ABSTRACT
Assessing the impacts of climate changes on water quality requires an understanding of the biogeochemical cycling of trace metals. Evidence from research on alluvial aquifers and coastal watersheds shows direct impacts of climate change on the fate and transformation of trace metals in natural environments. The case studies presented here use field data and numerical modeling techniques to test assumptions about the effects of climate change on natural arsenic contamination of groundwater in alluvial aquifers and mercury bioaccumulation in coastal salt marshes. The results show that the rises of sea level and river base during the warm Holocene period has led to an overall increase in groundwater arsenic concentration due to the development of reducing geochemical
ABSTRACT
Surubim (Pseudoplatystoma coruscans) is a predator fish found in the São Francisco River in Minas Gerais state, and it isfrequently consumed by both the local population as well as people throughout the entire state. Despite the significant advantagesof having fish as part of a normal diet, one of the more recent concerns of state and federal governmental agencies is the metalcontamination in these catches. In this context, a study was conducted on the content of mercury, lead, cadmium, arsenic andzinc in 59 sample units of liver, spleen, kidney, and muscular tissue from surubim fish captured during different periods of theyear in the São Francisco River. The liver and kidney samples presented mercury, cadmium, zinc, and lead contamination atlevels above the limits set forth under Brazilian law. The spleen samples also presented cadmium, zinc, and lead contaminationat levels above the legal limit as well. However, in muscular tissue, no presence of the metals analyzed herein was detected atabove the legal limits. A positive and directly proportional correlation of 72% was found among metals studied. The positivecorrelation between of lead and cadmium concentrations in the spleen was 82%. It is important to note that, although these fishare appropriate for human consumption, the presence of metals in these fish samples should serve as a warning for the periodicinspection of the
ABSTRACT
By atomic absorbance spectrophotometry, the content of heavy metals (lead, cadmium, arsenic, mercure) in freshwater fish and shelfish in the market and in 2 lakes in Hanoi from June to December 2002 was analysed. The contents are: lead 100%, arsenic 98.5%, cadmium 92.9% and mercury 88.6%, they are in the tolerable limits according to 1998 year Vietnam MOH regulation 867/BYT. The contents of various heavy metals are not similar in diverse genera of fish and shelfish. In some genera of fish, arsenic contents are higher than average from 0..68 to 0.601 mg/kg and mercury content 0.053mg/kg. Heavy metal contents in 2 lakes of Thanh Tri district and in diverse markets in Hanoi have not significant differences
Subject(s)
Metals, Heavy , Mercury , LeadABSTRACT
0.999 0) and higher precision (RSD