem estar relacionadas a um maior aporte de água subterrânea na região de praia. Os resultados obtidos na região do Farol podem ser usados na comparação qualitativa das flutuações de concentrações de metais ocorrentes na região portuária. A análise do camarão inteiro refletiu melhor as condições ambientais do que a fração limpa, com teores de As, Mn, Pb relacionados inversamente à salinidade e teores de cobre relacionados de forma direta a essa variável. A avaliação temporal de metais acumulados nos organismos mostrou uma redução das concentrações da maioria dos elementos analisados, sendo observado um aumento somente nas concentrações de Cd e Zn com relação ao estudo realizado, em mexilhões,há 10 anos, o que também foi observado para o Cd e Pb nas cracas. A avaliação sanitária dos teores de metais em mexilhões e camarões indicou teores de As, Cr e Cu acima dos limites máximos permitidos pela legislação, indicando a relevância da continuidade do estudo da acumulação de elementos por esses organismos para a identificação de possíveis fontes de contaminação. Soma-se a isso a necessidade de se obter um conhecimento mais aprofundado da variabilidade das concentrações metálicas associadas a aportes continentais e a variações biogeoquímicas do estuário e, sobretudo discernir as frações naturais das antrópicas. / In this study concentrations of trace elements As, Cd, Cu, Cr, Fe, Mn, Pb, Ni and Zn were analyzed in the pink shrimp, barnacles Balanus improvisus and in the mussel Perna perna, sampled between 2006 and 2010 in the Patos Lagoon estuary. The results were evaluated in terms of interannual hydrological variations occurred in this estuary and by comparison with previous data from studies with these species in this estuary. Barnacles total assessed presented to be suitable for monitoring of As, Cd, Pb and Mn, which levels have been correlated positively with concentrations of estuarine water and inversely related to salinity. Likewise, the juvenile mussels showed higher concentrations of As, Cd, Cr, Pb, Mn and Zn when the estuary is presented under less saline conditions, exhibiting the same behavior of these metals in the water. In contrast, the Cu in these organisms was associated directly with salinity of the estuary. The highest concentrations of some metals in mussels and barnacles sampled in Conceição Lighthouse, place whithout direct anthropogenic contribution, in relation with the port region, it may be related to a major input of groundwater in the coastal area. The data from the region of the Conceição lighthouse can be used in the qualitative comparison of the fluctuations of metal concentrations occurring in the port area. The analysis of whole shrimp reflect better the environmental conditions of the edible part, showed concentrations of As, Mn, Pb inversely related to salinity and concentration of Cu directly related to this variable. Temporal evaluation of metals accumulated in organisms showed a reduction in the concentrations of most elements analyzed. It has been observed an increase only in the concentrations of Cd and Zn in mussels and of Pb in barnacles, compared to the study conducted 10 years ago. The health assessment of the metal levels in mussels and shrimp showed concentrations of As, Cr and Cu exceeded the maximum allowed by law, indicating the relevance of studies related to element accumulation by these organisms in order to identify possible sources of contamination. Furthermore it is necessary to get a deeper understanding of the variability of metal concentrations associated with continental inputs and biogeochemical changes in the estuary and, especially, to discern the nature fraction to the anthropogenic one.

