论文部分内容阅读
Arsenic exposure threatens human health.Shanxi and Inner Mongolia are two provinces with highest groundwater As concentrations and most reported endemic As cases in China.The As concentrations ranged from <1~1160 μg L-1 in the Datong Basin,Shanxi and <1~804 μg L-1 in the Hetao Basin,Inner Mongolia.High concentrations of As,Fe,and Mn occurred in the pe range-2 to-4.High percentages of water(77%of n=131 total samples),vegetables(92%,n=120),cereals(32%,n=25),urine(70%,n=99),nails(76%,n=176),and hair(62%,n=61)contained As higher than the acceptable levels.Dietary As contributed 92%of the average daily dose(ADD)when the water As concentration was less than 10 μg/L,for which 5 out of 30 examined participants were diagnosed with arsenicosis symptoms.The distinct positive correlation between ADD and As concentrations in urine,nails,and hair suggests different applicability for these biomarkers.Methylated As as the predominant urinary As species confirms that the ingested inorganic As is methylated and is excreted through urine.In situ micro-distribution and speciation analysis indicate that As is mainly associated with sulfur in nails and hair.Nails,rather than hair and urine,could be used as a proper biomarker for arsenicosis.High ADD from the environment and low excretion could result in As toxicity to humans.High arsenic in groundwater and industrial wastewater could be effectively removed using nano-TiO2 which resulted in a dramatic reduction in urinary As concentrations.