Total and methylmercury in a Brazilian estuary, Rio de Janeiro

Kehrig, Helena A.; Costa, Mônica F.; Moreira, Isabel; Malm, Olaf

doi:10.1016/s0025-326x(02)00140-6

Cited by 73 publications

(53 citation statements)

References 21 publications

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“…Na última década alguns estudos foram desenvolvidos a respeito da bioacumulação de metilmercúrio na Baía de Guanabara, 18,19 porém poucos dados estão disponíveis a respeito da sua distribuição na base da cadeia (seston e comunidade planctônica) e ao longo da teia trófica desta baía. 20,21 Assim sendo, este trabalho apresenta novos dados a respeito da bioacumulação e biotransferência de metilmercúrio ao longo da cadeia trófica da Baía de Guanabara.…”

Section: Introductionunclassified

Bioconcentração e biomagnificação de metilmercúrio na baía de Guanabara, Rio de Janeiro

Kehrig¹,

Malm²,

Palermo³

et al. 2011

Quím. Nova

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Recebido em 4/2/10; aceito em 7/10/10; publicado na web em 26/1/11 BIOCONCENTRATION AND BIOMAGNIFICATION OF METHYLMERCURY IN GUANABARA BAY, RIO DE JANEIRO.Methylmercury was determined in water and aquatic biota from Guanabara Bay. Trophic transfer of methylmercury was observed between trophic levels from prey (microplankton, mesoplankton and fish with different feeding habits) to top predator (pelagicdemersal fish). Top predator fish presented the highest methylmercury concentrations (320.3 ± 150.7 µg kg -1 dry wt.), whereas microplankton presented the lowest (8.9 ± 3.3 µg kg -1 dry wt.). The successive amplification of methylmercury concentrations and its bioconcentration factor with increasing trophic levels from base to top indicate that biomagnification may be occurring along the food web. Results suggest the importance of feeding habits and trophic level in the bioaccumulation of methylmercury by aquatic biota.Keywords: biotransference of methylmercury; water and organisms; trophic levels. INTRODUÇÃOExiste uma grande preocupação com relação ao aumento da poluição ambiental resultante do incremento do emprego intensivo e extensivo de produtos químicos, da liberação de substâncias potencialmente tóxicas, dos lançamentos de efluentes industriais e urbanos, bem como de seus efeitos para os ecossistemas e, consequentemente, para o homem. 1 Com o aumento das atividades industriais, agrícolas e mineradoras, bem como o crescimento populacional observados no último século, uma série de contaminantes (matéria orgânica, poluentes orgânicos e um grande número de compostos metálicos) vem sendo liberada para o meio ambiente, principalmente para a atmosfera e os ecossistemas aquáticos. 2 Os contaminantes de compostos metálicos presentes nos efluentes das atividades antrópicas apresentam pouca solubilidade na água resultando, então, em baixas concentrações, mesmo em locais próximos às suas emissões pontuais, via efluente. Entretanto, em ambientes estuarinos, os contaminantes metálicos estão preferencialmente associados ao material particulado em suspensão, que lhes serve de veículo para áreas mais distantes das suas fontes. 3 Dentre os diferentes metais que despertam interesse ambiental, presentes nos efluentes industriais e agrícolas e que, também, em diversas regiões apresentam concentrações naturais relativamente elevadas, encontra-se o mercúrio (Hg). A exposição ambiental ao Hg via cadeia alimentar, principalmente para consumidores de nível trófico superior, incluindo-se o homem, é significativamente maior, uma vez que este metal apresenta alta toxicidade e capacidade de sofrer biomagnificação ao longo das cadeias tróficas. 4 Este metal na sua forma orgânica mais tóxica, metilmercúrio (MeHg), é bioacumulado em até um milhão de vezes ao longo da cadeia trófica aquática, desde a sua base (microorganismos e plâncton) até os organismos de topo (peixes predadores e mamíferos) através de adsorção na superfície corporal e, principalmente, pela ingestão de alimento (peixes, crustáceos e cefalópodes). 5 O metilmercúrio é um age...

