<p>This study forms part of a broader project co-funded by the Water Research Commission (WRC), and CSIR Parliamentary Grant (PG) and Strategic Research Panel (SRP) research grants, aimed at surveying selected water resources within the 19 Water Management Areas in South Africa. Furthermore, it aims at determining the concentrations of Hg and MeHg in various environmental compartments collected from priority water resources, to identify the potential Hg hotspots, and to assess the degree of compliance with national and international guidelines. Mercury concentrations in the environment have increased globally and this has caused much anxiety in terms of the adverse effects it has on aquatic ecosystems, their organisms, and the communities they sustain. Human health risks associated with the consumption of fish elevated containing Hg concentrations have received minimal attention particularly in South Africa. It is imperative that any potential adverse impacts of Hg on aquatic ecosystems, and the subsequent impacts on human health, be investigated.</p>

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Approximately 10,000 tones of Hg are deposited annually as a result of anthropogenic activities. This increased Hg burden is known to have adverse neurological and reproductive effects on Common loons. A positive correlation between mercury (Hg) and selenium (Se) has been reported to exist in marine mammals and various species of marine and aquatic piscivorous birds. It has been hypothesized that the Hg/Se interactions may involve in the multiple mechanisms of Hg detoxification. This study focused on the suggested Hg/Se complex that forms in association with specific proteins. Specifically, this project focuses on the nature of these interactions in different tissues from wild Common loons (Gavia immer) that have been collected by the Canadian Wildlife Service. The Hg and Se concentrations in the various tissues were quantified using AAS. MALDI-TOF-MS and protein sequencing characterized the nature of the Hg/Se complex binding protein. Among the tissues, the liver had the highest concentrations of Hg and Se followed by kidney; muscle and brain. A strong association between Hg and Se was found in liver, kidney and eggs whereas there was no association in muscle and brain. In contrast brain and muscle had highest percentage of organic Hg suggesting that only inorganic Hg is associated with Se. Two Hg-Se binding protein complexes were found in liver both in the 15,200-15,300 Da range while one such complex in the same weight range was found in kidneys, when sequenced it was found that these proteins were the alpha A chain of Hemoglobin. The protein complex found in eggs was unique and although it was impossible to fully sequence it, it represents an unknown protein. The role of Se in Hg toxicity in eggs warrants further study.

Mercury is one of the most serious heavy metal pollution sources that threaten people’s health. For decades, people have developed many technologies and materials to capture mercury from flue gas of coal-fired plant. Currently, the most effective material for mercury absorption is powdered activated carbon, which shows increased efficiency when modified with halogen functional groups such as bromine. Metal-organic frameworks (MOFs) have potential applications in mercury capture due to their fantastic properties such as high porosity and high thermal stability. More important, their pore sizes and topology structures can be controlled through choosing different organic ligands in the syntheses. However, their mercury removal properties have not been studied so far. In this project, mercury absorption properties of selected known porous MOFs were studied, and the syntheses of new porous MOFs with functional groups for mercury absorption were investigated. Three known porous MOFs for mercury sorption properties were investigated. One of these MOFs, compound 3 shows a total efficiency greater than 90% in laboratory scale tests. Moreover, three new MOFs: [Cu(Br2BDC)2](HTEA)2 ， [Co2(BrBDC)(HCOO)2(DMF)2] and Zn2(BrBDC)(Trz)2•3H2O, (BrBDC = 2,5- dibromoterepthalicate, DMF =dimethylformamide, TEA = trimethylamine, Trz=1,2,4-triazole) were synthesized successfully. The first two compounds have two-dimensional structures, while the last compound contains three-dimensional channels with opening over 4.7 Å.

Guld är ett grundämne och den bästa elektriska ledaren i tekniska apparater. Denna studie utvärderar vilka effekter guldbrytningen har på människors hälsa och miljö. Studien behandlar tre länder och hur de har påverkats av guldföretagen som opererar i respektive land. Det har framkommit att cyanid och kvicksilver har förödande effekter för människors hälsa i både Peru och Kongo. Problemet är att arbetsnormer och säkerhetsrutiner inte efterlevs. Sjukdomar som drabbat folk i Peru är bl.a. förlamning, leukemi, huvudvärk, utslag med mera. Dessa sjukdomar orsakades av en kvicksilverolycka. I Kongo utsätts arbetarna dagligen för kontakt med kvicksilver. Mark, vattendrag och grundvatten har blivit påverkade cyanid och kvicksilver. Gruvan i Sverige använder sig istället av kemikalien danafloat507 som är biologiskt nedbrytbar. Den kalkrika avfallsprodukten har haft positiv effekt på fisk och växter i det omgivande vattendrag. / Gold is a chemical element and the best electrical conductor in technological devices. This study shows the impact that gold mining has on health and the environment. The study addresses three countries and how they have been affected by gold companies operating in each country. It has turned out that cyanide and mercury have devastating effects on the health of humans in both Peru and Congo. The problem is that labor standards and safety procedures are not adhered to. Diseases affecting people in Peru are paralysis, leukemia, headaches, rashes etc. This was due to a mercury accident. In Congo workers are daily exposed to mercury.  Soil, rivers and groundwater has been affected by cyanide and mercury. A goldmine in Sweden is instead using danafloat507 a chemical that is biodegradable. The water from the mine is hence rich in lime and it has a positive effect on fish and plants.

