Edison Dausacker Bidone

Fish contamination and human exposure to mercury in Tartarugalzinho River, Amapa State, Northern Amazon, Brazil: a screening approach

This study reports for the first time, the Hg concentrations in the fish fauna of the Tartarugalzinho river basin - an important gold mining region in Amapa State, Northern Amazon - and evaluates human exposure to Hg due to fish consumption in the area. We analyzed 16 fish species (carnivorous and omnivorous) common in the aquatic environment of the Tartarugalzinho area and which are mostly consumed by the local population. Mercury concentrations in fish ranged from 35 µg.kg-1 to 1,225 µg.kg-1. Among the analyzed fish, 8 species (50%) presented Hg concentrations higher than 500 µg.kg-1, the U.S. Food and Drug Administration (FDA) Action Level for concentration of Hg in fish. No statistical difference was observed between Hg mean concentrations in carnivorous and omnivorous fish. Within a given species, Hg concentrations were positively correlated with fish size or weight. The Hg concentration ratio between fish and water showed values higher than 50,000. Human exposure was estimated through the daily Hg intake obtained through interviews with the local population on the amount and species of fish consumed and the Hg concentration in the fish. The estimated average daily intake was 114 µg.day-1. This amount is approximately one-half of the WHO recommended provisional tolerable Hg weekly intake. At screening level, it assumes that there is a level of exposure (e.g, USEPAs RfD = Reference of Dose) below which it is unlikely for even sensitive populations to experience adverse health effects. The estimated exposure level for adult humans (1.6 µg.kg-1.day-1) was nearly 5 times greater than Hg RfD (0.3 µg.kg-1.day-1). The results suggest a widespread Hg contamination in the local fish fauna. Due to high fish Hg concentrations and high fish intake by local population, environmental exposure to Hg is also high, presenting a health risk to population.

Heavy-metal pollution assessment in the coastal lagoons of Jacarepaguá, Rio de Janeiro, Brazil

The Jacarepaguá lagoon receives the waste from 239 industries and domestic sewage. Bottom sediment analysis revealed that metal pollution is not spread over the lagoons but restricted to the discharge areas of the main metal-carrier rivers. Metal concentrations in superficial water showed the following concentrations values in ng/ml: Zn, 9.63+/-3.59; Pb, 0.61+/-0.43; Cu, 0.94+/-0.45; Mn, 12.7+/-8.0. Metal concentration in fish (average of seven different species) presented the following results, in mg/kg wet weight: Cr, 0.08+/-0.01; Cu, 0.4+/-0.15; Zn, 4.6+/-3.4; Fe, 2.4+/-1.3; Mn, 0.4+/-0.3. These results imply, considering fish consumption rate and the RfD (USEPA Reference Dose), that the local population is not exposed to undue health risks. Metal concentrations in the water may, however, increase due to their dissolution induced by pH and redox changes in the sediments.

Influence of the properties of tropical soils in the toxicity and bioavailability of heavy metals in sewage sludge-amended lands

The toxicity and potential bioavailability of heavy metals were studied in sewage sludge-amended ferralsols and chernosols, using bioassays with earthworms (Eisenia andrei). Acute toxicity tests and avoidance assays were performed according to standard protocols. Potentially bioavailable concentrations of heavy metals were estimated by quantifying their concentrations in tissues of survival earthworms. The results revealed that soil properties played an important role in the toxicity and bioavailability of heavy metals. In this respect, higher levels of toxicity were detected for the ferralsol. The abundance of 2:1 clay minerals, high fertility and more basic values of pH seem to be very important in the reduction of toxicity levels for earthworms. Organisms exposed to the chernosols were able to uptake higher amount of metals. In that case, higher contents of nutrients in chernosols may have influenced such bioavailability processes. Avoidance responses were the most sensible indicator of toxicity. In the near future, such data can subsidize the establishment of toxic reference concentrations able to reflect the characteristics of important tropical pedological occurrences, supporting the definition of sustainable indicators for using sewage sludge in the tropical agriculture.

Mass balance in the monitoring of pollutants in tidal rivers of the Guanabara Bay, Rio de Janeiro, Brazil.

This study addressed the identification and monitoring of pollution sources of terrestrial origin in rivers (domestic sewage and industrial effluents) and critical fluvial segments in highly polluted environments under tidal influence (mixing marine and continental sources) from Guanabara Bay Basin, Rio de Janeiro, Brazil. The mass balance of contaminants was determined in conditions of continuous flow (low tide) during dry season (lower dilution capability). The results allowed the evaluation of the potential of contaminant mass generation by the different river segments and the estimation of their natural and anthropogenic components. The water quality of Iguaçú and Sarapuí Rivers were evaluated for metals and biochemical oxygen demand. The method gave an excellent response, including the possibility of sources identification and contaminated river segments ranking. The approach also offers fast execution and data interpretation, being highly efficient.

