重庆市本地产大米中镉污染调查及健康风险评价

发布时间：2018-04-26 05:23

本文选题：镉 + 大米　；参考：《重庆医科大学》2015年硕士论文

【摘要】：目的：经济的快速发展造成各种自然因素和人为因素导致的重金属污染愈加严重。镉是有毒非必需重金属元素之一,尤其是对某些遭受到镉暴露的环境或工作中的人群,危害更加严重。土壤中的镉会蓄积在农作物中,并且通过食物链对人类健康造成严重威胁。镉由于自身的特性,易于蓄积在大米中。各地镉污染事件已经引起了全球广泛关注。大米是重庆市当地居民主要食物,所以大米成为当地居民饮食镉暴露的主要来源。本文检测重庆市本地产大米中镉含量,分析检测数据,了解重庆市本地产大米镉含量水平,并对重庆市居民来自大米的镉膳食暴露所带来的健康风险进行评价,提出控制食品中镉含量的措施,为当地食品安全监管提供科学依据。方法：重庆市按行政区域划分为四个地区(主城区、“一圈”内其它区县、渝东北、渝东南),从2013年11月到2014年5月间对重庆市所有产大米区县进行随机抽样,每月各地区抽样数量为：主城区(1个)、“一圈”内其它区县(2个)、渝东北(2个)、渝东南(1个),七个月来所抽查大米样品覆盖全市34个区县,将所抽查区县的大米加工厂全部纳入,每个加工厂每次抽取时按照国家规范抽取当地所产大米4份。采集的大米样品按照国家标准GB/T5009-2003将样品进行前处理、微波消解仪进行样品消解,使用石墨炉原子吸收光谱仪,采用石墨炉原子吸收光谱法对重庆本地产大米镉含量进行检测,标准曲线和加标回收率均需要符合实验要求,将大米镉含量使用健康风险评估模型,对当地不同地区居民进行健康风险评估,这些检测的最终结果进行数据处理,统计分析。结果：①共检测大米样品1020份,检测值范围为0.001～0.231 mg/kg,平均值0,025 mg/kg,处于较低水平,镉含量超标数有7份,总合格率为99.31%；②镉含量频数分布表明镉含量大多数处于0～0.040mg/kg区间内,此区间范围内样品构成比为88.04%,高于镉含量限值(0.2mg/kg)样品构成比仅为0.69%,超标数较少,表明大多数样品镉含量处于较低范围；③观察不同区县间大米镉含量,各地区间镉含量均值较低,平均值范围为0.012 mg/kg～0.047mg/kg,潼南县、彭水县和大足区发现少数样品有镉超标情况,但超标率较低,其余31个区县大米镉含量均在规定限值内。比较潼南县、彭水县和大足区大米镉含量的平均数和中位数,三地区中位数值均明显低于平均值。不同区县镉含量差异有统计学意义(H=112.56,P0.01),不同区县镉超标率也存在差异(X 2=71.50,P0.01);④观察不同区域问大米镉含量,四区域间镉含量有差异(H=22.60,P0.01),主城区和渝东北地区均无镉超标情况,渝东南地区镉超标率最高,与主城区和“一圈内”其它区县地区相比无差异(X 2=2.79、1.74,P0.05),高于渝东北地区(X 2=12.93,P0.01);⑤评估重庆市当地居民大米镉暴露健康风险,本地产大米镉日摄入量(DI)远远小于允许限值72ug/(mg·天),出现了极少量大米样品DI超标现象,但各区县镉平均值DI均在限值内。本地产大米镉目标危险系数(THQ)也远远小于允许限值1,也出现极少量大米样品THQ超标现象,但各区县镉平均值的THQ也均在安全水平内。结论：本次重庆市本地产大米镉含量检测合格率较高,总体镉含量水平较低,镉暴露风险低,当地居民来源于大米的镉摄入水平处于安全范围,大米镉暴露对人体尚不能构成威胁。各地区间的镉含量水平有差异,原因可能是各区县之间不同的土壤环境或者实验人为因素造成,也可能是季节性原因和有限的样本数量,所以只能代表当时抽样时当地所产大米的镉水平,具体原因还需进一步调查,建议以后开展各地区的农田土壤检测工作,从根源处了解当地重金属污染情况。
[Abstract]:Objective: the rapid development of the economy causes the heavy metal pollution caused by various natural and human factors. Cadmium is one of the toxic and non essential heavy metals, especially for some people in the environment or work exposed to cadmium. The cadmium in the soil will be stored in the crops and through the food chain. Human health is a serious threat to human health. Cadmium is easily accumulated in rice because of its own characteristics. Cadmium pollution in various places has aroused widespread concern around the world. Rice is the main food of local residents in Chongqing, so rice has become the main source of cadmium exposure in local residents. This paper examined the content of cadmium in rice produced in Chongqing and analyzed the analysis of cadmium. Test data, understand the level of local rice and cadmium content in Chongqing, and evaluate the health risks of Chongqing residents from the cadmium dietary exposure from rice, put forward measures to control the content of cadmium in food, and provide scientific basis for the local food safety supervision. Method: Chongqing city is divided into four regions according to the Administrative Region (main city area, " A circle of other districts and counties, Northeast Chongqing, Southeast Chongqing, from November 2013 to May 2014, all rice districts and counties in Chongqing were randomly sampled, and the sample number in each region was: the main city area (1), "one circle" in other districts and counties (2), Northeast Chongqing (2), Southeast Chongqing (1), and seven months for the sampling of rice samples to cover 34 districts of the city. In the county, the rice processing plants in the district and county are all included, and each processing plant extracts 4 parts of the local rice according to the national standard each time. The samples are processed in accordance with the national standard GB/T5009-2003, the microwave digestion instrument is dissolved, the graphite furnace atomic absorption spectrometer is used, the graphite furnace atom is used. The CD content of rice produced in Chongqing was detected by absorption spectrometry. The standard curve and the recovery rate of the added standard need to meet the requirements of the experiment. The health risk assessment model of rice and cadmium was used to assess the health risk of the residents in different locals. The final results of these tests were processed and analyzed. Results: (1) the results were analyzed. 