Use of groundwater and reclaimed water for agricultural irrigation: Farmers' practices and attitudes and related environmental and health risks.

Agricultural reuse of treated wastewater (TWW) for irrigation is widely practiced. Its conjunctive use with freshwater is becoming more common to guarantee food security, while the rationale behind and its sustainability are quite arguable. The objective of this study is to better understand the drivers of the conjunctive use of TWW and groundwater (GW) in Nabeul region, Tunisia, and the potential environmental and health impacts taking into account farmers' practices and attitudes toward reuse. TWW used for irrigation exhibited relatively high salinity and high microbiological load. GW has a very high salinity. TWW and GW showed low concentrations of heavy metals (Al, Cd, Co, Cu, Cr, Mn, Ni, Pb, and Zn). Concentrations of pharmaceutical compounds were between Limits of Quantification and 13 µg/L. In GW, values were relatively high, especially for caffeine, carbamazepine, ofloxacin, and ketoprofen. Farmers have a low perception of the polluting load of TWW and GW and of their potential long-term impacts on agricultural environment, human health, and agricultural productivity. GW availability has facilitated its conjunctive use with TWW, either to augment water quantity and/or to improve its quality. Despite its low quality, GW timeliness for irrigation was the main driver to guarantee a better yield and quality of produces. Soil microbial community, bacterial biomass, denitrifying potential and carbon oxidation profiles were similar under TWW, GW and their conjunctive use. Though an effect of the sampling period was observed with a high abundance of denitrifying bacteria in the wet season and a low carbon oxidation activity at the end of the dry season. The conjunctive use of TWW and GW is very likely unsustainable from health and environmental perspectives. Balancing farmers' economic profit against the preservation of agricultural activity, linked to cultural and natural heritage, remains one of the challenges for decision-makers and regional stakeholders.

Monitoring of organochlorine pesticides in blood of women with uterine cervix cancer.

In Yucatan, Mexico, chronic exposure of Mayan population to pesticides is expected as about 30 per cent are drinking polluted water. Residues of organochlorine pesticides (OCP) were monitored in 18 municipalities of Yucatan with high mortality rates due to uterine cervix cancer. 70 blood samples collected from Mayan women living in livestock, agricultural and metropolitan area were analyzed for OCP. Solid Phase Extraction was performed on C18 cartridges and analyzed by Gas Chromatography with Electron Capture Detector. The results showed that the highest OCP levels were detected in blood of women living in the livestock area. OCP detected were endosulfan I (7.35 µg/mL), aldrin (3.69 µg/mL), 4,4' DDD (2.33 µg/mL), 1.39 and 1.46 µg/mL of δ-HCH. Women from the agricultural area had high concentrations of OCP in their blood, particularly dieldrin (1.19 µg/mL), and 1.26 µg/mL of 4,4' DDE. In the metropolitan area, 0.080 µg/mL of γ-HCH and 0.064 µg/mL of heptachlore were detected. This monitoring study was also based on epidemiological data of uterine cervical cancer. It was found that environmental factors may have facilitated the infiltration of OCP to the aquifer used for potable water supply. These factors in addition to poverty can have impacts on public health. This first exploratory study suggests that monitoring of OCP in human is important for the establishment of health promotion programs. The integrative analysis of both, environmental and social factors would be helpful to characterize the bioaccumulation of pesticides in humans.

Occurrence and distribution of PAHs, PCBs, and chlorinated pesticides in Tunisian soil irrigated with treated wastewater.

Treated wastewater (TWW) is a well recognized source of organic pollutants (OPs) that may accumulate during irrigation. For the first time, data on the occurrence of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyles (PCBs) and organochlorinated pesticides (OCPs) in wastewater irrigated soil in Nabeul (Tunisia) are reported. 13 PAHs, 18 PCBs and 16 OCPs were analyzed in soil samples collected at 0-10 and 10-20 cm depth before each and every irrigation and after the irrigation period expanding from June to October. Soil was extracted with an accelerated solvent extractor and analyzed by a tandem gas chromatograph in selected reaction monitoring mode (GC/MS/MS/SRM). OPs residues were detected before irrigation and accumulated at the end of the season for some of them. The total concentration of PAHs varied between 120.01 and 365.18 µg kg(-1) dry weight (dw) at 0-10 cm depth before and at the end of irrigation, respectively. The total concentration of PCBs varied between 11.26 and 21.89 µg kg(-1) dw at 0-10 cm, being higher than those reported for 10-20 cm. The six indicator PCB congeners (28, 52, 101, 138, 153, 180) were predominant. OCPs concentrations ranged between 12.49 and 21.81 µg kg(-1) at 0-10 cm and between 74.03 and 310.54 µg kg(-1) at 10-20 cm depth. DDT was predominant accounting for more than 94% of the total OCPs. In view of the present results, OPs are relevant to the agricultural environment, calling for more research on their persistence and potential transfer to plants and/or groundwater while taking into account farmers' practices.

Carbamazepine, carbamazepine epoxide and dihydroxycarbamazepine sorption to soil and occurrence in a wastewater reuse site in Tunisia.

Treated wastewater is being increasingly used for irrigation and aquifer replenishment through artificial recharge. However, wastewater reuse can result in contamination of exposed soil and groundwater by chemicals such as some pharmaceuticals and their metabolites. The fate of these molecules depends largely on their capacity to sorb onto soil and aquifer materials during infiltration. In this study, the sorption isotherm of carbamazepine (CBZ), an anti-seizure medication, and two of its metabolites, i.e. carbamazepine-10,11-epoxide (CBZ-EP) and 10,11-dihydro-10,11-dihydroxycarbamazepine (DiOH-CBZ), were determined in two soils in laboratory assays. In the field, the presence of CBZ and its metabolites were investigated in soil and in groundwater underlying an irrigated area with treated wastewater. The results showed that CBZ had the highest carbon normalised sorption coefficients in the two tested soils (irrigated soil and a Lufa SP2.4 reference soil) followed by CBZ-EP and DiOH-CBZ, indicating the relatively higher mobility of CBZ metabolites compared to CBZ. The chromatographic analysis revealed that CBZ and its two metabolites were present in treated wastewater used for irrigation and in groundwater. In soil samples, CBZ concentrations showed a build-up taking place with irrigation. The mobility of metabolites in soil and their potential biodegradation require further investigation.