Occurrence and microbial degradation of phthalate esters in Taiwan river sediments

Concentrations and microbial degradation rates were measured for eight phthalate esters (PAEs) found in 14 surface water and six sediment samples taken from rivers in Taiwan. The tested PAEs were diethyl phthalate (DEP), dipropyl phthalate (DPP), di-n-butyl phthalate (DBP), diphenyl phthalate (DPhP), benzylbutyl phthalate (BBP), dihexyl phthalate (DHP), dicyclohexyl phthalate (DCP), and di-(2-ethylhexyl) phthalate (DEHP). In all samples, concentrations of DEHP and DBP were found to be higher than the other six PAEs. DEHP concentrations in the water and sediment samples ranged from ND to 18.5 μg/l and 0.5 to 23.9 μg/g, respectively; for DBP the concentration ranges were 1.0–13.5 μg/l and 0.3–30.3 μg/g, respectively. Concentrations of DHP, BBP, DCP and DPhP were below detection limits. Under aerobic conditions, average degradation half-lives for DEP, DPP, DBP, DPhP, BBP, DHP, DCP and DEHP were measured as 2.5, 2.8, 2.9, 2.6, 3.1, 9.7, 11.1 and 14.8 days, respectively; under anaerobic conditions, respective average half-lives were measured as 33.6, 25.7, 14.4, 14.6, 19.3, 24.1, 26.4 and 34.7 days. In other words, under aerobic conditions we found that DEP, DPP, DBP, DPhP and BBP were easily degraded, but DEHP was difficult to degrade; under anaerobic conditions, DBP, DPhP and BBP were easily degraded, but DEP and DEHP were difficult to degrade. Aerobic degradation rates were up to 10 times faster than anaerobic degradation rates.     

木质素磺酸盐对尿素氮转化与蔬菜硝酸盐积累的影响

通过室内培养与小区蔬菜试验,研究了添加木质素磺酸盐对土壤中尿素氮转化的影响以及对蔬菜硝酸盐污染的控制机理结果表明,经过69h土壤培养,与对照比较,木质素磺酸盐对土壤中尿素水解有较好的抑制作用,土壤中残留尿素态氮含量高于脲酶抑制剂氢醌处理.木质素磺酸盐不仅能降低小区小白菜的硝酸盐含量,而且还可提高维生素C含量,并能提高蔬菜植株体内硝酸还原酶活性,加速N的同化,收获后土壤中脲酶活性较低,NH₄⁺-N仍较高,说明木质素对土壤氮素转化有较好的稳定作用与保肥效果因此,木质素磺酸盐可作为化肥氮素转化抑制剂在控释肥料中应用.     

无人值守AA3连续流动仪测定水和废水中氨氮研究

采用无人值守连续流动分析法对地表水和废水中氨氮进行检测,该方法在0.00~10.0 mg/L范围内线性良好,检出限为0.015 mg/L,相对标准偏差为0.6%~1.4%,实际样品加标回收率为95.0%~105%,精密度和准确度均满足地表水和废水中氨氮测定的要求,有较好的应用推广价值.无人值守连续流动分析法相对于传统的手工方法具有明显的优势:在线蒸馏装置可以完成对水中氨氮的蒸馏提取;节省时间,即使在夜间也能自动工作,分析完成样品后自动清洗管路并关机;试剂使用量少,降低了对环境和分析人员的危害.     

Pre-oxidation and coagulation of textile wastewater by the Fenton process

This paper evaluates the Fenton process, involving oxidation and coagulation, for the removal of color and chemical oxygen demand (COD) from synthetic textile wastewater containing polyvinyl alcohol and a reactive dyestuff, R94H. The experimental variables studied include dosages of iron salts and hydrogen peroxide, oxidation time, mixing speed and organic content. The results show that color was removed mainly by Fenton oxidation. The color removal reached a maximum of 90% at a reaction time of 5 min under low dosages of H2O2 and Fe2+. In contrast, the COD was removed primarily by Fenton coagulation, rather than by Fenton oxidation. The ratio of removal efficiency between Fenton process and ferric coagulation was 5.6 for color removal and 1.2 for COD removal. It is concluded that Fenton process for the treatment of textile wastewater favors the removal of color rather than COD.     

