黄土高原不同土地利用类型有机碳和黑碳的储量及意义

以黄土高原为研究对象,研究三种不同利用方式的表层土壤样品(0—20 cm),分析其有机碳(soil organic carbon,简称SOC)和黑碳(black carbon,简称BC)的含量、分布特征及其储量变化及意义。研究表明,黄土高原不同利用方式土壤有机碳和黑碳含量的平均值分别为:玉米地8.01 g?kg~(-1)和1.01 g?kg~(-1),林地6.80 g?kg~(-1)和0.59 g?kg~(-1),未利用地5.01 g?kg~(-1)和0.43 g?kg~(-1),有机碳和黑碳的含量均为玉米地最高,未利用地最低;耕地和自然土壤表土有机碳储量分别为0.796 Pg和0.710 Pg,表土黑碳储量分别为0.0858 Pg和0.0730 Pg,耕地相对于自然土壤有机碳和黑碳的储量分别增大12.1%和17.5%;说明黄土高原耕地是一个碳汇,起着固定碳的作用;采用推荐的管理实践活动和合理的土地利用方式,能够增加土壤碳储量,提高土壤质量和农作物产量,抵消部分二氧化碳的排放。     

钱塘江感潮河段污染物迁移扩散数值分析

感潮河流由于受到潮汐的作用,污染物会因潮汐的涨落作用沿河道往复运动,影响用水安全.以高锰酸盐指数作为主要水环境指标,分析了钱塘江感潮河段上游富阳水文站监测到的持续高锰酸盐污染物输入情况下对下游河段的影响,旨在得到不同水期情况下之江站污染物出现的时间,作为取水安全预警指标参考.同时,基于潮流连续性方程、动量方程和污染物扩散方程,模拟计算了9种流况下污染物的迁移扩散过程.结果显示,径流处于平水月份时,之江站最早受到上游污染物影响,其次是枯季,最后是洪季,说明径流作用有利于污染物向下游迁移扩散.在大潮作用下,之江站一般最晚受到上游污染物影响,中潮次之,最早受到影响的是在小潮情况下.说明在感潮河段,由于受到下游潮流的影响,对污染物往下迁移有一个阻滞作用,且潮流越强阻滞作用越明显.本文构建的潮流水质模型可作为污染物在感潮河段迁移扩散机理研究的模型基础,对于制定降低污染物迁移扩散对地表水环境质量影响措施具有现实意义.     

吸附法处理含砷废水的研究进展

水体砷污染严重威胁着人类健康和生态系统,砷污染防治成为全球性环境问题,含砷水处理受到人们的普遍关注.与其它除砷方法相比较,吸附法具有去除效率高,稳定性好,不产生或很少产生二次污染,吸附剂可重复使用等优点,因而备受青睐.本文简要介绍了吸附法除砷的原理与特点,重点综述了矿物质、活性炭、金属(氢)氧化物、生物吸附剂、离子交换...     

降雨型泥石流（水石流）预报模型研究

根据泥石流暴发具有某种周期性的特点，在获取了大量野外调查资料和历史资料的基础上，对降雨型泥石流进行了预报模型研究，并以北京市北部山区密云县为例作了泥石流预报尝试。以层次分析法和多元回归方法所得出的泥石流空间预报和时间预报模型对于泥石流的预报具有重要意义。     

