Abstract The present study assessed pesticide contamination in the reef sediments of Kavaratti Island to understand its spatial distribution and associated ecological risks. This study presents a comprehensive assessment of pesticide contamination in the reef sediments of Kavaratti Island, Lakshadweep, with a focus on spatial distribution and ecological risk. Out of 55 target pesticide compounds spanning multiple chemical classes, 30 (54.5%) were detected, reflecting extensive contamination across the reef system. Organochlorine pesticides (OCPs) dominated the profile (46%), followed by organophosphate pesticides (27%), dinitroanilines (10%), thiocarbamates (7%), ureas (5%), oxadiazoles (3%), and pyrethroids (2%). Insecticides accounted for the majority (62%) of detections, with herbicides, fungicides, and acaricides contributing 20%, 12%, and 6%, respectively. Diuron (1.178 µg/kg) was found to be dominant among the pesticides detected which falls below the category of urea pesticides. Persistent Organic Pollutants (POPs), particularly o,p’-DDE and o,p’-DDD, were prevalent, indicating historical usage and sustained anaerobic degradation, as evidenced by DDT derivative ratios exceeding 0.5. Spatial analysis revealed pronounced variation across reef zones, with lagoon stations exhibiting the highest mean concentrations (0.184 µg/kg), attributed to localized inputs and limited hydrodynamic flushing. Ecotoxicological risk assessments, both individual and cumulative, identified 42% of the detected pesticides as highly hazardous and risk quotient values exceeded critical thresholds (RQ > 10) in multiple lagoon stations, signifying considerable threats to aquatic biota, particularly coral reef ecosystems. These findings highlight the critical need to implement effective mitigation strategies and enforce improved pollution control measures to preserve the delicate reef ecosystem of Lakshadweep and prevent long-term damage from persistent pesticide contamination. Research highlights <UnorderedList Mark="Bullet"> <ItemContent> Diverse industrial and legacy pesticides including persistent organic pollutants were detected in Kavaratti’s reef sediments, indicating persistent pollution and historical inputs. </ItemContent> <ItemContent> Lagoon stations showed the highest contamination due to restricted flushing and higher anthropogenic influence, while outer and intermediate zones had lower concentrations. </ItemContent> <ItemContent> Nearly 42% of detected pesticides were highly hazardous, posing severe risks to coral reef biodiversity and marine organisms. </ItemContent> <ItemContent> Immediate pollution control measures are essential to prevent long-term pesticide-induced ecological threats in Lakshadweep’s fragile marine ecosystem. </ItemContent> </UnorderedList>

Distribution trends and risk assessment of pesticides: First report from the administrative capital of Lakshadweep

期刊论文
发表日期：

2026年2月25日

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R Dhinesh,
S S Kirthiga,
Anu Gopinath,
R S Mahendra,
Prakash Chandra Mohanty,
Sudheer Joseph,
T M Balakrishnan Nair,
R Harikumar

摘要

Abstract

The present study assessed pesticide contamination in the reef sediments of Kavaratti Island to understand its spatial distribution and associated ecological risks. This study presents a comprehensive assessment of pesticide contamination in the reef sediments of Kavaratti Island, Lakshadweep, with a focus on spatial distribution and ecological risk. Out of 55 target pesticide compounds spanning multiple chemical classes, 30 (54.5%) were detected, reflecting extensive contamination across the reef system. Organochlorine pesticides (OCPs) dominated the profile (46%), followed by organophosphate pesticides (27%), dinitroanilines (10%), thiocarbamates (7%), ureas (5%), oxadiazoles (3%), and pyrethroids (2%). Insecticides accounted for the majority (62%) of detections, with herbicides, fungicides, and acaricides contributing 20%, 12%, and 6%, respectively. Diuron (1.178 µg/kg) was found to be dominant among the pesticides detected which falls below the category of urea pesticides. Persistent Organic Pollutants (POPs), particularly o,p’-DDE and o,p’-DDD, were prevalent, indicating historical usage and sustained anaerobic degradation, as evidenced by DDT derivative ratios exceeding 0.5. Spatial analysis revealed pronounced variation across reef zones, with lagoon stations exhibiting the highest mean concentrations (0.184 µg/kg), attributed to localized inputs and limited hydrodynamic flushing. Ecotoxicological risk assessments, both individual and cumulative, identified 42% of the detected pesticides as highly hazardous and risk quotient values exceeded critical thresholds (RQ > 10) in multiple lagoon stations, signifying considerable threats to aquatic biota, particularly coral reef ecosystems. These findings highlight the critical need to implement effective mitigation strategies and enforce improved pollution control measures to preserve the delicate reef ecosystem of Lakshadweep and prevent long-term damage from persistent pesticide contamination.

Research highlights

Diverse industrial and legacy pesticides including persistent organic pollutants were detected in Kavaratti’s reef sediments, indicating persistent pollution and historical inputs.

Lagoon stations showed the highest contamination due to restricted flushing and higher anthropogenic influence, while outer and intermediate zones had lower concentrations.

Nearly 42% of detected pesticides were highly hazardous, posing severe risks to coral reef biodiversity and marine organisms.

Immediate pollution control measures are essential to prevent long-term pesticide-induced ecological threats in Lakshadweep’s fragile marine ecosystem.