Citizen-engaged screening of 230 pesticides in the Lake Naivasha catchment, Kenya, using stir bar sorptive extraction and GC-QToF-HRMS

The presence of pesticides in surface water samples from the Lake Naivasha catchment area in Kenya was investigated using Stir Bar Sorptive Extraction (SBSE) and Gas Chromatograph with Quadruple Time-Of-Flight High Resolution Mass Spectrometry (GC-QToF-HRMS). A total of 56 pesticides were detected,...

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Main Authors: Caterina Cacciatori, Giulio Mariani, Sara Comero, Enock Kiminta, Anham Salyani, Jackie Myers, Vincent Pettigrove, Bernd Manfred Gawlik
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-08-01
Series:Frontiers in Environmental Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fenvs.2025.1623651/full
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author Caterina Cacciatori
Caterina Cacciatori
Giulio Mariani
Sara Comero
Enock Kiminta
Anham Salyani
Jackie Myers
Vincent Pettigrove
Bernd Manfred Gawlik
author_facet Caterina Cacciatori
Caterina Cacciatori
Giulio Mariani
Sara Comero
Enock Kiminta
Anham Salyani
Jackie Myers
Vincent Pettigrove
Bernd Manfred Gawlik
author_sort Caterina Cacciatori
collection DOAJ
description The presence of pesticides in surface water samples from the Lake Naivasha catchment area in Kenya was investigated using Stir Bar Sorptive Extraction (SBSE) and Gas Chromatograph with Quadruple Time-Of-Flight High Resolution Mass Spectrometry (GC-QToF-HRMS). A total of 56 pesticides were detected, belonging to different classes including fungicides (48.2%), insecticides (17.9%), herbicides (12.5%), and other categories. The most frequently detected pesticides were the fungicides boscalid, fluopyram, hexachlorobenzene, tebuconazole, herbicide metolachlor, and insecticides bromopropylate, chlorpyrifos, diazinon, and the synergist piperonyl butoxide. The site with the highest pesticides detections was adjacent to Lake Naivasha, near a wastewater treatment plant discharge. Toxicological risk assessments revealed that the acute toxic unit threshold for crustaceans (TU = 0.01) was exceeded in several samples, primarily due to the presence of chlorpyrifos and diazinon. Notably, chlorpyrifos, banned for all agricultural purposes in Kenya in 2024, was detected in several samples. These findings highlight the presence of pesticides in Kenyan water bodies, posing potential risks to aquatic ecosystems and underscore a need for stricter regulation, ongoing monitoring, and the adoption of sustainable agricultural practices to minimise the impact of pesticides on the environment.
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publisher Frontiers Media S.A.
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spelling doaj-art-b0002b33056e4fb8a2a5100e243a1f642025-08-20T05:33:02ZengFrontiers Media S.A.Frontiers in Environmental Science2296-665X2025-08-011310.3389/fenvs.2025.16236511623651Citizen-engaged screening of 230 pesticides in the Lake Naivasha catchment, Kenya, using stir bar sorptive extraction and GC-QToF-HRMSCaterina Cacciatori0Caterina Cacciatori1Giulio Mariani2Sara Comero3Enock Kiminta4Anham Salyani5Jackie Myers6Vincent Pettigrove7Bernd Manfred Gawlik8European Commission, Joint Research Centre (JRC), Ispra, ItalyAquatic Environmental Stress Research Group (AQUEST), RMIT University, Bundoora, VIC, AustraliaEuropean Commission, Joint Research Centre (JRC), Ispra, ItalyEuropean Commission, Joint Research Centre (JRC), Ispra, ItalyKenya National Water Resource Users Association (KeNAWRUA), Nairobi, KenyaWorld Water Quality Alliance, Nairobi, KenyaAquatic Environmental Stress Research Group (AQUEST), RMIT University, Bundoora, VIC, AustraliaAquatic Environmental Stress Research Group (AQUEST), RMIT University, Bundoora, VIC, AustraliaEuropean Commission, Joint Research Centre (JRC), Ispra, ItalyThe presence of pesticides in surface water samples from the Lake Naivasha catchment area in Kenya was investigated using Stir Bar Sorptive Extraction (SBSE) and Gas Chromatograph with Quadruple Time-Of-Flight High Resolution Mass Spectrometry (GC-QToF-HRMS). A total of 56 pesticides were detected, belonging to different classes including fungicides (48.2%), insecticides (17.9%), herbicides (12.5%), and other categories. The most frequently detected pesticides were the fungicides boscalid, fluopyram, hexachlorobenzene, tebuconazole, herbicide metolachlor, and insecticides bromopropylate, chlorpyrifos, diazinon, and the synergist piperonyl butoxide. The site with the highest pesticides detections was adjacent to Lake Naivasha, near a wastewater treatment plant discharge. Toxicological risk assessments revealed that the acute toxic unit threshold for crustaceans (TU = 0.01) was exceeded in several samples, primarily due to the presence of chlorpyrifos and diazinon. Notably, chlorpyrifos, banned for all agricultural purposes in Kenya in 2024, was detected in several samples. These findings highlight the presence of pesticides in Kenyan water bodies, posing potential risks to aquatic ecosystems and underscore a need for stricter regulation, ongoing monitoring, and the adoption of sustainable agricultural practices to minimise the impact of pesticides on the environment.https://www.frontiersin.org/articles/10.3389/fenvs.2025.1623651/fullcitizen sciencepesticidesSBSEGC-QToF-HRMSLake Naivasha, Kenya
spellingShingle Caterina Cacciatori
Caterina Cacciatori
Giulio Mariani
Sara Comero
Enock Kiminta
Anham Salyani
Jackie Myers
Vincent Pettigrove
Bernd Manfred Gawlik
Citizen-engaged screening of 230 pesticides in the Lake Naivasha catchment, Kenya, using stir bar sorptive extraction and GC-QToF-HRMS
Frontiers in Environmental Science
citizen science
pesticides
SBSE
GC-QToF-HRMS
Lake Naivasha, Kenya
title Citizen-engaged screening of 230 pesticides in the Lake Naivasha catchment, Kenya, using stir bar sorptive extraction and GC-QToF-HRMS
title_full Citizen-engaged screening of 230 pesticides in the Lake Naivasha catchment, Kenya, using stir bar sorptive extraction and GC-QToF-HRMS
title_fullStr Citizen-engaged screening of 230 pesticides in the Lake Naivasha catchment, Kenya, using stir bar sorptive extraction and GC-QToF-HRMS
title_full_unstemmed Citizen-engaged screening of 230 pesticides in the Lake Naivasha catchment, Kenya, using stir bar sorptive extraction and GC-QToF-HRMS
title_short Citizen-engaged screening of 230 pesticides in the Lake Naivasha catchment, Kenya, using stir bar sorptive extraction and GC-QToF-HRMS
title_sort citizen engaged screening of 230 pesticides in the lake naivasha catchment kenya using stir bar sorptive extraction and gc qtof hrms
topic citizen science
pesticides
SBSE
GC-QToF-HRMS
Lake Naivasha, Kenya
url https://www.frontiersin.org/articles/10.3389/fenvs.2025.1623651/full
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