| Large antibiotics and pesticides used worldwide leads to a significant amount of contaminants released into environment each year,which would pose a potential threat to ecology as well as human health.It is essential to get a complete picture of the contamination profiles,human health and ecological risks in order to control the chemicals.Biliuhe Reservoir is a major drinking water source in Dalian which plays an important role in water supply for 4 million residents with living,agriculture and livestock.However,limited studies have concentrated on the occurrence of antibiotics and pesticides in this area,and there is a lack of systematic risk assessment based on field survey data.Therefore,the occurrence of antibiotics and pesticides in the water,sediment and soil of Biliuhe Reservoir and its inflow rivers have been well analyzed by field investigation and practical monitoring by this study.Meanwhile,the potential human health and ecological risks of antibiotics and pesticides were estimated based on the actual concentrations.An efficient removal method was established and applied to real source water.The main results are as follows:（1）This study carried out monitoring of antibiotics and pesticides in Biliuhe Reservoir and its inflow rivers for the very first time,and revealed the characteristics,temporal and spatial distribution of these chemicals in Biliuhe Reservoir basin.There were 10 antibiotics detected in water,9 in sediment and 5 in soil.The concentrations in water ranged from N.D.to 131ng L-1,enoxacin(131ng·L-1)and florfenicol(118ng·L-1)had higher concentrations and the most detectable antibiotic was florfenicol（21.6%）.The antibiotic concentrations were N.D.～48.2ng·g-1in sediment and N.D.～36.5ng·g-1in soil,respectively.Sulfodiazine had the highest concentration in sediments and soil.Antibiotics with a detection frequency more than20%were sulfamethoxazole,lincomycin and sulfadiazine.The pesticide detections were as follows:two triazine and amide herbicides were detected in water,and five kinds of organochlorine pesticides,triazine and amide herbicides were detected in sediment,while four organochlorine pesticides along with triazine and amide herbicides were detected in soil.No organophpshorus pesticide were detected in the area.The pesticide concentrations ranged from N.D.to 323ng·L-1in water,and atrazine had the maximum concentration and detection frequency(323ng·L-1,93.1%).The pesticide concentrations were N.D.～239ng·g-1in sediment and N.D.～98.6ng·g-1in soil,respectively.Acetochlor had the highest concentration.P,p’-DDE was the most detectable pesticide in sediment（78.1%）and soil（46.4%）.Antibiotic concentrations changed with seasons significantly,while the seasonal variation of pesticide concentration was not obvious.In aggregate the results showed that higher environmental concentrations of chemicals were found in the north area of the study region,which was consistent with larger basin area,higher population intensity and farmland quantity.（2）The carcinogenic and non-carcinogenic health risks of chemicals through drinking and dermal pathways were estimated based on the maximum concentrations monitored in water,using the assessment model and Monte-Carlo simulation recommended by the US EPA.The exposure parameters were referred to the local data which made the risk assessment results of adults and children close to the actual situation as possible.Our results indicated the non-carcinogenic risk of antibiotics was 10-14～10-10,the carcinogenic risk of pesticides was10-8～10-7and the non-carcinogenic risk of pesticides was 10-12～10-11.There was no apparent health risks associated with antibiotics and pesticides showed in the study area.The health risks of pesticides was more critical than antibiotics,and children aged 0～5 were much more sensitive to the risks than other groups.（3）Ecological risk quotients of antibiotics and pesticides were estimated according to the most sensitive ecotoxicity data,maximum concentrations and suitable assessment factors.The ecotoxicity data were calculated according to ECOTOX database provided by US EPA.The results indicated that antibiotics had low to medium risks（∑RQ=0.002～0.2）,and lincomycin had a remarkable contribution.The ecological risks of pesticides to aquatic organisms were far beyond 1.The highest risks in water occurred in Biliuhe Reservoir（∑RQ=8.0）.The ecological risks of pesticides in sediment were low to medium（∑RQ=0.001～0.13）and Biliuhe River took higher risks than other regions（∑RQ=0.001～0.04）.（4）The removal efficiency of trace antibiotics in actual water body was evaluated based on electro-assistant adsorption of activated carbon fiber.By applying a bias of-1.0V on the active carbon fibers filter the removal efficiency of levofloxacin was about 3 times as high as that without applying bias.A small water purification device with a capacity of 50L·h-1was designed for natural water treatment based on electro-assistant adsorption of active carbon fibers.This device consisted two PP cotton filter（5μm and 1μm）and two electro-assistant adsorption filter（+1.0V/-1.0V）.The influent concentrations of levofloxacin,roxithromycin and trimethoprim fluctuated in a range of 311～382ng·L-1,82.0～117ng·L-1and4.77～5.62ng·L-1,the effluent concentrations were 2.26ng·L-1,8.68ng·L-1and 0.259ng·L-1,respectively.The highest removal efficiencies were up to 99.8%,99.9%and 95.5%,which indicated this method be an effective technique for trace antibiotic removal in natural water.In this work,the result would show the occurrence characteristics,health risks and ecological risks of antibiotic and pesticide residues in Biliuhe Reservoir Basin.Antibiotics of low concentration in natural water were removal efficiently on ACFs under electrochemical assistant adsorption,which explored a theoretical and practical way for the treatment of antibiotic pollutants. |
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