Mercury (Hg) is a global pollutant, yet Hg biomagnification, the increase in Hg with trophic level, remains poorly characterized in many regions, especially at subtropical latitudes. The present study assessed subtropical reservoirs of eastern China, which provided an opportunity to quantify Hg biomagnification under highly altered conditions that included high atmospheric Hg deposition, use of reservoirs for fisheries, manipulation of food webs through stocking and high fishing pressure, and increasing eutrophication. Despite China’s Hg emission and deposition rates that are among the highest worldwide, low fish Hg concentrations and Hg biomagnification rates were found; this was explained by food web structure and fish species characteristics. Stocked species occupied lower trophic levels and had significantly lower Hg concentrations relative to wild fishes. Evidence of decreased Hg concentrations with eutrophication (as indicated by chlorophyll-a) was observed, suggesting algal biodilution and/or somatic growth dilution. Relative to temperate lakes, zooplankton density dilution may also be causing reduced Hg concentrations in subtropical biota. Hydrogeomorphic features, such as water retention time and percent crop cover, explained Hg bioaccumulation factors and Hg concentrations at the base of the food web. Eutrophication and hydrogeomorphic features also influenced the bioavailability of selenium, which can protect against the toxicity of Hg at adequate concentrations, and the concentration of eicosapentaenoic acid, a beneficial fatty acid, in the planktivorous Bighead Carp (Hypophthalmichthys nobilis). This may indicate that the risk of exposure to the neurotoxicant methylmercury relative to benefits of fish consumption may increase with eutrophication in some fish species. Overall, the findings of this study suggest food web structure, eutrophication, and hydrogeomorphic features together explain low Hg concentrations in anthropogenically modified subtropical reservoirs in eastern China. / Thesis (Ph.D, Biology) -- Queen's University, 2014-07-01 11:35:12.637

Consumption of mercury in fish in the human diet can cause developmental damage in fetuses and young children, cardiac infarction and infertility in adult men, and neurological damage in people in general. British Columbia does not have fish consumption advisories for sport-caught fish and province-wide testing of fish-mercury levels has not been conducted. Yet preliminary tests show that certain sport-caught fish have mercury concentrations above Health Canada guideline for normal consumption by the general population. Government officials are aware of the potential health damage from mercury in sport-fish from BC. and preliminary research into the necessity of policy to protect fish consumers is being conducted. But, the research required to ground the policy making process has not been done. There is a need for an assessment of the necessity, feasibility. and strategies for creating and disseminating freshwater fish consumption advisories in British Columbia. The objective of this project was to provide sound scientific research as part of the basis of policy development. I aimed to do this by evaluating what can be learned from a range of fish consumption policies in Canada and elsewhere to guide effective policy creation in BC, if it is deemed necessary. In addition, I assessed whether or not fish consumption advisories would be necessary to protect public health among a sport-fishing population on Elk Lake. Vancouver Island. by evaluating fish consumption, the state of mercury knowledge among these fishers (current awareness), how mercury information reaches them (information flow), and how they use this information to make decisions about their diet (personal diet management). I analyzed provincial strategies for the creation, implementation. and dissemination of fish consumption advisories and provided recommendations for BC. I advise that BC conduct one large-scale. province wide fish-mercury survey to ascertain if mercury levels are high enough to cause health concerns. If levels are above 0.5 ppm, guidelines should be instituted and advisories communicated using the Health Canada Tolerable Daily Intake levels. Stakeholder participation is required throughout the process to increase advisory and policy efficacy. I provide recommendations for contents and format of advisories. I designed and conducted a survey to obtain demographic information. fish consumption behavior, sources of health information. and levels of concern and knowledge regarding mercury, as well as to assess the fishers' level of desire to know more about the benefits and risks of eating fish. Results showed that 40% of respondents constituted a "sensitive population" or could potentially feed fish to a sensitive family member. Half (49%) of those surveyed were concerned about mercury in fish and had a basic or advanced understanding of the issues. The majority of fishers (67%) wanted to know more about the risks and benefits of eating fish and would read a guide about mercury in local fish if it were available (79%). Almost everyone (93%) said they would follow fish consumption guidelines if they were available, while 36% said they would stop eating fish with any mercury in them at all. Fishers trusted "scientists" more than the media" or "the government" to provide them with correct information and to have their best interests in mind. Based on this research. fishers could be consuming damaging amounts of mercury if fishers and fish-mercury data in all of BC are similar to those collected for Elk Lake and Vancouver Island. Risk is higher for those individuals who consume fish regularly. I offer recommendations for next-steps and risk assessment. This project endeavors to further the formation of science-based policy. In addition to the fish-mercury data of the Ministry of the Environment, this research aims to provide the means and the methods for creating and disseminating fish consumption guidelines.

