广州市蔬菜中重金属污染特征、影响因素及健康风险研究

发布时间：2018-06-06 17:12

本文选题：蔬菜 + 重金属　；参考：《长江大学》2016年硕士论文

【摘要】：蔬菜质量安全直接关系到人体健康,其重金属污染问题,已成为人们关注的热点。由于重金属在土壤-作物-人体系统中的迁移转化受重金属种类、土壤理化性质及其他环境因素的综合影响,环境中的重金属总量并不能真实反映作物中的重金属总量,更不能代表最终被人体吸收的含量。目前国内对重金属在蔬菜-人体之间的迁移转化(即重金属的生物可给性)报道较少,国际上现多采用体外模拟方法进行重金属生物可给性的研究。为科学评价重金属在土壤-蔬菜-人体途径中的迁移转化过程及对人体健康的潜在风险,本研究首先对广州市不同行政区内主要蔬菜批发市场春季的4类8种市售蔬菜中重金属进行分析,了解其污染特征并进行健康风险评价；然后以土壤-蔬菜-人体为基线,通过盆栽实验对重金属Cd在土壤-油麦菜及土壤-空心菜系统中迁移转化的影响因素进行研究,并采用体外胃肠模拟法对盆栽蔬菜地上部进行重金属生物可给性的健康风险研究。主要研究结论如下：(1)8种蔬菜中Cu与Zn的含量均远低于食品卫生标准限值；8种蔬菜中Cr的超标率比较高,高达91.67%；Pb超标蔬菜包括莴苣、丝瓜、番茄和胡萝卜,超标率高达35.71%,以胡萝卜超标最为严重；Cd超标的蔬菜只有番茄,超标率达31.25%；Ni超标的蔬菜包括油麦菜、空心菜与菜心,超标率最高为8.33%。蔬菜中重金属综合污染程度表现为叶菜类肉质根类茎类菜茄果类；8种蔬菜污染程度为：空心菜、油麦菜、菜心、白萝卜和胡萝卜均处于警戒级,而莴苣、丝瓜和番茄则属于安全级别,可见所检测的蔬菜样品均处于安全和尚清洁的污染程度。(2)健康风险评估表明,广州市居民中日常多食用空心菜、菜心和油麦菜的人群重金属累积的健康风险较高,且经膳食摄入重金属Cr对人体健康可能会造成危害,Cd对人体具有潜在的健康风险。经口摄入蔬菜重金属对儿童可能造成的暴露风险要高于成年人。(3)组配施加0.6%的生物腐植肥与0.3%的硅酸钠对2种土壤中Cd的钝化效果最佳,油麦菜土与空心菜土中Cd的降幅分别高达7.44%、56.86%；单施生物腐植肥或硅酸钠对土壤中Cd具有一定的钝化效果,但效果不显著且因作物种类不同而有差异。(4)添加不同处理的硅酸钠与生物腐植肥后,土壤中Cd形态产生了变化,且土壤pH、有机质、CEC、AP、NH4+N、AK、ASi均是影响土壤Cd形态的因素。单施生物腐植肥可降低土壤中弱酸提取态-Cd、可还原态-Cd含量,降幅分别达14.49%、8.80%,并增加可氧化态-Cd、残渣态-Cd含量,增幅分别达26.50%、27.90%。单施硅酸钠时,可降低油麦菜土中弱酸提取态-Cd含量,降幅达8.41%,2种土壤中可还原态-Cd含量均随硅酸钠施加量的增加而降低,降幅达26.85%,而残渣态-Cd含量则显著增多,增幅高达141.62%。生物腐植肥与硅酸钠的组配施加,均可降低土壤中Cd的活性,且效果优于单一施加。(5)单施生物腐植肥的处理可促进蔬菜的生长,并显著增高油麦菜与空心菜的株高与地上部干生物量：2种蔬菜的株高较对照组(CK)随生物腐植肥施加量的加大而显著增高,增幅高达6.34%；地上部干生物量的增幅高达39.08%。单施硅酸钠的处理对2种蔬菜的生长具有一定的抑制作用：2种蔬菜株高与地上部干生物量均低于对照组(CK),株高降幅达15.66%,油麦菜干生物量随硅酸钠施加量加大而略有上升,而空心菜干生物量则随硅酸钠的施加量加大而显著降低,最大降幅为68.32%。组配处理中0.6%的生物腐植肥与0.3%的硅酸钠的处理对2种蔬菜株高的增高效果最好,优于SF2处理,对2种蔬菜地上部干生物量效果优于其他2种组配处理,但不及SF2处理。(6)油麦菜和空心菜地上部Cd含量均小于地下部Cd含量,表现为根茎叶,说明2种蔬菜对Cd的富集能力均不强。所有处理均可起到抑制油麦菜与空心菜对Cd进行吸收的作用,且0.6%的生物腐植肥与0.3%的硅酸钠组配处理能显著降低油麦菜地下部Cd含量至最低,降幅为44.04%,而0.6%的生物腐植肥与0.6%的硅酸钠处理则能显著降低空心菜地上部Cd含量至最低,降幅为68.32%。相关性分析表明：影响油麦菜和空心菜中Cd含量的主要因素是土壤中可还原态-Cd与可氧化态-Cd含量。(7)不同处理下的2种蔬菜胃阶段的Cd生物可给性均高于小肠阶段Cd的生物可给性,表现为：油麦菜胃阶段Cd的生物可给性在4.44%-6.52%之间,小肠阶段Cd的生物可给性在0.69%-2.92%之间；空心菜胃阶段Cd的生物可给性在4.83%-15.20%之间,小肠阶段Cd的生物可给性在1.36%-7.21%之间。相关性分析表明：弱酸提取态-Cd、可还原态-Cd是蔬菜Cd生物可给性的主要贡献者。2种蔬菜中Cd的潜在健康风险评价表明：0.6%的生物腐植肥与0.3%的硅酸钠的组配处理后,空心菜的致癌风险和非致癌风险较其他处理最小；小肠阶段的致癌风险CR、非致癌风险HQ均低于胃阶段的结果；肠阶段HQ值都远小于1、CR值均超出可接受范围,说明摄取油麦菜与空心菜不会对人体带来非致癌危害,但可能会对成人和儿童带来潜在致癌风险,且对成人的危害高于儿童。综上所述,0.6%的生物腐植肥与0.3%的硅酸钠这一组配处理在改善土壤理化性质、促进蔬菜生长、抑制蔬菜对重金属Cd的吸收及降低蔬菜中Cd被人体吸收后的健康风险等方面,均具有较好的效果,可视为试验研究中最佳的修复方式。
[Abstract]:The quality and safety of vegetables are directly related to human health, and the pollution of heavy metals has become a hot topic of concern. The transfer and transformation of heavy metals in the soil crop human system are affected by the types of heavy metals, the physical and chemical properties of soil and other environmental factors, and the total amount of heavy metals in the environment can not truly reflect the crops. The total amount of heavy metals can not represent the content that is absorbed by the human body. At present, there are few reports on the migration and transformation of heavy metals between vegetables and human beings (that is, bioavailability of heavy metals). In the world, the research on the availability of heavy metals by the method of extracorporeal simulation is used in the world. In this study, the heavy metals in 4 kinds of 8 kinds of vegetables sold in the main vegetable wholesale markets in different administrative districts of Guangzhou were analyzed in this study to understand the pollution characteristics and evaluate the health risk. Then the soil vegetable human