Petrus Galvao

Ruditapes philippinarum and Ruditapes decussatus under Hg environmental contamination

The native species Ruditapes decussatus and the invasive species Ruditapes philippinarum have an important ecological role and socio-economic value, from the Atlantic and Mediterranean to the Indo-Pacific region. In the aquatic environment, they are subjected to the presence of different contaminants, such as mercury (Hg) and its methylated form, methylmercury (MeHg). However, few studies have assessed the impacts of Hg on bivalves under environmental conditions, and little is known on bivalve oxidative stress patterns due to Hg contamination. Therefore, this study aims to assess the Hg contamination in sediments as well as the concentration of Hg and MeHg in R. decussatus and R. philippinarum, and to identify the detoxification strategies of both species living in sympatry, in an aquatic system with historical Hg contamination. The risk to human health due to the consumption of clams was also evaluated. The results obtained demonstrated that total Hg concentration found in sediments from the most contaminated area was higher than the maximum levels established by Sediment Quality Guidelines. This study further revealed that the total Hg and MeHg accumulation in both species was strongly correlated with the total Hg contamination of the sediments. Nonetheless, the THg concentration in both species was lower than maximum permissible limits (MPLs) of THg defined by international organizations. R. decussatus and R. philippinarum showed an increase in lipid peroxidation levels along with the increase of THg accumulation by clams. Nevertheless, for both species, no clear trend was obtained regarding the activity of antioxidant (superoxide dismutase, catalase) and biotransformation (glutathione S-transferase) enzymes and metallothioneins with the increase of THg in clams. Overall, the present work demonstrated that both species can be used as sentinel species of contamination and that the consumption of these clams does not constitute a risk for human health.

Distinct bioaccumulation profile of pesticides and dioxin-like compounds by mollusk bivalves reared in polluted and unpolluted tropical bays: Consumption risk and seasonal effect

Mariculture activity has increased its production along the Atlantic Coast of Brazil over the last years. This protein source for human consumption may also represent risks due to the exposure to bioaccumulated contaminants in the tissues of organisms reared in polluted shallow waters. This study evaluated the bioaccumulation of pesticides and dioxin-like compounds in two commercial marine bivalve species reared at different sites along the Rio de Janeiro State coast (SE-Brazil). We observed distinct contamination profiles in bivalve tissues reared at each sampling site, which may be related to human activities historically developed in those areas. A pronounced tendency for higher contamination levels in animals sampled in the last month of winter (September) is discussed as being likely due to environmental issues, rather than biological factors. Based on Minimal Risk Level, Maximum Residue, Acceptable Daily Intake and Toxic Equivalent, bivalves are classified as safe for human consumption.

Use of passive samplers to detect organochlorine pesticides in air and water at wetland mountain region sites (S-SE Brazil)

Low-density polyethylene (LDPE) passive samplers were deployed in upland surface waters and the overlying atmosphere during May and June 2012, to determine the transport and trends of freely dissolved and gaseous organochlorine pesticides (OCPs) along altitudinal gradients in mountain regions in south and southeast Brazil. Gaseous OCP concentrations were dominated by hexachlorobenzene (3.0-29 pg m(-3)) and endosulfans (Ʃ = α-endosulfan + β-endosulfan + endosulfan sulphate, 170-260 pg m(-3)), whereas freely dissolved endosulfans were significantly higher than all other OCPs (p < 0.001). The presence of some target pesticides at the highest elevation sites indicated their efficient high-altitude transport from regional sources. Air-water exchange gradients indicated net deposition of most volatile and recently banned OCPs (e.g., HCB, endosulfan) over Brazilian mountains. Moreover, the exposure of these sites to large-scale continental airflows with varying source contributions may partly explain the atmospheric deposition of selected OCPs over upland freshwaters at tropical and subtropical mountains sites in Brazil. These findings, coupled with LDPE passive air and water sampling measurements, point out the potential inputs from distant sources of semi-volatile chemicals to the two high-altitude sites.

