Study On Children’s Soil Ingestion Rate Through Hand To Mouth Contact And Influencing Factors In Typical Regions Of China

At present,the situation of soil pollution in China is grim,and human health risks caused by soil exposure cannot be ignored.Compared with adults,children have a higher soil intake rate(SIR)and are more sensitive to pollutants due to their special physiological conditions.To effectively control the human health risks of soil exposure,it is necessary to first understand the SIR,the main intake pathway and its contribution.It is generally believed that hand-to-mouth contact is the main way for children to ingest soil,but lacks scientific basis.To this end,this study carried out a study on children’s hand soil and dust(SD)intake rate and its influencing factors in typical regions of China.This study selected typical cities and rural areas in Hubei,Gansu,and Guangdong provinces to carry out child case studies.First,according to certain rules,a number of children in different regions,different ages,and different genders were randomly selected to fill out the questionnaires(n=1,361)to obtain basic information related to hand SD intake rate,such as the frequency of hand-to-mouth contact,living environment,lifestyle,parental education level,etc.Then,among the children who participated in the questionnaire survey,240 children aged 2 to 14 years were selected(including 120 in urban areas and 120 in rural areas).The hand SD samples were collected by the wiping method.Its scope was 3.50-187.39 mg(median value 19.49 mg).The screened trace elements(Ce,Y,V,Sc)are then used to obtain the children’s theoretical hand SD amount,which ranges from 0.01-13.67 mg(median value 0.48 mg).The hand SD intake rate of children in China calculated by the tracer element Ce is 11.9 mg/d.Children in Gansu Province had the highest amount of hand SD and hand SD intake,followed by Guangdong and Hubei provinces.Children’s hand SD volume and hand SD intake rate are the highest among elementary school children,followed by kindergartens and middle schools.Finally,conditional inference tree analysis was used to find that geographic location,hand washing habits,age group and gender were the main factors affecting children’s hand SD.In this study,the main conclusions are as follows:(1)Using the tracer element method to study children ’s hand SD intake rate is a feasible way.The trace elements Ce,Y,V and Sc are better in soil and children’s hand SD samples in the study area.The Ce in the three typical areas of China can calculate the theoretical hand SD amounts well to show its changing trend.(2)Hand SD load and hand SD intake rate of children in typical regions of China are very different from foreign countries,and the hand SD intake rate of Chinese children only accounts for 26.6%of the soil intake rate.Not the main route of exposure for Children.(3)Due to the large differences in climate,children’s living habits,and parents’education level in Hubei,Gansu,and Guangdong Provinces,there are great differences in the hand SD intake rates of children in different regions and ages in China.(4)There is a big difference between the health risk assessment results of As and Pb using the SIR recommended by the US Environmental Protection Agency and the soil intake rate of children obtained in our study.