RESUMO
Soil solid-solution distribution coefficients (Kd) are used in predictive environmental models to assess public health risks. This study was undertaken to determine Kd for potentially toxic elements (PTE) Cd, Co, Cr, Cu, Ni, Pb, and Zn in topsoil samples (0-20â¯cm) from 30 soils in the State of São Paulo, southeastern Brazil. Batch sorption experiments were carried out, and PTE concentrations in the equilibrium solution were determined by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICPMS). Sorption data was fitted to the Freundlich model. The Kd values were either obtained directly from the slope coefficients of C-type isotherms or derived from the slope of the straight line tangent to the non-linear L-type and H-type isotherms. Stepwise multiple regression models were used to estimate the Kd values through the combined effect of a number of soil attributes [pHH2O, effective cation exchange capacity (ECEC) and contents of clay, organic carbon, and Fe (oxy)hydroxides]. The smallest variation in Kd values was recorded for Cu (105-4598 L kg-1), Pb (121-7020 L kg-1), Ni (6-998 L kg-1), as variation across four orders of magnitude was observed for Cd (7-14,339â¯Lâ¯kg-1), Co (2-34,473â¯Lâ¯kg-1), and Cr (1-21,267â¯Lâ¯kg-1). The Kd values for Zn were between 5 and 123,849â¯Lâ¯kg-1. According to median values of Kd, PTE were sorbed in the following preferential order: Pbâ¯>â¯Cuâ¯>â¯Cdâ¯>â¯Niâ¯>â¯Znâ¯>â¯Crâ¯>â¯Co. The Kd values were best predicted using metal-specific and highly significant (pâ¯<â¯0.001) linear regressions that included pHH2O, ECEC, and clay contents. The Kd values reported in this study are a novel result that can help minimize erroneous estimates and improve both environmental and public health risk assessments under humid tropical edaphoclimatic conditions.
Assuntos
Metais Pesados , Poluentes do Solo , Brasil , Monitoramento Ambiental , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análiseRESUMO
Specimens of the Cichla pinima are of ecological and economic importance in the Amazon region and are a good bioindicator species of Hg bioaccumulation. Adult specimens of Cichla pinima were obtained by fisheries in the Tapajós river region's impacted gold mining area. Tissues such as muscle, liver, skin, and gill were submitted for total mercury (THg) analysis. For hepatic bioavailability, assays were carried out in the whole liver and in the sub-cellular hepatic fraction. The weight-length relationship showed an equation of W = 2E - 06L3.3002 (R2 = 0.856) indicating an allometric growth. The mean THg values found in the muscle tissue of 676 ± 258 µg kg-1 were below the maximum limit established for human consumption, but were similar to Cichla fish from other areas impacted by Hg in the Amazon region. The trends of levels in the tissues were as follows: liver>muscle>gonads>skin>gill, with no significant differences between the gills and skin. A significant and positive correlation as rs = 0.65 was obtained between the THg contents in cytosolic fraction and the total hepatic THg (liver homogenate). However, only 7% of the THg were found and were available to the sub-cellular hepatic fraction. This profile can be an indicative of a hepatic cellular transference in fish exposed to high Hg levels in the Amazon region now that low concentrations of Hg have been found in the sub-cellular fraction. However, data of differential THg partition in the subcellular compartments should be considered, since others' hepatic fractions can act in the Hg linkage into the cell.
Assuntos
Exposição Dietética/estatística & dados numéricos , Monitoramento Ambiental , Peixes/metabolismo , Mercúrio/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Brasil , Ciclídeos , Ecologia , Ouro/análise , Humanos , Mercúrio/análise , Mineração , Músculos/química , Rios , Alimentos Marinhos/análise , Poluentes Químicos da Água/análiseRESUMO
The forensic interpretation of environmental analytical data is usually challenging due to the high geospatial variability of these data. The measurements' uncertainty includes contributions from the sampling and from the sample handling and preparation processes. These contributions are often disregarded in analytical techniques results' quality assurance. A pollution crime investigation case was used to carry out a methodology able to address these uncertainties in two different environmental compartments, freshwater sediments and landfill leachate. The methodology used to estimate the uncertainty was the duplicate method (that replicates predefined steps of the measurement procedure in order to assess its precision) and the parameters used to investigate the pollution were metals (Cr, Cu, Ni, and Zn) in the leachate, the suspect source, and in the sediment, the possible sink. The metal analysis results were compared to statutory limits and it was demonstrated that Cr and Ni concentrations in sediment samples exceeded the threshold levels at all sites downstream the pollution sources, considering the expanded uncertainty U of the measurements and a probability of contamination >0.975, at most sites. Cu and Zn concentrations were above the statutory limits at two sites, but the classification was inconclusive considering the uncertainties of the measurements. Metal analyses in leachate revealed that Cr concentrations were above the statutory limits with a probability of contamination >0.975 in all leachate ponds while the Cu, Ni and Zn probability of contamination was below 0.025. The results demonstrated that the estimation of the sampling uncertainty, which was the dominant component of the combined uncertainty, is required for a comprehensive interpretation of the environmental analyses results, particularly in forensic cases.
Assuntos
Água Doce/química , Sedimentos Geológicos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Brasil , Monitoramento Ambiental , Ciências Forenses , Resíduos Perigosos/análise , Humanos , Esgotos/análise , Estatística como Assunto , IncertezaRESUMO
In this work, 24-h PM10 samples were collected in Rio de Janeiro, Brazil, and analysed for trace elements (Cd, Ce, Cu, La, Mo, Ni, Pb, Pd, Rh, Sb and Sn). The sampling was carried out at five locations (Bonsucesso; Centro, downtown city; Copacabana; Nova Iguaçu and Sumaré) with different traffic densities and anthropogenic activities. An analytical method based on the EPA method for the determination of trace elements in airborne particulate matter (PM), using ultrasonic-assisted extraction and inductively coupled plasma mass spectrometry (ICP-MS) was applied. Our results suggest that vehicular traffic is the most important source of environmental pollution at the studied sites. The presence of Mo, Pd and Rh in the analysed filters reflects an additional source of pollution caused by the erosion and deterioration of automotive catalytic converters.
Assuntos
Poluição do Ar/análise , Atmosfera/química , Automóveis , Cidades , Brasil , Análise por Conglomerados , Filtração , Isótopos , Metais Pesados/análise , Metais Pesados/química , Material Particulado/análise , Material Particulado/químicaRESUMO
An outbreak of footrot occurred in a flock of Corriedale sheep; 27 animals were treated with antibiotic and footbathed in a 5% copper sulfate solution. Being deprived of water for > 17 h, many sheep drank the footbath solution. After 6 h 16 sheep became ill with acute copper poisoning, 10 animals died within 10 h; 6 were severely ill and were sent to Veterinary Hospital, and 4 had mild signs and recovered without treatment. The sick sheep had anorexia, dullness, grinding teeth, moaning, rumen atony, dehydration, dark blue-green diarrheic feces and congested membranes. They were treated with 3.4 mg tetrathiomolybdate/kg body weight and lactated Ringer's solution iv, oral molybdate, sulfate, kaolin and pectin, and drenched with antacids. Two of the 6 sheep died during hospitalization. The ingestion of copper solution caused an intense gastrointestinal injury that resulted in ulcers, petechial and echymotic hemorrhages in the mucosa, mild hemolysis detected by microscopic hemoglobinuria and a lowered packed cell volume, severe hepatic injury that raised the AST and gammaGT blood values, and moderate kidney lesions with increasing serum blood urea and nitrogen creatinine levels.