Parameters Affecting the Decay of Some Organophosphorus Pesticides: A Study by High-Performance Liquid Chromatography

Abstract

An HPLC procedure has been developed to follow the decay of malathion and methylparathion under control conditions using an μ‐Bondapak C18 column with a mixture of acetonitrile and water as to mobile phase and an ultraviolet detector for detection. Studies have been conducted to monitor their degradation in water and soil at different temperatures, pH and organic content. The results show that the persistance of the pesticides decreases with increase in temperature, pH and organic content. © 1997 by John Wiley & Sons, Ltd.

Degradation of thiram in water, soil and plants: a study by high‐performance liquid chromatography

“…In this regard thiram is more stable than the other carbamates, namely mancozeb ( t 1/2 = 1–3 days at pH 7 at 25°C; US Environmental Protection Agency, ) and carbofuran ( t 1/2 = 4 days on root; Menzie, ). If one compares the thiram with the two well‐known organophosphorus pesticides, malathion ( t 1/2 = 5.4 days at pH 6.3 in soil at 20°C) and methyl parathion ( t 1/2 = 6.2 days at pH 6.3 in soil at 20°C; Kaur et al , ) the average half life of thiram slightly more.…”

Dissipation and Residues of Thiram in Potato and Soil

“…Compared to the half-life of thiram on tomato fruit (10.3 days), radish leaf (11.3 days) and radish root (5.8 days) [21], paddy plants (1.5-1.8 days) [22], and mushroom (4.2 hours) [23], the varied decay rate of thiram in different crops was perhaps due to growth dilution besides environmental factors. In the case of soil, the decay of thiram was affected by many factors, such as light, heat, pH, moisture, content of clay, and mineral ion [24]. The degradation trial was conducted in July in Beijing and in May in Hunan and Jiangsu.…”