Spatial distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in soils from typical oil-sewage irrigation area, Northeast China

Air pollution is one of the major environmental problems in India, affecting health of thousands of 'urban' residents residing in mega cities. The need of the day is to evolve an 'effective' and 'efficient' air quality management plan (AQMP) encompassing the essential 'key players' and 'stakeholders.' This paper describes the formulation of an AQMP for mega cities like Delhi in India taking into account the aforementioned key 'inputs.' The AQMP formulation methodology is based on past studies of Longhurst et al., (Atmospheric Environment, 30, 3975-3985, 1996); Longhurst & Elsom, ((1997). Air Pollution-II, Vol. 2 (pp. 525-532)) and Beatti et al., (Atmospheric Environment, 35, 1479-1490, 2001). Further, the vulnerability analysis (VA) has been carried out to evaluate the stresses due to air pollution in the study area. The VA has given the vulnerability index (VI) of 'medium to high' and 'low' at urban roadways/intersections and residential areas, respectively.     

Thermochemical esterifying citric acid onto lignocellulose for enhancing methylene blue sorption capacity of rice straw

In this paper, rice straw was esterified thermochemically with citric acid (CA) to produce potentially biodegradable cationic sorbent. The modified rice straw (MRS) and crude rice straw (CRS) were evaluated for their methylene blue (MB) removal capacity from aqueous solution. The effects of various experimental parameters (e.g., initial pH, sorbent dose, dye concentration, ion strength, and contact time) were examined. The ratio of MB sorbed on CRS increased as the initial pH was increased from pH 2 to 10. For MRS, the MB removal ratio came up to the maximum value beyond pH 3. The 1.5g/l or up of MRS could almost completely remove the dye from 250mg/l of MB solution. The ratio of MB sorbed kept above 98% over a range from 50 to 450mg/l of MB concentration when 2.0g/l of MRS was used. Increase in ion strength of solution induced decline of MB sorption. The isothermal data fitted the Langmuir model. The sorption processes followed the pseudo-first-order rate kinetics. The intraparticle diffusion rate constant (k(id)) was greatly increased due to modification.     

Levels of polybrominated diphenyl ethers (PBDEs) in breast milk from Beijing, China

The levels of polybrominated diphenyl ethers (PBDEs) in breast milk from Beijing, China, were studied. The 6 predominant PBDEs congeners (BDE47, BDE99, BDE100, BDE153, BDE154 and BDE183) in 23 pooled breast milk samples from 205 mothers living in Beijing were measured. Mean and median of SigmaPBDEs concentrations in all samples were 1.12ngg(-1) lipid and 1.07ngg(-1) lipid, respectively. The Statistical difference in SigmaPBDEs concentrations was found between urban areas (1.22ngg(-1) lipid, n=14) and rural areas (0.97ngg(-1) lipid n=9). The sum of BDE47 and BDE153 accounted for more than 70% of SigmaPBDEs in most samples. The significant correlation was found between the SigmaPBDEs in pooled samples and average of consumption of food of animal origin in the pools in urban area. However, there was no correlation was found between the SigmaPBDEs in pooled samples and average of consumption of food of animal origin in the pools in rural area of Beijing. The current study showed that the level of PBDEs in breast milk from Beijing was lower than that from South China and some developed countries such as USA and Sweden.     

Genotoxicity assessment of soils from wastewater irrigation areas and bioremediation sites using the Vicia faba root tip micronucleus assay

Genotoxicity potential of soils taken from wastewater irrigation areas and bioremediation sites was assessed using the Vicia faba root tip micronucleus assay. Twenty five soils were tested, of which 8 were uncontaminated soils and taken as the control to examine the influence of soil properties; 6 soils were obtained from paddy rice fields with a history of long-term wastewater irrigation; 6 soils were obtained from bioremediation sites to examine effects of bioremediation; and 5 PAH-contaminated soils were used to examine methodological effects between direct soil exposure and exposure to aqueous soil extracts on micronuclei (MN) frequency ( per thousand) in the V. faba root tips. Results indicate that soil properties had no significant influences on MN frequencies (p > 0.05) when soil pH varied between 3.4 to 7.6 and organic carbon between 0.4% and 18.6%. The MN frequency measured in these control soils ranged from 1.6 per thousand to 5.8 per thousand. MN frequencies in soils from wastewater irrigation areas showed 2- to 48-fold increase as compared with the control. Soils from bioremediation sites showed a mixed picture: MN frequencies in some soils decreased after bioremediation, possibly due to detoxification; whereas in other cases remediated soils induced higher MN frequencies, suggesting that genotoxic substances might be produced during bioremediation. Exposure to aqueous soil extracts gave a higher MN frequency than direct exposure in 3 soils. However, the opposite was observed in the other two soils, suggesting that both exposure routes should be tested in case of negative results from one route. Data obtained from this study indicate that the MN assay is a sensitive assay suitable for evaluating genotoxicity of soils.     

Aerobic granulation for 2,4-dichlorophenol biodegradation in a sequencing batch reactor

Development of aerobic granules for the biological degradation of 2,4-dichlorophenol (2,4-DCP) in a sequencing batch reactor was reported. A key strategy was involving the addition of glucose as a co-substrate and step increase in influent 2,4-DCP concentration. After operation of 39d, stable granules with a diameter range of 1-2mm and a clearly defined shape and appearance were obtained. After granulation, the effluent 2,4-DCP and chemical oxygen demand concentrations were 4.8mgl(-1) and 41mgl(-1), with high removal efficiencies of 94% and 95%, respectively. Specific 2,4-DCP biodegradation rates in the granules followed the Haldane model for substrate inhibition, and peaked at 39.6mg2,4-DCPg(-1)VSS(-1)h(-1) at a 2,4-DCP concentration of 105mgl(-1). Efficient degradation of 2,4-DCP by the aerobic granules suggests their potential application in the treatment of industrial wastewater containing chlorophenols and other inhibitory chemicals.     

聚合硅酸氯化铝铁的制备及其絮凝性能

利用盐酸酸洗废液制备聚合硅酸氯化铝铁（PSAFC）,并用PSAFC处理造纸脱墨废水,考察了各种因素对絮凝效果的影响。实验结果表明：在废水pH为6、PSAFC加入量为240mg／L、搅拌转速为150r／min、搅拌时间为2min,静置时间为25min的条件下,COD、浊度、色度的去除率分别为87．2％,99．2％,94．5％;PSAFC的絮凝效果明显好于市售的聚合氯化铝和聚合氯化铁.     

水淬渣-累托石混合吸附剂处理含Cu2+冶金废水的研究

研究了以水淬渣-累托石为吸附剂对含Cu2 的冶金废水进行处理.实验结果表明,在不调节含Cu2 冶金废水pH值的条件下,水淬渣与累托石质量比为3∶1,吸附剂用量为0.03 g/mL,作用时间为20 min,温度为25℃(常温)时,Cu2 的去除率达99.8%,对Cu2 的吸附容量为0.302 mg/g,处理后的水符合国家污水综合排放标准(GB8978-1996)一级标准.水淬渣-累托石混合吸附剂比水淬渣或累托石单一吸附剂除Cu2 效果要好.     

辛一联合站污油处理的控制措施

介绍了集输泵站污油回收处理的现状，分析了污油回收对泵站正常生产的影响因素，提出了解决办法，使泵站安全、平稳的生产得到了保障。