| With high-efficiency,portability and low-price,antibiotics are widely used in the treatment and prevention of diseases in human and animal and feed additives to promote animal growth.As prototype or active products excreted into the aquatic ecosystem through various routes to act on environmental organism,above half of antibiotics have negative effects on the ecology and human health.Many scholars pay attention to the occurrence and ecological risk of antibiotics in various aquatic environmental matrix,but few studies investigate the sources,concentrations and behaviors of antibiotics in the Huaihe River Basin.The Huaihe River Basin,a traditional agricultural area in China with a dense population of 4.8 times to the average,has a relative developed medical system and livestock breeding size which lead to a large proportion and misuse of antibiotics and serious pollution of antibiotics.In this study,two types of antibiotics（sulfonamides,tetracycline）in the main section of Huaihe River through Anhui Province have been investigated to reveal the level,potential sources,sediment-water distribution,ecological and health risk assessments.The main conclusions of this article are as follows:（1）To analyze antibiotics in the surface water and sediment samples of the Huaihe River Basin,an instrument detection method（Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry）was established.And a pretreatment method（Accelerated solvent extraction-solid phase extraction technology）was optimized,which mainly optimizes the extraction solvent,temperature and cycles in accelerated solvent extraction,the activating solvents for enriching the small columns in solid phase extraction,and nitrogen blowing volume and final constant volume system.The actual sample detection limit and recovery can reach the requirements for the detection of antibiotic residues in the Anhui section of the Huaihe River Basin.（2）In comparison with the domestic water environment,the total antibiotic concentration in the surface water of the Anhui section of the Huaihe River Basin is at a comparatively low level.Among them,the concentration range of sulfonamides(6.2-19 ng L-1)is similar to those in Taihu and Shaoxi lakes,as that of tetracyclines(5.7-170 ng L-1)to those in Liaohe and Baiyangdian lakes.The total antibiotics concentration in sediment is at a comparatively low level compared with other aquatic environment.Among them,the concentration range of sulfonamides(2.5-6.9 ng g-1)is similar to those in Guanting Reservoir and Taihu Lake,as that of tetracyclines(6.9-27 ng g-1)to those in Haihe and Liaohe rivers.The usage habits and emission law of sulfonamides are consistent in the Anhui section of Huaihe River Basin,and the changes in the early sampling period are small;the usage habits of tetracyclines in the upstream are different from those in the midstream and downstream which changes significantly before sampling.Physical movements（such as dredging sand）may affect the occurrence of tetracyclines in the sediment.The highest value of tetracyclines appeared in Nanzhao Town,Fuyang City,which tributary pollution of upstream may be the main reason;and the highest value of sulfonamides occurred in Fengtai County,Huainan City,caused by medical wastewater pollution.Sulfonamides are mainly concentrated in the upstream of the Huai River basin,near Gushi County,Henan Province,livestock breeding is the main source,while the distribution of the antibiotic tetracycline is more scattered.The dam has an enrichment effect on sulfacetamide and doxycycline in the surface water of the Huaihe River Basin,and may not result in antibiotics enrichment in the sediment.The dam has a degradation effect on sulfisoxazole and sulfadimethoxine which have the same effect on sulfamethoxazole and metacycline in the sediment.The different physical structures of the two dam gates may lead to inconsistent effects on the antibiotics occurrence of surface water and sediments.（3）By calculating the Pseudo-partitioning coefficient of antibiotics between sediment and surface water,the deposition trend of antibiotics in the Huaihe River Basin is at a medium level in domestic aquatic environment.Antibiotics with larger molecular weight may be more likely to deposit in sediments,and the deposition tendency of tetracyclines is more susceptible to the physical and chemical properties of the environmental matrix than sulfonamides.In the whole river section of the Huaihe River Basin,sulfamethazine,sulfathiazole,sulfamethizole,sulfadoxine,minocycline and methacycline demonstrated a continuous and significant sedimentation trend,sulfacetamide,sulfameter,oxytetracycline,and doxycycline demonstrated a tendency to migrate to surface water.The other antibiotics had a partial tendency to deposit,and there were some differences in distribution.In addition,the effects of the dams on the deposition trends of sulfonamides and tetracyclines were similar.（4）By calculating the Pearson correlation between the antibiotics,the possible sources of antibiotics in the sediments and surface waters in the Anhui section of the Huaihe River Basin were analyzed.The main pollution sources were livestock breeding and medical wastewater,some were urban sewage treatment plants and solid waste treatment plants.Ecological risk assessment of three typical aquatic organisms was carried out by using the Risk Quotients.Sulfamethoxazole presented a continuous medium risk to algae throughout the Huaihe River and was at a high level in comparison with domestic water environment.Metacycline presented a persistently low risk to invertebrates in the upstream of Huaihe River.Doxycycline and demeclocycline presented a medium risk to invertebrates throughout the Huaihe River.All antibiotics presented no ecological risk to fish.By using the health risk assessment methods through the route of drinking water,the main drinking water health risk factors for adults and children,which are mainly sulfamethazine,doxycycline and tetracycline,are similar,and the health risk level of adults is higher than that of children. |
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