body was used as the baseline and the pot experiment was used. The influence factors of migration and transformation of metal Cd in soil - oil and wheat and soil - cabbage system were studied, and the health risk of heavy metals in the upper part of potted vegetable was studied in vitro. The main conclusions are as follows: (1) the content of Cu and Zn in 8 vegetables is far below the limit of food hygiene standards; The exceeding standard rate of Cr in the 8 vegetables was high, up to 91.67%, and the super standard vegetables including lettuce, silk gourd, tomato and carrot were up to 35.71%, the highest rate of exceeding standard was carrot, the only vegetables with Cd exceeding the standard were tomato, the rate of exceeding the standard was 31.25%, and the exceeding standard of Ni included the vegetable, the cabbage and the heart, the highest rate was the medium weight of 8.33%. vegetables. The degree of the comprehensive pollution of the metal is the carrot and vegetable, and the 8 kinds of vegetable pollution are: empty cabbage, oil and wheat, cabbage, white radish and carrot, while lettuce, towel gourd and tomato are in safety level, and the detected vegetable samples are in the level of safety and clean pollution. (2) health The risk assessment shows that the health risk of heavy metals accumulation in the people of Guangzhou city is high, and the heavy metal Cr can cause harm to human health. Cd has potential health risks to the human body. The exposure risk of heavy metals to children by oral intake of vegetables and vegetables is required. Higher than adults. (3) the effect of 0.6% biological humoral fertilizer and 0.3% sodium silicate on the passivation of Cd in 2 soils was best, and the decrease of Cd was 7.44%, 56.86%, respectively. Single application of biological humoral fertilizer or sodium silicate had a certain blunt effect on Cd in the soil, but the effect was not significant and the variety of crops was different. There were differences. (4) after adding different treatments of sodium silicate and biological humoral fertilizer, the morphology of Cd in the soil changed, and soil pH, organic matter, CEC, AP, NH4+N, AK, ASi were all factors affecting the soil Cd morphology. Single application of biological humoral fertilizer could reduce the extraction state -Cd and reducible -Cd content of the soil, which was 14.49%, 8.80%, and increased, respectively. Oxidation state -Cd, residue state -Cd content, the increase of 26.50%, 27.90%. single application of sodium silicate, can reduce the weak acid extracted state -Cd content in the oil and wheat vegetable soil, the decrease of 8.41%, the 2 kinds of soil reducible -Cd content decreased with the increase of sodium silicate, the decrease of 26.85%, and the residue -Cd content increased significantly, up to 141.62%. raw. The effect of soil humic plant fertilizer and sodium silicate can reduce the activity of Cd in the soil, and the effect is better than single application. (5) the treatment of single application of biological humoral fertilizer can promote the growth of vegetables, and significantly increase the plant height and upper dry biomass of the vegetable and cabbage. The height of the 2 vegetable plant height is higher than the control group (CK). Large and significant increase was increased by 6.34%, and the increase of dry biomass up to 39.08%. single application of sodium silicate could inhibit the growth of 