利用厌氧菌发酵产物处理含铅废水及机理研究

针对传统方法去除废水中重金属铅的缺陷,利用4株厌氧微生物的发酵产物,在不同投加量、pH、温度和反应时间下研究该产物的除铅效果。通过正交实验确定了微生物发酵产物对含铅废水处理的最佳反应条件为:发酵产物投加量为0.5 g,反应时间为20 min,pH=6,温度20℃,铅的去除率99.4%以上,并用蓄电池厂的实际废水进行验证实验,获得相同的效果;同时通过扫描电子显微镜和X-射线能量散射光谱分析厌氧细菌代谢的混合物成分,对去除机理进行了初步探讨,为生物技术处理含铅废水提供了一种新方法和理论依据。     

耐铅微生物的筛选及其吸附能力的初步研究

通过向土壤中添加一定量的铅来驯化土壤微生物,然后利用一系列不同铅浓度的PDA培养基分离耐铅微生物,结果获得一株耐300mg／L铅的细菌Pb—R-1和二株分别耐750mtg／L和900mg／L铅的真菌Pb—R-2和Pb—R-3,通过鉴定得知,Pb—R-2菌株为曲霉,Pb—R-3菌株为青霉;不同成分培养基（有铅或无铅）传代培养实验表明,3个菌株有稳定的耐铅遗传性;通过液体悬浮培养获得：Pb—R-1、Pb—R-2和Pb—R-3对Pb^2＋的吸附率依次为35．5％、75．5％和48．2％。采用3个菌株浸种试验表明,小麦的发芽率几乎不受影响,其它的受影响差别较大。因此,用Pb—R-2吸附小麦土壤中的铅,具有潜在的应用价值。     

Phospholipid fatty acid patterns of microbial communities in paddy soil under different fertilizer treatments

The microbial communities under irrigated rice cropping with different fertilizer treatments, including control （CK）, PK, NK, NP, NPK fertilization, were investigated using phospholipid fatty acid （PLFA） profile method. The results of this study revealed that the fertilizer practice had an impact on the community structure of specific microbial groups. The principal components analysis （PCA） showed that proportion of the actinomycete PLFAs （10Me 18：0 and 10Me 16：0） were the lowest in the PK treatment and the highest in the NPK treatment, which means that soil nitrogen status affected the diversity of actinomycetes, whereas nitrogen cycling was related to the actinomycets. Under CK treatment, the ratio of Gram-positive to Gram-negative bacteria was lower compared with that in fertilizer addition treatments, indicating that fertilizer application stimulated Gram-positive bacterial population in paddy soil. The fatty acid 18：2to6,9, which is considered to be predominantly of fungal origin, was at low level in all the treatments. The ratio of cyl9：0 to 18：1 to7, which has been proposed as an indicator of stress conditions, decreased in PK treatment. Changes of soil microbial community under different fertilizer treatments of paddy soil were detected in this study; however, the causes that lead to changes in the microbial community still needs further study.     

磷对降低土壤中铅的生物有效性的X-衍射及电镜分析

通过盆栽实验,对不同磷化合物处理的铅污染土壤和植物分别进行X-衍射(XRD)、能谱扫描电镜(SEM-EDS)及能谱透射电镜(TEM-EDS)分析.结果显示,不同磷化合物处理土样的X-衍射图在0.288 nm、0.296 nm及0.321 nm处有明显衍射峰生成,以SSP5、HA5及HASSP2处理土样的X-衍射谱图中生成的衍射峰比较明显,而PR5处理的衍射峰相对较弱,其原因可能与磷矿粉的弱溶解特性有关.这显示了土壤经不同磷化合物处理后,土壤中新生成了较多的磷酸铅及Ca-Pb磷酸铅盐的沉淀,不同程度地降低了土壤中铅的迁移和转化特性.对植株根系的SEM分析结果表明,土壤中加入不同的磷化合物处理后,磷酸铅类化合物在植株根表细胞有明显的晶体沉淀物.对植物根细胞的透射电镜分析结果发现,在不同磷处理土壤中,铅以不同的磷酸盐化合物的形式沉淀在植物的细胞壁及细胞间隙,从而有效地阻止了铅离子向原生质细胞及植物中柱内的迁移,不同程度地降低了污染土壤中铅的蓄积毒性.     

