Toxicity assessment of sediments from the Liaohe River Protected Area (China) under the influence of ammonia nitrogen, heavy metals and organic contaminants.

The aim of this study was to evaluate the toxicity of ammonia nitrogen, metals and organic contaminants in sediment collected from the Liaohe River Protected Areas. The TIE was applied to 16 samples. The zeolite, resin, and coconut charcoal were used to mask toxicity of the three kinds of pollutants, respectively. Then quantitative analyses together with a battery of bioassays were performed to evaluate toxic effects. At last, the spiking tests were used to confirm the major contributors to toxicity. The results of toxicity identification showed the ammonia nitrogen, γ-HCHs, As and Cd may cause toxic hazards to benthic organisms. The significant correlation between the survival and volume ratio of the sediment and overlying water confirmed ammonia nitrogen and Cd were the major toxic pollutants that cause the biological toxicity. We confirmed bioassays combined with masking agent, spiking tests and quantitative analyses were suitable tools for detecting toxicity.