| Atrazine is widely used in maize,sugar cane fields,tea garden and orchard garden and so on because of its specialty in weed control and low cost.Due to the comprehensive effect of environmental factors,atrazine residues are enriched in organisms,and even produce direct or indirect pollution on food.This study aimed at investigating two formulations of atrazine,those were 50%atrazine oil suspension and 61%acetochlor,atrazine and 2,4-D mixed suspoemulsion.The research explore the ecological environment where were applied two formulations of atrazine.This research also aimed at the residue of atrazine and other pesticides in tomatoes.Atrazine and other 84 pesticides residues in tomatoes were studied and the dietary risk assessment was performed.The reseach could be provided data support for people to learn the mobility of atrazine by environmental media.In order to provide data support for the removal and restoration of pesticide pollutants for the ecological ditches and ecological ponds,the potentials of two submerged macrophytes Potamogeton crispus L.and Myriophyllum spicatum L.on phytoremediation of atrazine were studied by using the pot experiment.Main results of our study are as follows:1. To evaluate the safety of atrazine on maize,the samples of maize,soil and corn plants were collected from Jinan and Haerbin which were applied with two forms of atrazine namely 50%atrazine oil suspension and 61%acetochlor,atrazine and 2,4-D mixed suspoemulsion.The results showed that the degradation of atrazine in corn plants and soil could be described by the first-order kinetics equation.The equation of 50% with a half-life of 4.95 d and 3.79 d,respectively.The dissipation equation of 61% a half-life of 4.47 d and 7.22 d,respectively.The dissipation equation of the 50%atrazine of 11.7 d and 9.00 d,respectively.The dissipation equation of 61%atrazine was C_T and 9.37 d,respectively.2. The maximum permissible intake(MPI)for atrazine was calculated to be 0.23?g per person per day for a child and 0.72?g per person per day for an adult according to Chinese maize consumption of dietary structure,children or adult weight and maximum residue limits of atrazine in China(MRL=0.05 mg/kg).Long-term and short-term risk assessments were calculated.Atrazine was not detected in the harvested maize(<0.01mg/kg).The stand mid-value of residues(STMR)and highest residue(HR)was assigned at 0.01 mg/kg(the method detection limit)according to risk maximization principle.The long-term risk assessment showed that National Estimated Daily Intake was 0.0014 mg,and the risk probability was 0.11%.The short-term risk assessment showed that National Estimates of Short-term Intake was 0.0014 mg and the risk probability was 0.02%.The results indicate the risk is low because the chronic and short-term risk probabilities are less than<100%.3. Atrazine was not detected in tomatoes and soil.The detected pesticides in tomato and soil overlapped to some extent.The residue of the detected pesticides was correlated with the types of the pesticides,application methods and spraying time.For example,the detection rate of imidacloprid,which was used as a soil treatment agent,was 48.8%.However,it was not detected in tomato.It also suggests that as a soil treatment agent,imidacloprid could conduct little to the fruit.The soil-treated pesticides were relatively safe for the fruit.The main source of ecological migration of pesticides is direct application on the agroproduct.4. The pesticides detected in tomatoes were ranked according to the three methods of pesticide risk by British FSA.Acetamiprid,thiamethoxam,procymidone,bifenthrin,cypermethrin,difenoconazole,fenbuconazole,pyrimethanil,iprodione,carbendazol,and thiophanate-methyl were detected in tomato.These pesticides might pose a potential risk to humans.The results showed that the calculation results were less than 100,which means the risk of these pesticides could be acceptable.Dietary assessment was performed according to the diet,body weight,pesticides residues.The chronic risk assessment result(%ADI)was below 100%,which was acceptable.The%Arf D of bifenthrin was 155.1%,indicating bifenthrin should be under close supervision and monitoring.There would be certain dietary risk if bifenthrin without in accordance with the regulations and safety interval samlling.5. The half-life of atrazine in the overlying water of Yuehu lake sediment was 6.95 d without the submerged plants,and the half-life of atrazine was 7.82 d and 5.00 d when atrazine was added into the sediment,which was treated by Potamogeton crispus L.and Myriophyllum spicatum L.,respectively.The half-life of atrazine in the overlying water of Tangxun lake sediment was 5.68d without the submerged plants,and the half life of atrazine was 6.03 d and 5.29 d when atrazine was added into the sediment,which was treated by Potamogeton crispus and Myriophyllum spicatum,respectively.The half-life of atrazine in Yuehu lake sediment was 14.8d without the submerged plants,and the half-life of atrazine was 12.4 d and 23.7 d when atrazine was added into the sediment,which was treated by Potamogeton crispus L.and Myriophyllum spicatum L.,respectively.The result was showed that the sediment was polluted by atrazine,the half-life of atrazine in sediment which was treated by Potamogeton crispus L.was significantly shortened,while the half-life of atrazine in the sediment which was treated by Myriophyllum spicatum L.had little change.The ability of absorbtion of atrazine Potamogeton crispus L.was much more than Myriophyllum spicatum L..The metabolites of atrazine in submerged macrophytes and their corresponding environments were determined.It was found that a small amount of metabolites of 2-hydroxy-atrazine and Atrazine-desethyl-desisopropyl were produced in the water and sediment system.Only Atrazine-desethyl-desisopropyl was detected in submerged plants,which indicated that submerged plants had a certain inhibitory effect on the decomposition of atrazine into 2-hydroxy-atrazine. |
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