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

IntroductionNorth-east China is one of the most importantindustrial bases and also a main agriculturalproduction area. Land disposal of wastes and irrigatingwith sewage have led to increasing heavy metalcontents in soil (Chen, 1996) and the problemsinduce…     

Effect of incubation temperature and wet-dry cycle on the availabilities of Cd, Pb and Zn in soil

The effect of incubation temperature and wet-dry cycle on the availabilities of Cd, Pb and Zn was studied. Three soils with pH ranging from 3.8 to 7.3, organic carbon （OC） from 0.7% to 2.4%, and clay from 12.3% to 35.6% were selected. Soils were spiked with reagent grade Cd（NO3）2, Pb（NO3）2, and Zn（NO3）2 at concentrations of 30 mg Cd/kg soil, 300 mg Zn/kg soil and 2000 mg Pb/kg soil. The soils were incubated at 35, 60, 105℃, respectively and went through four wet-dry cycles. Metal availability in soils was estimated by soil extraction with 0.1 mol/L Ca（NO3）2. According to this study, the effect of the spiking temperature on the metal availabilities was different among the metals, soils and wet-dry cycles. Mostly, 35 ~C was the first recommended spiking temperature for Cd and Pb while no spiking temperature was obviously better than others for Zn. Three wet-dry cycles was recommended regardless of the type of metals and incubation temperature.     

原子吸收光谱法测定污水中铅的最佳操作条件研究

主要研究了测定波长、工作电流、燃烧器高度、光谱通带、燃气与助燃气流量等操作条件对测定工业污水中铅含量的影响 ,确定了最佳的测试条件。     

双硫腙－醋酸丁酯萃取石墨炉原子吸收法测定海水中痕量铜、铅和镉

用双硫腙－醋酸丁酯萃取石墨炉原子吸收法测定海水中痕量Ｃｕ,Ｐｂ,Ｃｄ。试验选定了测定条件,结果表明,在弱碱性介质中,能同时定量萃取Ｃｕ,Ｐｂ,Ｃｄ。方法的相对标准偏差〈３％。加标回收率９２％－１０２％,检出限分别为Ｃｕ０．０６,Ｐｂ０．１４,Ｃｄ０．００２。本法操作简便,快速,已应用于海水中Ｃｕ,Ｐｂ,Ｃｄ的分析,取得令人满意的结果。     

DBS-偶氮氯膦分光光度法测定铅的研究

为了克服用双硫腙比色法测环境样品中铅的选择性差和条件要求严等缺点,研究了铅与ＤＢＳ－偶氮氯膦的显色反应,并提出了用分光光度测定铅的新方法,在稀盐酸介质中,铅与ＤＢＳ－偶氮氯膦形成１：２的蓝色配合物,最大吸收波长位于６３５ｎｍ,表观摩尔吸光系数为４．７×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１,铅量在０－２５μｇ／２５ｍｌ范围内符合比耳定律。     

Metal Concentrations in Fish Species from the Northeast Mediterranean Sea

Samples of Mugil cephalus and Mullus barbatus were collected in the Northeast Mediterranean coast of Turkey the contents of cadmium, copper, iron, zinc and lead in the liver, gill and muscle tissues were determined by atomic absorption flame spectrophotometry.Except for lead, highest levels of each metal were found in the liver and this was followed by the gill and muscle in both species. Among the metals analyzed, Cu, Zn and Fe were the most abundant in the different tissues while Cd and Pb were the least abundant both in M. cephalus and M. barbatus. Seasonal changes in metal (Cd, Cu, Pb, Fe and Zn) concentration were observed in the tissues of both species, but these seasonal variations may not influence consumption advisories. In general, the highest concentrations were detected for all metals in summer.