文献名： Influence of water chemistry on colloid-size Cu-based pesticides particles: A case of Cu (OH) 2 commercial fungicide/bactericide

 

作者：Ayenachew Tegenawa; George A.Soriala; Endalkachew Sahle-Demessieb; Changseok Hanc 

aEnvironmental 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

bU.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther Drive, Cincinnati, OH, 45268, United States

cDepartment of Environmental Engineering, College of Engineering, INHA University, 100 Inharo, Nam-gu Incheon, 22212, South Korea

 

摘要：The intensive, widespread, and ever-increasing applications of Cu-based pesticides in agriculture could potentially increase environmental exposures via different routes. Unlike ionic/bulk forms, the fate, transport, and toxicity of colloid-size Cu-based pesticides are not well studied. This paper provides evaluation outcomes of granule and dispersion characterizations, stability, and dissolution of colloid-size particles of Cu(OH)2 commercial pesticide product at a range of water chemistry. The evaluated product contained about 35% weight of metallic Cu equivalent and Cu(OH)2 particles with sizes < 1 μm of which a fraction of nanoscale particles exist. The presence of Ca2+ at ionic strengths of >0.01 M and 0.001–0.2 M significantly influenced (p < 0.001) particle size (PS) and ζ-potential values, respectively at all investigated pH values. Cu dissolution at pH 5.5 was significant (p < 0.001) and exceeded Cu dissolutions at pH 7.0 by 87–90% and at pH 8.5 by 87–95% in all dispersions. The order of Cu dissolution was pH 5.5 > pH 7.0 > pH 8.5 in all dispersions. Cu dissolution was relatively reduced by 53% by increasing HA from 0 to 5 mg L−1 and enhanced by 55% by increasing HA from 5 to 15 mg L−1, however, the overall Cu dissolution was decreased by 27% by increasing HA from 0 to 15 mg L−1. Thus, HAs reduced the dissolution of Cu at pH < 7. The findings provide an insight into how water chemistry influences the fate and transport of colloid-size Cu-based pesticides particles.