Metal bioaccumulation in consumed marine bivalves in Southeast Brazilian coast.

This work aimed to investigate metal bioaccumulation by mussels (Perna perna) and Lions Scallop (Nodipecten nodosus) farmed in tropical bays, in order to estimate spatial and temporal variation in the exposure to these elements, as well as human health risk. The concentration of each measured element was considered for this evaluation, using maximum residue level (MRL) in foods established by the Brazilian (ANVISA), American (USFDA) and European Communities (EC) legislations. Values for estimated daily ingestion (EDI) were determined for metals intake through mussel and scallop consumption. These estimates were compared with the reference value of (PTDI) proposed by World Health Organization (WHO). Trace elements concentration was measured on ninety mussels P. perna (tissue) and ninety Lions Scallop N. nodosus (muscle and gonad) reared in four different tropical areas of the Southeast Brazilian coast, between 2009 and 2010. Zinc (Zn), Iron (Fe), Copper (Cu), Manganese (Mn), Chrome (Cr), Nickel (Ni), Cadmium (Cd) and Lead (Pb) concentrations were measured by flame atomic absorption spectrometry after acid mineralization. Cd and Mn were more efficiently bioaccumulated by scallops than mussels and the opposite was found for Fe, Cu and Ni. Guanabara Bay and Sepetiba Bay were considered the most impacted between ecosystems studied. Higher Cd values in Arraial do Cabo in the other sites studied were associated with upwelling that occurs in the region. Consumption of both species cannot be considered safe, because the Cu and Cr concentrations, in accordance with the limits established by the Brazilian Agency (ANVISA). On the other hand, any EDI value exceeded the corresponding value of the PTDI, proposed by World Health Organization (WHO).

Estimating the Potential Production of the Brown Mussel Perna perna (Linnaeus, 1758) Reared in Three Tropical Bays by Different Methods of Condition Indices

Perna perna (Linnaeus, 1758) is the main marine bivalve mussel yielded commercially in Brazil. In spite of this, scientific data is very scarce regarding its productivity in tropical shallow waters. The Condition Index (CI) is used worldwide in mariculture to assess animal health, harvest time, and yield. In this study, the authors used CI results from nine different methods to assess the season effect on the mussel CI and also to evaluate the potential yield of three southern Brazilian bays. The results from nine CI methods were used for the comparison of the seasonality and yield of mussels reared in three marine bays. Sampling was carried out monthly within two 4-month periods, from December 2008 to August 2009. The results show a trend for seasonal effects on the CI results. The winter months showed the highest and the lowest values. Between bays, higher CI values were detected in animals reared at Sepetiba Bay, followed by Guanabara Bay and Ilha Grande Bay. We suggest that the CI (that considers the ratio between bivalve soft tissue wet weight and total length) should be used by fishermen, since this formula was able to detect differences between sites and is more easily applied.

Partition of organochlorine concentrations among suspended solids, sediments and brown mussel Perna perna, in tropical bays

For evaluating the brown mussel Perna perna as a sentinel organism regarding environmental concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), the present study reports original data on the relationship between the concentrations of these chemicals in bottom surface sediments, suspended solids (SS) and concentrations bioaccumulated by this bivalve. Three P. perna cultivation areas, located at three bays in southeastern Brazil were used in this study. The three estuaries are under different degrees of environmental impact. Variations in the OCP and PCB concentrations bioaccumulated by the bivalves tended to be similar to those observed in the sediment, but differed from those found in SS. This latter difference might suggest that the SS trapping apparatuses should have been left in place for approximately 60 days (not only 15 days). This longer period would allow the integration of the environmental variability of the OCP and PCB burden adsorbed to this compartment. Authors encourage future studies to evaluate P. perna exposure to OCPs and PCBs through the evaluation of sediment concentrations.