Distribution of Organophosphorus Pesticides in the Bed Sediments of a Backwater System Located in an Agricultural Watershed: Influence of Seasonal Intrusion of Seawater

Abstract

This article focuses on the temporal and spatial distribution of three organophosphorous pesticides-malathion, methyl parathion, and chlorpyrifos-in the sedimentary environment of a backwater ecosystem, Kuttanad backwaters, situated in Kerala, India. Based on salinity distribution, geographic characteristics, and human activities prevailing in the area, the study area was divided into three zones: zone 1 with riverine characteristics, zone 2 with freshwater characteristics during and after the monsoon season and estuarine characteristics during the premonsoon season, and zone 3 with estuarine characteristics. The organophosphorus pesticides in the study area showed the order of enrichment as chlorpyrifos >malathion >methyl parathion. While studying the variations in pesticide concentrations seasonally, higher concentrations were observed during the premonsoon monsoon season, with the concentrations being lower than the detectable level. Sediment characteristics, such as pH, texture, organic carbon, moisture content, etc., had reflective effect on the degradation rates of pesticides. The runoff water from the paddy fields made a larger contribution of pesticide pollution to the study area.

Monitoring of organochlorine and organophosphorus pesticide residues in water during different seasons of Tighra reservoir Gwalior, Madhya Pradesh, India

“…The farers of the region are spraying huge amount of this pesticide along with fertilizers to control different pests that results in an appreciable amount of methyl parathion in the water samples of Tighra reservoirs. The present study is in accordance with the results of Babu et al (2011) and Rehana et al (1995), who reported either absence of The overall concentration of dichlorovas is higher as compared to other organophosphorus pesticides as shown in Fig. 2.…”

Low and high doses of UV-B differentially modulate chlorpyrifos-induced alterations in nitrogen metabolism of cyanobacteria

“…2 mg ml À 1 remained inhibitory. In order to assess the instantaneous effect (and not the long term effect), the tested doses were selected too high to be environmentally realistic doses [which ranges from 1 to 7 ng g À 1 sediment, 0.002-0.172 mg g À 1 soil and 0.607-1.121 mg L À 1 in ground water (Kumari et al, 2008;Babu et al, 2011)]. Further, the tested doses are relevant because at the time of exposure, farmers generally add pesticides more than the recommended dose.…”

Removal of methyl parathion by surfactant-assisted soil washing and subsequent wastewater biological treatment

“…6) Several studies have reported the presence of MP and its metabolite residues in human food, vegetables, honey, milk, and processed products, such as yogurt. [7][8][9] In addition, MP has been reported in atmospheric samples, 10) sediment samples, 11) fresh water samples, 12) and marine water samples. 13) Furthermore, the e ects of MP on the behavior of bees have been reported at sublethal doses.…”