Organophosphate pesticides in South African eutrophic estuaries: Spatial distribution, seasonal variation, and ecological risk assessment. (1st August 2022)

• Record Type: Journal Article
• Authors: Olisah, Chijioke; Rubidge, Gletwyn; Human, Lucienne R.D.; Adams, Janine B.
• Is Part Of: Environmental pollution. Volume 306(2022)
• Publication Date: 2022-08-01
• Subjects: Organic contaminants -- Ecotoxicology -- Aquatic organisms -- Sundays Estuary -- Swartkops Estuary; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.119446
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The seasonal variation, spatial distribution, and ecological risks of thirteen organophosphate pesticides (OPPs) were studied in the Sundays and Swartkops estuaries in South Africa. Ten pesticides were detected in surface water samples from both estuaries, while all OPPs were detected in sediments. The highest concentration of OPPs (18.8 μg pyrazophos L −1 ) was detected in surface water samples from Swartkops Estuary, while 48.7 μg phosalone kg −1 dw was the highest in sediments collected from Sundays Estuary. There was no clear seasonal pattern in OPPs occurrence in surface water from both systems. However, their occurrence in sediments was in the following order: winter > autumn > summer > spring, perhaps indicating major pesticide input in the winter seasons. Results from ecological risk assessment showed that pyraclofos and chlorpyrifos (CHL) in surface water from both systems are respectively likely to cause high acute and chronic toxicity to fish (risk quotient – RQ > 1). For sediments of both estuaries, the highest acute and chronic RQs for fish were calculated for isazophos and CHL respectively. The majority of the detected OPPs in sediments posed potential high risks to Daphnia magna from both systems. These results suggest that these aquatic organisms (fish, and Daphnia), if present in the studied estuaries, can develop certain forms of abnormalities due to OPP exposure. To this end, proper measures should be taken to reduce OPP input into the estuarine systems. Graphical abstract: Image 1 Highlights: At least one of the 13 OPPs was detected in sample matrices from both estuaries. Pyrazophos recorded the highest concentration of OPPs in water. Phosalone recorded the highest concentration of OPPs in sediments. Winter season recorded the highest ∑13 OPPs concentration in sediments. Most pesticides in sediments pose high acute and chronic ecotoxicological risks.