硅胶腕带被动采集多环芳烃的可行性分析

多环芳烃（polycyclic aromatic hydrocarbons,PAHs）对人体危害巨大,目前关于人体暴露于大气环境PAHs研究主要以主动采样方式开展。硅胶腕带作为一种新的大气被动采样装置,具有体积小、价格低、耐磨耐热、无毒无味等优点,适合人体环境暴露监测。国际上研究刚起步,尚未建立完善的腕带被动采样与主动采样技术之间的定量关系。本研究于2019年秋冬季和2021年冬季在西安市城区,同时开展硅胶腕带被动采样与大气主动采样对低分子量（MW＜203 g·mol^?1）PAHs的对比实验,力求建立两者的联系。2019年和2021年西安冬季大气中低分子量PAHs浓度分别为(52.81±14.76) ng·m^?3和(134.59±39.48) ng·m^?3,与前人研究相当。相对应的腕带浓度为(183.07±40.43) ng·d^?1和(524.99±150.32) ng·d^?1。Pearson相关分析发现：萘、苊烯、1-甲基萘、2-甲基萘、荧蒽以及总PAHs的主、被动采样之间显著相关（P＜0.05）,相关系数均大于0.4,证明硅胶腕带被动采样方法适用于低分子量PAHs的人体暴露监测。     

Bioremediation of oily sludge-contaminated soil by stimulating indigenous microbes

In situ bioremediation of oily sludge-contaminated soil by biostimulation of indigenous microbes through adding manure was conducted at the Shengli oilfield in northern China. After bioremediation for 360 days, total petroleum hydrocarbon (TPH) content was reduced by 58.2% in the treated plots compared with only 15.6% in the control plot. Moreover, bioremediation significantly improved the physicochemical properties of the soil in the treated plot. Soil microbial counts and community-level physiological profiling were also examined. Manure addition increased TPH degraders and polycyclic aromatic hydrocarbon (PAH) degraders in the contaminated soil by one to two orders of magnitude. The activity and biodiversity of soil microbial communities also increased markedly in the treated plot compared with that of the control. Finally, biotoxicity was used to evaluate the soils and a sharp increase in the EC50 of the soil after bioremediation was observed, indicating that bioremediation had reduced the toxicity of the soil.     

镉污染对红壤和潮土微生物的生态毒理效应

以土壤微生物生物量碳(Cmic)、土壤酶活性及微生物多样性为微生物学指标,以0.01mol·L-1CaCl2作为Cd有效态提取剂,以江西红壤和天津潮土为供试土壤,在室内25℃连续培养28d的条件下探讨了外源Cd对土壤微生物的生态毒理效应。结果表明:1)不同培养时间潮土CaCl2提取态Cd含量均显著低于红壤,潮土微生物受到Cd的抑制作用也明显小于红壤。2)各微生物指标的敏感性不同,并受土壤类型和培养时间的影响,其中,脱氢酶的敏感性强于脲酶,微生物功能多样性指标中BiologEco板上每孔的平均吸光值(AWCD)的敏感性强于Shannon指数;Cmic、脲酶、脱氢酶、AWCD和Shannon指数均在红壤中更为敏感。选取的5个微生物指标对Cd污染都有良好的响应,均可作为Cd污染土壤微生物生态毒理实验中的测试指标。在土壤酶指标中,可优先选取脱氢酶作为测试指标。3)Cd对Cmic、土壤酶、微生物功能多样性的抑制作用存在时间效应。14dCd对Cmic的抑制作用大于28d,而对脲酶和脱氢酶的抑制作用小于28d。建议Cd污染土壤微生物生态毒理实验中将培养时间设置为28d或适当延长。4)28d时,红壤中Cd对Cmic、脱氢酶、脲酶、AWCD、Shannon指数的EC10分别为1.31、0.26、0.93、0.08、22.71mg·kg-1,而在潮土中分别为1.97、0.69、13.12、0.09、>200mg·kg-1。     

A new procedure combining GC-MS with accelerated solvent extraction for the analysis of phthalic acid esters in contaminated soils

