ORIGINAL RESEARCH article
Front. Environ. Sci.
Sec. Environmental Citizen Science
Volume 13 - 2025 | doi: 10.3389/fenvs.2025.1623651
Citizen-Engaged Screening of 230 Pesticides in the Lake Naivasha Catchment, Kenya, Using Stir Bar Sorptive Extraction and GC-QToF-HRMS
Provisionally accepted
Caterina Cacciatori1,2*
Giulio Mariani1Sara Comero1
Enock Kiminta3
Anham Salyani4Jackie Myers2
Vincent Pettigrove2Bernd Manfred Gawlik1- 1European Commission, Joint Research Centre (JRC), Ispra, Italy
- 2Aquatic Environmental Stress Research Group, RMIT University, Bundoora, Australia
- 3Kenya National Water Resource Users Association (KeNAWRUA), Nairobi, Kenya
- 4World Water Quality Alliance, Nairobi, Kenya
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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.
Keywords: Citizens science, Pesticides, SBSE, GC-qTOF-HRMS, Lake Naivasha
Received: 06 May 2025; Accepted: 04 Aug 2025.
Copyright: © 2025 Cacciatori, Mariani, Comero, Kiminta, Salyani, Myers, Pettigrove and Gawlik. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Caterina Cacciatori, European Commission, Joint Research Centre (JRC), Ispra, Italy
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