Adsorption of Selected Pesticides on a Rigid PVC Lysimeter

Abstract

AbstractLysimeters have traditionally been made out of stainless steel and teflon to monitor soil solutions and groundwater. The possibility of adsorption of organic chemicals to polyvinyl chloride (PVC) lysimeters, a more economical alternative to stainless steel, has led to debate over their suitability for groundwater sampling. The adsorption of different pesticide chemistries, chloroacetanilide (alachlor (2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)acetamide)), s‐triazine (atrazine (6 ‐ chloro ‐ N ‐ ethyl ‐ N′‐1‐methylethyl)‐1‐3‐5‐triazine‐2,4‐diamine)), chloronicotinyl (intidacloprid (1‐[(6‐chloro‐3‐pyridinyl)‐methyl]‐N‐nitro‐2‐imidazolidinimine)), organophosphorus (isofenphos (1‐methylethyl 2‐[[ethoxy[(1‐methylethyl)amino]phosphinothioyl] oxy]benzoate)), sulfonylurea (nicosulfuron (2‐[[[[(4,6‐dimethoxy‐2‐pyr‐imidinyl) amino ] carbonyl]amino]sulfonyl]‐N,N‐dimethyl ‐3‐pyridine carboxamide)), and azole (triadimefon (1‐(4‐chlorophenoxy)‐3,3‐dimethyl‐1‐(1H‐1,2,4‐triazol‐1‐yl)‐2‐butanone)), on a lysimeter constructed from rigid PVC was determined to evaluate the suitability of PVC material for use in groundwater sampling. Among all pesticides tested, only isofenphos demonstrated slight adsorption (9% of applied) on the lysimeter; adsorption was rapid and isophenfos was not easily desorbed with methanol and water. None of the other pesticides adsorbed to the lysimeter. When selecting a lysimeter, potential adsorptive interactions between other pesticide chemistries and the materials used in the lysimeter construction should be evaluated.