Abstract

Heavy metals incidence in the aquatic environment and its accumulation in fish are under constant review. Gilthead seabream (Sparus aurata ) specimens were exposed for two weeks to sediments highly concentrated in metals, collected at the Portman Bay (Murcia, Spain). The metals bioaccumulation was tested in liver, muscle and skin. The potential of the sediment exposure to induce variation of the stress biomarkers genes was conducted in liver and skin. Results revealed that sediments were highly contaminated with metals. However, following 2 weeks exposure to the sediments, Cd accumulates only in liver. Interestingly, the expression of the genes mta, hsp 70 and hsp 90 were significantly down-regulated in skin. Nevertheless, cyp1a1 gene was up-regulated only in liver. Results uphold that the stress response magnitude was organ-dependent and the skin was the most responsive tissue to metal stress conditions. These results suggest that skin should be considered as target organ for biomarkers analysis in fishes.

Abstract

The concentrations of heavy metals in the bottom sediments (fraction < 0.1 mm) of streams of the Sikhote-Alin Nature Reserve and streams draining the mines of the protective and transit zone of the reserve, as well as in the tailing material, was examined. The background ranges of the Fe, Cu, Ni, Zn, and Cd concentrations in bottom sediments of streams of the eastern and central Sikhote-Alin were defined. The concentrations of Zn are elevated, and the concentrations of Cd are comparable in the bottom sediments of the reserve compared to the approximate permissible concentration in the soil. Elevated concentrations of Zn, Cu, Cd, Mn, Pb, and Ni compared to the background were found in the bottom sediments of the streams draining the territory of the tin mines. The concentrations of Zn and Cd in these bottom sediments exceeded the approximate permissible concentration. Elevated concentrations of Cu were observed in the bottom sediments of the streams, even at a distance of 10 km from the mine. The content of metals in the bottom sediments in the stream draining the gold and silver mine did not exceed the approximate permissible concentration, whereas the concentrations of Cu, Mn and Pb were increased compared to the background. The surface layer of the sediments of the tin mines tailing ponds was enriched in Cu and Pb and starved of Cd, Ni, and Zn compared to the bottom sediments and the approximate permissible concentrations in the soil.

Abstract

Interactions of metals with the biomass of plant organisms, including algae, are of interest for biology, biogeochemistry and biotechnology. This work studies the interactions of the unique thermophilic red algae Galdieria sulphuraria (Class: Rhodophyta, Family: Cyanidiaceae) with copper and lead in the aquatic environment. This extremophilic, acidophilic organism is found in such ecosystems as hot springs and geothermal habitats. This paper presents the results of experiments with the biomass and mortmass of this organism. The results indicate that the biomass of this organism immobilises copper after incubation in aquatic medium with heavy metals. Lead was also added to the incubation environment, but no immobilisation of lead from the aquatic environment was observed. The mortmass of G. sulphuraria immobilised neither copper nor lead.

Abstract

Heavy metals constitute an important group of persistent toxic pollutants occurring in ambient air and other media. One of the suspected sources of these metals in the atmosphere is combustion of transport fuels in road vehicles. However estimates of the emissions of these metals from road vehicles as reported in national emission inventories show a very high variability in emission factors used. This paper provides high quality data on concentrations of heavy metals in fuels and derives default emission factors from these. The paper discusses these values against the emission estimates presently reported by the Parties to the LRTAP Convention. The measured concentrations of heavy metals in petrol and diesel fuel show a high variability between different samples taken at gas stations throughout Europe. Metal concentrations in road transport fuels vary over two orders of magnitude, but all remain in the ppb region (a few tenths of a ppb to a few hundred ppb for all metals). The frequency distributions of the measurements could be approximated by lognormal distributions. We could not detect a significant difference between samples from different countries. The fuel based emission factors as derived in this study are compared with those related to lubricant use as published by Winther and Slentø (2010). For most HMs studied here, this would lead to an two to fourfold increase of the tailpipe emissions as derived from the fuel concentrations. The emission factors, including 95 percent confidence intervals were derived from a statistical analysis of the survey data. The proposed emission factors were generally lower than previously published emission factors. National emissions of heavy metals from vehicle exhaust, estimated in this study therefore are in many cases considerably lower than those reported by the countries for this source.

Abstract

The objective of the study was to evaluate soil quality in population centers near gold mining areas. The concentration of heavy metals and metalloids (As, Cd, Cu, Cr, Ni, Pb, and Zn) was analyzed in soil samples collected in public areas, yards, gardens, and cultivation areas. As a result, it was identified that the concentration of Ni and Cr exceeded the maximum permissible limit (MPL) established in the Unified Text of Secondary Environmental Legislation of Ecuador (TULSMA) in 100 % of the samples analyzed, while the concentration of Cu and Zn was higher than the MPL in 90 % of the sites sampled. Cd exceeded the MPL in 64 % of the samples, and As and Pb exceeded the MPL in 26 % and 21 % of the samples, respectively. Cd, As and Pb are elements of special concern due to their high toxicity and significant presence in the study area. Regarding pH analysis, values between 3.31 and 8.21 were obtained, indicating acidic conditions in 60 % of the soil samples, possibly as a result of anthropogenic activity in the area. Strong positive correlations were detected between As-Cd, Cr-Ni, Cu-Ni, and moderate correlations between Cr-Cu and Pb-Zn, which is related to the mineralization of the area. Cluster analysis indicated that cluster C1, characterized by a high content of potentially toxic elements, is mostly located south of the study area. These preliminary results can serve as a baseline for future research in the area, highlighting the importance of soil quality assessment in mining areas.

Abstract

The use of Permeable Reactive Barriers as a material for the removal of heavy metals from the leachates of the Sanitary Landfills has been verified for various materials, the Silica Sand from the coasts of the municipality of Alvarado Veracruz in Mexico have the characteristics of size and composition Required to be used for this purpose, samples of leachate were collected from the Sanitary Landfill of the City of Veracruz and the concentrations of Ni, Cr+6 and Zn were determined were respectively 0.0818, 0.186 and 0.224 mg/l, three columns were built of acrylic and were filled with 20, 30 and 40 cm of washed and dried Silica Sand, treated and stabilized leachate was passed through the porous medium at a flow of 1.7 ml/s, taking samples at 40.75, 115 , 165 and 235 seconds for each column and the efficiency for the removal of these heavy metals was measured and a significant reduction of these pollutants was found, ranging from 76 to 93%. for Nickel, from 44 to 81 % in the case of hexavalent Chromium and from 65 to 92% for Zinc for a maximum time of 235 seconds, which indicates that this material can be used in the remediation of leachate.