Occurrence of benzotriazoles (BTRs) in indoor air from Albany,New York,USA, and its implications for inhalation exposure

Despite the widespread use of benzotriazoles as corrosion inhibitors in many household goods, studies on the occurrence of these compounds in indoor air are scarce. In this study, five benzotriazole derivatives were measured in 83 indoor air samples collected from various locations in Albany, New York, USA. Benzotriazoles were found in a majority of the indoor air samples, and the concentrations of their sum in bulk (vapor plus particulate phases) indoor air ranged from below the method limit of quantification to 492 ng·m^?3 (geometric mean: 5.8 ng·m^?3). The highest geometric mean concentration was found in air samples collected in parking garages (155 ng·m^?3), followed by barbershops (13.6), public places (11.5), auto repair shops (5.2), automobiles (4.5), homes (4.5), offices (3.7), and laboratories (2.8). Inhalation exposure to benzotriazoles was calculated on the basis of the measured geometric mean concentrations and air inhalation rate. The highest exposure dose was found for teenagers, with a geometric mean inhalation exposure dose of 79 ng·day^?1. The body-weight normalized exposure dose, however, was the highest for infants, at 3.2 ng·(kg bw)^?1·day^?1.     

颗粒状污泥活性炭流化床吸附处理含铜矿山废水

以城市污水处理厂活性污泥为原料,通过高温热解制备了颗粒状污泥活性炭吸附剂。在自制的流化床吸附装置上研究了该吸附剂对含铜矿山废水的吸附处理效果。实验结果表明：在初始废水pH6、吸附剂加入量15g/L、废水循环流量6.0L/min、吸附时间120min的最佳吸附条件下,废水中Cu²⁺去除率达98.2%。     

Kinetics of peanut shell pyrolysis and hydrolysis in subcritical water

Biomass is recognized as an important solution to energy and the environmental problems related to fossil fuel usage. The rational utilization of biomass waste is important not only for the prevention of environmental issues, but also for the effective utilization of natural resources. Pyrolysis and hyrolysis in subcritical water are promising processes for biomass waste conversion. This paper deals with hydrolysis and pyrolysis of peanut shells. Hydrolysis and pyrolysis kinetics of peanut shell wastes were investigated for the in-depth exploration of process mechanisms and for the control of the reactions. Hydrolysis kinetics was conducted in a temperature range of 180–240 °C. A simplified kinetic model to describe the hydrolysis of peanut shells was proposed. Hydrolysis activation energy as well as the pre-exponential factor was determined according to the model. The target products of peanut shell hydrolysis, reducing sugars, can reach up to 40.5 % (maximum yield) at 220 °C and 180 s. Pyrolysis characteristics were investigated. The results showed that three stages appeared in this thermal degradation process. Kinetic parameters in terms of apparent pyrolysis activation energy and pre-exponential factor were obtained by the Coats–Redfern method.     

Simazine biodegradation and community structures of ammonia-oxidizing microorganisms in bioaugmented soil: impact of ammonia and nitrate nitrogen sources

The objective of the present study was to investigate the impact of ammonia and nitrate nitrogen sources on simazine biodegradation by Arthrobacter sp. strain SD1 and the community structures of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in non-agricultural soil. Soil microcosms with different treatments were constructed for herbicide biodegradation test. The relative abundance of the strain SD1 and the structures of AOA and AOB communities were assessed using quantitative PCR (q-PCR) and terminal restriction fragment length polymorphism (TRFLP), respectively. The co-existence of two inorganic nitrogen sources (ammonia and nitrate) had certain impact on simazine dissipation by the strain SD1. Bioaugmentation could induce a shift in the community structures of both AOA and AOB, but AOA were more responsive. Nitrogen application had significant impacts on AOA and AOB communities in bioaugmented soils. Moreover, in non-bioaugmented soil, the community structure of AOA, instead of AOB, could be quickly recovered after herbicide application. This study could add some new insights towards the impacts of nitrogen sources on s-triazine bioremediation and ammonia-oxidizing microorganisms in soil ecosystem.     

