湘中某工矿区土壤、水稻镉砷污染特征与迁移规律

发布时间：2018-05-20 23:03

本文选题：红壤 + 紫色土　；参考：《中南林业科技大学》2015年硕士论文

【摘要】：重金属污染耕地导致农产品超标事件时有发生,超标农产品通过食物链威胁人类健康。现阶段我国重金属污染耕地的农业利用仍然难以避免,粮食安全受到重大挑战。土壤重金属污染组分交织,污染物去除困难,目前耕地重金属污染的治理往往针对单一重金属如耕地Cd污染,单一的治理方案忽略了其它污染元素,如As污染。因此研究矿区周边不同污染组分尤其是Cd、As污染特征,探明Cd、As在土壤-水稻中的迁移规律和影响因素,提出降低或者避免农产品污染的对策措施显得尤为必要。以湘中某铅锌工矿区周边重金属污染稻田为研究对象,连续两年定点采集工矿区周围红壤母质和紫色土母质发育的水稻土(红黄泥、紫泥田,本文简称红壤、紫色土)和水稻植株样品,研究土壤和水稻Cd、As的污染特征,分析土壤-水稻系统中Cd、As迁移规律,研究糙米中Cd、As含量的影响因素。主要研究结果如下：(1)网格法采样调查分析表明,调查区稻田土壤Cd、As污染严重,全部采样点(n=94)稻田土壤处于严重的Cd污染,80.30%采样点处于不同程度As污染,Cd污染程度大于As。调查区所采集的糙米样品(2011年,n=94；2012年,n=48)Cd、As污染同样严重,超标率分别为：96.21%、100%,糙米Cd污染程度大于As。食用调查区所产糙米具有一定的健康风险,危害程度CdAs。(2)调查区红壤(n=54)和紫色土(n=40)中Cd含量均值分别为12.87 mg·kg-1、 13.24 mg·kg-1,有效态Cd含量均值分别为8.27 mg·kg-1、7.94 mg·kg-1,总As含量均值分别为79.64 mg·kg-1,103.46 mg·kg-1。红壤Cd、As含量均低于紫色土,但不存在显著差异(P0.05)。红壤和紫色土土壤有效态Cd与总Cd含量之间均存在显著线型相关关系,其中红壤有效态Cd含量占总Cd含量的64.26%,紫色土占59.97%；红壤和紫色土砷的各形态含量之间不存在显著差异(P0.05),但均以铁型砷(37.69%)和残渣态砷(37.68%)含量为主,随着污染程度的增加,两者含量比例明显增加。红壤和紫色土样品中总Cd与总As含量、有效态Cd与总As含量均表现出一定的正相关性,土壤中Cd含量随着As含量的降低而降低；紫色土中Cd与As相关性优于红壤。(3)红壤和紫色土剖面Cd和As含量整体呈表面富集型,含量主要集中在0-20 cm。0-100 cm深度,红壤和紫色土剖面Cd含量均大于标准限值；红壤剖面0-30 cm,紫色土剖面0-50 cm,As含量均大于标准限值。如果采取客土方式来治理该地区土壤Cd、As污染,需要考虑土壤Cd、As的垂直分布特征。(4)水稻Cd、As的富集、迁移和累积特征存在一定的差异。水稻根部As含量均值是Cd含量的12.30倍。茎叶、颖壳、糙米中As含量与Cd含量差别不大。2011年和2012年采集的红壤和紫色土母质水稻土上生长的水稻各部位的Cd和As含量和富集系数均表现为：稻根茎叶颖壳糙米2011年和2012年水稻各部位Cd含量和富集系数均值均表现为：红壤紫色土,但是没有达到显著性(P0.05)。被水稻吸收的重金属有约2/3的Cd累积于水稻茎叶,约1/5的Cd累积于水稻根部,约1/20的Cd累积于糙米；约2/3的As累积于水稻根部,约1/3的As累积于水稻茎叶中,约1/50的As累积于糙米中。水稻不同部位Cd迁移系数均表现为：茎叶根颖壳糙米。水稻不同部位As迁移系数均表现为：根茎叶颖壳糙米。糙米中Cd总量占水稻全株中Cd总量的6.35%,糙米中As占水稻全株中As总量的1.93%。与As相比,Cd更容易在糙米中累积。(5)应用多元线性回归和相关系数对影响糙米Cd、As的因素进行了分析,结果表明,影响红壤对应的糙米Cd的主要因素是土壤总Cd、有机质,而紫色土的主要影响因素是土壤总Cd、有机质、黏粒(0.002mm)；糙米无机砷与土壤理化性质、总As含量以及各形态As含量有一定的相关关系,其中红壤的含水率对糙米无机As含量的影响达到了显著水平(P0.05)。红壤和紫色土对应的糙米中Cd含量与土壤中总As含量、糙米无机As含量与土壤中总Cd和有效态Cd含量均呈正相关关系。
[Abstract]:Heavy metal pollution arable land has led to the occurrence of agricultural products exceeding the standard, exceeding the standard agricultural products threaten human health through the food chain. At this stage, the agricultural utilization of heavy metal polluted farmland in China is still difficult to avoid, and the food safety is greatly challenged. The treatment is often directed against single heavy metals such as Cd pollution such as cultivated land, and the single treatment scheme neglects other pollution elements, such as As pollution. Therefore, the study of the different pollution components around the mining area, especially the Cd, As pollution characteristics, the migration rules and influencing factors of Cd, As in soil rice, and the Countermeasures of reducing or avoiding the pollution of agricultural products are suggested. It is particularly necessary that the paddy field around a lead-zinc industrial area around Hunan Province is taken as the research object, and the paddy soil developed in red soil and purple soil matrix (red yellow mud, purple soil field, red soil, purple soil) and rice plant samples are collected for two years. The soil and rice Cd, As pollution characteristics are studied, and the soil is analyzed. - the influence factors of Cd, As migration in rice system and the influence factors of Cd and As content in brown rice. The main results are as follows: (1) grid method sampling investigation shows that the soil Cd, As pollution in the rice field of the investigation area is serious, all sampling point (n=94) paddy soil is in serious Cd pollution, the 80.30% sampling point is in different As pollution, Cd pollution degree is greater than A The brown rice samples collected in the S. area (2011, n=94; 2012, n=48) Cd, As pollution is equally serious, the rate of exceeding the standard is 96.21%, 100%, and the degree of Cd pollution in brown rice is greater than that of