| In recent years,China’s aquaculture industry is developing towards modernization,intensification,scale and modernization,and the demand for agricultural and veterinary drugs in aquaculture is increasing The scientific and rational use of pesticides and veterinary drugs plays a significant positive role in promoting the growth of aquaculture products,improving production efficiency,preventing aquatic diseases,and reducing production losses.Therefore,pesticides and veterinary drugs are also an indispensable material basis in aquaculture production.However,the use of pesticides and veterinary drugs not only brings good economic benefits and promotes the rapid development of aquaculture,but also brings residual risks.On the one hand,due to the increase of aquaculture species and the increasing density of aquaculture,the pollution of industrial,pesticides and urban domestic sewage discharge to aquaculture waters and the so-called"home pollution"generated by the aquaculture industry itself,the aquaculture environment is deteriorating rapidly,and the harm of various diseases to aquatic aquaculture is becoming increasingly serious,making China’s aquaculture industry face the trend of increasing old diseases and new diseases,This means that a large number of fishery medicine inputs are needed to control the aquaculture environment and prevent and treat diseases of aquatic products.On the other hand,due to the limited absorption of drugs in aquatic animals,only 20%～30%of antibiotics and other drugs can be absorbed and utilized,and most of them will eventually enter the aquatic environment with the discharge of food residues and feces,posing an ecological threat to the aquaculture environment.This article takes the aquaculture of aquaculture in Shanghai as the research object,and adopts high-resolution mass spectrometry technology to screen and analyze the water body,bottom mud and agricultural drugs in the breeding environment,and selects typical pesticides to carry out the accumulation and elimination of drugs in common aquaculture aquatic products,in order to provide basic research for the control technology of the use of pesticides and veterinary drugs in aquaculture.The specific research contents are as follows:（1）Exposure level and risk Impact assessment of pesticides and veterinary drugs in aquaculture environmentTaking the aquaculture environment in Shanghai as an example,in July and September 2022,the water body,sediment and intermediates from 40 major aquaculture farms were collected,and the types and contents of pesticides and veterinary drugs were screened by ultra-high pressure liquid chromatography-electrostatic field orbital ion trap mass spectrometry,and the ecological risk assessment of pesticides and veterinary drug pollution in water body and sediment was carried out using the risk quotient（RQ）method.The results showed that a total of 13 drugs were screened from 204 samples（72water samples,72 mud samples,and 60 input samples）,including prometryn,carbendazim,simazine,flufenicol,simazine,amantadine,diazepam,trimethoprim,ciprofloxacin,ofloxacin,mebendazole,and enrofloxacin,12 of which were in water samples,with a concentration of 0.016-2.084μg·L-1.7 kinds of mud samples with a concentration of 0.018-23.101μg·kg-1.4 kinds of inputs,1.979-101.940μg·kg-1。There are 7 kinds of drugs found in water and sediment at the same time.The results of risk quotient evaluation showed that the residual pesticides and veterinary drugs in aquaculture environment would bring ecological risks,and the ecological risk of carbendazim in aquaculture water and sediment was the highest,with the RQ value of3.848 and 1.580 respectively,showing high risk.（2）Bioaccumulation and elimination of prometryn in Macrobrachium rosenbergiiThe pesticide prometryn,which is found most frequently in screening,is selected as the target pollutant.With Macrobrachium rosenbergii as the research object,the semi-static experimental method is used to determine the acute toxicity of prometryn to Macrobrachium rosenbergii by exposing Macrobrachium rosenbergii to different concentrations of prometryn.According to the 96 h maximum half-lethal concentration（LC50）,1/10 LC50 concentration group and 1/100 LC50 concentration group are set to study the enrichment dynamics and elimination rules of prometryn in Macrobrachium rosenbergii.The results showed that the 96 h-LC50 of prometryn to Macrobrachium rosenbergii was 10.53 mg·L-1,the maximum total survival concentration was 1.5 mg·L-1,the minimum total lethal concentration was 28.6 mg·L-1,and the toxicity grade was low.In the enrichment experiment stage,in the 1/10 LC50 concentration group,the maximum enrichment concentrations of hemolymph,hepatopancreas and muscle were 2.381mg·L-1,1.170 mg·kg-1 and 0.370 mg·kg-1,respectively;In the 1/100 LC50 concentration group,the highest concentration of hemolymph,hepatopancreas and muscle was 0.269mg·L-1,0.138 mg·kg-1 and 0.039 mg·kg-1,respectively;Prometryn in all concentration groups reached a stable state on the 21st to 28th day.In the elimination test stage,prometryn was gradually eliminated in Macrobrachium rosenbergii.At the 60th day,the residual concentrations of prometryn in the hemolymph,hepatopancreas and muscle of the high concentration group were 0.0015 mg·L-1,0.0013 mg·kg-1 and 0.0011 mg·kg-1,respectively;In the high concentration group,the residual concentrations of prometryn in hemolymph,hepatopancreas and muscle were 0.0008 mg·L-1,0.0008 mg·kg-1 and 0.0005 mg·kg-1,respectively.（3）Bioaccumulation and elimination of deltamethrin and cypermethrin in crucian carpUsing the semi-static experimental method,taking crucian carp as the research object,select deltamethrin and cypermethrin as the target drugs,set up high concentration group and low concentration group to study the enrichment and elimination of deltamethrin and cypermethrin in crucian carp,and further analyze the concentration capacity of the two drugs in different tissues of Macrobrachium rosenbergii by using the biological enrichment factor（BCF）.The results showed that the BCF of crucian carp tissues to deltamethrin ranged from large to small,which was liver>blood>kidney>muscle,and the enrichment ability of crucian carp to low concentration deltamethrin was stronger;In the high concentration group,the maximum BCF of deltamethrin in liver,blood,kidney and muscle was 25.514,25.532,24.329 and 15.474 respectively;In the low concentration group,the maximum BCF of deltamethrin in liver,blood,kidney and muscle was 36.618,34.750,33.119 and 20.421,respectively.The BCF of cypermethrin in different tissues of crucian carp was from large to small,which was muscle>liver>kidney>blood,and the concentration of cypermethrin in low concentration was stronger in crucian carp;The maximum BCF of cypermethrin in muscle,liver,kidney and blood in the high concentration group was 28.992,22.846,21.054 and 22.714,respectively;In the low concentration group,the maximum BCF of cypermethrin in muscle,liver,kidney and blood was 45.166,37.075,29.847 and 26.166,respectively.Low-concentration drugs are easier to be eliminated by crucian carp;In the high concentration group,deltamethrin decreased to below the minimum detection limit on the 15th day,while in the low concentration group,it was on the 12th day;In the high concentration group,cypermethrin decreased to below the minimum detection limit on the 15th day,and in the low concentration group,it decreased to below the minimum detection limit on the 10th to 12th day. |
