Study On Absorption And Toxic Effect Of Heavy Metal Cd And Herbicide Butachlor In Vegetable

With the continuous development of the social economic, contamination of heavy metal and organic pollutant in soil became increasingly serious. Quality and safety of vegetables attracted more and more attention. Therefore, lotus root and mushroom samples were collected from some areas in Zhengzhou and Kaifeng city, the transport of heavy metals in the lotus root and mushroom was studied, and their pollution status were evaluated. Amaranth was selected as experimental material, and pot experiment was carried out to study the toxicity of combined pollution of Cd with Butachlor on amaranth, The results are as follows:(1) Among 18 lotus root planting sites, site plot 2 of He gouwang was only contaminated with Cd, and the rest were not contaminated by heavy metals, content of Pb, Cd, Cu and Zn in all the lotus root were below the national food hygiene standards for vegetables, thus, these lotus root were not polluted by these four heavy metals. On the other hand, lotus root had strongest enrichment ability of Cu and Zn, Cd followed, Pb weakest. The enrichment ability of Cu was significantly negatively correlated with soil organic matter content, enrichment ability of Pb and Zn had highly significant negative correlation with soil organic matter content. enrichment ability of Pb had highly significant negative correlation with soil conductivity. PCA analysis results showed that enrichment mechanism of lotus root of Pb, Zn and Cu were similar.(2) The content of Pb, Cd, Cu and Zn in mushrooms and mediums changed greatly. Among four kinds of mushrooms, Pb content in Agaricus bisporus and shiitake were higher, while content of Cd in Pleurotus eryngii and oyster mushroom were higher. Cu content in Agaricus bisporus was highest, and Zn content in shiitake and Pleurotus eryngii were higher. The order of the accumulation of four heavy metals was as follows: Zn > Cu > Pb > Cd. Additively, content of Pb, Cd, Cu and Zn in mushroom samples were lower than the national relevant standards, so these mushrooms were not polluted by Pb, Cd, Cu and Zn. Furthermore, the order of enrichment ability was as follows: Cd > Zn > Cu > Pb.(3) With single Cd pollution, amaranth's growth was promoted with the treatment of 5mg/kg Cd, while it was inhibitted when concentration of Cd was above 15 mg/kg, and the toxicity enhenced with the concentration increased. 15mg/kg Cd had little impact on amaranth germination and seedling survival, it mainly effected the growth of amaranth in the later stage, while 20 mg/ kg Cd not only effected the seedlings survival rate, but also influenced amaranth's growth in the later stage, causing great reduce of plant height, leaf area and biomass. Amaranth mortality increased with pollution of low concentration butachlor (5mg/kg) during early stage, but the growth of surviving plants was promoted during later stage. When concentration of butachlor was above 15mg/kg, amaranth could germinate within 2-3 days, But they can't survive after germination, it indicated that higer concentration of butachlor had acute toxicity. With Combined pollution of Cd and butachlor, only high concentration such as Cd5Bu15, Cd10Bu10, Cd15Bu5, Cd15Bu15 showed different degree of inhibition on amaranth, the other low concentration of combined pollution promoted the growth of amaranth. Interaction mechanism of cadmium and butachlor was very complicated, and the type of interaction changed with the concentration.