the brown rice produced in the As. food survey area, and the degree CdAs. (2) of the harm degree CdAs. (n=54) and purple soil (n=40) is 12.87 mg. Kg-1 and 13.24 mg. Kg-1, the mean values of effective state Cd were respectively 8.27 mg. Kg-1,7.94 mg. Kg-1, and the total As content was 79.64 mg. Kg-1103.46 mg. The content of Cd in red soil is 64.26% of total Cd and 59.97% in purple soil; there is no significant difference between the contents of arsenic in red soil and purple soil (P0.05), but the content of iron type as (37.69%) and residue arsenic (37.68%) is dominant. With the increase of pollution degree, the proportion of both content increases obviously. The content of Cd and total As showed a positive correlation with the content of effective Cd and total As, and the content of Cd in the soil decreased with the decrease of As content, and the correlation between Cd and As in purple soil was better than that of red soil. (3) the content of Cd and As in red soil and purple soil profile was surface enrichment, and the content was concentrated in 0-20 cm.0-100 cm depth, red soil and purple soil profile. The content of the surface Cd is greater than the standard limit; the red soil profile is 0-30 cm, the purple soil profile is 0-50 cm, and the As content is greater than the standard limit. If the soil Cd and As pollution in this area is taken to control the soil Cd and As pollution, the vertical distribution characteristics of the soil Cd and As are considered. (4) there are some differences between the rice Cd, the As enrichment, the migration and accumulation characteristics. The root of rice is As containing The mean value is 12.30 times of the content of Cd. The difference of As content and Cd content in the stem, leaf, brown rice and brown rice is not significant. The Cd and As content and enrichment factor of all parts of rice grown in red soil and purple soil mother soil in 2012 and 2012 are all: Cd content and enrichment coefficient of rice rhizome Ye Yingke brown rice in 2011 and 2012. The mean values are: Red Soil purple soil, but not significant (P0.05). The heavy metals absorbed by rice have about 2/3 Cd accumulated in rice stem and leaf, about 1/5 Cd accumulates in the root of rice, and about 1/20 Cd accumulates in brown rice; the As of 2/3 is accumulated in the root of rice, and 1/3 As accumulates in the stem and leaves of rice, and approximately 1/50 is accumulated in brown rice. The migration coefficients of Cd in different parts of rice were all: stem Ye Genying shell brown rice. The As migration coefficients in different parts of rice were all: Rhizome Ye Yingke brown rice. The total amount of Cd in brown rice accounted for 6.35% of the total Cd in the whole rice plant, and As in brown rice accounted for 1.93%. in the total amount of As in the whole rice plant and Cd more easily accumulated in brown rice than As. (5) multiple linear applications were applied. Regression and correlation coefficients were used to analyze the factors affecting Cd and As in brown rice. The results showed that the main factors affecting Cd of brown rice in red soil were total soil Cd and organic matter, while the main influencing factors of purple soil were total soil Cd, organic matter, 0.002mm, inorganic arsenic and soil physicochemical properties, total As content and As content of various forms. The effect of water content of red soil on the content of inorganic As in brown rice reached a significant level (P0.05). The content of Cd in brown rice and the total As content in brown rice, and the content of inorganic As in brown rice were positively correlated with the total Cd and active Cd content in the soil.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X56

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