生物沥滤污泥重金属污染的潜在生物毒性评价

采用沉积物质量基准法(SQGs)和Hakanson指数法对沥滤前后城市污泥中重金属的潜在生物毒性进行了定性和定量的评价,结果表明氧化亚铁硫杆菌(A.ferrooxidans菌)对Cu、Cd的脱毒作用优于氧化硫硫杆菌(A.thiooxidans菌)。沥滤后污泥的综合潜在生态危害指数均能下降91.0%以上,且A.ferrooxidans菌沥后污泥的潜在生物毒性最弱,其综合潜在生态危害指数为84.75,是生物沥滤去除城市污泥重金属工程应用的适合菌种。     

输卤管道卤水漏失对地下水的影响分析

通过卤水对土壤的淋滤试验，模拟卤水管道发生漏失事故时，盐分在土壤和地下水中的迁移转化规律，为卤水漏失对地下水的影响提供定量依据。对正在开发之中的叶县盐田的环境管理具有一定的指导意义．     

A stochastic model of urinary nitrogen and water flow in grassland soil in New Zealand

A mathematical model of urinary nitrogen and water flow in soil has been developed that incorporated stochastic rainfall and stochastic temperature events. This model was used to characterise the variability in urine patch nitrogen leaching at Taupo, New Zealand. This stochastic model was also used to more accurately determine the effect of urinary patch overlap on cow urinary nitrogen flow and leaching in soil. Nitrogen leaching from single urine deposits on pasture in the winter ranged from 0 to 75% of applied nitrogen as a result of stochastic rainfall events. Rainfall effects explained 98% of the variance in nitrogen leaching due to stochastic rainfall and temperature effects combined. The model predicted that on average 38, 61, and 71% of the nitrogen in single, double and triple urine patches is leached in the winter. Nitrogen leaching rates were significantly greater in the winter than the summer months. The distribution in the amount of nitrogen leached from single urine patches was close to normal in the winter but approximately exponentially distributed in the summer. The variability in total nitrogen leached from a field also decreased as the stocking rate increased. A quantitative modelling framework is crucial for understanding nitrogen transport in pastoral systems and for effectively setting and enforcing restrictions imposed by regulatory bodies on nitrogen losses from pastoral farming and this study represents a component of this framework.     

Assessing the feasibility of land application of fly ash, sewage sludge and their mixtures

Land disposal of fly ash (FA) and sewage sludge (SS) is a major problem due largely to their potentially harmful constituents. Combined use of FA and SS however may help reduce the associated pollution potential. In this paper we summarize the results of several case studies designed to assess the feasibility of land application of FA with and without SS. A wide range of application rates was tested under laboratory, greenhouse and field conditions. The leaching of metals from soil columns amended with moderate rates of FA applications (8-16 Mg ha⁻¹) generally had no significant impact on the metal content of leachate or their downward migration in the soil. The application of FA or SS at a much high rate (74.1 Mg ha⁻¹) significantly increased both leaching and downward migration of metals. The use of 1:1 FA+SS mixture at 148.2 Mg ha⁻¹ reduced metal leaching compared to the combined metal quantities leached when FA or SS applied at 74.1 Mg ha⁻¹. The results indicate that combined use of FA and SS at a rational rate of application should not cause any significant effect on drainage water quality. Plant studies conducted using FA and SS mixtures indicated that these materials could be beneficial for biomass production, without contributing significant metal uptake or leaching. The application of FA as high as 560 Mg ha⁻¹ in a long-term field trial had no detectable deterioration in soil or groundwater quality and no substantial increases in plant uptake of metals and other trace elements were observed. Low to moderate rates of FA and SS therefore could be successfully used as soil amendments, particularly so when used as a mixture.     

三峡库区堆存垃圾浸出污染物的水质影响模拟

以三峡库区坝前水位135～175m范围的生活垃圾为研究对象,调查分析了其堆存量、空间分布和理化特性;通过污染物溶出动态模拟和放大实验研究,估算了生活垃圾中有机污染物的溶出源强,并运用河流岸边稳态衰减模式计算了不同处置方案对库区水质的影响程度.针对基准方案和135m蓄水期处置方案,分别对库区局部河段水质和干流水质的影响进行了分析比较.结果表明,若采用基准方案,即将淹没区内约600×104t的生活垃圾就地处置,淹没于水中,将会对库区水质安全构成较大的威胁;若采用135m蓄水期处置方案,则水体中CODcr值增加不超过0.03mg·L-1,对库区干流水质的影响较小.     

