Simplified methods for monitoring petroleum‐contaminated ground water and soil vapor

Portable meters and simplified gas Chromatographic (GC) techniques were investigated for monitoring volatile hydrocarbon (HC), CO₂, and O₂, concentrations in groundwater, exhaust gases, and soil vapor during in situ remediation using soil vapor extraction (SVE) and air sparging (AS). Results of groundwater samples analyzed in‐house using a headspace technique compared well to split samples analyzed by a certified analytical laboratory (r² = 0.94). SVE exhaust gas HC and CO₂ concentrations measured using a GT201 portable HC/O₂ meter and a RA‐411A meter (GasTech), respectively, were highly correlated with in‐house laboratory GC analyses (r² = 0.91). O₂ concentrations fell in a small range and meter analyses were not well correlated with laboratory analyses. Results of soil gas monitoring were not as well correlated as those for exhaust gases for HC, CO₂, or O₂, perhaps due to environmental conditions such as changes in relative humidity or the wider range of soil gas values. Overall, the meters were good indicators of vapor contamination, they greatly simplified estimates of total HC mass removal, and they allowed estimates of the biological contribution to contaminant removal during the remediation process.     

Biodeterioration of natural stone with special reference to nitrifying bacteria

An evaluation of field data from historical buildings in Germany showed that chemoorganotrophic bacteria are the most numerous microorganisms in building stones, followed by fungi and nitrifying bacteria. Chemoorganotrophic bacteria and fungi were present in almost every sample. Ammonia and nitrite oxidizers were found in 55 and 62% of the samples, respectively. Within months, natural stone was colonized by chemoorganotrophic microorganisms. The highest cell numbers were usually found near the surface. The colonization of natural stone by nitrifying bacteria took several years. The highest cell numbers were in some cases found underneath the surface. Nitrifying bacteria showed a preference for calcareous material with a medium pore radius between 1 and 10 m. Cell numbers of nitrifying bacteria did not correlate to the nitrate content of the stone material. We demonstrated that the stone inhabiting microflora can cause significant loss of nitrate by denitrification. Our data strongly suggested that microbial colonization of historical buildings was enhanced by anthropogenic air pollution. Samples taken from stone material with a pore radius 1 m had significantly higher cell numbers when they were covered with black crusts. A comparison of samples taken between 1990–1995 from buildings throughout Germany showed that in eastern Germany a significantly stronger colonization with facultatively methylotrophic bacteria and nitrifying bacteria existed. The same was true for natural stone from an urban exposure site when compared to material from a rural exposure site. Data from outdoor exposure and laboratory simulation experiments indicated that the colonization of calcareous stone by nitrifying bacteria was enhanced by chemical weathering.     

Effects of amendments on biodegradation of crude petroleum by sediment bacteria from Bonny River Estuary

The biodegradation of Bonny light crude petroleum by bacteria in batch culture was enhanced by the addition to culture media, of 0.2 mg of urea and soya bean lecithin per 100 ml of crude oil, sediment and water mixture. Biodegradation was found to be purely an aerobic process. There was a direct relationship between hydrocarbon content and proportion (%) of total heterotrophic count that was capable of growing on crude petroleum as sole carbon and energy source.     

转基因作物与非转基因作物的共存立法动态研究——以美、日、欧应对基因污染事件为视角

随着基因工程技术的运用与发展,越来越多的转基因作物基因污染事件的发生也引起了世界各国对转基因作物与非转基因作物之间的和谐发展问题的高度重视。以美、日、欧为代表,世界各国对转基因作物与非转基因作物的共存问题都进行了积极地探索。借鉴美、日、欧转基因与非转基因作物共存法律制度,以期为我国转基因与非转基因作物共存法律制度的构建提供参考。     

重金属污染土壤稳定/固化修复技术研究进展

修复重金属污染土壤一直是国际上的难点和热点研究课题.目前常用的污染场地修复技术主要包括挖掘、稳定/固化(solidification/stabilization,S/S)、化学淋洗、气提、热处理、生物修复等.本文在参考美国环境保护署(EPA)、英国环境署的S/S技术规范、国内外发明专利基础上,对S/S的概念、国内外发展现状及今后的发展方向进行了系统论述.固定化技术通过把污染物囊封入惰性基材中,或在污染物外面加上低渗透性的材料,来减少污染物暴露的淋滤面积以达到限制污染物迁移的目的.稳定化技术是从改变污染物的有效性出发,将污染物转化为不易溶解、迁移能力或毒性更小的形式.S/S技术包括:水泥固化、石灰火山灰固化、塑性材料包容固化、玻璃化技术、药剂稳定化.在稳定化技术中,加入药剂的目的是改变土壤的物理、化学性质,通过pH控制技术、氧化还原电势技术、沉淀技术、吸附技术、离子交换技术等改变重金属在土壤中的存在状态,从而降低其生物有效性和迁移性.本文还论述了S/S修复效果评价方法,并指出需加强S/S技术中的分子键合技术、土聚合物以及我国的S/S技术导则制定等工作.     

