Metals and arsenic in soils and corresponding vegetation at Central Elbe river floodplains (Germany).

Floodplain soils at the Elbe river are frequently polluted with metals and arsenic. High contents of these pollutants were detected down to subsoil layers. NH4NO3-extractable (phytoavailable) Cd, Ni, and Zn were elevated in horizons with high acidity. Among five common floodplain plant species, Artemisia vulgaris showed highest concentrations of Cd, Cu, and Hg, Alopecurus pratensis of As and Phalaris arundinacea of Ni, Pb, and Zn. Relationships were weak between metal concentrations in plants and phytoavailable stocks in soil. As and Hg uptake seems to be enhanced on long submerged soils. Enrichments of Cd and Hg are linked to a special plant community composition. Grassland herbage sampled in July/August revealed higher concentrations of As (+122%), Hg (+124%), and Pb (+3723%) than in May. To limit harmful transfers into the food chain, low-lying terraces and flood channels revealing highest contaminations or phytoavailabilities should be excluded from mowing and grazing.

Leaching behaviour of pharmaceuticals in soil-testing-systems: a part of an environmental risk assessment for groundwater protection.

The leaching behaviour of six selected pharmaceuticals was tested in different soils. Leaching experiments are a part of environmental risk assessment to estimate the distribution and fate of these pharmaceuticals in the environment. Based on the results of this assessment their mobility in soil and their potential to contaminate groundwater was evaluated. When assessing the leaching behaviour of these compounds, the influence of the properties (e.g. grain size distribution, pH, Corg) of different soils has to be taken into account. The test results indicated that the leaching potential found could be rated as low for diazepam, ibuprofen, ivermectin and carbamazepine. Therefore, contamination of the groundwater with these substances seems to be unlikely if the groundwater level is covered with sufficient layers of the soils investigated. Clofibric acid and iopromide were very mobile under the experimental conditions and thus, groundwater contamination would be possible if the soil is exposed to these pharmaceuticals, i.e. wastewater irrigation. These results are more or less in agreement with groundwater monitoring data found in the literature for ibuprofen and diazepam which were in general not present in groundwater, while clofibric acid and iopromide were frequently detected. However, a discrepancy was found for carbamazepine, since it occurs very often in groundwater. This discrepancy might be explained by the fact that the leaching tests were performed with soil, whereas in reality the groundwater contamination occurs mainly over river sediments and sub soil from receiving waters.