Comparison of Heavy Metal Accumulation in Four Vegetables Grown in the Soils Contaminated with Multiple Heavy Metals

In order to compare the differences in the accumulation of plumbum(Pb),cadmium(Cd),chromium(Cr),cuprum(Cu),nickel(Ni)and zinc(Zn)from the multi-contaminated,alkalescent soil in the plants of four-season big-leaf coriander,butter lettuce,four-season fast-growing pakchoi and four-season parsley to choose low accumulation vegetables,a pot experiment was conducted by using heavy metal salts to simulate high-,moderate-and low-level heavy metals multi-contaminated soils.The results showed that the multi-contaminated soil by high levels of Pb,Cd,Cr,Cu and Zn produced inhibition on biomass of four-season fast-growing pakchoi,failing to collect samples,but had no obvious inhibition on the growth of the three other vegetables.Among the four kinds of vegetables examined,the accumulation ability of four-season parsley to the five heavy metals of Pb,Cd,Cr,Cu and Zn was the strongest,while the accumulation ability of four-season fast-growing pakchoi to Ni was the strongest.In the high-level contaminated soil,the underground part of these four vegetables grown was more likely to accumulate heavy metals than their aboveground part.Both of vegetable varieties and heavy metal types can affect the accumulation of heavy metals in vegetables.Our research also found that four-season big-leaf coriander was high yielding and low accumulation of heavy metals.

Research on Face Tracking in Community Monitoring System

This paper proposes a block Mean-Shift algorithm based on target real-time update and LBP texture features, through the target update improves the accuracy of target tracking, enhances the local character of the target through the target block, so as to improve the robustness of algorithm based on skin color backgrounds. And then analyze the Mean-Shift algorithm cannot recover quickly lost target tracking defects, and its improvement by combining the frame difference method.

Transformation and immobilization of hexavalent chromium in the co-presence of biochar and organic acids:effects of biochar dose and reaction time

A batch experiment was conducted to examine the effects of biochar dose and reaction duration on the transformation and immobilization of Cr(VI)in the combined biochar and low-molecular-weight organic acid systems.The results showed that increase in the dosage level of biochar caused increase in the solution pH,particularly for the Biochar300 treatments but did not enhance the reduction of Cr(VI)after 1-day reaction.Over 35%of the converted Cr(III)was immobilized by sorption to the biochar due to increased negatively charged sites on the biochar surfaces driven by pH rise.The elevated pH due to biochar dose increase tended to slow down the reduction of Cr(VI)to Cr(III),resulting in more Cr(VI)being adsorbed at a higher biochar dose.For the higher-temperature biochars,the increase in biochar dose did not markedly change the transformation and immobilization of the added Cr.Increase in the reaction duration markedly increased the pH for Biochar300.This resulted in the disappearance of all Cr(VI)in the solution after the 7-day reaction,possibly through sorption of cationic Cr(III)to the biochar surfaces.Increase in reaction time for the higher-temperature biochars resulted in re-oxidation of Cr(III)to Cr(VI)due to the increased exposure of solution Cr(III)to atmospheric oxygen.The research findings obtained from this study have implications for optimizing treatment procedure for wastewater that contains elevated level of toxic Cr(VI).Simulation experiments are required to determine appropriate biochar dose and reaction time to achieve cost-effective treatment goals.