Identifying The Causes Of Sediment-associated Toxicity Of The Liaohe Conservation Area, China

As part of a recently completed water quality assessment, a series of water column and sediment toxicity tests was performed throughout the watershed. Twenty-one sediments collected of the Liaohe Conservation Area in China were screened for acute toxicity using C. riparius(Chironimus riparius) in addition to being examined for potential contributors of sediment toxicity, including polycyclic aromatic hydrocarbons,7 metals, and ammonia.Finally, considering the current situation of water environment pollution control at home and abroad choose modified potential hazard index method and got a list of priority pollutants for Liaohe Conservation Area Sediment.The result of intial test and chemical analysis provided a strong evidence that the ammonia and heavy metal are the probable causes of toxicity in the sediments and the spiking experiment finally confirmed that the ammonia is the contaminants in terms of toxicity, although toxic effects from metals were also a concern in at least three sites.The modified potential ecological risk assessment results show that Cd is the significant contributions based on the potential ecological risk degree is at all sites. Using the species sensitivity distribution method(US- SSD) deduced criteria maximum concentration(CMC) and criteria continuous concentration(CCC) of ammonia for liaohe and then using the method of risk quotients(RQ) evaluate the ecological risk of ammonia,the result of preliminary assessment shows that Liaohe Conservation Area Sediment has high ecological risk at each samp site.The integration of assessment and potential hazard index method showed that suitable priority pollutants listing of Liaohe area sediment is ammonia, Cd, As, Cr, Benzeno(a)pyrene, Pyrene,Chrysene,Benzo(k)fluoranthene,Benzo(a)anthracene,Dibenzo(a,h)anthracene, Benzo(b)fluoranthene, and Diphenyl(a,h) anthracene.