Characterization of colloid-size copper-based pesticide and its potential ecological implications. (October 2019)

• Record Type: Journal Article
• Authors: Tegenaw, Ayenachew; Sorial, George A.; Sahle-Demessie, Endalkachew; Han, Changseok
• Is Part Of: Environmental pollution. Volume 253(2019)
• Page Start: 278
• Page End: 287
• Publication Date: 2019-10
• Subjects: Agriculture -- Bioavailability -- Colloidal stability -- Cu2O pesticide -- Exposure pathways; 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.2019.07.036
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The intensive use of Cu-based pesticides in agriculture could have an unintended impact on the ecosystems and human health via different exposure pathways. This paper presents the results of experiments involving colloidal stability, aggregation, and dissolution of Cu2 O commercial pesticide under various environmental conditions in view of ecological implications. The investigated pesticide contains ∼750 g kg −1 Cu (75% weight of product), Cu2 O particles with sizes < 1 μm, and nominal size fraction of Cu2 O nanoparticles. The co-presence of Ca 2+ (20 mM) and humic acid (HA, 15 mg L −1 ) significantly modulates (p < 0.001) the colloidal stability and mobility of particles. The dissolution of Cu at pH 5.5 was about 85%, 90%, and 75% weight more than the dissolution of Cu at pH 7.0, pH 8.5, and pH 7.0 and pH 8.5 combined, respectively in all dispersions. However, increasing HA content from 0 to 15 mg L −1 reduced the dissolution of Cu by 56%, 50%, and 40% weight at pH 5.5, 7.0, and 8.5, respectively. Thus, pH below 7.0 is a critical factor to control the dissolution and bioavailability of Cu that may pose ecotoxicity and environmental pollution, whereas pH above 7.0 and the presence of HA attenuate the pH effect. These findings provide insight into how the potential mobility and bioavailability of Cu is modulated by the water chemistry under various environmental scenarios and media. Graphical abstract: Image 1 Highlights: Colloid-size Cu-based pesticides contain a fraction of nanoscale particles. The copresence of humic acid and Ca 2+ modulates colloidal stability and mobility. pH < 7 is a critical factor to control the dissolution and bioavailability of Cu. Increasing humic acid content attenuates pH effect on bioavailability of Cu.