| Food safety is closely related to human health.In recent years,food safety issues emerge one after another.Rice is the dominant product in China and its quality affects human health directly.Among the factors influencing the rice quality,soil contamination has become one of the main sources.Heavy metals can easily accumulate in the soil and hinder the normal growth of crops due to their non-biodegradability and persistence and cause biomagnification effects in human body through the food chain.Nowadays,waste electrical and electronic equipment?WEEE or E-waste?has become a major source of heavy metal contamination.Majority of E-waste in China is recycled by the informal sector.Toxic and harmful substances such as residual liquid and residue of dismantling cause heavy metal contamination in paddy soils and water through atmospheric deposition and sewage irrigation.Thus,it is necessary to carry out the investigation of E-waste recycling behavior to explore the collection channels for urban E-waste and to analyze household recycling behaviors.In addition,it is also important to conduct some investigations on the contamination and relationship of heavy metals in the soil-rice system at a typical E-waste dismantling region.The results will provide guidelines beneficial to the establishment of integrated WEEE recycling system,scientific distribution of rice plant and food security in rice production region.In this study,the students and families of Zhejiang A&F University were the main questionnaires and 273 valid samples were obtained.A total of 90 topsoil samples,90 rice samples,8 groundwater samples and 5 soil profiles at different depth from the paddy fields and 5 topsoil samples,6groundwater samples and 5 soil profiles?contrast group?away from the E-waste dismantling area were collected in Wenling City,Zhejiang Province.In this paper,based on GIS technique and kinds of spatial methods,we studied heavy metal contaminations,spatial variance and spatial relationship.The main results were summarized as follows:?1?According to the survey,there was a large amount of household electrical and electronic equipment with high abandonment rate.Few people bought second-hand products.IT and telecommunication equipment have a shorter lifespan,faster update than large household appliances.And there was significant room for recirculation of these categories of IT and telecommunication equipment.WEEE was still dominated by informal recycling.The result showed that the cost of recycling was the primary factor affecting the efficiency of formal recycling enterprises and economic benefit was the key determinant of choosing disposal channels.Most consumers were inclined to the formal disposal channel in the future.At present,E-waste disposal system of China still needs to be improved.And informal recycling can be incorporated into a more environment friendly and standardized E-waste recycling and treatment to reduce the heavy metal contamination in the meanwhile.?2?Compared with the background values of Zhejiang Province,the mean concentration of total heavy metals Cd,Cu,Pb,Ni and Zn were all higher with 0.38 mg·kg-1,35.13 mg·kg-1,35.40mg·kg-1,28.13 mg·kg-1,121.38 mg·kg-1,respectively.In addition,68%of samples were mildly polluted while 24%were moderately polluted and another 8%were seriously polluted.The average Ei value of soil heavy metal potential ecological risk parameters is less than 40.Average RI value of each grade is less than 150 which indicated that the overall potential ecological risk of the study area is low.According to the single factor pollution index and the Nemerow multifactor pollution index of heavy metals in the study area.The results indicated that Cd,Cu,Ni,Zn and Pb were enriched to different degrees in paddy soils.Especially Cd,which further threatened the groundwater safety in study area.However,the quality of the paddy soils in the study areas was generally acceptable for agriculture production.The concentrations of Cu,Pb,Zn and Cd in TS layer?020 cm?and SS layer?2040 cm?were higher than those in other soil layers and significantly higher than those in the control group?P<0.05?.The concentration of Ni did not change significantly due to some natural factors.Local Morans'I index results showed that the high-value agglomeration areas of soil Cd,Cu and Zn were mainly distributed in the northern part of the study area while the high-value area of Pb was mainly located in the northwest.And the high-value area of Ni was distributed in the northeast.The spatial distribution pattern of soil Pb and Cd showed a decreasing trend from northwest to southeast.Soil Zn showed a north-south decreasing trend while Cu was higher in the south and north.Ni was affected by soil texture and parent material so that the spatial pattern was different.Informal E-waste dismantling activities and other industrial developments were main factors for the accumulation of heavy metals in paddy soils in the study area.?3?The mean concentration of heavy metal Cd,Cu,Ni and Zn in rice were 0.095 mg·kg-1,5.342mg·kg-1,0.303 mg·kg-1and 28.20 mg·kg-1,respectively,all of which did not exceed the national food safety limits.The rice in the study area was generally at the safe production level.The variation coefficients of heavy metals Cd,Cu,Zn and Ni were 123.16%,18.12%,19.17%and 95.71%,respectively.And heavy metals Cd and Ni in rice were highly variable while Cu and Zn were moderately variable.According to the evaluated results of single factor pollution index,the overrun rates of Zn and Cd in rice were 1.11%and 8.9%,respectively.And there were different accumulations of rice Zn and Cd,indicating that there was a potential health risk in the study area.According to the spatial variability of heavy metals in rice,Cd and Cu variation structures were exponential models,Ni and Zn fitted Gaussian and spherical respectively.The relative ratio with fixed base of Cd,Cu and Ni was 41.85%,31.73%and 46.34%with moderate spatial correlation.And the rate of Zn was 0.43%with strong spatial correlation.The spatial distribution of rice Cd and Zn were similar with the decreasing from the northwest to and the southeast and east,concentration of Cu was higher in the north.There was an area with high concentration in the southwest for rice Ni.In general,the spatial distribution pattern of heavy metals in rice was consistent with that of the same heavy metals in soil,especially in areas with high value of heavy metals.It indicated that the concentration of heavy metals in soil affects the accumulation of heavy metals in rice to some extent.?4?The correlation coefficients between heavy metals in soil and rice showed that Cd and Zn were significantly correlated,Cu and Ni were irrelevant.Rice Cd,Zn and Ni were significantly correlated with the effective state of corresponding heavy metals in soil.The results indicated that the total heavy metals concentrations alone in soil cannot estimate the bioavailability of most heavy metals to crops.The heavy metal enrichment ability in the soil-rice system was generally in the order of Cd>Zn>Cu>Ni,which indicated that Cd has strongest migration ability so that there was potential risk of Cd contamination in the study area.The spatial distribution patterns of heavy metal enrichment index?EI?indicated that Ni,Zn and Cd in soil-rice system were the most effective in the western part of the study area.Soil properties,soil type,rice variety and other factors can influence the bioavailability of heavy metals to rice.By analysis of variance,the enrichment ability of hybrid rice to Ni,Zn and Cd was stronger than that of conventional late rice varieties.Principal component analysis showed that soil physical and chemical properties had certain effects on the migration and accumulation of heavy metals in soil-rice system,indicating that the bioavailability of heavy metals were related to soil physical and chemical properties and rice varieties. 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