Pesticides groundwater monitoring

The goal of a groundwater monitoring plan for pesticides is to produce water samples that are representative of the aquifer under study at the time of sample collection. Materials and methods must be established prior to implementing a monitoring program... 

Keyword Catalonia, Groundwater, Monitoring, Polar pesticides... 

In order to ascertain the degree of accomplishment of the aforementioned Directive 2006/118/EC in Catalonia (NE, Spain) and better characterise the nature of the contamination of these aquifers by pesticides, a monitoring programme was carried out on various selected hydrological units intended to be among the most vulnerable and relevant ones because of intensive agricultural activity and use for human consumption. The number of aquifers analysed depends more or less on the extension of the groundwater body. Eor example, bodies M46 and M21 present extensions of 18 and 72 km, respectively, and just one and two aquifers of each body were analysed, respectively. In contrast, body Ml8 (Maresme) presents an extension of more than 400 km, and nine different aquifers were analysed. 

Groundwater monitoring is increasing in importance as part of the Water Framework Directive (WFD). In 2001, over 600 groundwater sites were monitored. Figure 4 shows some pesticides between the most frequendy detected in groundwater at concentrations greater than 0.1 pg/1. ... 

Bentazone has been monitored in the NRA Anglian Region since 1993 and the results show that bentazone is regularly present in surface and groundwaters. Currently there are no restrictions on its use, but bentazone is due to be reviewed under the Authorizations Directive, the new European legislation for pesticide approvals, and the issue of water pollution will be raised. 

About 1.3 billion is projected to be spent monitoring pesticides in wells and groundwater resources if an effective program were initiated (Pimentel, D., in manuscript). 

The solubility of methyl parathion is not sufficient to pose a problem in runoff water as determined by an empirical model of Wauchope and Leonard (1980). Some recent monitoring data, however, indicate that methyl parathion has been detected in surface waters (Senseman et al. 1997). In a study to determine the residue levels of pesticides in shallow groundwater of the United States, water samples from 1,012 wells and 22 springs were analyzed for methyl parathion. No methyl parathion was detected in any of the water samples (Kolpin et al. 1998). In a study of water from near-surface aquifers in the Midwest, no methyl parathion was detected in any of the water samples from 94 wells that were analyzed for pesticide levels (Kolpin et al. 1995). Leaching to groundwater does not appear to be a significant fate process. 

Barcelo D, Chiron S, Fernandez Alba A, Valverde A, Alpendurada MF (1996) Monitoring pesticides and metabolites in surface water and groundwater in Spain. Herbicide Metabolites in Surface Water and Groundwater, vol 630, pp 237-253... 

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