Estrogen-like and dioxin-like organic contaminants in reclaimed wastewater: transfer to irrigated soil and groundwater

In semi-arid regions, treated wastewater reuse for irrigation is a common practice since wastewater is considered as a non negligible water resource in these areas. However, treated wastewater contains traces of organic compounds which may contaminate the receiving environment i.e. soil and groundwater. Some of these organic compounds have the ability to bind to estrogen receptor (ER) or dioxin receptor (AhR, aryl hydrocarbon receptor). The fate of these compounds in effluent reused for irrigation, irrigated soils and groundwater is not well addressed yet. In the present study, estrogenic and dioxin-like activities were studied in three media: i) effluents reused for irrigation, ii) soils samples collected from the reclaimed water irrigated plot during six month irrigation, and iii) groundwater sampled before and after irrigation periods. Effluents reused for irrigation exhibited ER and AhR activities at 38.5±9.9 ng estradiol-equivalent/L (ng E2-EQ/L) and 113.3±27.7 ng dioxin-equivalent/L (ng TCDD-EQ/L), respectively. Soils showed ER activity (0.05 ng E2-EQ/g) only after 4 months of irrigation. AhR activities detected in all soil samples have not changed during irrigation. In groundwater, ER activities were detected in two piezometers indicating transfer of some estrogenic compounds.