Heavy metals in the liver and muscle of <Emphasis Type="Italic">Micropogonias manni</Emphasis> fish from Budi Lake,Araucania Region,Chile: potential risk for humans

The concentrations of cadmium, lead, manganese and zinc were determined in the fish species Micropogonias manni captured in Budi Lake, Araucanía Region (Chile). The measurements were made by atomic absorption spectroscopy, and the analysis considered the sex, weight and size of the species; the representative samples were taken from the liver and muscle tissue. The method was validated using certified reference material (DOLT-1). The ranges of concentrations found in the muscle tissue were: Cd, not determinate (n.d.)–0.26; Pb, n.d.–1.88; Mn, 0.02–12.17 and Zn, 0.48–39.04 mg kg⁻¹ (dry weight). The concentrations in muscle tissue were generally lower than those found in the liver. With respect to the average concentrations recorded for each metal in the edible part of the fish (muscle tissue), it was found that the levels of Cd, Pb, Mn and Zn are within the ranges published by other authors in similar works and below the maximum concentration limits permitted by current legislation (FAO/WHO 2004; EU 2001) and do not constitute a health hazard for consumers of this species. The results were subjected to statistical analysis to evaluate the correlations between the content of the various metals and the sex, weight and size of each sample.     

Enhancement by anthraquinone-2-sulphonate of the photonitration of phenol by nitrite: implication for the photoproduction of nitrogen dioxide by coloured dissolved organic matter in surface waters

Anthraquinone-2-sulphonate (AQ2S) under UVA irradiation is able to oxidise nitrite to (·)NO(2) and to induce the nitration of phenol. The process involves the very fast reactions of the excited triplet state (3)AQ2S(*) and its 520-nm absorbing exciplex with water, at different time scales (ns and μs, respectively). Quinones are ubiquitous components of coloured dissolved organic matter (CDOM) in surface waters and AQ2S was adopted here as a proxy of CDOM. Using a recently developed model of surface-water photochemistry, we found that the oxidation of nitrite to (·)NO(2) by (3)CDOM(*) could be an important (·)NO(2) source in water bodies with high [NO(2)(-)] to [NO(3)(-)] ratio, for elevated values of column depth and NPOC.     

Evaluation of extracted organic carbon and microbial biomass as stability parameters in ligno-cellulosic waste composts

Extracted organic C and microbial biomass were evaluated as stability parameters in 3 different ligno-cellulosic waste composts. Organic C was extracted by both water and alkali and further separated in humic-like carbon (HLC) and nonhumic carbon (NHC). Conventional humification parameters, such as humification index and degree of humification were calculated from NHC and HLC. Microbial biomass carbon (B(C)) was determined as an indicator of the degree of biochemical transformation, whereas ninhydrin reactive N (B(NIN)) was measured to obtain the stability parameter B(NIN)/N(TOT) (N(TOT), total N). The water-extracted organic C did not provide reliable information on the transformations underwent by the ligno-cellulosic wastes during composting, since its content remained almost unaltered during the whole process. In contrast, parameters based on the alkali-extracted organic C and microbial biomass clearly reflected organic matter (OM) changes during the process. There was an increase in the net amount of HLC in the alkali extracts throughout composting, especially in the first 7 to 12 wk of the process, as well as a relative enrichment of HLC with respect to NHC. Values of humification index and degree of humification in end products were consistent with an adequate level of compost stability. The stability parameter B(NIN)/N(TOT) showed to be a reliable indicator of stability in ligno-cellulosic wastes. Parameters based on the alkali-extracted C and microbial biomass clearly reflected the transformation of the OM during composting and can be used as stability parameters in ligno-cellulosic waste composts.     

Embryo/larval toxicity and transcriptional effects in zebrafish (Danio rerio) exposed to endocrine active riverbed sediments

Environmental Science and Pollution Research - Sediment toxicity plays a fundamental role in the health of inland fish communities; however, the assessment of the hazard potential of contaminated...     

Assessing heavy metal pollution by biomonitoring honeybee nectar in Córdoba (Spain)

Environmental Science and Pollution Research - Nectar of honeybee colonies has been used in order to identify heavy metals and establish the benefit of this type of studies as a tool for...     

Assessing the steady-state [·NO<Subscript>2</Subscript>] in environmental samples

Based on available literature data of [NO₂ ⁻], steady-state [·OH], and ·OH generation rate upon nitrate photolysis in environmental aqueous samples under sunlight, the steady-state [·NO₂], could be calculated. Interestingly, one to two orders of magnitude more ·NO₂ would be formed in photochemical processes in atmospheric water droplets compared to transfer from the gas phase. The relative importance of nitrite oxidation compared to nitrate photolysis as an ·NO₂ source would be higher in atmospheric than in surface waters. The calculated levels of ·NO₂ could lead to substantial transformation of phenol into nitrophenols in both atmospheric and surface waters.     

Review of potential environmental impacts of transgenic glyphosate-resistant soybean in Brazil

Transgenic glyphosate-resistant soybeans (GRS) have been commercialized and grown extensively in the Western Hemisphere, including Brazil. Worldwide, several studies have shown that previous and potential effects of glyphosate on contamination of soil, water, and air are minimal, compared to those caused by the herbicides that they replace when GRS are adopted. In the USA and Argentina, the advent of glyphosate-resistant soybeans resulted in a significant shift to reduced- and no-tillage practices, thereby significantly reducing environmental degradation by agriculture. Similar shifts in tillage practiced with GRS might be expected in Brazil. Transgenes encoding glyphosate resistance in soybeans are highly unlikely to be a risk to wild plant species in Brazil. Soybean is almost completely self-pollinated and is a non-native species in Brazil, without wild relatives, making introgression of transgenes from GRS virtually impossible. Probably the highest agricultural risk in adopting GRS in Brazil is related to weed resistance. Weed species in GRS fields have shifted in Brazil to those that can more successfully withstand glyphosate or to those that avoid the time of its application. These include Chamaesyce hirta (erva-de-Santa-Luzia), Commelina benghalensis (trapoeraba), Spermacoce latifolia (erva-quente), Richardia brasiliensis (poaia-branca), and Ipomoea spp. (corda-de-viola). Four weed species, Conyza bonariensis, Conyza Canadensis (buva), Lolium multiflorum (azevem), and Euphorbia heterophylla (amendoim bravo), have evolved resistance to glyphosate in GRS in Brazil and have great potential to become problems.     

Socioecological transition in the Cauca river valley,Colombia (1943–2010): towards an energy–landscape integrated analysis

Regional Environmental Change - Agroecosystems are facing a global challenge amidst a socioecological transition that places them in a dilemma between increasing land-use intensity to meet the...     

Silver nanoparticles induce histopathological alterations in juvenile Penaeus vannamei

Environmental Science and Pollution Research - The objective of this study was to evaluate the histopathological alterations in juvenile Penaeus vannamei caused by silver nanoparticles (AgNPs) for...