When field pollution is heterogeneous due to localized pesticide application, as is the case of chlordecone (CLD), the mean level of pollution is difficult to assess. Our objective was to design a decision support tool to optimize soil sampling. We analyzed the CLD heterogeneity of soil content at 0-30- and 30-60-cm depth. This was done within and between nine plots (0.4 to 1.8 ha) on andosol and ferralsol. We determined that 20 pooled subsamples per plot were a satisfactory compromise with respect to both cost and accuracy. Globally, CLD content was greater for andosols and the upper soil horizon (0-30 cm). Soil organic carbon cannot account for CLD intra-field variability. Cropping systems and tillage practices influence the CLD content and distribution; that is CLD pollution was higher under intensive banana cropping systems and, while upper soil horizon was more polluted than the lower one with shallow tillage (<40 cm), deeper tillage led to a homogenization and a dilution of the pollution in the soil profile. The decision tool we proposed compiles and organizes these results to better assess CLD soil pollution in terms of sampling depth, distance, and unit at field scale. It accounts for sampling objectives, farming practices (cropping system, tillage), type of soil, and topographical characteristics (slope) to design a relevant sampling plan. This decision support tool is also adaptable to other types of heterogeneous agricultural pollution at field level. (Résumé d'auteur)

The terrestrial moss Hypnum cupressiforme was collected in the surroundings of oil plant Slovnaft (Slovakia) and oil industry in Ploiesti (Romania) to monitor heavy metal atmospheric deposition. A comparative evaluation of heavy metal atmospheric deposition recorded at the two locations versus a background area in Europe as Norway is presented. The highest concentrations were observed for V, Cr, Fe, Co, Ni and As at Ploiesti and for V, Cr, Fe, Co, and Ag at Slovnaft. This moss is very useful as biomonitoring organism to indicate and characterize deposition of atmospheric pollutants nearby oil plants

The mosses Pleurozium schreberi, Hylocomium splendes and Dicranum scoparium were used as biomonitors to study the atmospheric deposition of heavy metals on the territory of Slovakia. The samples of mosses were collected on 86 permanent plots. Comparison with limit values from Norway shows strong pollution of the examined areas of Slovakia with many different heavy metals. The maximum level of pollution by heavy metals was observed in the region Gemer-Spis. The most important feature of sampling is that it correlates with the European Moss-Survey-2000 and the results obtained will be incorporated in the Atlas of Heavy Metal Atmospheric Deposition in Europe