Lei Chao

Single and joint stress of acetochlor and Pb on three agricultural crops in northeast China

In order to evaluate ecological risk of agrochemicals in agricultural environment, single and joint toxic effects of an important herbicide and a typical heavy metal on root elongation of crops were investigated. Seeds of the three crops including wheat (Triticum aestivum), Chinese cabbage (Brassica pekimensis) and soybean (Glycine max) as the main crops in northeast China were exposed to acetochlor as a herbicide and lead (Pb) as a heavy metal using the pot-culture method, and meadow brown soil as one of the main soils distributed in northeast China was applied in the investigation. The results indicated that the interactive effects of the two pollutants on root elongation of the three crops were very complicated although they had markedly significant (P < 0.01) linear interrelationships based on the regression analyses. When the concentration of added Pb2+ reached 200 mg/kg, acetochlor and Pb had an antagonistic effect on the inhibition of root elongation of the three crops. However, acetochlor and Pb had significantly (P < 0.05) synergic effects on the inhibition of root elongation when concentration of added Pb2+ was up to 1000 mg/kg. At the low concentration of added Pb, joint toxicity of acetochlor and Pb was more dependent on the concentration of Pb. Among the three crops, wheat was the most sensitive to the toxicity of Pb and Chinese cabbage was the most sensitive to the toxicity of acetochlor.

Influences of phosphate nutritional level on the phytoavailability and speciation distribution of cadmium and lead in soil

A pot experiment was conducted to examine the influence of phosphate levels on the phytoavailability and speciation distribution of cadmium (Cd), lead (Pb) in soil. Spring wheat (Triticum aestivum L.) was selected as the tested plant. There were 5 phosphate fertilizer(Ca(H2PO4)2) levels including 0, 50, 100, 200, and 400 mg P2O5/kg soil, marked by PO, P1, P2, P3, and P4, respectively. CdCl2 x 2.5H2O and Pb(NO3)2 were added to soil as the following levels: Cd + Pb = 25+0, 0+1000, and 25+1000 mg/kg, marked by T1, T2, and T3, respectively. The results showed that the P fertilizer promoted the dry weight of wheat in all treatments and alleviated the contamination induced by Cd and Pb. With increasing levels of the additional P fertilizer, Cd concentration in different parts (root, haulm, chaffand grain) of wheat decreased at the P1 level at first and then increased. The soluble plus exchangeable (SE) fraction of Cd in soil decreased at the P1 level and then increased from P2 to P4 levels. The moderate P fertilizer reduced the phytoavailability of Cd. The application of P could obviously restrain the uptake of Pb by wheat and there were significantly negative correlations between the levels of P and the uptake of Pb. Phosphorus supply resulted in a decrease in the SE fraction of Pb and there was a significantly negative correlation between the levels of P and the SE fraction of Pb in soil. All the levels of the P fertilizer in this experiment could reduce the phytoavailability of Pb. Thus, it is feasible to apply the P fertilizer (Ca(H2PO4)2) to Pb contaminated soils. However, the levels of P application should be restricted in case that redundant P may increase the phytoavailability of Cd.

Effects of Bacteria on Cadmium Bioaccumulation in the Cadmium Hyperaccumulator Plant Beta Vulgaris Var. Cicla L.

To investigate the effects of two cadmium-tolerant bacteria, Staphylococcus pasteuri (S. pasteuri X1) and Agrobacterium tumefaciens (A. tumefaciens X2), on cadmium uptake by the cadmium hyperaccumulator plant Beta vulgaris var. cicla L., a pot experiment with artificially contaminated soil was conducted. The results demonstrated that both cadmium-tolerant bacteria enhanced the dry weight of Beta vulgaris var. cicla L. The total dry weights of plants in the control CK20, S. pasteuri X1 and A. tumefaciens X2 treatments were 0.85, 1.13, and 1.38 g/pot, respectively. Compared with the control CK20 findings, the total dry weight of plants was increased by 32.8 and 61.1% after inoculation with S. pasteuri X1 and A. tumefaciens X2, respectively, indicating that A. tumefaciens X2 more strongly promoted the growth of Beta vulgaris var. cicla L. than S. pasteuri X1. In addition, inoculation with S. pasteuri X1 and A. tumefaciens X2 significantly (p < 0.05) promoted cadmium uptake by plants and improved the bioaccumulation of cadmium by the plants from the soil. Moreover, the inoculation of S. pasteuri X1 and A. tumefaciens X2 effectively facilitated the transfer of cadmium in the soil from the Fe-Mn oxide and residual fractions to the soluble plus exchangeable and weakly specially adsorbed fractions in the rhizosphere soils of plants. The bacterial enhancement of cadmium phytoavailability might provide a potential and promising method to increase the efficiency of phytoextraction.

