Behaviour of endosulfan residues in peppers, cucumbers and cherry tomatoes grown in greenhouse: evaluation by decline curves

Decline of endosulfan residues in pepper, cucumber and cherry tomatoes grown in greenhouses, and the corresponding statistical parameters, were evaluated assessing the formal approaches proposed by Timme, Frehse and Laska to study the behaviour of pesticide residues in crops. In all cases, the first-order reaction function was confirmed to describe the behaviour of endosulfan residues, but functions that best fit the experimental data were first-order for cucumber, RF-first-order for pepper and RF-1·5th-order for tomato. Half-life periods of endosulfan residues determined from the first-order function were 11·1(±1·3) days (cucumber), 15·2(±3·3) days (pepper) and 20·1(±6·6) days (tomato), whereas the values obtained from the optimal functions were close to 10 days for the three plantations.