Effects of anthropogenic activities on chemical contamination within the Grand Canal, China

Contamination of nutrients and heavy metals within aquatic system is of great concern due to its potential impact on human and animal health. The Grand Canal of China, the largest artificial river in the world, is of great importance in supplying water resource, transporting cargo, and recreating resident, as well as great historical heritage. This study assessed and examined the impact of human activities on characters of contamination distribution within the section of the Canal in Taihu watershed. Physicochemical parameters of surface water quality were determined monthly from the year 2004 to 2006 at 11 sites that were influenced by different anthropogenic activities along the Canal. Moreover, contaminations at surface sediments (20 cm) at the same locations were also analyzed in September 2006. Results showed that the Canal had been seriously polluted, which was characterized with high spatial variations in contaminations distribution. The sites influenced mainly by industry and urbanization showed higher contents of nutrients and lower levels of dissolve oxygen than other sites. Concentrations of nitrogen at all studied sites exceeded the worst level of surface water quality according to the National Criterion of Surface Water Quality, China, with the average values varying from 2.27 to 10.34 mg/L. Furthermore, the site influenced mainly by industry (i.e., Site 4) presented the highest contents of cadmium (3.453 mg/kg), chromium (196.87 mg/kg), nickel (87.12 mg/kg), zinc (381.8 mg/kg), and copper (357.32 mg/kg). While sites in vicinity to cities had presented relatively higher contents of metals, especially for the site located downstream of Changzhou City (Site 3) had presented the highest contents of mercury (1.64 mg/kg) and lead (197.62 mg/kg). Copper at Sites 2 to 6, Nickel at Sites 2 to 9 except for Site 7, chromium, lead, and zinc at Sites 3 to 6 had exceeded New York State Department of Environmental Conservation (NYSDEC) Severe Effect Level (SEL). By multivariate statistical, nutrient variables, companied with V-phen, had contributed the most variation of water quality, while nutrient and metals had explained the most part of total variance of contaminations in sediment. This study indicated that the canal had been polluted severely and urgently need to control.     

生活垃圾生物好氧预处理技术研究

以快速降低含水率、提高生活垃圾热值为研究目的,利用工程用堆肥料仓作为试验平台,通过控制进仓物料、堆高、通风量、翻堆等反应条件进行生物干化过程,研究有机物的降解情况以及含水率与热值的变化规律.试验结果表明,以原生垃圾为进料,堆高1.5m,通风量0.32 m3/(min·m3),反应进行到第4天进行翻堆,生活垃圾中水分去除率达到16％,热值可提高到5376 kJ/kg.     

The formation kinetics and control of biofilms by three dominant fungi species isolated from groundwater

Filamentous fungi can enter drinking water supply systems in various ways, and exist in suspended or sessile states which threatens the health of individuals by posing a high risk of invasive infections. In this study, the biofilms formation kinetics of the three genera of fungal spores, Aspergillus niger (A. niger), Penicillium polonicum (P. polonicum) and Trichoderma harzianum (T. harzianum) isolated from the groundwater were reported, as well as the effects of water quality parameters were evaluated. In addition, the efficiency of low- concentrations of chlorine-based disinfectants (chlorine, chlorine dioxide and chloramine) on controlling the formation of fungal biofilms was assessed. The results showed that the biofilms formation of the three genera of fungi could be divided into the following four phases: induction, exponential, stationary and sloughing off. The optimum conditions for fungal biofilms formation were found to be neutral or weakly acidic at 28 °C with rich nutrition. In fact, A. niger, P. polonicum, and T. harzianum were not observed to form mature biofilms in actual groundwater within 120 hr. Carbon was found to have the maximum effect on the fungal biofilms formation in actual groundwater, followed by nitrogen and phosphorus. The resistance of fungal species to disinfectants during the formation of biofilms decreased in the order: A. niger > T. harzianum > P. polonicum. Chlorine dioxide was observed to control the biofilms formation with maximum efficiency, followed by chlorine and chloramine. Consequently, the results of this study will provide a beneficial understanding for the formation and control of fungal biofilms.     

政府推动型城镇化对企业污染排放的影响研究

现阶段，资源过度消耗与环境恶化成为中国经济与社会可持续发展的障碍。虽然现有研究从多方面探究了环境污染的治理机制，但对政府推动型城镇化这一重要的宏观政策的关注不足。本文以中国工业企业为研究样本，利用撤县设区改革的准自然实验构建双重差分模型，考察政府推动型城镇化对企业污染排放的影响。实证结果显示，撤县设区改革显著地减少了原县辖区内企业的污染排放量，即政府推动型城镇化对企业污染排放具有“治理效应”。异质性分析发现，撤县设区改革对企业污染排放的“治理效应”来源于主动推动型撤县设区而非被动实施型撤县设区；相比于在非重污染行业的企业以及隶属于县级以上的企业中，撤县设区改革对企业污染排放的“治理效应”在重污染行业的企业以及隶属于县级以下的企业中更强。影响机制分析发现，撤县设区改革后，原县级政府的财政收入显著下降、基础建设性财政支出显著减少而民生性财政支出显著增加，说明撤县设区后，原县级政府财政收入的经济激励弱化，财政支出目标亦从基础设施建设转变为提供公共服务，从而有助于治理企业污染排放问题。     

连云港市冬季霾污染成因分析及应急管控效果评估

针对2022年1月5—14日连云港发生的细颗粒物（PM_2.5）连续污染事件（PM_2.5超标共计5 d），基于常规空气质量参数、气象要素、颗粒物组分参数等数据资料，系统分析了污染期间PM_2.5时空变化特征及污染成因，结合大气化学与天气预测模式（WRF Chem）和敏感性试验方法，定量评估了应急减排措施对连云港各区县PM_2.5浓度的影响。结果表明，5 d超标日中有3 d为轻度污染，2 d为中度污染，全市PM_2.5浓度呈现先上升后下降的趋势。不利的气象条件（静稳、小风、高湿）、本地排放（机动车尾气、工业工艺源）和二次生成共同导致了PM_2.5污染的发生。实施黄色预警管控后，ρ（PM_2.5）平均值下降了4.6μg/m³，降幅为5.2%，其中东海县和灌云县ρ（PM_2.5）的降幅最大，分别为6.1%和8.3%，同时污染天ρ（PM_2.5）峰值平均下降了9.4μg/m³（6.0%）。通过PM_2.5过程分析方法发现，应急减排导致人为排放、化学过程和背景浓度对近地面ρ（PM_2.5）正贡献的减少量要显著大于垂直混合、区域输送和对流过程负贡献的增加量。