Nitrates leaching from agricultural land in Hamadan, western Iran

Nitrogen (N) is vital for plant and microbial growth and rather large amounts are required by most arable and horticulture plants. High nitrate (NO₃⁻) levels of water supplies have been attributed to leaching from the soil and into water systems. In the arid and semi-arid regions, irrigation water carries NO₃⁻ into groundwater. This study was conducted to investigate NO₃⁻ pollution of groundwater in Hamadan, western Iran. The water samples were mostly taken from domestic and community wells. In this area, the drinking water supply comes mainly from groundwater sources. Nitrate concentrations in the well samples varied from 3 to 252 with the average of 49 mg l⁻¹. Results showed that of 311 wells, 196 (63%) had levels less than 50 mg l⁻¹ and 115 (37%) had levels in excess of the 50 mg l⁻¹ NO₃⁻. Agriculture is the dominant land use in the area and application of N fertilizers clearly has an impact on groundwater. If agricultural losses remain stable, it could be expected that the concentration of NO₃⁻ in groundwater will reach or exceed the international recommendations for drinking water (50 mg l⁻¹) in the future. Irrigation with high NO₃⁻ groundwater can minimise the requirement for N fertilizers. To maintain yield increase and minimise NO₃⁻ pollution of the groundwater, best management practices, for N fertilizer use should be applied and excessive fertilizer application prevented.     

Dissipation and Leaching of 14C-Monocrotophos in Soil Columns under Subtropical Climate

Dissipation and leaching behavior of ¹⁴C-monocrotophos was studied for 365 days under field conditions using PVC cylinders. The first set (24 cylinders) was spiked with 1.0 μCi ¹⁴C-labeled monocrotophos along with 1.06 mg unlabeled monocrotophos to give a concentration of 2 mg kg ^?1 in the soil up to 15 cm depth. The second set (24 cylinders) received ¹⁴C-labeled monocrotophos along with other non-labeled insecticides viz., dimethoate @ 300 g a.i ha^?1, deltamethrin @ 12.5 g a.i ha^?1, endosulfan @ 750 g a.i ha^?1, cypermethrin @ 60 g a.i ha^?1, and triazophos @ 600 g a.i ha^?1 at an interval of 15 days each as recommended for the cotton crop. ¹⁴C-monocrotophos dissipated faster, up to 45% in first 90 days in columns treated with only monocrotophos compared to 25% in columns that received monocrotophos along with other insecticides. However, both the columns showed similar residues 180 days onward. After 180 days of treatment, 46% radiolabeled residues were observed, which reduced up to 39.6% after 365 days. Leaching of ¹⁴C-monocrotophos to 15–30 cm soil layer was observed in both the experimental setups. In the 15–30 cm soil layer of both soil columns, up to 0.19 mg ¹⁴C-monocrotophos kg^?1d. wt. soil was detected after 270 days.     

对固体废物中挥发性有机物浸出方法的几点实验探讨

采用零顶空提取器,对陈旧油墨渣和蒽琨渣样品中的挥发性有机物进行了浸出实验和分析测定,浸出液采用静态顶空分流进样、GC/MS法分析。对影响挥发性有机物浸出效率的因素进行了研究,结果表明,浸提剂加入方式、浸出时间和浸出液收集方法等对分析结果准确度有较大影响。     

Leaching of nitrogen, phosphorus, TOC and COD from the biosolids of the municipal wastewater treatment plant of Thessaloniki

Biosolids from the WWTP of Thessaloniki were examined for the leaching of phosphorus (as ), nitrogen (as and ), and organic matter (as TOC and COD), using two tests: (1) a pH static leaching test and (2) a characterization test, relating contaminant release to the liquid to solid (L/S) ratio. Moreover, a Microtox toxicity test was conducted, to examine the pH dependency of the toxicity of the sludge leachate on the Vibrio fischeri bacterium. Maximum phosphorus release was observed at pH < 3 and at pH > 10. Ammonium nitrogen exhibited maximum leachability at near neutral pH conditions, while nitrate nitrogen exhibited a mild increase in the leachate, as the leachant pH increased from 2 to 12. Both TOC and COD exhibited an increase in the leachate concentration, as the leachant pH was increased from 2 to 12. Ecotoxicological analysis showed that maximum toxicity occurred at very low and very high pH-conditions. As liquid-to-solid ratio increased, the leachate concentration (in mg/l) of all parameters studied decreased. The results of the study were used to conduct a release assessment estimate for the case of Thessaloniki.     

The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain

In winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain, maize roots do not extend beyond 1.2 m in the vertical soil profile, but wheat roots can reach up to 2.0 m. Increases in soil nitrate content at maize harvest and significant reductions after winter wheat harvest were observed in the 1.4-2.0 m depth under field conditions. The recovery of 15N isotope (calcium nitrate) from various (1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 m) soil depths showed that deep-rooting winter wheat could use soil nitrate up to the 2.0 m depth. This accounted partially, for the reduced nitrate in the 1.4-2.0 m depth of the soil after harvest of wheat in the rotation system.