Disinfection by-product formation and mutagenic assay caused by preozonation of groundwater containing bromide

Brominated organic and inorganic by-products are generated during ozonation of groundwater containing high bromide concentrations. This study measured concentrations of bromate, bromoform, bromoacetic acids, bromoacetonitriles, bromoacetone, 2,4-dibromophenol and aldehyde generated by ozonation. The potential mutagenicity of ozonated waters was assessed using the Ames and Microtox tests. Test results for the 18 ozonated groundwater samples demonstrate that bromate formation is associated with high pH, bromide and alkalinity content, low levels of dissolved organic carbon (DOC) and ammonia, and low alkalinity. Brominated organic by-products were correlated with high bromide ion and natural organic matter content, and low ammonia concentrations. The Ames test results demonstrate that all extracts from ozonated water have mutagenic activity; however, the 18 raw groundwater samples had no mutagenicity. The Microtox test results also show that the ozonated water samples were highly toxic. Generally, both bromide and DOC content promoted the formation of ozonation by-products and mutagenicity. Controlling of bromide and DOC concentrations is an effective method of reducing potential by-product formation and eliminating mutagenicity problems associated with groundwater ozonation.     

广州PM2.5污染特征及影响因素分析

对广州市2008—2010年PM_2.5质量浓度、影响因素数据资料进行整理统计,通过定性分析、定量计算以及对各物理量之间的相互作用过程研究,得出PM_2.5质量浓度变化特征和各影响因素之间的关系。结果表明,PM_2.5质量浓度变化呈现夏季和非夏季2种典型的季节性特征,夏季月平均值0.049 mg/m³,主要分布在0.03～0.05 mg/m³,非夏季月均值为0.063 mg/m³,分布于0.05～0.08 mg/m³之间;夏季、非夏季PM_2.5质量浓度超标率(采用美国EPA标准)分别为70.7%、77.8%,质量标准2倍、3倍以上出现的概率都表现出明显的季节性差异;PM_2.5与温度正相关,和其他因素负相关,其中与能见度相关性最大,其次是温度、风速,与降雨量相关性最差,与气压、相对湿度相关系数季节性特征显著。     

中波台电磁辐射叠加影响估算及与实测对比分析

以某中波电台为例,对多个不同频率的中波发射台同时运行时复合场强进行理论估算,对电磁辐射叠加影响进行分析,并将理论估算值与该台电磁辐射环境现状监测数据进行比对,得出距离发射塔近,复合场强理论估算值高于实测值,距离较远理论估算值与实测值较接近等结论。     

Tolerance values of benthic macroinvertebrates for stream biomonitoring: assessment of assumptions underlying scoring systems worldwide

Tolerance values (TVs) based on benthic macroinvertebrates are one of the most widely used tools for monitoring the biological impacts of water pollution, particularly in streams and rivers. We compiled TVs of benthic macroinvertebrates from 29 regions around the world to test 11 basic assumptions about pollution tolerance, that: (1) Arthropoda are < tolerant than non-Arthropoda; (2) Insecta < non-Insecta; (3) non-Oligochaeta < Oligochaeta; (4) other macroinvertebrates < Oligochaeta + Chironomidae; (5) other macroinvertebrate taxa < Isopoda + Gastropoda + Hirudinea; (6) Ephemeroptera + Plecoptera + Trichoptera (EPT) < Odonata + Coleoptera + Heteroptera (OCH); (7) EPT < non-EPT insects; (8) Diptera < Insecta; (9) Bivalvia < Gastropoda; (10) Baetidae < other Ephemeroptera; and (11) Hydropsychidae < other Trichoptera. We found that the first eight of these 11 assumptions were supported despite regional variability. In addition, we examined the effect of Best Professional Judgment (BPJ) and non-independence of TVs among countries by performing all analyses using subsets of the original dataset. These subsets included a group based on those systems using TVs that were derived from techniques other than BPJ, and groups based on methods used for TV assignment. The results obtained from these subsets and the entire dataset are similar. We also made seven a priori hypotheses about the regional similarity of TVs based on geography. Only one of these was supported. Development of TVs and the reporting of how they are assigned need to be more rigorous and be better described.     