菌藻共生体去除废水中砷初探

研究了菌藻共生体对废水中砷的去除效果。研究发现：培养分离所得菌藻共生体中以小球藻为主，此时菌藻共生体积累砷达７．４７ｇ／ｋｇ干重。在引入菌藻共生体并培养１６ｈ后，其对无营养源的含Ａｓ（Ⅲ）、Ａｓ（Ｖ）的废水除砷率达８０％以上，并趋于平衡；含营养源的Ａｓ（Ⅲ）、Ａｓ（Ｖ）的废水中，菌藻共生体对Ａｓ（Ｖ）的去除率大于Ａｓ（Ⅲ），对Ａｓ（Ｖ）去除率超过７０％，但对Ａｓ（Ⅲ）的去除率也在５０％以上，在除砷     

Construction and comparison of fluorescence and bioluminescence bacterial biosensors for the detection of bioavailable toluene and related compounds

Environmental pollution with petroleum products such as benzene, toluene, ethylbenzene, and xylenes (BTEX) has garnered increasing awareness because of its serious consequences for human health and the environment. We have constructed toluene bacterial biosensors comprised of two reporter genes, gfp and luxCDABE, characterized by green fluorescence and luminescence, respectively, and compared their abilities to detect bioavailable toluene and related compounds. The bacterial luminescence biosensor allowed faster and more-sensitive detection of toluene; the fluorescence biosensor strain was much more stable and thus more applicable for long-term exposure. Both luminescence and fluorescence biosensors were field-tested to measure the relative bioavailability of BTEX in contaminated groundwater and soil samples. The estimated BTEX concentrations determined by the luminescence and fluorescence bacterial biosensors were closely comparable to each other. Our results demonstrate that both bacterial luminescence and fluorescence biosensors are useful in determining the presence and the bioavailable fractions of BTEX in the environment.     

不同温度下约束钢梁的落锤冲击响应分析

研究不同温度和冲击荷载作用下约束钢梁的动力响应问题。利用通用非线性有限元分析程序ANSYS/LS-DYNA,分别模拟了两端固支、一端固支一端轴向弹簧约束的钢梁在不同温度下受到落锤冲击时的动力响应。在温度荷载和冲击荷载联合作用下,分析了位移响应、撞击力时程曲线及冲量等的温度效应。通过撞击力时程曲线分析得出最大撞击力随温度的变化趋势与欧洲规范EC3给出的不同温度下的钢材的屈服强度折减系数的变化趋势相似,钢梁跨中的横向位移随着温度的升高而增加。还分析了高温和冲击荷载联合作用下落锤的撞击速度、不同的质量—速度组合、横向加劲肋对钢梁的变形的影响。     

Temporal dynamics of microcystins in two reservoirs with different trophic status during the early growth stage of cyanobacteria

Environmental Science and Pollution Research - Harmful cyanobacterial blooms are increasing in frequency and severity, which makes their toxic secondary metabolites of microcystins (MCs) have been...     

Heavy metal characteristics in porewater profiles,their benthic fluxes,and toxicity in cascade reservoirs of the Lancang River,China

Environmental Science and Pollution Research - The construction of cascade reservoirs on the Lancang River (the upper Mekong) has an important influence on the distribution and accumulation of...     

页岩气油基钻屑脱油灰渣资源化利用进展

针对页岩气开发过程中产生的油基钻屑在堆放、运输和处理过程中均有可能对环境造成危害的问题,研究油基钻屑脱油灰渣的处置和资源化利用现状。在实际应用中,各种资源化利用技术由于政策、环保标准、经济性等原因,除水泥窑协同处置技术外,很多技术还不能大量推广应用。文章通过系统调研,阐述了各项技术的原理、优缺点及资源化利用所面临的政策障碍、实际应用及二次污染等问题,指出了资源化利用技术在开发过程中需要加强过程污染控制、开展相关政策和标准制定、提高产品高附加值等方面研究。