| Hexabromocyclododecane?HBCD?is a kind of brominated flame retardant,which is widely used in environment.Since HBC D is a persistent organic pollutant,it is not only long-term in the environment but also can be bio-enriched and amplified.HBC D can affect the normal physiological activities of organisms,so it is necessary to study the environmental behavior of HBC D.HBCDs in soil can be absorbed by plants,which is one of the important ways to migrate into terrestr ial ecosystem.However,there are few reports on the origin and distribution of HBCDs isomers in soil and their migration and transformation in environment the origin and distribution of HBCDs in the soi and there are less reports of their absorption and migration in plants.Therefore,it is of great practical significance to study the pollution status of HBCDs in soil,the environmental behavior of HBC Ds and the law of organism migration.The migration rule of HBCD in soil and vegetable was systematically studied In this experiment,First,through pot experiment,three kinds of HBCD contaminated soill was prepared?red soil,vegetable soil,paddy soil,the concentration of 0,1,5,10mg/kg?.The concentrations of HBC D in different soil and corresponding ve getables were determined at the end of pot experiment,Third,the effects of different initial concentrations of HBCD on some physical and chemical indexes of plants and soils were analyzed.Fourth,health risk assessment of three isoforms of HBCD in vegetables from different regions were analyzed.The results of this study are as follows:?1?In the pot experiment,the content of HBC D in the root and leaf of the spinach was lower than in root and leaf of maize.The HBC D residue is higher in spinach soil was higher than in corn soil,it was the opposite of the HBCD content in vegetables,which showed that the absorption ability of different vegetables to HBCD was obviously different.The contents of three isomers in vegetables and soils were increased with the soil initial HBCD concentration increased The results showed that the residue of three isoforms of HBCD in vegetables and soil increased with the increase of soil initial HBCD concentration.?2?Vegetables in vegetable fields were more polluted than HBCD in soil and the average content of?-HBCD in vegetables was approximately 10 times than that of the soil Vegetables in four vegetable fields were polluted by HBCD.The most polluted feild is Jiangmen,and the lightest one is Foshan The content of?-HBCD in the soil of Jiangmen was higher,while the other two isomers were higher in Huizhou,but the difference was small.?3?Different concentrations of HBC D?0?1?5?10mg/kg?had some effects on physical and chemical indexes of plants and soils.When the concentrat ion was 5mg/kg HBCD,the activity of catalase reached its peak.But when the concentration was 10mg/kg,the enzyme activity was the lowest in the four concentrations It showed that the enzyme activity was increased first with the increase of concentration,but the enzyme activity was inhibited by too high concentration It was found that soil organic matter,soil p H,plant chlorophyll and plant growth length were the same as catalase,which were promoted at 5mg/kg and inhibited at 10mg/kg.But compared with the blank experiment,it had inhibition effect.?4?Vegetable in different areas was used as the object of health risk assessment and USEPA?1996?health risk assessment method was adopted..Compared with the HBCD life cycle,the carcinogenic reference risk level is1 x 10-6,lifetime cancer risk level of three HBC D isomers of was 4.06 x 10-5,1.12 x 10-5,9.86 x 10-5,respectively The greater risk of cancer was?--HBCD,followed by?-HBCD,and?-HBCD was less carcinogenic.According to the formula,?-HBC D content of carcinogenic risk level in Ipomoea aquatica Forsk of Foshan and Lactuca sativa of Huizhou was less than the carcinogenic benchmark risk level and the rest was higher than the carcinogenic benchmark risk level. |
PDF Full Text Request