1020 samples of rice were measured, the detection range was 0.001 ~ 0.231 mg/kg, the average value was 0025 mg/kg, at a lower level, the cadmium content exceeded the standard number 7, the total qualified rate was 99.31%, and the cadmium content frequency distribution showed that the cadmium content was in the 0 ~ 0.040mg/kg interval, and the sample composition ratio within this range was 88.04%, higher than the cadmium content limit value (0.2mg /kg) the composition ratio is only 0.69%, and the number of super standard is less. It shows that the content of cadmium in most samples is in a lower range. (3) to observe the content of cadmium in different districts and counties, the mean value of cadmium in each region is low, the average range is 0.012 mg/kg to 0.047mg/kg, and a few samples in Tongnan County, Pengshui county and big foot area have been found to exceed the standard of cadmium, but the exceeding standard rate is more than the standard. Low, the contents of rice and cadmium in the other 31 counties were within the prescribed limits. The average and median of rice and cadmium content in Tongnan, Pengshui and Dazu regions were compared. The median values of the three regions were significantly lower than those of the average. The cadmium content in different districts and counties was statistically significant (H=112.56, P0.01), and the cadmium exceeding standard rates in different districts and counties were also different (X 2=71.50, P0.01). (4) to observe the content of rice and cadmium in different regions, the cadmium content in the four regions is different (H=22.60, P0.01), and there is no cadmium exceeding the standard in the main city and the northeast of Chongqing, and the super standard rate of cadmium in the southeast of Chongqing is the highest, and there is no difference (X 2 =2.79,1.74, P0.05) with the main city and the "one circle" area (P0.05), which is higher than that in the northeast of Chongqing (X 2=12.93, P0.01); 5 To assess the health risk of rice and cadmium exposure in Chongqing, the daily intake of rice and cadmium (DI) was far less than the allowable limit value 72ug/ (mg day), and a very small amount of rice samples had been exceeded by DI, but the average DI of cadmium in each district was within the limit. The local hazard coefficient (THQ) of the local rice and cadmium (THQ) was also far less than 1 of the allowable limit. A small amount of rice sample THQ exceeded the standard, but the average cadmium value of THQ in all districts and counties was also in the safe level. Conclusion: the local rice cadmium content detection rate is high, the total cadmium content level is low, the cadmium exposure risk is low, the local residents are in the safe range from the cadmium intake level of rice, and the rice and cadmium exposure are still on the human body. It can not constitute a threat. There is a difference in the level of cadmium in each region, which may be caused by different soil environment or artificial factors between the districts and counties. It may also be seasonal and limited samples. Therefore, it can only represent the level of cadmium in the local rice at the time of sampling. The specific reasons should be further investigated and suggested. We will carry out farmland soil testing work in various areas and understand the local heavy metal pollution from the source.

【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R155.5

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