O crescente desenvolvimento populacional, industrial e a expansão agrícola vêm contribuindo de forma significativa para o aporte de nutrientes e metais nos ecossistemas aquáticos, interferindo na composição e estrutura das comunidades, dentre elas as macrófitas, ocasionando desequilíbrio ambiental, com perda das funções e serviços ecossistêmicos. Entre os diversos elementos inseridos de forma direta e indireta nos corpos hídricos, destacam-se fósforo, cobre e zinco, os quais, apesar de serem fundamentais para o metabolismo biológico, quando em excesso tornam-se prejudiciais, requerendo avaliações mais efetivas, de forma a melhor compreender e prevenir os potenciais riscos da exposição biológica a estes elementos estressores. Considerando o acima exposto, o objetivo da presente pesquisa foi avaliar o efeito do metal cobre sobre o desenvolvimento da macrófita Pistia stratiotes e o efeito dos metais cobre e zinco sobre o desenvolvimento e capacidade bioacumuladora da macrófita Azolla filiculoides, em diferentes concentrações de fósforo, por meio de testes ecotoxicológicos. Para tanto, aspectos nutricionais (nitrogênio, fósforo, cobre total e clorofila a e total) e de desenvolvimento (biomassa, TCR, número de folhas nascidas, ganho de diâmetro, altura e largura foliar, número de raízes nascidas, comprimento das raízes principais, clorose e necrose foliar) foram avaliados em estudos laboratoriais para P. stratiotes e aspectos nutricionais (todos acima citados) e de desenvolvimento (biomassa e TCR) para A. filiculoides. Pelos resultados obtidos verifica-se que os metais cobre e zinco, nas concentrações testadas, ocasionaram interferência no desenvolvimento e nutrição das macrófitas, sendo a maior sensibilidade ao cobre observada para P. stratiotes, registrando-se efeitos de maior toxicidade do cobre em relação ao zinco em ambas as macrófitas. Verificou-se, ainda, que o fósforo proporcionou maior proteção a A. filiculoides contra o efeito dos metais conforme o aumento de sua concentração e já no teste ecotoxicológico com P. stratiotes não foram registradas diferenças significativas em função do aumento das concentrações de fósforo. Dessa maneira, conclui-se que o metal cobre causou maior toxicidade às macrófitas do que o zinco, principalmente em concentrações mais baixas de fósforo, verificando-se maior capacidade bioacumuladora da espécie A. filiculoides quando comparada com P. stratiotes. / The increasing population and industrial growth and the agricultural expansion have contributed significantly to the supply of nutrients and metals in aquatic ecosystems, affecting the composition and structure of communities, among them the macrophytes, causing environmental imbalance, with loss of ecosystem functions and services. Among the various elements inserted directly and indirectly on water bodies, phosphorus, copper and zinc stand out, which, despite being fundamental to the biological metabolism, when in excess become harmful, and assessments that are more effective are required to better understand and prevent the potential risks of biological exposure to these stressors. Considering the above, the objective of this research was to evaluate the effect of copper metal on the development of the macrophyte Pistia stratiotes and the effect of copper and zinc metals on the development and the bioaccumulation capacity of the macrophyte Azolla filiculoides, in different concentrations of phosphorus, through ecotoxicological tests. To do that, nutritional (nitrogen, phosphorus, copper total and chlorophyll a and total) and development (biomass, RGR, number of leafs born, diameter gain, leaf height and width, number of roots born, length of the main roots, leaf chlorosis and necrosis) aspects were evaluated in laboratory studies for P. stratiotes and nutritional (all above) and development (biomass and RGR) aspects for A. filiculoides. From the results obtained it appears that the metals copper and zinc, on the tested concentrations, caused interference in the development and nutrition of the macrophytes, where more sensitivity to copper was observed for P. stratiotes, and the effects of enhanced toxicity of copper relative to zinc in both macrophytes. It was also found that the phosphorus provided greater protection to A. filiculoides against the effects of metals as its concentration was increased and, on the ecotoxicological test with P. stratiotes, no significant differences where found with the increasing concentrations of phosphorus. Thus, it is concluded that the copper metal has caused more toxicity to macrophytes than zinc, especially at lower concentrations of phosphorus, and was verified a greater bioaccumulation capacity on the A. filiculoides species when compared to P. stratiotes.

M.Sc. / The increasing demand for water in South Africa arises from a rapid population growth and supporting industrial development. This demand has to be met from limited water resources that are shared by competing user groups and neighbouring states. Deteriorating water quality further limits the sustainable use of water through point and diffuse source pollution of macro constituents, metals and biocides. Metals in the environment can originate as point sources, including industrial and mining effluent, or diffuse sources from geological origin, agricultural activities, acid mine draining and leachate from dumps. Biocides increase crop yields, protect forests and control vectors of serious human disease, but are in the process also carried to water courses. Bioaccumulation studies have been identified as a method to monitor pollutants in the environment. The analyses of data from bioaccumulation studies share a common problem in having to deal with many independent variables, for example variations in time and space, environmental conditions and biological parameters. The objectives of this study were to; investigate the metal levels in water and metal and biocide bioaccumulation