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Section: Introductionunclassified

Bioconcentração e biomagnificação de metilmercúrio na baía de Guanabara, Rio de Janeiro

Kehrig¹,

Malm²,

Palermo³

et al. 2011

Quím. Nova

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“…Indeed, Hg found in fish is chiefly present as MeHg (Cappon and Smith, 1981;Bloom, 1992;Wagemann et al, 1997;Kehrig et al, 2002). The study of Hg impregnation in top predators is crucial as it serves as evidence for environmental exposure levels.…”

Section: Introductionmentioning

confidence: 99%

Mercury content in commercial pelagic fish and its risk assessment in the Western Indian Ocean

Kojadinovic

Potier

Corre³

et al. 2006

Science of The Total Environment

123

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As top predators of pelagic food webs, large fish naturally bioaccumulate mercury (Hg). Determining Hg burdens in commercialized fish is essential considering the concern about effects of contaminants on human health and the legal thresholds that are therefore set for local consumption and/or exportation. Total Hg levels were measured in the muscular tissue of 183 fish of five commercially important species from the tropical zone of the Western Indian Ocean. All individuals were measured and sexed in order to study the impregnation of Hg with size and sex within each species. Values of Hg found in this part of the Indian Ocean were comparable to Hg in muscular tissue of the same species studied in other areas. The highest Hg levels were noted in Swordfish (Xiphias gladius) caught in waters surrounding Reunion Island (3.97 ± 2.67 µg.g −1 dry weight). Following the Swordfish, in decreasing order of Hg content, were the Yellowfin Tuna (Thunnus albacares) and the Skipjack (Katsuwonus pelamis), then the Common Dolphinfish (Coryphaena hippurus) and the Wahoo (Acanthocybium solandri). In the North of the Mozambique Channel, Swordfish had higher Hg levels than Yellowfin Tunas, and Dolphinfish exhibited intermediate Hg levels. The size of a fish was a determinating factor of its Hg burden, as was the species. Differences in size-normalized Hg levels were observed between the two study zones for Swordfish and Common Dolphinfish. Sex, in contrast, did not influence Hg levels suggesting that females and males have similar feeding habits. The muscular Hg levels presented here suggest that consumers of fish originating from the Western Indian Ocean should limit themselves to one Swordfish based meal per week, or one fish meal a day if they choose to eat tuna or Common Dolphinfish.

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“…In the marine environment, almost all of the mercury in the muscle of fish is methylated (Joiris et al [4], Kehrig et al [5,6]). However, the major part of mercury accumulated in the internal organs especially in the liver, exist as inorganic mercury, suggesting that demethylation of methylmercury is possible (Kehrig et al [6], Holsbeek et al [7]).…”

Section: Introductionmentioning

confidence: 99%

Total mercury and methylmercury in fish from a tropical estuary

Baêta¹,

Kehrig²,

Malm³

et al. 2006

WIT Transactions on Biomedicine and Health, Vol 10

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Mercury content, as methylmercury, in aquatic biota varies greatly among species from the same location. Many parameters may affect its accumulation and concentration in fish tissues. The study assessed total mercury (T-Hg) and methylmercury (MeHg) in the muscle, liver and gonad of Micropogonias furnieri -carnivorous fish, Bagre spp. -omnivorous fish and Mugil lizailiophagous fish from a polluted eutrophic estuary in the Brazilian Southeast coast, Guanabara Bay. Fish were collected during the years 1990, 1999 and 2003. T-Hg was determined by CV-AAS with sodium borohydride as a reducing agent. MeHg was identified and quantified in the toluene layer by GC-ECD. In all cases, the liver appears to be the preferential organ for mercury accumulation. T-Hg in muscle was higher and more variable in carnivorous than in omnivorous and iliophagous fishes. Carnivorous and omnivorous fishes presented a similar percentage of MeHg (99% and 97%) in the muscle. Iliophagous fish, which is at the lower level of this food chain, presented the lowest % MeHg in the muscle and liver, 52% and 9% respectively. However, the percentage of MeHg to T-Hg was around 25% in the liver of carnivorous and omnivorous fishes. In all cases, the gonad presented the lowest T-Hg, and the ratio of MeHg to T-Hg was around 1. In the year 1999, the samples of carnivorous and iliophagous fishes presented the highest T-Hg in the muscle. In this year, the fish specimens of both species showed sexual maturity and the highest total length. The sex of the specimens did not show any influence in the accumulation of mercury by the fish. The total length of the fish specimens presented a significant relationship with T-Hg in the muscle. The different feeding habits of the studied species are important for the accumulation of mercury and methylmercury by the organisms. Mercury, as methylmercury, is biomagnified through this food chain.

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Total and methylmercury in a Brazilian estuary, Rio de Janeiro

Cited by 73 publications

References 21 publications

Bioconcentração e biomagnificação de metilmercúrio na baía de Guanabara, Rio de Janeiro

Bioconcentração e biomagnificação de metilmercúrio na baía de Guanabara, Rio de Janeiro

Mercury content in commercial pelagic fish and its risk assessment in the Western Indian Ocean

Total mercury and methylmercury in fish from a tropical estuary

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