An optimized procedure based on gas chromatography-mass spectrometry (GC-MS) combined with accelerated solvent extraction (ASE) is developed for the analysis of six phthalic acid esters (PAEs), which are priority soil pollutants nominated by United States Environmental Protection Agency (USEPA). Quantification of PAEs in soil employs ultrasonic extraction (UE) (USEPA 3550) and ASE (USEPA 3545), followed by clean up procedures involving three different chromatography columns and two combined elution methods. GC-MS conditions under selected ion monitoring (SIM) mode are described and quality assurance and quality control (QA/QC) criteria with high accuracy and sensitivity for target analytes were achieved. Method reliability is assured with the use of an isotopically labeled PAE, di-n-butyl phthalate-d4 (DnBP-D4), as a surrogate, and benzyl benzoate (BB) as an internal standard, and with the analysis of certified reference materials (CRM). QA/QC for the developed procedure was tested in four PAE-spiked soils and one PAE-contaminated soil. The four spiked soils were originated from typical Chinese agricultural fields and the contaminated soil was obtained from an electronic waste dismantling area. Instrument detection limits (IDLs) for the six PAEs ranged 0.10–0.31 μg·L^-1 and method detection limits (MDLs) of the four spiked soils varied from a range of 20–70 μg·kg^-1 to a range of 90– 290 μg·kg^-1. Linearity of response between 20 μg·L^-1 and 2 mg·L^-1 was also established and the correlation coefficients (R) were all>0.998. Spiked soil matrix showed relative recovery rates between 75 and 120% for the six target compounds and about 93% for the surrogate substance. The developed procedure is anticipated to be highly applicable for field surveys of soil PAE pollution in China.     

Remediation of soil heavily polluted with polychlorinated biphenyls using a low-temperature plasma technique

Polychlorinated biphenyls （PCBs） were removed by low-temperature plasma technique （dielectric barrier discharge） from heavily polluted soil and their intermediate products were analyzed. The removal rate ranged from 40.1 to 84.6% by different treatments, and they were also influenced significantly （P 〈 0.01） by soil particle-size, electric power, gas flow rate and reaction time. The optimal reaction conditions of PCB removal from the soil were obtained experimentally when soil particle-size, electrical power, flow rate and reaction time were 5-10mm, 21w, 120mL. rain and 90rain, respectively. However, decreasing electrical power, flow rate and reaction time to 18 w, 60 mL. min- and 60 min respectively were also acceptable in view of the cost of remediation. This technique was characterized by the additional advantage of thorough oxidation of PCBs in the soil, with no formation of intermediate products after reaction. The technique therefore shows some promise for application in the remediation of soils contaminated with persistent organic pollutants in brown field sites in urban areas.     

Phytotoxicity in seven higher plant species exposed to di-n-butyl phthalate or bis (2-ethylhexyl) phthalate

We investigated phytotoxicity in seven plant species exposed to a range of concentrations (0– 500 mg·kg⁻¹ soil) of di-n-butyl phthalate (DnBP) or bis (2-ethylhexyl) phthalate (DEHP), two representative phthalate esters (PAEs) nominated by USEPA as priority pollutants and known environmental estrogens. We studied seed germination, root elongation, seedling growth, biomass (fresh weight, FW) and malondialdehyde (MDA) content of shoots and roots of wheat (Triticum aestivum L.), alfalfa (Medicago sativa L.), perennial ryegrass (Lolium perenne), radish (Raphanus sativus L.), cucumber (Cucumis sativus L.), oat (Avena sativa) and onion (Allium cepa L.), together with monitoring of plant pigment content (chlorophyll a, b and carotinoids) in alfalfa, radish and onion shoots. Root elongation, seedling growth and biomass of the test species were generally inhibited by DnBP but not by DEHP, indicating a lower level of phytotoxicity of DEHP than of DnBP. MDA contents of four species were promoted by PAE exposure, but not in alfalfa, ryegrass or onion shoots, indicating lower sensitivity of these three species to PAE pollutants. Plant pigment contents were clearly affected under the stress of both pollutants, implying the potential damage to the photosynthetic system of test plants, mainly by decreasing the content of chlorophyll a and b. Results of DnBP and DEHP phytotoxicity to the primary growth of test plants has provided information for the assessment of their environmental risk in the soil and also forms a basis for the further analysis of their toxic effects over the whole growth period of different plant species.