ABSTRACT Mercury content, as methylmercury, in aquatic biota varies greatly among species from th... more ABSTRACT 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 liza - iliophagous 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. Keywords: tropical fish species, different feeding habits, biological parameters, methylmercury, total mercury, Brazilian estuary.
Waters and sediments from the Potiguar Basin (NE Brazilian coast) were investigated for the prese... more Waters and sediments from the Potiguar Basin (NE Brazilian coast) were investigated for the presence and nature of polycyclic aromatic hydrocarbons (PAH) and aliphatic hydrocarbons. The region receives treated produced waters through a submarine outfall system serving the industrial district. The total dispersed/dissolved concentrations in the water column ranged from 10-50 ng L(-1) for ∑16PAH and 5-10 μg L(-1) for total aliphatic hydrocarbons. In the sediments, hydrocarbon concentrations were low (0.5-10 ng g(-1)for ∑16PAH and 0.01-5.0 μg g(-1) for total aliphatic hydrocarbons) and were consistent with the low organic carbon content of the local sandy sediments. These data indicate little and/or absence of anthropogenic influence on hydrocarbon distribution in water and sediment. Therefore, the measured values may be taken as background values for the region and can be used as future reference following new developments of the petroleum industry in the Potiguar Basin.
ABSTRACT Mercury content, as methylmercury, in aquatic biota varies greatly among species from th... more ABSTRACT 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 liza - iliophagous 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. Keywords: tropical fish species, different feeding habits, biological parameters, methylmercury, total mercury, Brazilian estuary.
Waters and sediments from the Potiguar Basin (NE Brazilian coast) were investigated for the prese... more Waters and sediments from the Potiguar Basin (NE Brazilian coast) were investigated for the presence and nature of polycyclic aromatic hydrocarbons (PAH) and aliphatic hydrocarbons. The region receives treated produced waters through a submarine outfall system serving the industrial district. The total dispersed/dissolved concentrations in the water column ranged from 10-50 ng L(-1) for ∑16PAH and 5-10 μg L(-1) for total aliphatic hydrocarbons. In the sediments, hydrocarbon concentrations were low (0.5-10 ng g(-1)for ∑16PAH and 0.01-5.0 μg g(-1) for total aliphatic hydrocarbons) and were consistent with the low organic carbon content of the local sandy sediments. These data indicate little and/or absence of anthropogenic influence on hydrocarbon distribution in water and sediment. Therefore, the measured values may be taken as background values for the region and can be used as future reference following new developments of the petroleum industry in the Potiguar Basin.
Uploads
Papers by Aida Baêta