An Exposure Assessment Of Lead Via Diet Upon Local Residents In A Mining Area

Objective:Through analyzing lead content in drinking water and vegetables of local residents in a certain mining area, investigating the dietary structure and calculating the lead exposure to the residents via local diet, the health risk of lead exposure was assessed and scientific clues for locating the main reason of the lead pollution on local children and source of lead were presented.Materials and Methods: 20 female families in the area were randomly selected to collect samples. Corresponding samples include 61 samples of drinking water, 166 samples of vegetables and cereals and 50 samples of soil. Flame-AAS and GF-AAS were used to analyze the lead content in samples. Sample preparation and analyzing process were carried out strict quality control measures to make sure the authenticity and accuracy of the results. Housewives of the chosen families were selected as interviewers to undertake the dietary survey. The index of risk was calculated by combining data of lead content in samples and dietary survey to indicate that whether or not the risk level of lead exposure is acceptable.Results: (1)The average level of lead content in the soil is not beyond the safe limit, (2)The average level of lead content in the water in three different sampling time was 18.29±10.83μg/L, 42.74±36.36μg/L and 30.33±16.75μg/L. They are 6.12,14.29 and 10.14 times of the control(2.99±1.13μg/L) respectively. Significantly variation among water lead content sampled in Nov.2004 and April.2005 was observed(P<0.01).The average daily lead exposure in three sampling time via water was 32.36μg/d, 100.00μg/d and 63.60μg/d. They are 5.41,16.72 and 10.64 times of the control(5.98μg/d) respectively. (3)The lead content in all vegetable samples were beyond the safe limit with range of 1.41±0.22 mg/kg(cucumber)～5.47±0.71mg/kg(green chinese cabbage). Different varieties of vegetables and cereals have different bioconcentration factors(BCF) with following sequence: green chinese cabbage>shallot>corn>pumpkin>foxtail millet>leek>radish>cabbage>eggplant>cucumber. The average daily lead exposure in three sampling time via local diet was 730μg/d,995μg/d,1790μg/d. (4)The average weekly lead exposure of local residents...