Influence of organic acid and amino acid on cadmium and lead desorption from soil

A study was conducted to investigate the influence of organic acid (citric acid, oxalic acid) and amino acid (histidine) on the desorption of cadmium and lead from artificial contaminated soil in north-east China. Results showed that when the concentration of organic acid and amino acid in desorption solution was relatively low, the presence of organic ligands inhibited the desorption behaviour of Cd. When organic acid and amino acid concentrations were higher (> 2 mmol/L), the presence of organic acid and amino acid obviously promoted Cd desorption. The increment of citric acid, oxalic acid, and histidine concentration significantly (P oxalic acid > histidine. This revealed that the organic acids had stronger affinity with heavy metals than that of amino acids. Functional group positions and types were important in determining if an organic acid or an amino acid would complex metals and increase their potential leaching. The results of this work implicated that amendment of organic acid and amino acid would enhance conditionally the bioavailability of heavy metals adsorbed by soils, relying on the type and concentration of organic acid and amino acid in soil solution.

Investigation of the Antibiotics in Animal Manure and Agricultural Soils in Shenyang and Surrounding Cities

In this study, oxytetracycline, chlortetracycline and roxithromycin examples, general family of farmers livestock and poultry breeding point scale livestock and poultry breeding plant in Shenyang, Tieling and Fushun representative soil samples and the application of livestock manure are sampled and analyzed, in order to understand the situation of the antibiotic residues in manure in these regions and application of antibiotic residues in soil containing antibiotics in livestock and poultry manure.

Plant-Microorganism Combined Remediation for Sediments Contaminated with Heavy Metals

In order to investigate the effects of four heavy metal tolerant microorganisms, Staphylococcus pasteuri (X1), Agrobacterium tumefaciens (X2), Penicillium chrysogenum (Z1) and Paecilomyces lavender (Z2), on heavy metals uptake by the heavy metal tolerance plant-maize and the cadmium hyperaccumulator plant-Beta vulgaris var. cicla L., a pot experiment with sediments was conducted. Through comparing the overall situations of four microorganisms’ role in enhancing maize and Beta vulgaris var. cicla L. to gather cadmium, lead, copper and zinc, plant biomasses, and enrichment characteristics, the combination of bacterium X2, fungus Z2 and these two plants can effectively repair these four heavy metals in sediments.

Research of Antibiotics Pollution in Soil Environments and theirs Biological Degradation

With the increase of antibiotics usage, concerns on antibiotics contamination have been raised because of their serious environmental impacts in recent years. Antibiotics have become the emerging contaminants of soil. This paper reviews the pollution situation, the potential harm and the way of biodegradation of antibiotics in order to provide the reference to eliminate antibiotics pollution.

Study on Plant-Microbial Remediation of Antibiotic and Heavy Metal Contaminated Soil

In the recent years, antibiotics and heavy metals have become common pollutants in soil. Plant-microbial remediation is promising for the management of antibiotics and heavy metals pollution in soil. This paper talks about the mechanization of plant-microbial remediation, finds the advantages and disadvantages about plant-microbial technology, summarizes the method of selection of the plant and microbial, influential factors, and discusses the future research priorities of plant-microbial remediation.

Application and Development of Artificial Floating Island Technology

As a rising phytoremediation technology, artificial floating island technology is increasingly used in wastewater purification. In this paper, studies on artificial floating islands at home and abroad were overviewed, including the variety of floating island, construction method of artificial floating island and the water improvement principle of artificial floating island. Artificial floating island technology is a kind of new ecological environment technology with many functions, such as pollutant purification, habitat restoration, ecosystem restoration, and landscape improvement. It has good application prospects in the area of comprehensive water body control.

The Research Progress of Biosyufactants on the Degradation of Antibiotics during the Compost Process

In recent years, the environmental impact of antibiotic pollution from animal manure has gradually become the focus of attention. The compost is a common method for degradation of antibiotics, the rapid degradation of antibiotics can be achieved by adjusting the different compost conditions. Biosurfactants caused all the attention as a new class of surfactants, biosurfactants used in compost will have an impact on the degradation of antibiotics in livestock and poultry manure.