2 vegetables. The height of 2 vegetable plants and the aboveground biomass were lower than that of the control group (CK), and the height of plant height was 15.66%. The dry biomass of oil and wheat was slightly increased with the amount of sodium silicate. There was a rise, while the dry biomass of the cabbage decreased significantly with the increase of the amount of sodium silicate. The maximum decrease was that the treatment of 0.6% biological humic fertilizer and 0.3% sodium silicate in the 68.32%. group had the best effect on the height of 2 vegetable plants, superior to the SF2 treatment, and the effect of the dry biomass on the upper part of the 2 vegetable fields was better than the other 2 groups. Less than SF2 treatment. (6) the content of Cd in the upper part of the oil and wheat and cabbage is less than the Cd content in the underground, which shows the root and stem leaves, which shows that the enrichment ability of the 2 vegetables is not strong. All treatments can inhibit the absorption of Cd by the vegetable and the cabbage, and the treatment of 0.6% biological humoral and 0.3% sodium silicate can be significantly reduced. The lower Cd content in the lower part of the vegetable field was the lowest, the decrease was 44.04%, while the 0.6% biological humoral fertilizer and 0.6% sodium silicate could significantly reduce the Cd content in the upper part of the cabbage, and the decrease was 68.32%. correlation analysis. The main factors affecting the Cd content in the vegetable and the cabbage were the reducible -Cd and the oxidizable -Cd content in the soil. (7) the Cd bioavailability of the 2 vegetable gastric stages under different treatments is higher than the bioavailability of Cd in the small intestinal stage, which shows that the bioavailability of Cd in the stomach stage of the wheat and wheat is between 4.44%-6.52%, and the bioavailability of Cd in the small intestine stage is between 0.69%-2.92%; the bioavailability of Cd in the stomach stage of the cabbage is between 4.83%-15.20% and small intestine. The bioavailability of phase Cd was between 1.36%-7.21%. The correlation analysis showed that the weak acid extracted state -Cd, the reducible -Cd was the main contributor to the Cd bioavailability of vegetable Cd, the potential health risk assessment of Cd in.2 vegetables showed that the carcinogenic risk and non carcinogenesis of 0.6% biological humoral fertilizer and 0.3% sodium silicate were found. The risk of the intestinal cancer risk CR and the non carcinogenic risk HQ are lower than the results of the gastric stage; the HQ value of the intestinal stage is far less than 1, and the CR values are all beyond the acceptable range, indicating that the intake of oil, wheat and cabbage will not cause non carcinogenic harm to the human body, but it may bring potential carcinogenic risk to adults and children, and it may be possible The harm of human is higher than that of children. To sum up, 0.6% biological humoral fertilizer and 0.3% sodium silicate have good effects on improving soil physical and chemical properties, promoting vegetable growth, inhibiting the absorption of heavy metal Cd and reducing the health risk of Cd absorbed by human body in vegetables, which can be considered as the best in the experimental study. The way to repair it.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S63;R155.54

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