Bioaccumulation of zinc,lead, copper,and cadmium from contaminated sediments by native plant species and Acrida cinerea in South China

This research was conducted to search and identify spontaneously growing heavy metal-tolerant plant species that are potentially useful for phytoremediation in contaminated sediment. Five sites were selected for collection of plants growing on polluted shore (river bank) sediment of the Xiang River, China. The concentrations of Zn, Pb, Cu and Cd in plants, sediments, and grasshoppers were determined using flame atomic absorption spectrophotometer (AAS700, Perkin-Elmer, USA). Considering translocation factor and bioaccumulation factor, Rumex crispus (Polygonaceae), Rumex dentatus (Polygonaceae), and Lagopsis supina (Labiatae) could be potentially useful for phytostabilization of metals. R. crispus can be considered potentially useful for phytoextraction of Cd. In light of the biomagnification factors, grasshoppers are deconcentrators for Pb and Cd, microconcentrators for Zn and macroconcentrators for Cu to the plants, respectively. To the best of our knowledge, the present study is the first report on Zn, Pb, Cu and Cd accumulation in R. crispus and L. supina, providing a pioneer contribution to the very small volume of data available on the potential use of native plant species from contaminated sediments in phytostabilization and phytoremediation technologies.     

天津市中心城区集中供应管网末梢水的抗生素耐药基因污染特征研究

为了研究天津市中心城区集中供应管网末梢水的抗生素耐药基因(antibiotic resistance genes,ARGs)污染特征,采集了天津市中心城区6个采样点的管网末梢水样,分别采用微孔滤膜正压过滤法及核酸吸附-洗脱法富集水中细菌和胞外核酸后,利用实时定量PCR技术对15种胞内ARGs和胞外ARGs进行定量检测....     

Age and contributing factors to unlicensed teen motorcycling

This study aims to examine the initial age when teenagers engage in unlicensed motorcycling in Taiwan and the factors contributing to their unlicensed behavior. Data were collected from the retrospective experience of a cohort of senior high school students and a Cox regression model was applied. The results indicated that an estimated 63.4% of the students had experienced riding before the legal age of 18 years. Contributing factors such as whether the students were in a vocational senior high school, male, and in households with higher motorcycle ownership rates led to an earlier riding age; in contrast, a higher degree of parental monitoring, fewer motorcycles in the household, living in Greater Taipei, and an increase in the bus density in the district delayed the ages of beginning motorcycling. The higher minimum licensing age of 18 in Taiwan has caused a debate about its effectiveness because of the high prevalence of unlicensed teenage riding. Measures such as parental monitoring, power- or speed-limited mopeds, training programs, and no duo-passengers should be carefully examined if a policy is to be made on lowering the age limit of motorcycling.     

Cell phone recycling experiences in the United States and potential recycling options in Brazil

This paper presents an overview of cell phone recycling programs currently available in the United States. At the same time, it also provides analyses of the current recycling situation and possible recycling alternatives for Brazil. Although there are several recycling options in the United States, collection rates are still only 10% of all potential devices because customers are not aware of these possibilities. The whole system is financially based on reselling refurbished cell phones and recycled materials to developing countries which represent an effective and strong market. Several recyclers offer funds to collection partners who are either charities or who work with charities while obtaining the materials that they need in order to run their operations. A mobile phone recycling system for Brazil considering the United States experience and the Extended Producer Responsibility (EPR) principle is suggested. A deposit/refund/advance-recycling fee is proposed which might be implemented as a voluntary industrial initiative managed by PRO Brazil, a producer responsibility organization. One widespread public–private agreement will integrate all mobile phone stakeholders, and environmental education actions and promotional events will promote citizen’s participation.     

Uptake of metals by food plants grown on soils 10 years after biosolids application

Potentially hazardous trace elements such as Cd, Cu, Cr, Ni and Zn are expected to accumulate in biosolids–amended soil and remain in the soil for a long period of time. In this research, uptake of metals by food plants including cabbage, carrot, lettuce and tomato grown on soils 10 years after biosolids application was studied. All the five metals were significantly accumulated in the biosolids-amended soils. The accumulation of metal in soil did not result in significant increase in concentrations of Cu, Cr and Ni in the edible plant tissues. However, the Cd and Zn concentrations of the edible tissues of plants harvested from the biosolids receiving soils were significantly enhanced in comparison with those of the unaffected soils. The plant uptake under Greenfield sandy loam soil was generally higher than those under the Domino clayey loam soil. The metal concentration of edible plant tissue exhibited increasing trends with respect to the concentrations of the ambulated metals. The extents of the increases were plant species dependent. The indigenous soil metals were absorbed by the plants in much higher rates than those of the biosolids–receiving soils. It appeared that the plant uptake of the indigenous soil-borne metal and the added biosolids-borne metals are independent of one another and mathematically are additive.