Legacy (Organochlorine) and Current Use (Neonicotinoid) Pesticides in Fish from Two Subtropical River Basins
- 1Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
- 2Department of Environmental Science, School of Ecological and Human Sustainability, College of Agriculture and Environmental Sciences, University of South Africa, Gauteng, South Africa
- 3Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
Abstract
The rapid population growth across Africa has increased the demand for food production, resulting in increased pesticide use. South Africa is among the top four pesticide importers in Sub-Saharan Africa, raising significant concerns regarding the contamination of freshwater ecosystems. Organochlorine pesticides (OCPs), historically used for agriculture and vector control, persist in the environment due to their high lipophilicity and long half-lives. Despite bans on many OCPs, residues remain in aquatic systems, potentially affecting non-target organisms such as fish. Similarly, neonicotinoids, introduced as safer alternatives, are now linked to adverse effects on aquatic biota, yet little is known about their bioaccumulation in wild fish species in southern Africa. This study investigated 13 neonicotinoids and 19 OCPs in fish muscle tissue from the Inkomati and Letaba catchments. Only two OCPs, p,p’-DDE and p,p’-DDD, were detected, likely due to ongoing DDT use in malaria control. Concentrations were generally low and varied between sites, with higher values found in the Letaba catchment. Neonicotinoids were detected at low concentrations, with acetamiprid and imidacloprid being the most prevalent, although the concentrations were lower than those reported globally. Muscle tissue, representing long-term exposure, may underestimate total pesticide burdens due to lower lipid content than other tissue types. Findings suggest that the detected residues reflect the persistent legacy of historical DDT use, potential ongoing localised DDT use for malaria vector control, as well as ongoing neonicotinoid use in agricultural systems. Although concentrations were below levels of concern for vertebrates, this study highlights the need for continued monitoring and expanded tissue analysis to better understand bioaccumulation and ecological risks in southern African freshwater systems.
Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s00244-026-01219-z.
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BibTeX
@article{marsay2026legacy,
title = {{Legacy (Organochlorine) and Current Use (Neonicotinoid) Pesticides in Fish from Two Subtropical River Basins}},
author = {Marelize Marsay and Chinemerem R. Ohoro and Collins Nimako and Yared B. Yohannes and Yoshinori Ikenaka and Nico J. Smit and Mayumi Ishizuka and Victor Wepener},
journal = {Archives of Environmental Contamination and Toxicology},
year = {2026},
month = oct,
doi = {10.1007/s00244-026-01219-z},
url = {https://doi.org/10.1007/s00244-026-01219-z},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Legacy (Organochlorine) and Current Use (Neonicotinoid) Pesticides in Fish from Two Subtropical River Basins
AU - Marelize Marsay
AU - Chinemerem R. Ohoro
AU - Collins Nimako
AU - Yared B. Yohannes
AU - Yoshinori Ikenaka
AU - Nico J. Smit
AU - Mayumi Ishizuka
AU - Victor Wepener
PY - 2026
DA - 2026/10/26
JO - Archives of Environmental Contamination and Toxicology
DO - 10.1007/s00244-026-01219-z
UR - https://doi.org/10.1007/s00244-026-01219-z
AB - The rapid population growth across Africa has increased the demand for food production, resulting in increased pesticide use. South Africa is among the top four pesticide importers in Sub-Saharan Africa, raising significant concerns regarding the contamination of freshwater ecosystems. Organochlorine pesticides (OCPs), historically used for agriculture and vector control, persist in the environment due to their high lipophilicity and long half-lives. Despite bans on many OCPs, residues remain in aquatic systems, potentially affecting non-target organisms such as fish. Similarly, neonicotinoids, introduced as safer alternatives, are now linked to adverse effects on aquatic biota, yet little is known about their bioaccumulation in wild fish species in southern Africa. This study investigated 13 neonicotinoids and 19 OCPs in fish muscle tissue from the Inkomati and Letaba catchments. Only two OCPs, p,p’-DDE and p,p’-DDD, were detected, likely due to ongoing DDT use in malaria control. Concentrations were generally low and varied between sites, with higher values found in the Letaba catchment. Neonicotinoids were detected at low concentrations, with acetamiprid and imidacloprid being the most prevalent, although the concentrations were lower than those reported globally. Muscle tissue, representing long-term exposure, may underestimate total pesticide burdens due to lower lipid content than other tissue types. Findings suggest that the detected residues reflect the persistent legacy of historical DDT use, potential ongoing localised DDT use for malaria vector control, as well as ongoing neonicotinoid use in agricultural systems. Although concentrations were below levels of concern for vertebrates, this study highlights the need for continued monitoring and expanded tissue analysis to better understand bioaccumulation and ecological risks in southern African freshwater systems. Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s00244-026-01219-z.
SN - 0090-4341
SN - 1432-0703
ER -