Effect Of Organic Acids On Toxicity Of Copper In Soil

Soil contamination,the copper is a heavy metal that has a greater impact on human health and cause a lot of concerns and more research which can enter the body with the food chain,then cause harm to human health.Biological absorption of copper in the soil depends on environmental factors such as soil texture,pH,Eh,organic matter,etc..Especially low molecular weight organic acids,it is commonly found in the soil environment,whose chelation with copper and other heavy metals is an important factor affecting the effectiveness and toxicity of heavy metals in the soil environment.The earthworm is the most representative soil animals in the farmland ecosystems,which has important research value on plant nutrient up taking,material decomposition cycle,farmland ecological environment.Its survival,growth and reproduction are affected by environmental contaminants.Heavy metals can get lots of enrichment in earthworms,causing lots of abnormalities on the physiological,cellular,molecular and individual,population levels.However,with the presence of organic acids,heavy metals absorption pathways in earthworms are still not clear,are they to inhibit or promote?In this paper,we take soil simulation solution method to study copper on earthworm mortality,enrichment of copper in the body,physiological and biochemical and epithelial cell damage and elemental analysis under the influence of organic acids,to reveal the impact mechanism of organic acids on copper toxicity,to provide a scientific basis for research on biological toxicity of pollutants.The results are as follows1 Exogenous organic acids significantly reduced earthworm mortality under Cu stress.Under a single copper stress,the earthworm mortality increases with increasing copper concentration.Copper concentrations increased from 0.05mg/L to 0.lmg/L,earthworms 24h mortality increased from zero to 30%,48h mortality rate from 30%to 70%.Copper concentrations increased from 0.1mg/L to 0.2mg/L,earthworms 24h mortality from 30%to 70%,48h mortality rate from 70%to 90%.Organic acids can significantly reduce the mortality of earthworms under copper stress.2 Exogenous organic acids increased the copper content in earthworm under copper stress.Under a single copper stress,earthworms copper content increases as the concentration of copper increases.When the concentration of copper solution was 0.05mg/L,O.lmg/L,0.2mg/L,the copper of earthworms rose79.7%,137%,253%.Different concentrations of copper and different kinds of organic acids complex,earthworms copper content all increased significantly.3 Under a single copper under stress,earthworms SOD activity increases as the concentration of copper increases.When different concentrations of copper and 1 times,5 times the concentration of different types of organic compound,earthworms POD activity presented basically unchanged or slightly increasing trend.Under a single copper stress,earthworms CAT activity increased slightly.When different concentrations of copper and five times the concentration of different types of organic compound,earthworms CAT activity presents a slightly increasing trend.Under a single copper stress,with increasing copper concentrations,MDA concentration showed a gradual increasing trend.Description,with increasing concentration of copper,earthworms increased membrane permeability,increased damage to the body of the earthworm.When different concentrations of copper and 1 times,5 times the concentration of different types of organic compound,earthworms MDA content in the body changes inconsistent.Under a single copper stress,earthworms soluble protein content compared with no treatment earthworms,have different degrees of decline.When different concentrations of copper and different kinds of organic compound,earthworms soluble protein content changed little.4 Organic acids can alleviate the damage of earthworm surface cells under Cu stress in varying degrees.Earthworms under normal conditions have smooth skin without damage.Earthworm under copper stress skin fold,skin breakdown,injury seriously.Copper and organic compound-treated earthworm skin damage,skin with respect to earthworms under copper stress treatment,there are varying degrees of ease.5 C content of the earthworm epidermis under copper stress increases,N,S content is reduced.Copper Stress treated earthworms,organic acid can increase earthworm epidermal cells N,S content,reducing C content in varying degree,showing organic acids effectively alleviate the toxicity of copper.A little Na appeared in earthworm epidermis under Cu stress.Na also appeared in earthworm epidermis exposed to EDTA and Cu mixed solution.