Status and fuzzy comprehensive assessment of combined heavy metal and organo-chlorine pesticide pollution in the Taihu Lake region of China

The status of combined heavy metal and organo-chlorine pesticide (OCPs; i.e. HCH and DDT) pollution was investigated and the soil environmental quality of the Taihu Lake watershed, one of the most developed regions in China, was evaluated using a fuzzy comprehensive assessment. Statistical analyses showed the presence of combined pollution in the soil. At many sampling sites, heavy metal concentrations were above corresponding background values, indicating the effects of extraneous pollutants. It has been over 20 years since China banned the use of OCPs, but they can still be found in soil samples of this region. HCH levels at all investigated sites were below the Chinese Environmental Quality Standard for Soils. Fuzzy comprehensive assessment showed that the overall soil quality in this region could be categorized as class I. Nevertheless, the high coefficients of variation for levels of DDT, Cd and Hg indicated the existence of some point-source pollution. Continuous monitoring and further studies of the region are recommended to prevent pollution of farmland from these sources.     

Suicide by crashing into a heavy vehicle: Focus on professional drivers using in-depth crash data

Objective: Road traffic suicides typically involve a passenger car driver crashing his or her vehicle into a heavy vehicle, because death is almost certain due to the large mass difference between these vehicles. For the same reason, heavy-vehicle drivers typically suffer minor injuries, if any, and have thus received little attention in the research literature. In this study, we focused on heavy-vehicle drivers who were involved as the second party in road suicides in Finland.

Methods: We analyzed 138 road suicides (2011–2016) involving a passenger car crashing into a heavy vehicle. We used in-depth road crash investigation data from the Finnish Crash Data Institute.

Results: The results showed that all but 2 crashes were head-on collisions. Almost 30% of truck drivers were injured, but only a few suffered serious injuries. More than a quarter reported sick leave following their crash. Injury insurance compensation to heavy-vehicle drivers was just above €9,000 on average. Material damage to heavy vehicles was significant, with average insurance compensation paid being €70,500. Three out of 4 truck drivers reported that drivers committing suicide acted abruptly and left them little opportunity for preventive action.

Conclusions: Suicides by crashing into heavy vehicles can have an impact on drivers’ well-being; however, it is difficult to see how heavy-vehicle drivers could avoid a suicide attempt involving their vehicle.     

Effects of organic matter on Leymus chinensis germination,growth, and urease activity and available nitrogen in coastal saline soil

ABSTRACT

The present study was carried out to investigate the effect of three organic matters (stalk powder, microbial fertilizer, and manure) on Leymus chinensis germination, growth, and urease activity and available nitrogen (N) in coastal saline soil. The study was conducted in a completely randomized design with eight treatments: J₀V₀Y₀, J₁V₀Y₀, J₀V₁Y₀, J₀V₀Y₁, J₁V₁Y₀, J₁V₀Y₁, J₀V₁Y₁, J₁V₁Y₁. The notations were based on the quantities of each agent added to 1 kg of coastal saline soil: J₀ – no straw powder, J₁ – 0.2 kg straw powder, Y₀ – no manure, Y₁ – 0.3 kg manure, V₀ – no microbial fertilizer, V₁ – 0.2 L microbial fertilizer, each in quantic repeat. L. chinensis was sown as 50 seeds per pot. Results indicated that addition of organic agents exerted a significantly enhanced germination, increase in fresh weight and elevated soil urease activity. Soil available N levels were significantly positively correlated with soil urease activity and fresh weight, but not with germination rate. It is noteworthy that the halophyte L. chinensis showed improved characteristics when grown in coastal saline soil with addition of organic amendments.     

Full-scale blending treatment of fresh MSWI leachate with municipal wastewater in a wastewater treatment plant

Fresh leachate, generated in municipal solid waste incineration (MSWI) plants, contains various pollutants with extremely high strength organics, which usually requires expensive and complex treatment processes. This study investigated the feasibility of blending treatment of MSWI leachate with municipal wastewater. Fresh MSWI leachate was pretreated by coagulation–flocculation with FeCl₃ 2 g/L and CaO 25 g/L, plate-and-frame filter press, followed by ammonia stripping at pH above 12. After that, blending treatment was carried out in a full-scale municipal wastewater treatment plant (WWTP) for approximately 3 months. Different operational modes consisting of different pretreated leachate and methanol addition levels were tested, and their performances were evaluated. Results showed that throughout the experimental period, monitored parameters in the WWTP effluent, including COD (<60 mg/L), BOD₅ (<20 mg/L), ammonium (<8 mg/L), phosphorus (<1.5 mg/L) and heavy metals, generally complied with the Chinese sewage discharged standard. Under the experimental conditions, a certain amount of methanol was needed to fulfill TN removal. An estimation of the operation cost revealed that the expenditure of blending treatment was much lower than the total costs of respective treatment of MSWI leachate and municipal wastewater. The outcomes indicated that blending treatment could not only improve the treatability of the MSWI leachate, but also reduce the treatment cost of the two different wastewaters.     

