【作者】 谭勇壁；

【导师】 陈同斌； 李志刚；

【作者基本信息】 广西大学 ， 植物学， 2008， 硕士

【摘要】 本文为研究矿业污染耕地种桑养蚕利用模式的可行性,在广西环江矿业污染区开展了桑地土壤污染特征、桑叶重金属含量和品质调查,着重研究污染桑地土壤和桑叶重金属含量的关系、土壤重金属含量对桑叶品质的影响以及污染桑叶的生物毒性。主要研究结果如下:1.广西环江污染桑地(受携带尾矿的洪水淹没的)重金属、酸污染严重,污染桑地土壤Pb、Zn、As含量分别是对照桑地(污染桑地附近的未受洪水淹没的)的17.2、3.8、3.5倍,铅、锌、砷含量超标率分别为61.7%、58.8%、47.1%(《土壤环境质量标准》二级);污染桑地在酸性修复之前土壤极度酸化,虽然经初步酸性修复,但是还有近三分之一的污染桑地为强酸性土壤(pH＜4.5)。2.桑树耐酸性能力强,能在强酸性土壤上生长;桑树也比较耐土壤铅、锌、砷复合污染,能在铅、锌、砷含量分别高达734、1194、53 mg/kg的污染土壤上生长而没有在外观上表现出明显的受胁迫现象。3.污染老桑叶的Pb、Zn、As和土壤相应重金属含量显著相关;污染桑叶的Pb、Zn含量均显著高于对照桑叶,污染桑叶与对照桑叶的As含量差异不显著;污染桑叶对Pb、Zn、As的富集能力与普通植物相当。4.桑叶Pb、Zn、As的积累量随桑叶生长周期的延长而增加;在污染桑地,老桑叶(5-8叶位)中的Pb、Zn、As与嫩桑叶(4叶位以上)中相应重金属含量均显著相关;在对照桑地,老桑叶的Zn、As含量与嫩桑叶中相应重金属含量均显著相关,而Pb更易被嫩桑叶富集。5.污染桑地的桑叶品质没有受到污染物的破坏,污染老桑叶的蛋白质含量反而显著高于未污染老桑叶的。污染桑叶的可溶性蛋白质含量的增高与桑叶重金属含量不相关,与土壤pH值负相关。土壤酸度影响到桑树植株体内的酸度,酸环境有助于可溶性蛋白质含量的增加。6.污染桑叶重金属含量对蚕的生物毒性小。蚕对污染桑叶和对照桑叶的食下率、消化率无显著差异;污染桑叶和对照桑叶喂养的蚕结茧情况虽然表现为它们的上茧个数、下茧个数存在显著性差异,但是它们的上茧重量并没有达到显著性差异,蚕茧茧层率亦无显著性差异。7.污染桑叶喂养的蚕吐的蚕丝重金属含量均在《生态纺织品技术要求(GBT18885-2002)》标准限量之内;污染桑叶喂养的蚕的蚕粪Pb、Zn、As含量显著高于对照桑叶喂养的蚕的蚕粪,但远低于《农用污泥中污染物控制标准(GB4284-84)》中相关重金属的限量;蚕蛹的重金属含量也均在《饲料卫生标准(GB3078-2001)》限量之内。8.桑树耐土壤重金属毒性较强,桑叶重金属的生物毒性小,养蚕产物生态安全,养蚕经济效益高,因此种桑养蚕是矿业污染耕地的合理利用模式。更多还原

【Abstract】 In order to study the possibility of mulberry-sericulture model applied in mining pollution farmland, a field investigation of soil pollution characteristic, heavy metal content and quality of mulberry leaf was conducted in mulberry land of mining pollution area in Huanjiang county of Guangxi province. The thesis mainly studied the heavy metal content relation between soil and mulberry leaf, the quality of mulberry leaf effected by polluted soil, the bio-toxicity of polluted mulberry leaf. The main result can be summarized as follows:1) The soil heavy metal and acid pollution of contaminated mulberry land( submerged by flood with tailings) was severe in Guangxi Huanjiang. The content of Pb, Zn and As in contaminated soil was respectively 17.2, 3.8 and 3.5 times as the content of Pb, Zn and As in control soil( not submerged by flood with tailings, near polluted land). The over standard rate of Pb, Zn and As content was respectively 61.7%, 58.8% and 47.1%("Environmental quality standard for soils",Ⅱ). The polluted soil acidified extremely before acidity remediation. After primary acidity remediation, there was still about one third polluted land which was strong acid soil (pH<4.5). 2) Mulberry had a strong resistance of acid and toxicity of Pb, Zn and As in soil. Mulberry could grow normally in contaminated soil with 734mg/kg Pb, 1194mg/kg Zn, 53mg/kg As.3) The contents of Pb, Zn and As in the old mulberry leaf and the content of corresponding heavy metals in soil were significantly related. Pb and Zn content of pollution leaf were significant higher than the control leaf(p<0.01). But As content of pollution leaf and control leaf had no significant difference. The accumulation Pb, Zn and As ability of polluted mulberry leaf was nearly equivalent to normal plants.4) The accumulation of Pb, Zn and As in mulberry leaf increased with the. leaf growth cycle prolonging. The content of Pb, Zn and As between old leaf(5-8 leaf position) and tender leaf(above 4 leaf position) had significant correlation in polluted mulberry land. In unpolluted land, only the content of Zn and As between old leaf and tender leaf showed significant con-elation, but Pb was more easily accumulated by tender leaf.5) Not only the quality of mulberry leaf were not reduced, but also the protein content of old leaf in pollution land were significantly higher than the control. The soluble protein content and heavy metal content in mulberry leaf didn’t show correlation, but the soluble protein content in mulberry leaf and pH in soil showed negative correlation. The soil acidity affected on acidity inside mulberry plant body. Acid environment inside plant body promoted the soluble protein content increasing. 6) The bio-toxicity of heavy metals in polluted mulberry leaf was low. The percentage of food ingestion and digestion between the polluted leaf and control leaf had no significant difference. There was significant difference of the good cocoon number between the polluted leaf and control leaf. But there was not significant difference of the good cocoon weight between the polluted leaf and control leaf. The rate of silk between the polluted leaf and control leaf also had no significant difference.7) The heavy metal content of silk from silkworm fed with polluted mulberry leaf was lower than the limit of heavy metals content seted by "Technical specification for ecological textiles(GBT18885-2002)". The heavy metal content of faecal from silkworm fed with polluted mulberry leaf was significant higher than the heavy metal content of faecal from silkworm fed with control leaf. But the heavy metal content of faecal from silkworm fed with polluted leaf was lower than the limit of heavy metals content seted by "Control standards for pollutants in sludges from agricultural use (GB4284-84)". The heavy metal content of silkworm chrysalis was lower than the limit of heavy metals content seted by "Hygienical standard for feeds(GB3078-2001)".8). To sum up, mulberry-sericulture is the model of the rational utilization of heavy metal polluted farmland.更多还原