A proposed methodology for the definition of background and reference values for trace elements in fluvial sediments.

The Water Framework Directive (WFD, 2000/60/EC) mandates member states to consider trace element background values when establishing environmental quality standards (EQS) for sediments. This study proposes defining the "background" value as the trace element concentration that is consistently present in the unaltered natural environment, and the "reference" value as an upper limit of variation of naturally occurring concentrations, suggestive of anthropogenic enrichment if exceeded. We argue that background and reference values can be computed as the upper limits of the one-sided 95 % confidence interval for the median and for the 90th percentile, respectively.

Assessment of lettuces grown in urban areas for human consumption and as bioindicators of atmospheric pollution.

This study proposes using the network of urban gardens to grow vegetables and to monitor air quality, and it also evaluates whether food grown on a clean substrate in an urban environment is safe for consumption. For this purpose, lettuces were exposed to different degrees of air pollution in five locations in the city of Copenhagen, plus a reference site. Six specimens were placed at each site and, after the exposure period, half of each sample was washed.

1D_RnDPM: A freely available Rn production, diffusion, and partition model to evaluate confounding factors in the radon-deficit technique.

The radon-deficit technique is a powerful tool to detect and delineate sub-surface accumulations of organic contaminants. Field measurements of Rn in soil air, however, are affected by several confounding factors that can lead to the misinterpretation of results. Among the most influential are: vertical and lateral changes of lithology, fluctuating contaminant saturations with depth, varying water saturation ratios along the soil profile and atmospheric (and, therefore, soil) thermal oscillations.

Field performance of the radon-deficit technique to detect and delineate a complex DNAPL accumulation in a multi-layer soil profile.

The performance of the radon (Rn)-deficit technique has been evaluated at a site in which a complex DNAPL mixture (mostly hexachlorocyclohexanes and chlorobenzenes) has contaminated all four layers (from top to bottom: anthropic backfill, silt, gravel and marl) of the soil profile. Soil gas samples were collected at two depths (0.8 m and 1.

Modelling the Transference of Trace Elements between Environmental Compartments in Abandoned Mining Areas.

An openly accessible cellular automaton has been developed to predict the preferential migration pathways of contaminants by surface runoff in abandoned mining areas. The site where the validation of the results of the Contaminant Mass Transfer Cellular Automaton (CMTCA) has been carried out is situated on the steep flank of a valley in the Spanish northwestern region of Asturias, at the foot of which there is a village with 400 inhabitants, bordered by a stream that flows into a larger river just outside the village. Soil samples were collected from the steep valley flank where the mine adits and spoil heaps are situated, at the foot of the valley, and in the village, including private orchards.

Applicability and limitations of the radon-deficit technique for the preliminary assessment of sites contaminated with complex mixtures of organic chemicals: A blind field-test.

A blind field test with 136 independent measurements of radon (Rn) in soil air retrieved from a depth of 0.8 m in a decommissioned lindane (γ-hexachlorocyclohexane) production plant was undertaken to evaluate the performance of the Rn-deficit technique as a screening methodology for the location and delineation of subsurface accumulations of complex mixtures of organic contaminants. Maps of Rn iso-concentrations were drawn and interpreted before direct analytical information regarding concentrations of hexachlorocyclohexanes, chlorobenzenes and BTEX compounds in soil, groundwater and soil air were disclosed to the authors.

Urban Allotment Gardens for the Biomonitoring of Atmospheric Trace Element Pollution.

This study evaluates the results of the characterization of air pollution in urban green areas using edible plants. To this purpose, we examined the effect of location (i.e.

Applicability of radon emanometry in lithologically discontinuous sites contaminated by organic chemicals.

The applicability of radon (Rn) measurements to delineate non-aqueous phase liquids (NAPL) contamination in subsoil is discussed at a site with lithological discontinuities through a blind test. Three alpha spectroscopy monitors were used to measure radon in soil air in a 25,000-m area, following a regular sampling design with a 20-m grid. Repeatability and reproducibility of the results were assessed by means of duplicate measurements in six sampling positions.