Suchergebnisse

Air pollution legislation and control worldwide is based on the size of particulate matter (PM) to evaluate the effects on environmental and human health, in which the small diameter particles are considered more dangerous than larger sizes. This study investigates the composition, stability, size and dispersion of atmospheric settleable particulate matter (SePM) in an aqueous system. We aimed to interrogate the changes in the physical properties and characteristics that can contribute to increased metal uptake by aquatic biota. Samples collected in an area influenced by the steel and iron industry were separated into 8 fractions (425 to ≤10 μm) and analysed physically and chemically. Results from ICP-MS and X-ray showed that the PM composition was mainly hematite with 80% of Fe, followed by Al, Mn and Ti. Among 27 elements analysed we found 19 metals, showing emerging metallic contaminants such as Y, Zr, Sn, La, Ba and Bi. Scanning electron microscopy (SEM) showed that SePM fractions are formed by an agglomeration of nanoparticles. Furthermore, dynamic light scattering (DLS), zeta potential and nanoparticle tracking analysis (NTA) demonstrated that SPM were dissociated in water, forming nanoparticles smaller than 200 nm, which can also contribute to water pollution. This study highlights that SePM contamination may be substantially higher than expected under that allowed in atmospheric regulatory frameworks, thereby extending their negative effect to water bodies upon settling, which is an underexplored area of our knowledge. We therefore provide important insights for future investigations on safety regulations involving SePM in the environment, indicating the need to revise the role of SePM, not solely associated with air pollution but also considering their deleterious effects on water resources.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Consejo Nacional de Investigaciones Científicas y Técnicas ; Scottish Government ; Processo FAPESP: 2014/04832-3 ; Processo FAPESP: 2014/05701-0 ; Processo FAPESP: 2015/05258-1 ; Consejo Nacional de Investigaciones Científicas y Técnicas: FONCyT/PICT-1411 ; Consejo Nacional de Investigaciones Científicas y Técnicas: FONCyT/PICT-1597 ; Anthropogenic activities including metal contamination create well-known problems in coastal mangrove ecosystems but understanding and linking specific pollution sources to distinct trophic levels within these environments is challenging. This study evaluated anthropogenic impacts on two contrasting mangrove food webs, by using stable isotopes (δ13C, δ15N, 87Sr/86Sr, 206Pb/207Pb and 208Pb/207Pb) measured in sediments, mangrove trees (Rhizophora mangle, Laguncularia racemosa, Avicennia schaueriana), plankton, shrimps (Macrobranchium sp.), crabs (Aratus sp.), oysters (Crassostrea rhizophorae) and fish (Centropomus parallelus) from both areas. Strontium and Pb isotopes were also analysed in water and atmospheric particulate matter (PM). δ15N indicated that crab, shrimp and oyster are at intermediate levels within the local food web and fish, in this case C. parallelus, was confirmed at the highest trophic level. δ15N also indicates different anthropogenic pressures between both estuaries; Vitória Bay, close to intensive human activities, showed higher δ15N across the food web, apparently influenced by sewage. The ratio87Sr/86Sr showed the primary influence of marine water throughout the entire food web. Pb isotope ratios suggest that PM is primarily influenced by metallurgical activities, with some secondary influence on mangrove plants and crabs sampled in the area adjacent to the smelting works. To our knowledge, this is the first demonstration of the effect of anthropogenic pollution (probable sewage pollution) on the isotopic fingerprint of estuarine-mangrove systems located close to a city compared to less impacted estuarine mangroves. The influence of industrial metallurgical activity detected using Pb isotopic analysis of PM and mangrove plants close to such an impacted area is also notable and illustrates the value of isotopic analysis in tracing the impact and species affected by atmospheric pollution.