苏云金芽胞杆菌治理镍污染的方法的建立

利用微生物治理重金属污染已经成为一个研究的热点,并被视为将最终替代传统的物理、化学等处理方式的一种方法.但由于一些微生物存在安全性、繁殖速度慢等问题而造成了处理效果不佳.因此,以安全性高、繁殖速度快的苏云金芽胞杆菌(Bacillus thuringiensis,简称Bt)为研究载体,寻找最适Bt的镍污染处理方法对于提高...     

Rice (Oryza sativa) as a Remediation Tool for Nutrient Runoff

Hypereutrophication of U.S. surface waters is one of the leading causes of impairment for water quality. With nutrient criteria development and total maximum daily load (TMDL) issues looming for regulators, agricultural research is focusing on practices aimed at decreasing nutrient contributions to receiving aquatic ecosystems. This study examined the use of rice (Oryza sativa) for luxury uptake of nitrogen and phosphorus components associated with agricultural storm runoff. Mesocosms (379 L) planted with rice were exposed to two concentrations (5 and 10 mg/L) of nitrate, ammonia, and orthophosphorus. Results from these mesocosms were compared to unvegetated controls (also amended with 5 or 10 mg/L nitrate, ammonia, and orthophosphorus) to determine efficiency of rice in remediating nutrient runoff. Statistically significant differences in ammonia and nitrate retention of vegetated mesocosms amended with 5 mg/L versus vegetated mesocosms amended with 10 mg/L were noted after the first exposure. Although rice is a nutrient-dependent aquatic plant, this study suggests that more efficient mitigation is possible at lower inflow concentrations as opposed to higher inflow concentrations.     

微生物耐砷机理及其在砷地球化学循环中的作用北大核心CSCD

砷是一种无处不在的有毒类金属,其强致癌性引起了人类的广泛关注。在自然环境中,砷的转化存在物理化学过程和生物过程,其中微生物介导的砷转化是环境砷行为的主要影响因素。微生物的耐砷特性与砷吸收、氧化还原、甲基化、区隔化和外排等过程密切相关。砷在微生物体内的转运转化主要与砷解毒有关,但某些微生物可利用氧化还原过程产生的能量以维持其生长需求。本文综述了微生物介导的砷吸收、转化、区隔化和外排机制,这对阐明砷的地球化学循环过程及指导砷污染土壤和水体修复、阻控农作物砷吸收等方面具有重要意义。     

近岸污染指示半知菌灰黄青霉(Penicillium griseo fulvum)的分子检测

【目的】通过分子方法检测近海污染环境优势种灰黄青霉,并为由此而推断污染程度做准备。【方法】根据GenBank中青霉属不同种和相近属种的ITS序列差异和灰黄青霉特有的IAO序列,设计了污染区优势种灰黄青霉的特异性引物AS1/RS4和IAO1/IAO2,建立相应的特异探针检测体系。通过PCR和套式PCR技术,分析比较两对特异序列检测灰黄青霉的差异。【结果】建立的分子检测体系可以排除其它近似或相关菌株干扰,从环境中扩增到目的基因片段。利用引物AS1/RS4作为核酸探针,通过套式PCR菌株DNA的检测灵敏度可达到10fg/μL,当仅有10个数量级分生孢子时即可检测出,从沉积物中检测灵敏度为102个数量级孢子/0.25g。特异酶基因IAO1/IAO2检测灵敏度较前者稍低。【结论】利用特异序列作为探针检测污染环境优势种灰黄青霉的方法可行,在一定范围内,灰黄青霉的出现频率及数量对污染程度有较好的指示作用。     

The sinking ark: pollution and the worldwide loss of biodiversity

Humans are making increasing demands on natural ecosystems. One recent study has concluded that our species is consuming or diverting some 40% of the net photosynthetic productivity of our planet. Many habitats are being converted to simpler systems which provide more harvestable goods to people. As a result, genetic diversity, species and whole ecosystems are disappearing; some scientists suggest that as many as 25% of the world's species could be lost in the next several decades.The sinking ark is usually characterized in terms of pollution, habitat loss, poaching, introduced species and illegal trade in wildlife products, but these are symptoms rather than causes. At a more fundamental level, many of the same factors which have enabled pollution to become such a problem have also been responsible for the loss in biodiversity; the most important factor is that the effects of pollutants on biodiversity have been considered an externality, an unintended side effect of industrial activity which brought measurable benefits to people. Development activities which have depleted biodiversity have proven profitable only because the real costs have been hidden.Keeping the ark afloat will require the Five-I Approach: investigation (learning how natural systems function); information (ensuring that the facts are available to inform decisions); incentives (using economic tools to help conserve biodiversity); integration (promoting a cross-sectoral approach to conserving biodiversity); and international support (building productive collaboration for conserving biodiversity).