This thesis provides insights into the transport and fate of contaminants of concern (polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and mercury (Hg)), as well as results on the impacts of these compounds on marine mammal health. Atmospheric transport is known to be a significant pathway for the delivery of contaminants to remote food webs. Air and rain samples were collected from one remote site on the west coast of Vancouver Island, British Columbia (BC), Canada, and from one near-urban site in the Strait of Georgia, BC. While global atmospheric dispersion was observed for the legacy PCBs, 40% of PBDEs detected in BC air appeared to be originating from trans-Pacific transport. It was estimated that 3kg of PCBs and 17kg of PBDEs were deposited every year in the Strait of Georgia. Once deposited, PCBs, PBDEs and Hg biomagnify up the food chain. Harbour seals are non-migratory and can be used to provide signals of local contaminant sources. They have been extensively used as indicators of PCB and PBDE food web contamination in the BC coastal environment. The collection of over 200 harbour seal fur samples from various locations around Vancouver Island, BC and Puget Sound, WA, USA helped us pinpoint three sites where Hg levels were significantly higher than our reference site, Bella Bella (Queen Charlotte Strait, Port Renfrew and central Puget Sound). A combination of anthropogenic sources and marine food web processes appeared to influence the delivery of methylmercury (MeHg) to the top of this coastal marine food chain. Our results also suggested that these Hg levels (1.6-46.9 µg/g) could be a concern for the health of these harbour seals. Genomic techniques were used to generate insights into the implications of contaminant exposure on the health of marine mammals inhabiting industrialized regions (harbour seals from the Northeastern Pacific and Northwestern Atlantic) and remote, supposedly pristine, environment (Arctic beluga whales). In harbour seal blubber, there were positive correlations between the mRNA levels of several genes, including estrogen receptor alpha (Esr1), thyroid hormone receptor alpha (Thra), and glucocorticoid receptor (Nr3c1), and PCB levels. In beluga blubber, aryl hydrocarbon receptor (Ahr) and cytochrome P450 (Cyp1a1) mRNA levels increased with PCBs, consistent with their role in toxicity.While PCB-related toxic responses were observed in both species, additional factors appeared to be affecting the expression of important genes in beluga. Our results suggested that a shift in beluga diet during periods of low sea ice extent, as evidenced by changes in δ13C isotope ratios, had a significant impact on mRNA levels coding for genes involved in growth, metabolism and development. The use of a dual study design to evaluate the long range versus local sources of contaminants highlighted the importance of trans-Pacific transport in the delivery of PBDEs to coastal BC and the occurrence of local Hg sources in this marine environment. However, consistent with previous studies, our results suggested that PCBs remain the top contaminant of concern for marine mammal health. We also raised questions about the potential exacerbation of toxic risks due to PCBs as a consequence of climate changes currently underway in the Arctic. / Graduate / 0768 / 0383 / marie.t.noel@gmail.com

Ringed seal (Phoca hispida) is a major component and a major source of mercury (Hg) in the Inuit traditional diet. A high correlation between Hg and selenium (Se), as different forms of Hg-Se complex, has been reported in many species of marine mammals. The chemical form of the Hg-Se complex in ringed seals has never be characterised. In this study, Hg and Se concentrations in different seal tissues: liver, kidney, muscle and brain, were measured. The highest Hg and Se concentrations were found in the liver and a strong linear correlation was also observed between Hg and Se concentration in the seal liver. Extensive chromatographic and mass spectrometry techniques have been used to isolate and characterize the Hg and Se ligands in seal liver. Extraction of Hg and Se showed that Hg and Se were bound to ligands within the cell membranes of ringed seal liver. The Hg/Se binding protein has a MW range of about 65 kDa and Hg and Se had a 1:1 molecular ratio. The Hg/Se binding protein may contain 3 major polypeptides with MW of 6510.8, 14305.1 and 14353.1 Da. The toxicology of this Hg/Se binding protein will be studied using an animal feeding experiment.

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