长期施肥下浙江稻田不同颗粒组分有机碳的稳定特征

依托浙江水网地区稻田长期定位施肥试验(1996~2013年),利用固态13C核磁共振波谱技术,研究长期不同施肥措施下土壤各颗粒组分有机碳含量及其化学结构特征.结果表明,与不施肥对照(CK)相比,秸秆与化肥配施(NPKRS)、栏肥与化肥配施(NPKOM)、单施化肥(NPK)和单施栏肥(OM)处理均显著(P0.05)增加了砂粒(2~0.02 mm)、粉粒(0.02~0.002mm)和黏粒(0.002 mm)组分中有机碳含量;而单施秸秆(RS)处理仅显著增加砂粒组分有机碳含量.此外,与单施化肥处理相比,有机肥和化肥配施促进了新增有机碳在粉粒和黏粒组分的分配,更有利于新增有机碳的稳定.应用13C-NMR波谱技术进行结构表征,结果表明粉粒和黏粒组分有机碳的化学结构存在明显差异,粉粒组分烷氧碳、芳香碳的相对含量高于黏粒,而烷基碳、羰基碳的相对含量低于黏粒.长期有机肥与化肥配施下粉粒和黏粒烷基碳相对含量较单施有机肥处理分别降低9.1%~11.9%和13.7%~19.9%,烷氧碳的相对含量则分别增加2.9%~6.3%和13.4%~22.1%,表明有机肥与化肥配施处理降低了粉粒和黏粒组分有机碳的分解程度.长期单施化肥处理下粉粒和黏粒组分有机质的芳化度和疏水性低于单施有机肥处理和不施肥处理,有机质的矿化稳定性较低.长期有机肥与化肥配施,尤其是NPKOM处理,通过增加化学抗性化合物和碳水化合物的积累,并且减缓活性组分的分解提高粉粒和黏粒组分有机碳含量,是促进稻田土壤有机碳可持续积累的有效措施.     

矿区植被恢复方式对土壤微生物和酶活性的影响

矿区废弃地生态退化形势严峻,生态修复已成为矿区可持续发展的主要措施,土壤微生物和酶活性可作为评价土壤恢复质量的敏感因子.本研究将以山西省安太堡煤矿复垦区作为对象,分析植被恢复方式对土壤微生物和酶活的影响.结果表明,不同植被方式对土壤理化特征、参与氮代谢的3类菌群(固氮菌、硝化细菌和反硝化细菌)和4种酶活性(蔗糖酶、过氧化氢酶、脲酶和多酚氧化酶活)均有显著影响.土壤总氮含量与固氮菌和硝化细菌数量均显著相关,而与反硝化细菌不相关.多酚氧化酶活性与有机碳和总氮含量之间为负相关,而其它3种酶与有机碳和总氮之间呈正相关.通过主成分分析计算综合肥力指标,刺槐-油松混交林土壤综合肥力指标最高,而未复垦综合肥力指标最低.可见,刺槐-油松混交林是晋西北干旱区矿区复垦较为适宜的植被恢复模式.     

黄河岸边土壤中类二(口恶)英类多氯联苯污染现状及风险

研究了全黄河范围内40个国家重点控制断面岸边土壤样品中类二噁英类多氯联苯(dioxin-like polychlorinated biphenyls,DL-PCBs)的污染现状,并利用毒性当量法和健康风险评价模型定量描述黄河岸边土壤中DL-PCBs对沿岸居民的毒性风险、致癌风险和非致癌风险.结果表明,黄河岸边土壤中各采样断面岸边土壤中ΣDL-PCBs的含量(以dw计,下同)范围为:0.37~7.17 ng·g~(-1),均值为0.38 ng·g~(-1).毒性风险计算表明,黄河岸边土壤中DL-PCBs的毒性当量范围为:0.00~30.31 pg·g~(-1),均值是13.63 pg·g~(-1),基本不会对沿岸居民产生毒性风险;健康风险模型计算表明,黄河岸边土壤中DL-PCBs对儿童和成人的致癌风险、非致癌风险均未超过美国EPA规定的限值,基本不会产生明显的健康风险.相比而言,黄河中游沿岸居民更易受到DL-PCBs危害.     

不同国家基于健康风险的土壤环境基准比较研究与启示

20世纪90年代以来,许多发达国家颁布了基于健康风险的土壤环境标准及基准背景技术文件,为发展中国家启动标准制订和开展基准研究提供了重要的方法学参考.然而,由于各国在环境立法框架、基准推导过程、环境气候特征、土壤类型、人群生活方式与习惯等方面的不同,导致其基准名称、基准功能、保护受体以及基准取值等存在较大的差异.本文在综述基于健康风险的土壤环境基准科学内涵与基本特征的基础上,对不同国家场地土壤环境基准的名称、功能及基准值的差异进行了比较研究,从土地利用类型划分、暴露情景和暴露途径设定、致癌物可接受风险水平选择以及人体暴露参数确定等4个方面,对不同国家制定场地土壤环境基准的关键技术和影响因素进行了总结分析,探讨了借鉴国外经验考虑区域差异制定我国土壤环境基准的对策与方略,并指出了当前我国制定场地土壤环境基准和标准面临的困难和挑战.     

城市分散式粪便颗粒化有机肥用作叶菜肥的肥力及环境影响

城市分散式粪便的处理已经成为现代化城市管理的一个难题.本研究在将城市分散式粪便经收集、除渣、絮凝脱水后制成颗粒肥;通过盆栽小青菜试验,评价了不同施肥量对小青菜的增产效果以及对土壤、淋溶水性质的影响,探讨了颗粒肥用于叶菜施肥的可行性.结果表明,施用颗粒肥可显著提高小青菜产量,试验条件下未对小青菜叶片造成大肠杆菌、大肠菌群等病原菌污染;在适当比例的施肥水平下,颗粒肥施用后淋溶水中的病原菌浓度低于对照组.施用颗粒肥能显著提高土壤氮、磷、钾、有机质等营养物质含量,提高土壤孔隙度水平,降低土壤容重,改善土壤理化性质;同时颗粒肥施用不会对土壤和淋溶水造成重金属离子污染,且能有效降低土壤氮、钾的淋溶.