Environmental Engineering Program, Department of Chemical and Environmental Engineering, College of Engineering and Applied Science, University of Cincinnati, 701 Engineering Research Center, 2901 Woodside Drive P.O. Box 210012, Cincinnati, OH, 45221-0012, United States.
Environmental Engineering Program, Department of Chemical and Environmental Engineering, College of Engineering and Applied Science, University of Cincinnati, 701 Engineering Research Center, 2901 Woodside Drive P.O. Box 210012, Cincinnati, OH, 45221-0012, United States.
Environ Pollut. 2019 Oct;253:278-287. doi: 10.1016/j.envpol.2019.07.036. Epub 2019 Jul 9.
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 CuO commercial pesticide under various environmental conditions in view of ecological implications. The investigated pesticide contains ∼750 g kg Cu (75% weight of product), CuO particles with sizes < 1 μm, and nominal size fraction of CuO nanoparticles. The co-presence of Ca (20 mM) and humic acid (HA, 15 mg L) 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 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.
农业中大量使用含铜农药，可能会通过不同的暴露途径对生态系统和人类健康产生意想不到的影响。本文从生态角度出发，研究了商业氧化铜农药在不同环境条件下的胶体稳定性、聚集和溶解情况。所研究的农药含有约 750g/kg 的铜（产品重量的 75%），氧化铜颗粒尺寸<1μm，纳米氧化铜颗粒的名义粒径。Ca（20mM）和腐殖酸（HA，15mg/L）的共同存在显著调节了颗粒的胶体稳定性和迁移性（p<0.001）。在所有分散体中，pH 值为 5.5 时，Cu 的溶解量比 pH 值为 7.0、8.5 和 7.0 与 8.5 组合时分别高出约 85%、90%和 75%重量。然而，当 HA 含量从 0 增加到 15mg/L 时，在 pH 值为 5.5、7.0 和 8.5 时，Cu 的溶解量分别减少了 56%、50%和 40%重量。因此，pH 值低于 7.0 是控制 Cu 溶解和生物有效性的关键因素，这可能会对生态系统产生毒性和环境污染，而 pH 值高于 7.0 和 HA 的存在则会减弱 pH 值的影响。这些发现为了解在不同环境场景和介质下，水化学如何调节 Cu 的潜在迁移性和生物有效性提供了新的见解。