in fish tissues from the Berg, Luvuvhu, Olifants and Sabie Rivers; develop a procedure to predict areas and biocides at risk of causing diffuse source pollution and; evaluate the available data and procedures to propose more efficient and cost effective bioaccumulation programmes. The investigation evaluated current and potential contamination of the selected catchments and identified research needs. Fish tissues and water grab samples were collected in the Berg, Luvuvhu, Olifants and Sabie Rivers. The samples were tested for physical variables and analysed for macro constituents and metal levels according to standard analytical procedures. Fish were caught (gill and seine nets) and larger specimens were selected for tissue analyses. Species were identified and standard length, mass, gender, gonadotrophic development index and age indicators were collected. Standard procedures were used to analyse fish tissues for metal levels with the atomic absorption spectrophotometer (AAS) and biocide levels with gas chromatographic methods. A flow diagram of a statistical methodology was developed to incorporate the effects of all biological parameters in the analyses of bioaccumulation data. The procedures used to calculate human health risks are that of the Risk Assistant package reviewed by the United States Environmental Protection Agency (EPA). A Geographical Information System (GIS) model was developed, incorporating the factors affecting runoff of surface water and biocides, to predict areas and variables that could cause diffuse source pollution. The pH values of the rivers studied ranged from of 7.2 to 8.7 except for the Klipspruit River before its confluence with the Olifants River that had a pH of 4.8. Nutrient levels in the Berg River are within the South African guidelines. Nutrients in the Luvuvhu River mostly exceed the guideline values for ortho-phosphate, ammonia nitrogen, nitrate nitrogen and total phosphorus. In the Olifants River the values for ortho-phosphate, total phosphorus, ammonia nitrogen and nitrate and nitrite nitrogen often exceed the South African guideline values. Nutrients in the Sabie River have low concentrations with only ammonia nitrogen exceeding the guideline values. TDS values in the Olifants River is the highest, which is an indication of the high salt loads in the river. The concentrations of various metals in water from the Berg, Luvuvhu, Sabie and Olifants Rivers exceeded the proposed South African and international guidelines.

M.Sc. / During the last decade, Cape Wagtails (Motacilla capensis) have been observed with several forms of feet abnormalities, such as missing toes and clubbed feet. The aim of this research was to find the reason for these abnormalities. The initial hypothesis was that ‘Feet abnormalities in the Cape Wagtail (M. capensis) are caused by the internal action of contaminants (e.g. pesticides and metals) through direct contact and/or secondary poisoning’. Wagtails were caught with mist nets and/or ground traps depending on the area and accessibility of the sampling sites. Wagtails with feet abnormalities, as well as those without, were caught at six localities around South Africa. Indicators of pollutant exposure and effect were studied. The bioaccumulation of certain metals (measures of exposure) in the feathers such as aluminium (Al), arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), Pb, nickel (Ni), manganese (Mn), silver (Ag), strontium (Sr) and zinc (Zn) and Al, As, calcium (Ca), Cd, Cr, Co, Cu, Fe, Pb, Ni, Mn, Ag and Zn in the blood plasma were analyzed on the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Biomarker testing (measures of effect) was carried out in the blood such as acetylcholinesterase (AChE) which tested for nerve transmission inhibition, ä-aminolevulinic acid dehydratase (ALA-D) which tested for lead (Pb) bioaccumulation, catalase (CAT) which tested for the invasion of oxyradicles and oxidative stress and DNA damage which tested for DNA band length alteration caused by stress due to xenobiotics. Biomarker outcomes and metal analysis results were carried out on a site comparison basis. Acetylcholinesterase, ALA-D and DNA damage were found not to be linked to the occurrence of feet deformities at these sites. However, CAT revealed stress at all the sites which may have indicated the presence of a stress (or stresses) which could have been caused by feet abnormalities or other factors. A non-metric multidimensional scaling graph (NMDS) ordination suggested that biomarkers were not grouped according to sites that had affected birds and those that did not, but were rather assorted. Consequently, few real differences in biomarker responses were noted between healthy and affected birds. Catalase enzyme activity and DNA damage were suggested to be indicative of feet abnormalities although results were not convincing. Secunda displayed the highest concentrations of metals in the feathers when compared to the other sites. Most metals were higher than reference values for contaminated areas and recent South Africanreported concentrations. Almost all of the metals tested at each site exceeded the Ecological Quality iii Objectives (EcoQOs) for metals in bird feathers, based on Weavers (Ploceus sp.) in the Gauteng region. Zinc levels at all the sites posed some concern. Chromium and Ni were suspected to possibly trigger feet and toe abnormalities in Cape Wagtails. Levels of various metals in the plasma were higher at sites that had no deformities. This suggested that these metal concentrations did not cause or influence feet or toe deformities. Calcium levels were found to be lower at sites with affected birds which indicated that the deformities may perhaps be caused by decreased Ca concentrations. Metal concentrations were higher than the uncontaminated reference levels, but were lower than contaminated site reference values. / Prof. V. Wepener

No description available.