In Guadeloupe, the use between 1972 and 1993 of chlordecone, an organochlorine insecticide, has permanently contaminated the island's soil, thus contaminating the food chain at its very beginning. There is today a strong societal requirement for an improved mapping of the contaminated zones. Given the extent of the areas to be covered, carrying out soil tests on each plot of the territory would be a long and expensive process. In this article, we explore a method of demarcating polluted areas. The approach adopted consists in carrying out, using surface water analyses, a hydrological delimitation that makes it possible to distinguish contaminated watersheds from uncontaminated ones. The selection of sampling points was based on the spatial analysis of the actual and potential contamination data existing at the beginning of the study. The approach was validated by soil analyses, after having compared the contamination data of the watersheds with the soil contamination data of the plots within them. The study thus made it possible to highlight new contaminated areas and also those at risk of contamination and to identify the plots to be targeted as a priority during future analysis campaigns by State services.

Three wells lying downstream of the Kirbet es-Samra sewage treatment plant (KS) waste stabilization ponds, and two wells lying upstream of them were monitored. Historic results over the two past decades were used in evaluating of KS effluent on the groundwater resources of the area. Prior to 1985, the downstream wells were of high quality, but later the water started to deteriorate. An increases in all parameters was encountered, although initially, the increase in certain parameters was mild and due to overpumping of the well water. Later this increase continued at a much higher rate, although the water table in the area by some 20m with a variety of indications showing domestic wastewater pollution effects. Groundwater measurements indicated a recharge mouth in the KS area and along Wadi Dhuleil. Hence, it can be deducted that a source of inferior water quality is recharging the groundwater and causing this increase in parameters. Since no source of pollution other than KS is encountered in the area, and because the parameters in the groundwater increase towards the KS and Wadi Dhuleil, it can be deducted that the effluent from KS is polluting the groundwater and rendering it unsuitable for almost all purposes. Comparatively, the two sample wells taken upstream of KS showed a mild increase in the water quality parameters until 1981-82, due to overpumping of the well water. But due to several wet years, the water table rose and these values decreased, continuing at a constant level. Since the groundwater flow is in the direction of Wadi Dhuleil, the negative effect of KS on groundwater resources can be clearly seen. If not stopped, this continuous manipulation of the groundwater resources will further pollute the groundwater resources of the entire area

Reductions in the apparent soil-water partition coefficients (K(d)* ) for 28 polychlorinated biphenyls (PCBs) caused by the surfactant sodium dodecylsulphate (SDS) in the aqueous phase were studied. Above the critical micelle concentration (CMC) of the surfactant, K(d)* was reduced by 2-3 orders of magnitude, but even far below CMC at environmentally relevant surfacant concentrations significant reductions in Kd3 were observed. The plot of the soil-water partition coefficient (K(d)) divided by K(d)* versus the concentration of SDS allowed for the calculation of monomer (K(mn)(oc)) and micellar (K(mc)(oc)) surfactant-water parrition coefficients normalized to organic carbon for each PCB congener. K(mn)(oc) values were comparable with published values for the partition of PCBs between natural dissolved organic matter and lake water. K(mc)(oc) values were up to 30 times higher than K(mn)(oc) values and comparable with published octanol-water distribution coefficients. The findings of the present study underline the potential of surfactants at concentrations below their CMC to mobilize otherwise strongly bound hydrophobic compounds in soil-water systems.