Purpose Soil consists of various sizes of aggregates, and different soil aggregates vary in their abilities to adsorb or transport metals. This study aimed to investigate the distribution behaviors of Cu from different fungicides in soil aggregates after a 15-month incubation. Materials and methods Bordeaux mixture (CuSO4/Ca(OH)(2) = 1/1 by weight, BR), copper nitrate (Cu(NO3)(2)center dot 4H(2)O, CN), and copper oxychloride (3Cu(OH)(2)center dot CuCl2, CO) were applied to a representative Chinese Mollisol to reach the Cu content 200 mg kg(-1). Five soil aggregate fractions, i.e., > 2000 mu m, 2000-1000 mu m, 1000-500 mu m, 500-250 mu m, and < 250 mu m, were obtained by the wet sieving method. The modified Bureau Communautaire de References (BCR) sequential extraction was applied to assess the Cu distribution among the main soil fractions. Results and discussion The highest Cu mass loading was found for the > 2000-mu m soil aggregate. The input Cu was mainly in stable fractions, and the highest proportion was found for the residual fraction. The bioavailability and mobility of Cu from different fungicides in soils varied from each other, and they presented an order of CO > CN > BR. High bioavailability and transferring coefficients were found in the < 250-mu m and > 2000-mu m soil aggregates. Conclusions This study indicated that the input Cu from fungicides mainly distributed in the > 2000-mu m soil aggregates. Moreover, the CO-derived Cu presented a higher availability than the BR- and CN-derived Cu in the soil.

Purpose Soil consists of various sizes of aggregates, and different soil aggregates vary in their abilities to adsorb or transport metals. This study aimed to investigate the distribution behaviors of Cu from different fungicides in soil aggregates after a 15-month incubation. Materials and methods Bordeaux mixture (CuSO4/Ca(OH)(2) = 1/1 by weight, BR), copper nitrate (Cu(NO3)(2)center dot 4H(2)O, CN), and copper oxychloride (3Cu(OH)(2)center dot CuCl2, CO) were applied to a representative Chinese Mollisol to reach the Cu content 200 mg kg(-1). Five soil aggregate fractions, i.e., > 2000 mu m, 2000-1000 mu m, 1000-500 mu m, 500-250 mu m, and < 250 mu m, were obtained by the wet sieving method. The modified Bureau Communautaire de References (BCR) sequential extraction was applied to assess the Cu distribution among the main soil fractions. Results and discussion The highest Cu mass loading was found for the > 2000-mu m soil aggregate. The input Cu was mainly in stable fractions, and the highest proportion was found for the residual fraction. The bioavailability and mobility of Cu from different fungicides in soils varied from each other, and they presented an order of CO > CN > BR. High bioavailability and transferring coefficients were found in the < 250-mu m and > 2000-mu m soil aggregates. Conclusions This study indicated that the input Cu from fungicides mainly distributed in the > 2000-mu m soil aggregates. Moreover, the CO-derived Cu presented a higher availability than the BR- and CN-derived Cu in the soil.