Zinc Contaminated Soil, Hyperaccumulators And Research

In recent years, due to the development of metallurgical industry and mining lead to the heavy metal pollution problems arised,soil heavy metal pollution with its concealment, accumulating, microbial cannot degradation and difficult remove,so it becomes a task challenging in front of environmental science and workers. Because of soil heavy metal contamination could directly or indirectly through the food chain damage human body health, so heavy metal pollution soil renovation become an important aspect of environmental governance. Using hyperaccumulator phytoremediation has low cost, high purification efficiency advantages, is most promising bioremediation technology, so search and select heavy metal hyperaccumulator become imperative. In view of the present status that the zinc super accumulation plant had discovered less, this paper on the basis of previous studies, chose Trifolium repens,Matthiola incana,Dianthus barbatus,Oenothera odorata,Portulaca pilosa,Ouamoclit pennata,Salvia splendens,Lolium perenne,Amaranthus mangostanus,Brassica campestris,Althaea rosea.Designed different zinc concentration gradient processing, and carry on outdoor potted simulation experiment, by means of measuring the content of plant biomass, cotent of zinc in plant, estimates BCF,TF.Study of soil under different zinc concentration, plant absorption, enrichment and transport capacity, the main research results are as follows:(1) Zinc affects plant growth inhibition concentration exists significant difference. Such as Loose leaf peony of critical concentration by poisoned for 600 mg-kg-1, sweet william by the poison of planting bracts critical concentration of 400 mg-kg-1(2)Different zinc concentration affect plant biomass, show the following rules:①With the increase of soil zn concentrations, the ground and underground biomass increased, at this critical concentration, plant biomass achieve maximum, but more than this concentration range, biomass presents degressive trend, such as violet, three-colored amaranth, lolium perenne;②With the increase of soil zn concentrations, plant biomass appeared volatility trends, such as fragrant eveningprimrose, hollyhock;③With the increase of soil zn concentrations, plant biomass decreased gradually, such as white clover.(3)With different zinc concentration conditions, the plant absorb zinc ability has obvious difference,show the following rules:①With the increase of soil zinc concentrations,underground and ground parts of zinc content presents increase trends,the underground zinc content more than the ground part,such as hollyhock;②With the increase of soil zinc concentrations, ground and underground parts of zinc content increased, within certain zinc concentration,the zinc content reach maximum,but more than the concentration range,the zinc content of plants presents degressive trend, and the underground zinc content above the ground parts, such as bird rape,red sage,white clover;③With the increase of soil zinc concentrations, the ground and underground parts of zinc content increased, within a critical concentration, the zinc content reach maximum, but more than the critical concentration range, the zinc content of plangt decreased,and the ground zinc content above the underground parts,such as sweet william, loose leaf peony;④With the increase of soil zn concentrations, the zinc content of plant showed volatility, such as common stock violet,cypress vine ,ryegrass,amaranth.(4) The plant enrich zinc capacity, due to the soil zinc concentration and plant species have different change. Within these plants, the BCF of aboveground mostly less than 1, the BCF do not satisfied the zinc super accumulation that the aboveground BCF more than 1 conditions.(5) The plant transit zinc ability, show the following rules:①With the increase of soil zn concentrations,the plants of TF present volatility trends,such as common stock violet,fragrant eveningprimrose, hollyhock,ryegrass,bird rape;②With the increase of soil zn concentrations, the TF of plant present volatility increase, and TF are more than 1, such as sweet william;③With the increase of soil zn concentrations, the TF of plant presents degressive tendency,representative plants are white clover,red sage,cypress vine;④With the increase of soil zn concentrations, the TF of plants are increase first,beyond a certain zinc concentration 600mg·kg-1 performance for a downward trend, such as loose leaf peony.(6) Screening zinc hyperaccumulator conclusion. Zinc hyperaccumulator plant refers to the plant aboveground zinc content more than 10,000 mg·kg-1, the plant BCF and TF are greater than 1. From experimental plants are not screened fit the zinc hyperaccumulator conditions. But through the outdoor potted simulation experiment, discover the patience of fragrant eveningprimrose,cypress vine, hollyhock and ryegrass absorb zinc ability are stronger than other plants, these could used as afforestation plants in the future.In addition, this experiment provide certain reference for later screening of zinc hyperaccumulator.