Leaching Characteristics of Glutaraldehyde and Organic Dyes Utilized in Tannery Industry in Soil

Abstract

ABSTRACT The discharge of effluents and sludge from the leather industry is raising a growing concern. However, the mobility and hazards of tannery organic pollutants in soils are easily ignored. Herein, soil column leaching experiments were conducted using typical tannery organic pollutants glutaraldehyde (GA) and two azo dyes [Acid Red 73 (AR 73) and Direct Blue 6 (DB 6)]. Under simulated rain conditions, the leaching behavior of GA and organic dyes showed significant differences even though they were both water-soluble organic pollutants. AR 73 and DB 6 could be detected in the leachates throughout 7 leaching events for 28 days and in soil columns after leaching, while GA failed to be detected in both leachates and soil columns, indicating that AR 73 and DB 6 with more complex molecular structures had poorer degradability than GA under the condition of similar initial concentrations. The results demonstrated that the azo dyes AR 73 and DB 6 used in the experiment were more likely to cause adverse effects on soil and underground water under the condition of the covering thickness of dyes ≥ 0.5 mm on soil, and thus possessed higher environmental risk than GA. This study is also conducive to further evaluating the risk of tannery contamination sites.