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Health Risk Assessment Via IEUBK Model and Epidemiological Investigation for Environmental Lead Exposed Children

Author: XuSong
Tutor: ZhouYiKai
School: Huazhong University of Science and Technology
Course: Occupational and Environmental Health
Keywords: IEUBK model Child Lead Health Risk Assessment
CLC: R179
Type: Master's thesis
Year: 2011
Downloads: 56
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Abstract

First-part IEUBK blood lead prediction model introduction, inspection and exposure source contribution constitutes the purpose of the analysis: a brief description of IEUBK blood lead prediction model, the difference between the basic structure of a clear model, comparing the model predicted and observed values, measurement model predictive capability; major contributing factor to explore various exposure routes contribution to the results of the model predictions, screening affect the forecast results. : ○ 1 selected 44 cases of children measured blood lead and the detailed environmental lead exposure data, applications IEUBK model predicts children's blood lead; blood lead data geometric mean (GM) and beyond 10μg/dl the probability value assessment indicators , and the combination of the two indicators measure the predictive ability of the model of the 95% confidence interval (CI). ○ 2 Select to the detailed environmental lead exposure data, 113 cases of children IEUBK the model blood lead predict BP neural network model to investigate the contribution of various exposure pathways of lead exposure on the predictive value of IEUBK model use Clementine12.0 software. Results: 44 cases of children's blood lead observations geometric mean (95% CI) for 7.49μg/dl (6.56 8.54μg/dl) the model predictions geometric mean (95% CI) 12.85μg/dl (10.00 ~~ 16.40μg/dl); observed and predicted values ??beyond 10μg/dl proportion of children were 27.27%, 61.75%, corresponding to a 95% confidence interval of 15.00% to 43.00% and from 42.20% to 81.40%, respectively. BP neural network sensitivity analysis showed that children through diet, soil / dust, air, drinking water pathway of lead exposure on the predictive value of IEUBK model blood lead contribution rate of 55.52%, 27.73%, 12.80% and 3.95%, respectively. Conclusion: IEUBK model predicted value and the actual value of some gaps need to be cautious analysis of the model to predict blood lead results; diet, and soil / dust lead exposure is the main source contribution factors affect the predictive value of the model for blood lead. The second part of CH children of lead and zinc smelting mine environmental lead exposure purpose of the survey: The survey area of ??environmental lead the investigation and detection of crops lead in children's blood lead load forecast, the judgment of the Regional Environment Environmental Lead Pollution, tracking the source of lead contamination , the main way analysis of children's exposure to lead and lead load data distribution characteristics, epidemiological evidence for children's health risk assessment. Methods: CH lead and zinc smelter in the region as the center, local perennial dominant wind direction, wind speed, the mine chimney height and villages distance of the reference, select the annual dominant wind and sub-dominant wind direction below the village B, B Point Primary School in south-west of the town of A, C village, Village D, Village E, D point primary school for the contaminated area monitoring point, select the same geological conditions, economic conditions, demographic conditions, the same habits northwest direction 10km outside the village of F and F point primary school as the control point. Cluster random sampling method to extract the investigation more than five years of residence in the region and the consumption of local homemade food, vegetables, and other major food children (elementary school grades 1 to 2 students) for the survey, each survey point (Primary) extract 1 ~ 100 2nd grade students. According to the relevant provisions of the requirements for environmental samples, sampling of drinking water and crop samples, such as in accordance with the requirements of the National Soil Survey Technical Provisions, soil distribution, on-site sampling, sample preparation, analytical testing, data processing; detected through laboratory analysis of drinking The lead content in the water, dust / soil and crop samples, combined dietary surveys to estimate the average daily lead intake in children; the use of IEUBK blood lead prediction model children's blood lead load data to obtain the corresponding survey area. Finally, the SPSS software for statistical analysis of the difference between the comparison contaminated areas and control each index. Results: investigation of soil test results show that the detection of the lead content of the water body, in addition to C, A and D of the high lead content of tap water in three villages, tap water lead content of the remaining points are in line with national health standards; groundwater quality is good, not by heavy metals lead contamination. Agricultural testing results show that the survey point vegetables lead exceeded common between the average lead content of different surveys point vegetables was no statistical difference (P gt; 0.05). Soil test results show that the addition to the the F points soil samples exceeded the standards, the remaining points of the survey area are beyond the limits specified level of the country, and with varying degrees of pollution. According to estimates, the B Point Primary School, D point primary school and primary school children of the point F average daily lead intake 1546.69μg / (person · day) 1063.65μg / (person · day) 560.19μg / (person · day) The three survey points the main source of childhood lead intake of dust, followed from vegetables. Three primary school students, the average blood lead load 40.15μg/dl, 30.30μg/dl, 21.25μg/dl, a statistically significant difference (P lt; 0.05). Conclusion: B Village, A Village C, D, E, there are varying degrees of environmental lead contamination, and with the the CH lead and zinc smelter emissions. Survey area children lead burden seriously overweight, the Environmental Lead enters the body of the main migration path for the intake, dust and vegetables are the main source. Health objectives of the survey of the third part of the the CH lead and zinc smelting mining environmental lead exposure in children: epidemiological survey, qualitative analysis of the the survey regional environmental lead contamination of the exposed population health damage for the survey area environmental lead pollution and children's health effects causal inference lead evidence of health effects. Method: site cluster sampling Select survey more than five years of residence and consumption of local homemade food for children (primary school grades 1 to 6 students) for the survey and collect the appropriate blood by means of the EPA provided IEUBK blood lead prediction model lead information. Understanding of the local children's habits, general health status, history of present illness and past medical history questionnaire. Application Conners Scale and the Raven Standard Progressive Matrices Test Scale Evaluation of children's behavior and intelligence level. Statistical analysis method mainly involves χ2 test and linear correlation. Results: contaminated area children three symptoms (often dizziness, frequent colds, abdominal pain or nausea) compared to the control area were statistically significant (P lt; 0.05); contaminated areas suspected ADHD children and control children hyperactive behavior findings show zone compared with the statistical significance (P lt; 0.05); children's intelligence level of the three schools have not yet found statistical differences; incidence of children's blood lead level exceeding multiples with various clinical symptoms high exposure - should be efficient, exposed to low - low effects associated trends. Conclusion: CH lead and zinc smelting lead mine pollution accumulation heavier body lead burden of local children, and has contributed to the generation of children's behavioral problems and the adverse impact the health status of the local children. The fourth part of the the CH lead and zinc smelting mining environmental lead exposure in children's health risk assessment purposes: Childhood Lead intake survey, the use of the United States Environmental Protection Agency (EPA) recommended non-carcinogenic risk model (risk index HI) and carcinogenic model excess risk (average annual cancer ERy), the evaluation lead and zinc smelting mine environmental lead exposure children's health risks, and provide the scientific basis for risk management and decision-making of the relevant departments, to provide a clear guide for the implementation of the follow-up interventions. Methods: JECFA (JECDFA) of lead in foods formulated weekly tolerable intake area children intake PTDI, per person per day to allow local children in average daily lead intake, the use of risk assessment models, calculated Survey of Child lead intake average annual excess cancer risk and the risk index. Results: B Point Primary School, the D Point Primary School and the F point primary school children oral intake of lead ERy were 0.606 × 10 ^{-5 0.446 10-5,0.227 × 10-5; respectively, HI 13.98,10.27,5.23. Conclusion: The environmental exposure to lead has been a threat to the local health situation of children, but the carcinogenic risk is not significant.}

Health Risk Assessment Via IEUBK Model and Epidemiological Investigation for Environmental Lead Exposed Children

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