土壤及场地持久性有机污染的生物修复技术发展及应用

以土壤及场地持久性有机污染物为对象,较为系统地综合评述了国内外污染土壤及场地的生物修复技术发展与应用,并结合当前土壤及场地污染的新特点,提出了生物修复的发展趋势和研究方向.     

Occurrence and congeners specific of polychlorinated biphenyls in agricultural soils from Southern Jiangsu, China

A total of 198 agricultural soil samples were collected from Zhangjiagang and Changshu in Southern Jiangsu for analysis of 13 polychlorinated biphenyls （PCBs） in order to assess the levels of pollution, sources, area distribution, and potential risk for the environment. All methods were rigorously tested and an adequate quality control was ensured. Only one site had no PCBs residues, and the highest total PCBs concentration in the surface soils was 32.83 ng/g. The average concentration in all the soil samples was 4.13 ng/g, signaling low-level pollution. Tetra-, penta-, and hexa-chlorinated biphenyls were dominant species in soil samples, accounting for more than 75% of ∑PCBs in the soil samples. PCB118 was the most abundant congener in all the samples. The PCB118 was about 20% of ∑PCBs. The soil organic matter content showed only a weak correlation with the levels of all PCB congeners, in which a better correlation was noted for the more volatile lighter PCB congeners than for the heavier homologues. To a certain extent, the sources and land use seemed to influence the levels of PCBs.     

Effect of sorbed and desorbed Zn(Ⅱ) on the growth of a green alga (Chlorella pyrenoidosa)

Toxic effect of Zn(Ⅱ) on a green alga (Chlorella pyrenoidasa) in the presence of sepiolite and kaolinite was investigated.The Zn-free clays were found to have a negative impact on the growth of C.pyrenoidosa in comparison with control samples (without adding any clay or Zn(Ⅱ)).When Zn(Ⅱ) was added,the algae in the presence of clays could be better survived than the control samples,which was actually caused by a decrease in Zn(Ⅱ) concentration in the solution owing to the adsorption of Zn(Ⅱ) on the clays.When the solution system was diluted,the growth of algae could be further inhibited as compared to that in a system which had the same initial Zn(Ⅱ) concentration as in the diluted system.This in fact resulted from desorption of Zn(Ⅱ) from the zinc-contaminated clays,although the effect varied according to the different desorption capabilities of sepiolite and kaolinite.Therefore the adsorption and desorption processes of Zn(Ⅱ) played an important part in its toxicity,and adsorption and desorption of pollutants on soils/sediments should be well considered in natural eco-environmental systems before their risk of toxicity to aquatic organisms was assessed objectively.     

不同类型土壤对SO42-吸附特性的研究

为了进一步探讨我国酸沉降对水陆生态环境的影响以及典型地区生态系统对酸沉降的缓冲能力和临界负荷值,笔者对赣、鄂、湘３省具有代表性的土壤的ＳＯ吸附特性进行了研究。结果表明,红壤,待别是江西省的红壤,吸附ＳＯ的能力最强,最大吸附量达１１．５２ｍｇ／ｇ士;其余依次为黄壤、棕红壤、黄褐壤和黄红壤,最大吸附量分别为１１．１４,８．８３,６．８６和６．５３ｍｇ／ｇ土;红色石灰壤对ＳＯ的吸附能力最弱,最大吸附量仅３．５５ｍｇ／ｇ土,只及红壤的３０．８％。可以预计,就地区而言,以红壤为主的江西省是我国对酿沉降最敏感的地区之一。     

Soilaluminum, Iron, and Phosphorus Dynamics in Response to Long-Term Experimental Nitrogen and Sulfur Additions at the Bear Brook Watershed in Maine, USA

Atmospheric deposition of nitrogen (N) and sulfur (S) containing compounds affects soil chemistry in forested ecosystems through (1) acidification and the depletion of base cations, (2) metal mobilization, particularly aluminum (Al), and iron (Fe), (3) phosphorus (P) mobilization, and (4) N accumulation. The Bear Brook Watershed in Maine (BBWM) is a long-term paired whole-watershed experimental acidification study demonstrating evidence of each of these acidification characteristics in a northeastern U.S. forested ecosystem. In 2003, BBWM soils were studied using the Hedley fractionation procedure to better understand mechanisms of response in soil Al, Fe, and P chemistry. Soil P fractionation showed that recalcitrant P was the dominant fraction in these watersheds (49%), followed by Al and Fe associated P (24%), indicating that a majority of the soil P was biologically unavailable. Acidification induced mobilization of Al and Fe in these soils holds the potential for significant P mobilization. Forest type appears to exert important influences on metal and P dynamics. Soils supporting softwoods showed evidence of lower Al and Fe in the treated watershed, accompanied by lower soil P. Hardwood soils had higher P concentrations in surface soils as a result of increased biocycling in response to N additions in treatments. Accelerated P uptake and return in litterfall overshadowed acidification induced P mobilization and depletion mechanisms in hardwoods.     

