Arsenic Content In Crops And Biomarkers Of Arsenic Exposure In Arsenic-affected Areas Of The Hetao Basin

More than 100 millions of residents are being at risk of chronic arsenic poisoning.More and more attention was attracted by the international and national scientist to As contents in crops and As exposure biomarkers in As-affected areas.This paper investigated the As species and total As contents in crops,saliva,urine,nail and hair samples,calculated daily As intake by residents,and revealed the suitable As exposure biomarkers in the Hetao basin,based on data reviews,field survey,field sampling and laboratory analysis of the samples.Major conclusions have been drawn as follows.1.The main As species in grains,vegetables and fruit include DMA,As(V)and As(III).The contents of As species and total As in different crop samples varied greatly,and the As contents of the same crop species in different villages were different.2.Organic As was transformed into inorganic As during crop processing,which increased the As toxicity.Arsenic extraction efficiency was different in different crop samples,showing that the extraction efficiency was dependent on crop species.3.Arsenic species in saliva mainly included inorganic As(V)As(III).As species in urine included inorganic As(V)and As(III),dimethylarsinic acid(DMA),arsenobetaine(AsB)and monomethylarsonic acid(MMA).Organic As species were the major species in urine.Total As contents in urine samples were higher than those in saliva samples.Arsenic species in nail and hair were MMA,DMA,As(V)and As(III),which mainly dominated by inorganic As.Contents of As in nails were higher than those in hairs.4.There were positive correlations between saliva As,urine As,nail As,hair As and daily As intake(TDIAs).Urine As and saliva As were positively correlated.The positive relationship was also found between nail As and hair As.It indicated that saliva,urine,nail and hair can be used as As exposure biomarkers.By comparing the four biomarkers,it was found that saliva can be as a better biomarker.5.TDIAs in each village was consistent with the prevalence rate,indicating that the high intake of As is the major cause of chronic As poisoning.The main way of As intake was ingestion of grains,vegetables and fruits,among which vegetable and grain ingestion were the most important pathway.Therefore,it was possible to minimize the intake of high-As crops,so as to prevent chronic As poisoning and avoid the health risks of the local residents.6.Relationship between urine As,saliva As,nail As,hair As and sex,age,smoke and other factors showed that men,older and residents with skin lesions had higher saliva As,urine As,nail As and hair As.Relationship between saliva As,urine As,nail As,hair As and BMI and smoking were not obvious.