Occurrence of Unapproved Pesticides and their Ecotoxicological Significance for an Agriculturally Influenced Reservoir and its Tributaries in Nepal

A - Papers appearing in refereed journals

Acharya, S., Upadhayay, H. R, Houbraken, H., Bajracharya, R. M. and Spanoghe, P 2023. Occurrence of Unapproved Pesticides and their Ecotoxicological Significance for an Agriculturally Influenced Reservoir and its Tributaries in Nepal. Water Air And Soil Pollution. 234, p. 565. https://doi.org/10.1007/s11270-023-06570-8

AuthorsAcharya, S., Upadhayay, H. R, Houbraken, H., Bajracharya, R. M. and Spanoghe, P
Abstract

Many catchments in Nepal are affected by intensive agricultural activities, leading to extensive pesticide usages. This study aimed to assess pesticide abundance in concurrently collected water, sediment and fish samples for the first time in intensively cultivated catchment (Indra Sarowar) located in the mid-hill region of Nepal during the rice and vegetables growing season. A total of 75 pesticides were analysed, of which 4 pesticides (alachlor, diuron, metalaxyl and pyrimethanil) were present in water with detection frequency (DF) > 40%, with alachlor (0.62 – 2.68 µg L−1) being ubiquitous. In the sediment of tributaries, the pesticides p,p′-DDT, β-HCH, alachlor and diuron were detected with DF exceeding 40%, where β-HCH was commonly observed (DF = 92%) with concentration ranging from 6.29 – 99.22 µg kg−1. The ecotoxicological risk indicated that herbicides (alachlor and diuron) posed a high risk to aquatic organisms in both tributaries and reservoir water. Such risk in sediment was even more pronounced, with alachlor and diuron showing up to 2.3 and 53.7 times higher risk respectively compared to water samples. However, none of these herbicides were detected in fish muscles. Among the fish species studied, pyrimethanil was the only quantified pesticide in edible tissue of both cage cultured (0.35 – 1.80 µg g−1 ww) and open stock fishes (0.06 – 1.12 µg g−1 ww). The consumer risk assessment showed very low human health risk associated with fish consumption (HQ < 0.2). Nonetheless, long-term consumption of contaminated fish may pose some risk that cannot be ignored. Overall, this study generated the benchmark data highlighting pervasive presence of banned (DDT, endosulfan, HCH) and unapproved (alachlor, diuron, pyrimethanil) pesticides in the environmental compartments in the mid-hill’s streams of Nepal.

KeywordsEnvironmental compartments ; Sediments; Pesticide cocktail; Risk assessment ; Catchment; Water–sediment-fish continuum
Year of Publication2023
JournalWater Air And Soil Pollution
Journal citation234, p. 565
Digital Object Identifier (DOI)https://doi.org/10.1007/s11270-023-06570-8
Web address (URL)https://link.springer.com/article/10.1007/s11270-023-06570-8
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeS2N - Soil to Nutrition - Work package 3 (WP3) - Sustainable intensification - optimisation at multiple scales
Publisher's version
Supplemental file
Output statusPublished
Publication dates
Online18 Aug 2023
Publication process dates
Accepted31 Jul 2023
PublisherSpringer
ISSN0049-6979

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