Degradation-elimination rules and influences on aquatic ecosystems of arsenilic acid in simulating pond

Objective In this paper, by simulating the pond water ecosystem, degradation rule in water and sediment and the impact on aquatic ecosystem of arsanilic acid were studied.

Method Four mini-aquatic pond ecosystems were established; the control was added 100 g pig manure and treated with different mass concentrations of 50, 150 and 500 mg/L of arsanilic acid. Samples of water and 2 cm-depth-sediment were taken. Arsanilic acid was determined by HPLC and the total arsenic contents were determined by HG-AFS.

Result and conclusion The half-life of arsanilic acid increased with the extension of the delivery drug concentration in pond water and surface sediment, which was 3.73 to 16.04 d and 35.17 to 61.27 d, respectively, and the total arsenic showed a distinguished subsidence trend in sediment and degraded slowly. The values of dissolved oxygen(DO), pH, primary productivity(P/R), activities of sediment alkaline phosphatase and catalase, and the content of total nitrogen and phosphorus indicators were regularly detected. The results showed that 500, and 150 mg/L arsanilic acid could cause irreversibly detectable effects on the ponds. High mass concentration of arsanilic acid obviously inhibited catalase activities. The total nitrogen content of sediment showed an inhibition-promotion-change process, and all mass concentrations of the total phosphorus content declined and presented a concentration dependent relationship.