A model-based assessment of the environmental impact of land-use change across scales in Southern Amazonia

Regional Environmental Change - This article describes the design of a new model-based assessment framework to identify and analyse possible future trajectories of agricultural development and...     

Carbon-optimised land management strategies for southern Amazonia

Regional Environmental Change -     

Human exposure to polybrominated diphenyl ethers (PBDE), as evidenced by data from a duplicate diet study, indoor air, house dust, and biomonitoring in Germany

Polybrominated diphenyl ethers (PBDE) are used as flame retardants in a wide variety of products. As part of the Integrated Exposure Assessment Survey (INES), this study aimed to characterize the exposure of an adult German population using duplicate diet samples, which were collected daily over seven consecutive days, and indoor air and house dust measurements. Our study population consisted of 27 female and 23 male healthy subjects, aged 14–60 years, all of whom resided in 34 homes in southern Bavaria. In these 34 residences the air was sampled using glass fiber filters and polyurethane foams and the dust was collected from used vacuum cleaner bags.The median (95th percentile) daily dietary intake of six Tetra- to HeptaBDE congeners was 1.2 ng/kg b.w. (3.3 ng/kg b.w.) or 67.8 ng/day (208 ng/day) (calculated from the 7-day median values of each study subject). Concentrations in indoor air and dust (cumulative Tri- to DecaBDE congener readings) ranged from 8.2 to 477 pg/m³ (median: 37.8 pg/m³) and 36.6 to 1580 ng/g (median: 386 ng/g), respectively. For some congeners, we identified a significant correlation between air and dust levels.The median (95th percentile) blood concentration of total Tetra- to HexaBDE congener readings was 5.6 (13.2) ng/g lipid. No significant sex differences were observed, but higher blood concentrations were found in younger participants. Using a simplified toxicokinetic model to predict the body burden from exposure doses led to results that were of the same order of magnitude as the measured blood concentrations.Based on these measurements and given our exposure assumptions, we estimated for the total tetra- to heptabrominated congener count an average (high) comprehensive total daily intake of 1.2 ng/kg b.w. (2.5 ng/kg b.w.). Overall, our results suggest that dietary exposure is the dominant intake pathway at least in our study population, responsible for 97% (average intake) and 95% (high intake) of the total intake of an adult population.     

Rüstungsaltlasten

Risk assessment of contaminated sites from abandoned ammunition plants follows a multi-stage procedure with its own specific requirements for the toxicological assessment of chemical contaminants. Thus, the 22 explosives and related compounds (STVs) were classified according to carcinogenicity, genotoxicity and evaluation numbers for their toxicological potential (ENs). These characteristics permit a specific toxicological assessment and ranking at the stage of “historical reconnaissance”, independent of an evaluation of the contaminant concentrations. With a view to “orientative site evaluation” for the assessment of explosives and related compounds in groundwater and drinking water, toxicologically related guide values based on the ENs of toxicological potential as well as TDI-based guide values for STVs in soil were derived as based on toxicologically safe body doses and lifelong exposure (TDI=Tolerable Daily Intake). For regulatory purposes, substance related precautionary values are defined for probable carcinogens and contaminants with essential lacks in the toxicological data base.     

Atmospheric lead and bromine in Germany: post-abatement levels,variabilities and trends

INTENTION, GOAL, SCOPE, BACKGROUND: Abatement measures since the 1970s have depleted lead and bromine levels in the atmosphere over large parts of Europe. Our knowledge of the atmospheric cycling of these elements while a several decade-long period of intensive mobilization reaches its end is incomplete. OBJECTIVE: We have characterized the trends in the atmospheric levels of Pb and Br and present-day temporal and spatial variabilities. METHODS: This was achieved by short-term (weeks) and long-term (years) measurements of particulate Pb and Br at various sites in Germany. Samples of atmospheric particulate matter were collected on filter membranes and analyzed by x-ray fluorescence. RESULTS AND DISCUSSION: Average Pb levels at rural and urban inland sites did not exceed concentrations in background aerosols, sampled at a Baltic Sea coastal site, by more than a factor of 3. Due to sea salt, bromide inland particulate Br levels are below those at a coastal site. There, non-sea salt Br, however, is significant as well. Urban Pb and Br levels are not necessarily higher than rural levels. The concentration levels have decreased in such a way that the previously common source, local vehicular traffic emissions, is no longer predominant. Regional rather than local sources have been increasingly determining the concentrations since the 1990s. This is more pronounced for Br than for Pb. We found indications for coal burning and long-range transport as significant Pb sources. For particulate Pb species, a range of ages (elapsed time since Pb emission) has been found. This range shows two maxima corresponding to characteristic times of 72 and 24 h. CONCLUSIONS: The (mean) atmospheric residence time of particulate Pb is longer than the residence time of Br, in particular in the wintertime. The chemical species contributing to atmospheric Pb should be addressed in future studies. RECOMMENDATION AND OUTLOOK: Clearly, despite effective abatement measures, atmospheric Pb will continue to be dominated by anthropogenic mobilization. The influence from long-range transport can be expected to decrease with the effectiveness of abatement programmes in neighbouring countries of the region.