Improvement Of Species Sensitivity Distributions Model For Aquatic Ecological Risk Assessment

Aquatic ecosystems are seriously impacted by algae blooms and chemicals pollution from anthropic activities.How to evalute the aquatic ecological health risk with experimental data and to predict the potential risk in the aquatic region,are becoming urgent problems,and need to be advanced the methods of risk assessment.The objective of this study is to update the model and method to estimate aquatic species sensitivity risk.Based on species sensitivity distributions method(SSDs),in this work,experimental toxicity data of two typical contaminants categories,i.e.cyanotoxins and antibiotics were collected from databases and literatures worldwide.The interspecies correlation estimation model(ICE)and acute to chronic ratios method(ACR)were adopted to improve the method of ecological risk assessment.Several chinese aquatic ecosystems were then used to test the performance of the proposed ICE/ACR-SSD ecological risk assessment model.The main conclusions are as follows:(1)ICE-SSD models to assess ecological risks of four cyanotoxins were improved.We selected two typical cyanobacterial hepatotoxins(nodularins,cylindrospermopsin)and two typical cyanobacterial neurotoxins(anatoxin-a,saxitoxins)as 4 cyanotoxins examples,then collected acute toxicity data by reviewing the 1629 literatures in Web of Science from 1864 to 2016,and predicted acute toxicity data by ICE model.Based on 71 available acute toxicity datasets covering 64 aquatic organisms,ICE-SSD equations were constructed.With the goal of protecting 95%aquatic species,the hazardous concentrations for 5%of the species(HC5)and the potentially affected fractions(PAF)under various concentrations were calculated.Results show that the sensitivity between hepatotoxins and neurotoxins were not obvious,the estimated HC5 values for nodularins,cylindrospermopsin,anatoxin-a and saxitoxins were 74.96?g·L-1,205.39?g·L-1,194.39?g·L-1 and 0.3?g·L-1,respectively.Highest risk posed by saxitoxins,the PAF of 1-100?g·L-1 saxitoxins was 7.8-43.2%,which reflecing that saxitoxins is one of the hazardous cyanotoxins.(2)ACR-SSD models for assessing ecological risks of six antibiotics was improved.We chose two sulfonamides(sulfamethoxazole,sulfamethazine),two tetracyclines(tetracycline,oxytetracycline)and two macrolides(erythromycin,roxithromycin)as 6 antibiotics examples.Toxicity data were selected from ECOTOX database,WikiPharma database,7045 literatures in Web of Science and CNKI(China National Knowledge Infrastructure)from 1864-2016,chronic toxicity data were inferred by ACR method.Based on 144 available chronic toxicity datasets covering 79 aquatic organisms,ACR-SSD models were constructed.HC5 and PAF values were calculated for all species,and the ecological risks of tetracycline and erythromycin to primary producers were analyzed furtherly.Results show that the sensitivity among sulfonamides,tetracyclines and macrolides were unconspicuous,the highest risk of all species posed by erythromycin,the second one is tetracycline.The HC5 values for sulfamethoxazole,sulfamethazine,tetracycline,oxytetracycline,erythromycin and roxithromycin were 34.98?g·L-1?555.64?g·L-1?10.95?g·L-1?60.87?g·L-1?2.08?g·L-1 and 19.44?g·L-1,respectively.Primary producers are more sensitive to erythromycin,the PAF of 5?g·L-1 erythromycin to primary producers was 19.16%,which demonstrating that primary producers are the most susceptible species under antibiotics stress.(3)The ecological risks of two cyanotoxins and four antibiotics in several chinese water body were not obvious.Based on 5831 literatures in Web of Science and CNKI from 1864 to 2016,we acquired the concentration data of cylindrospermopsin,anatoxin-a in reservoirs of Guangdong province and Hebei province,respectively,collected sulfamethoxazole,sulfamethazine,tetracycline and oxytetracycline concentration data in Yangtze River and sulfamethoxazole,sulfamethazine,erythromycin,roxithromycin concentration data in Pearl River.The aquatic ecological risk of cyanotoxins and antibiotics were assessed by applying the ICE-SSD and ACR-SSD models,respectively.Results suggest that the ecological risks of cylindrospermopsin and anatoxin-a were unconspicuous,the PAF of cylindrospermopsin in Shuilianshan Reservoir of Guangdong province was 0.1%,the one of anatoxin-a in Yanghe Reservoir of Hebei province was 0.01%,the PAF of both cylindrospermopsin and anatoxin-a below 5%which set as threshold for protecting aquatic species by US EPA.The ecological risks of antibiotics in Yangtze River and Pearl River were not obvious,the PAF of 4 antibiotics in Yangtze River under 0.17%,and the PAF of 4 antibiotics in Pearl River below 0.59%.