南亚热带丘陵土壤水分循环及其有效性的研究──Ⅱ.丘陵赤红壤水分循环动态特征

根据定位观测资料,阐述了南亚热带丘陵赤红壤水分循环的动态特征。研究结果表明,南亚热带丘陵赤红壤贮水量存在年际变化和显著的季节变化：雨季（4～9月）土壤贮水量相当于田间持水量的90％以上,个别月甚至超过贮水库容量。但旱季月土壤贮水量低,相当于田间持水量的50％～80％,需要补充水分才能及时满足植物所需的水分。     

Response of Lupinus albus to Pb–EDTA indicates relatively high tolerance

White lupin plants were grown in hydroponics with 0, 90 and 180 µmol L^?1 Pb(II) ethylenediaminetetraacetate complex for 30 days. Pb distribution (shoot/root ratio) was 0.34 and 0.46 for both Pb treatments. In the shoots, no decrease in biomass nor in photosynthetic pigment levels and no changes in the concentrations of malondialdehyde and glutathione were detected. In the roots, malondialdehyde increased by 20%, glutathione 2–3.6 times and phytochelatin concentrations 4–5 times. The high tolerance of white lupin makes it a valuable plant for phytoremediation of Pb-contaminated soil.     

氮肥运筹和少免耕对麦田氮素径流流失的影响

采用田间小区定位试验研究了自然降雨条件下氮肥运筹和少免耕措施对稻麦两熟农田麦季氮素径流流失特征的影响。结果表明：自然降雨后麦田耕层土壤平均水分质量分数26.34%为径流事件发生的临界土壤水分质量分数。常规施肥（T0）条件下,麦季径流水量达2185.05 m3·hm-2,径流侵蚀泥沙量达716.08 kg.hm-2,少免耕（T2）处理增加麦田径流水量达29.67%,减少径流侵蚀泥沙量达13.96%,而肥料运筹（T1）与T0处理差异不显著;就整个麦季而言,T0处理条件下,径流水全氮（TN）平均质量浓度和径流侵蚀泥沙TN平均质量分数分别为10.51 mg·L-1和1.19 g·kg-1,T1处理显著降低径流水TN质量浓度和侵蚀泥沙TN质量分数分别达11.63%和5.93%,T2处理显著降低径流侵蚀泥沙TN质量分数达7.95%;麦季氮素径流流失主要集中在小麦生育前期,包括径流水氮素流失量和径流侵蚀过程中由泥沙流失的氮素量。T0处理条件下,氮素流失总量达31.76 kg·hm-2,其中,径流水氮素流失量占麦季氮素总流失量95%以上,T1处理减少麦季氮素总流失量达9.25%,而T2处理则增加麦季氮素总流失量达16.75%。     

铬污染土壤的微生物修复

采用淋溶实验研究微生物对铬污染土壤中Cr(Ⅵ)的修复,研究培养基成分、培养基添加量及淋溶液pH值对修复效果的影响.结果表明,培养基淋溶能完全修复铬污染土壤中水溶性Cr(Ⅵ),浸出液中Cr(Ⅵ)浓度由初始的700.3mg·L-1降低至检出限以下.单独加入碳源作为培养基时,土壤中Cr(Ⅵ)不能得到完全修复,碳源与氮源结合作...     

不同类型土壤中外源镍对赤子爱胜蚓的急性毒性

按照国际标准化组织(ISO)颁布的蚯蚓毒性试验方法,研究了镍离子在我国13种典型土壤中对赤子爱胜蚓(Eisenia fetida)的急性毒性,发现镍离子在不同类型土壤中对蚯蚓的半数致死浓度(LC50)变化范围为243.8-1970.6 mg·kg-1,镍离子在不同土壤中的毒性大小顺序为:湖南红壤＞重庆紫壤＞江西红壤＞河...