Modeling cold soak evaporative vapor emissions from gasoline-powered automobiles using a newly developed method

ABSTRACT

Volatile organic compounds (VOCs) evaporate and vent from a vehicle’s fuel tank to its evaporative control system when the vehicle is both driven and parked. VOCs making it past the control system are emissions. Driving and parking activity, fuel volatility, and temperature strongly affect vapor generation and the effectiveness of control technologies, and the wide variability in these factors and the sensitivity of emissions to these factors make it difficult to estimate evaporative emissions at the macro level. Established modeling methods, such as COPERT and MOVES, estimate evaporative emissions by assuming a constant in-use canister condition and consequently contain critical uncertainty when real conditions deviate from that standard condition. In this study, we have developed a new method to model canister capacity as a representative variable, and estimated emissions for all parking events based on semi-empirical functions derived from real-world activity data and laboratory measurements. As compared to chamber measurements collected during this study, the bias of the MOVES diurnal tank venting simulation ranges from ?100% to 129%, while the bias for our method’s simulation is 1.4% to 8.5%. Our modeling method is compared to the COPERT and MOVES models by estimating evaporative emissions from a Euro-3/4/5 and a Tier 2 vehicle in conditions representative for Chicago, IL, and Guangzhou, China. Estimates using the COPERT and MOVES methods differ from our method by ?56% to 120% and ?100% to 25%, respectively. The study highlights the importance for continued modeling improvement of the anthropogenic evaporative emission inventory and for tightened regulatory standards.

Implications: The COPERT and MOVES methodologies contain large uncertainties for estimating evaporative emissions, while our modeling method is developed based on chamber measurements to estimate evaporative emissions and can properly address those uncertainties. Modeling results suggested an urgent need to complete evaporative emissions inventories and also indicated that tightening evaporative emission standards is urgently needed, especially for warm areas.     

Agricultural pesticide residues of farm runoff in the Okanagan Valley, British Columbia, Canada

The objectives of this study were to determine environmental occurrence and concentrations of selected currently-used-pesticides and some transformation products in agricultural farms in the Okanagan Valley (OKV), and to conduct a simple risk assessment of environmental pesticides levels detected in OKV on non-target aquatic organisms. The OKV is the tree fruit country of the Province of British Columbia where considerable amount of pesticides are applied annually. Water, sediment and soil samples were collected at eleven sites in early June and late September following rainfall events and/or extended periods of irrigation from drainage ditches and/or from small streams. Undisturbed reference sites were also sampled. Study results showed that forty of the eighty chemicals analyzed, including organochlorine, nitrogen-containing and organophosphate pesticides commonly used for OKV crops, were detected in runoff and small stream water samples. Among which, endosulfan-sulfate was the most frequently detected chemical. Also, azinophos-methyl (0.699-25.5 ng/L), diazinon (0.088-214 ng/L) exceeded, and α-, β- endosulfan, endosulfan sulphate approached the guidelines for the protection of aquatic life.     

高分子量高纯度阳离子聚丙烯酰胺的合成

以丙烯酰胺与丙烯酰氧乙基三甲基氯化铵为单体,在复合引发剂的作用下,选择水溶液共聚法合成高分子量与高纯度阳离子型聚丙烯酰胺(CPAM)。实验表明,有机偶氮引发剂A用量0.5‰、氧化还原引发剂用量0.45‰、还原剂与氧化剂摩尔比2∶1、反应体系pH为4与反应时间5 h条件下,CPAM分子量为1 042万,且溶解性好。通过对聚合物残单含量影响因素添加剂用量、反应时间的研究,结果表明,添加剂EDTA和增溶剂D对残留AM含量影响小,而苯甲酸钠对聚合物残留AM的含量影响显著;延长反应时间至7 h,残单含量可降低至0.27%,CPAM的纯度高。通过与国内外3种同类型产品进行对比,结果表明,自制产品的分子量明显高于其他产品,且残单含量比国内产品降低了50%～75%。     

磁絮凝处理废水工艺条件的响应曲面法优化研究

以聚硅硫酸铁(PFSS)为絮凝剂、磁流体为磁种,采用磁絮凝法处理模拟废水。在正交实验基础上,利用Matlab软件进行响应曲面分析,研究磁絮凝法处理模拟废水的各因素间具有的交互作用关系。回归拟合结果表明最佳工艺条件为:PFSS加入量36.8g/L,模拟废水pH7.4,磁种加入量14.7mg/L,搅拌转速266r/min。在最佳工艺条件下进行实验,TP去除率为97.70%。     

城市自来水中挥发性有机氯污染物检测及健康风险评价初步研究

水质安全是饮用水安全的重中之重,直接关系到人体健康。采用健康风险评价模式,对某市饮用水进行了分析和评价。研究结果表明,该市通过饮水途径引起的非致癌健康风险中四氯化碳最大,三氯甲烷次之,两者风险水平在10-5～10-6,远低于美国环境保护署推荐的最大可接受风险水平。通过饮水途径所致健康风险中,四氯乙烯所引起的致癌风险最大(1.2×10-8),但远远低于美国环境保护署推荐的通过饮水途径最大可接受风险水平(5×10-5)。根据美国环境保护署的推荐值,初步认为目前该市饮用水中挥发性有机污染物不会对人体产生明显的健康危害。