Investigation And Risk Assessment Of Soil Pollution In Three Different Industrial Sites

In recent years,with the rapid development of the scale of urbanization in my country,the urban layout has been continuously adjusted.Many factories and enterprises in the old city have been moved out of the city or made business changes,and a large number of abandoned industrial sites has been left.The pollution investigation and reuse of these abandoned production sites has become a key direction in the field of environmental science research and engineering practice.There are a large number of "three wastes" in the abandoned site,which carry a large amount of pollutants into the soil.Under the influence of accumulation,leakage and other activities of pollutants in the soil,when the soil content exceeds the national standard,it will cause toxicity to the animals and plants around the site.The second use of the site can also cause great harm to human health.Based on this,this paper takes medical rubber field(rubber field),auto parts manufacturing field(auto parts field)and chemical processing field(acid processing field)as research objects,Through preliminary survey,sampling and experimental analysis,the concentration distribution characteristics of detectable pollutants in soil and groundwater of industrial sites are revealed,the pollution status of the site and the human health risk of the pollutants concerned were evaluated.The main research results are as follows:(1)The investigation of the soil pollution status of the site shows that heavy metals can be detected in three sites.The distribution of heavy metals in the three sites was similar to that in the production area and the treatment area,and the content in the storage area was lower than that in other functional areas.Only total petroleum hydrocarbons(TPH)could be detected in the two sites.TPH distribution in the production area is higher than that in other functional areas,especially in the automobile parts field.Fluoride was detected only in the acid processing site,and the distribution was characterized by office area(1315.00 mg·kg~-1)>production area(1148.57 mg·kg~-1)>storage area(959.80 mg·kg~-1)>treatment area(772.00 mg-kg~-1).Except for fluoride,the contents of pollutants detected in the three sites did not exceed the screening value in "The standard for soil pollution risk control of construction land(Trial)(GB 36600-2018)",the content of fluoride(2170.00 mg·kg~-1)exceeded that of soil screening(2000.00 mg·kg~-1),and the exceeding standard rate was 5.89%.It was speculated that the reason of excessive fluoride was improper operation in acid processing process(2)According to the investigation of groundwater pollution,different indicators were tested for different industrial activities in the auto parts site and acid processing site.The results showed that among the heavy metals and other indicators detected in the two sites,only one point of TPH in the steam fittings site exceeded the class IV water quality limit in the groundwater quality standard(GB/T 14848-2017),with the exceeding rate of 25%.Other indicators did not exceed the class TV water quality limit in the standard.(3)In terms of site pollution evaluation,the comprehensive pollution index on heavy metal indicators of the three sites all showed a clean level.The single factor pollution index(Pi)of heavy metal arsenic(As)exceeded 0.7 level in the functional areas except office area(0.25),which should be paid attention to in the future use of the site.In the organic matter index,the single factor pollution index of the three sites showed a clean level.Fluoride is clean on acid processing sites,The Pi values(0.574,0.658)in the production area and office area of the acid processing site were higher than the single factor value(0.553)of the whole site.There were some spatial differences in fluoride pollution distribution(4)Through the health risk assessment of the soil fluoride in the site,it is concluded that the soil fluoride in the acid processing site generates human health risks through inhalation of soil particles and oral intake of the soil.Through the risk assessment calculation model,the risk of carcinogenesis was calculated as 0.135,which was lower than the critical risk of human body.The reason for the risk is that the historical area of the point is the production area,and improper operation resulted in fluoride leakage and migration to soil,resulting in accumulation of soil fluoride health risk.(5)In the risk uncertainty analysis,the proportion of risk contribution showed that the contribution rates of oral intake and inhalation of soil particles were 89.08%and 10.92%,oral intake was the main fluoride exposure route.In terms of parameter sensitivity,parameters such as exposure period,body weight,exposure frequency,and daily intake of soil are highly correlated with non-carcinogenic risk results.The risk control value will increase or decrease with the changes of the above four types of sensitive parameters.It is suggested that more research efforts and attention should be paid to the sensitive parameters in the risk control research,and reasonable parameter values should be selected according to the on-site pollution situation of the target site.(6)Based on the purpose of protecting human beings,the risk control suggestions for soil and groundwater were put forward from three aspects of pollution sources,contact routes and protection receptors.For the risk control of soil fluoride in acid processing sites,it is suggested to carry out soil fluoride remediation.Suggestions for prevention and control of soil index were put forward for rubber field and auto parts factory site.It is suggested to strengthen the awareness of groundwater treatment site and groundwater treatment site to enhance the awareness of groundwater and groundwater treatment site.Figure 12 table 36 reference 114...