Geotextile fibres retention properties to prevent surface water nonpoint contamination by pesticides in agricultural areas

In order to investigate the possible use of geotextiles for the retention of pesticides in agricultural watersheds, batch studies of the adsorption and desorption of three widely used pesticides onto/from commercially available geotextiles were performed. The three pesticides considered were diuron, isoproturon and azoxystrobin. Natural and polymeric fibres of jute, hemp, linen, polyamide, polyester and polypropylene were studied. The three most promising fibres appear to be polyamide, jute, and hemp, with adsorption percentages ranging from 35% to 80% at equilibrium. The adsorption kinetics obtained were rather fast. The observed adsorption data are discussed in the light of the physico-chemical characteristics of the different fibres. For jute, hemp and polyamide, desorption at equilibrium does not exceed 50% of the initially sorbed pesticide amount, with rather fast kinetics. Adsorption data are compared with those previously obtained for natural substrates (dead leaves and sediments) typical of agricultural watersheds. Adsorption on geotextile fibres was larger than for sediments, but was lower than for dead leaves.