Environmental risk increase due to heavy metal contamination caused by a copper mining activity in Southern Brazil

The Camaquã Copper Mines (CCM) were the main sulphide deposit in Southern Brazil and have been in operation from last century to 1996. To evaluate water contamination and environmental risk increase by heavy metals from mining operations, two points on the João Dias Creek were sampled (Station 1, background area and Station 2, contaminated area). Mining activity increased the natural weakly heavy metal fluxes by approximately 5424 kg. (approximately 60%) of the total metal flux, 1542 kg. (approximately 49%) of dissolved and 3881 kg (approximately 66%) of particulate metal flux. Total metal flux of anthropic origin was mostly due to Fe followed by Cu > Zn > Mn whereas Cd, As and Pb fluxes were negligible. The potential human health hazards and risk assessment related to daily intake of water from João Dias Creek are mostly due to Mn and should be of concern for the contaminated area. The ingestion of water from station 2 represents incremental risks of 130% and 59% respectively, considering the non-carcinogenic and the carcinogenic effects. The real increase of human health hazards may be greater than those related to the total concentrations since Mn and As dissolved concentrations were 5.5 and 2.0 higher than acceptable, respectively.

Bioaccumulation of heavy metals by shrimp (Litopenaeus schmitti): A dose–response approach for coastal resources management

We reveal a dose-response relationship for bioaccumulation of Zn, Cu and Cr in shrimp Litopenaeus schmitti from Sepetiba Bay, Rio de Janeiro, Brazil. Our model estimates the current risk (AD50 was 70% of the legal limit) and the daily metal uptake rate for each metal. It can also evaluate the relative reliability of predictions for tissue concentrations reaching the legal limits for human consumption (approximately 1year) and predictions related to asymptotic length, arising from (i) direct regression of the metal concentration (MeC) versus total length (TL) and age (duration of exposure), and (ii) correlation of the incorporation rate (IR=MeC/TL) with age. Metal incorporation rates (IR), i.e. a kinetic proxy for absorption during growth up to attainment of asymptotic length, decrease with age, reflecting a slow-down in metal absorption. This pattern mitigates the high initial concentrations observed for juveniles.

A Practical Method to Internalize Environmental Impacts into Cost-Benefit Analysis

Governments and managers have generally conducted inadequate cost-benefit analysis (CBA) by failing to incorporate environmental impact costs. This is not a straightforward task, owing to the intangibility, in monetary terms, of most environmental goods and services. By means of a theoretical example, we present a practical approach to correct cost-benefit analysis for environmental externalities that do not need natural resource valuations. The theoretical example is based on ventures that potentially pollute river waters. However, we think that the methodological approach presented here may be used to internalize (in monetary terms) the costs of negative external impacts on the environment, which may result from any type of venture or project.

Statistical modelling of heavy metal partitioning among their geochemical carrjers in sediments of rffieira bay, Rio de Janeiro, Brazil. A critical analysis

Abstract A critical analysis is made concerning to the use of statistical correlation in the modelling of metal distribution among its geochemical supports in a non‐polluted bay. A misunderstanding of metal dynamics in the studied area would take place if detailed chemical/mineralogical compositional mass‐balance of soils and sediments were not performed before the use of statistical correlations.

Natural indicators of the behaviour of heavy metals in Ribeira bay, (Rio de Janeiro ‐ Brazil).

Abstract The behaviour of natural geochemical carriers was studied in Ribeira Bay (SE coast of Brazil). Results show that distribution patterns of heavy metals in superncial sediments are intimately associated with the stability of geochemical carriers and the hydrodynamic pattern of the bay.

An alternative approach to bioaccumulation assessment of methyl-Hg, total-Hg, Cd, Pb, Zn in bivalve Anomalocardia brasiliana from Rio de Janeiro bays

We present an alternative approach for establishing in situ bioaccumulation assessment of methyl-Hg (MeHg), total-Hg, Cd, Pb and Zn in bivalve Anomalocardia brasiliana from four bays of Rio de Janeiro presenting varying degrees of eutrophication, acid volatile sulfides (2-55 μmol g-1), simultaneously extracted metals (SEM) and total metals (TM) in sediments. Using metal concentrations of composite samples from three size classes of bivalve and their incorporation rates (IR = metal concentration / total length), which depend on exposure time, we calculated asymptotic IR and respective consequent metal concentrations. Both IR and the metal concentration presented inverse relationships with total length (excepting MeHg) and bay contamination. Lead and zinc concentrations were above Brazilian legal criteria in the most anoxic and contaminated bay, suggesting significant metal bioavailability (SEM/TM between 8% and 63%).