Leaching of styrene and other aromatic compounds in drinking water from PS bottles

Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene （PS） bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as ＂purge and trap＂ and analysed by gas chromatograph-mass spectrometer （GC/MS）. Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks.     

Water quality characteristics along the course of the Huangpu River （China）

Huangpu River is about 114.5 km from upriver Dianfeng to downriver Wusong,near the estuary of the Yangtze River.It plays a key role in supplying water for production,life,shipment and irrigation.With the industrial development,the pollution of the Huangpu River has become serious recently.The biological oxygen demand (BOD),total nitrogen (TN),total phosphorus (TP),oil,phenol and suspended solids (SS) were lower in the upstream sites than in the downstream sites,indicating pollutants being input along its course. Water quality was the worst in the Yangpu site,near the center of Shanghai City.Dissolved oxygen (DO) content was less than 2 mg/L in the site of Yangpu in July.Among relations between thirteen characteristics,relations between BOD,DO,TN,TP,NH_4~ -N, NO_3~--N and the count of total bacteria or Escherichia coli were significant and interdependent.Inner relationships between these main characteristics in the Huangpu River were studied.High nutrient concentration led to growth of microorganisms,including E.coli. Degradation of organic matters and respiration of bacteria made oxygen concentration decreased in the water body,and DO was a key factor for nitrification-denitrification process of nitrogen.In the Yangpu site,DO was decreased to less than 3.0 mg/L with BOD higher than 7.5 mg/L in May and July.Low DO concentration will decrease nitrification rate.Nitrification need at higher DO value than other organic substrate oxidation.Consequently,river water contains low NO_3~--N values with high amounts of TN and NH_4~ -N there.This will block the self-purification of surface water,by decreasing the rate of nitrification-denitrification transformation process in the water body.     

Effects of nitrate concentration in interstitial water on the bioremediation of simulated oil-polluted shorelines

Nutrient addition has been proved to be an effective strategy to enhance oil biodegradation in marine shorelines.To determine the optimal range of nutrient concentrations in the bioremediation of oil-polluted beaches,nitrate was added to the simulated shoreline models in the initial concentration of 1,5 and 10 mg/L.Whenever the NO3-N concentration declined to 70% of its original value, additional nutrients were supplemented to maintain a certain range.Results showed adding nutrients increased the oil biodegradation level,the counts of petroleum degrading bacteria(PDB)and heterotrophic bacteria (HB),and the promoted efficiency varied depending on the concentration of nitrate.Oil degradation level in 5 mg/L(NO_3-N)group reached as much as 84.3% accompanied with the consistently highest counts of PDB;while in 1 mg/L group oil removal efficiency was only 35.2%,and the numbers of PDB and HB were relatively low compared to the other groups supplemented with nutrients.Although counts of HB in the 10 mg/L group were remarkable,lower counts of PDB resulted in poorer oil removal efficiency (70.5%) compared to 5 mg/L group.Furthermore,it would need more NO_3-N(0.371 mg)to degrade 1 mg diesel oil in the 10 mg/L group than in the 5 mg/L group(0.197 mg).In conclusion, Nitrate concentration in 5 mg/L is superior to 1 and 10 mg/L in the enhancement of diesel oil biodegradation in simulated shorelines.     

A quantitative water resource planning and management model for an industrial park level

This paper introduces an integrated water management model at the industrial park level. It suggests four approaches to water management: first, direct water reuse among users; second, water reuse among users by blending with freshwater; third, water reuse between users and a wastewater treatment plant; and fourth, groundwater recharge by reclaimed wastewater or other feasible applications in order to optimize the overall water efficiency. The model results in a comprehensive management methodology for optimizing water resources within an industrial park, seeking potential water reuse among industries, and incorporating the size and cost of reclaimed wastewater delivery systems. A case study is employed to test the model’s feasibility. An economic analysis of the optimized water use network is also carried out, showing the potential water and cost savings.     

三峡库区坡耕地利用与水土保持种植制

三峡库区耕地资源十分有限,且坡耕地占有相当大的比重,陡坡地多,在不良的耕作方式下肥力低下,水土流失十分严重在分析三峡库区自然条件与坡耕地资源特点的基础上,讨论了坡耕地种植制度与土壤侵蚀的关系,提出通过合理搭配作物种类进行多熟制间套作,一年生农作物与多年生经饲作物间作及农作物与木本植物等高间作等手段来建立坡耕地水土保持种植制,从而达到减轻土 蚀之目的。     

湖泊型水源地管理研究——以苏州市太湖水源地为例

饮用水安全是最大的民生工程,也是自然资源管理研究的热点。基于实地调研、部门访谈和制度条文的梳理与分析,以苏州市太湖水源地为例研究湖泊型水源地管理体制。研究表明：我国水源地管理由国家、省、市、县的法律法规、规章和规范性文件构成相对完善的制度体系,具有水资源和水环境分割管理、流域管理和行政区管理交错的制度特征,初步具备了综合管理的架构;水源保护缺乏流域管治的思维,农村面源污染治理制度支撑不足;在管理手段上以命令控制型手段为主,经济激励与公众参与不足。建立水源地综合管理协调机制,完善经济激励手段,推进公众参与,实施水源地管理共同责任机制将有利于提高水源地管理效率     

鄱阳湖湿地现状问题与未来趋势

近年来鄱阳湖秋冬季水文呈干枯态势,湿地生态系统及其关键因子也发生了变化。如何合理保护和利用鄱阳湖湿地引起各方关注。系统综述了鄱阳湖湿地生态系统在水文、江湖关系、水质、水鸟栖息地、渔业资源等方面存在的问题,梳理了引起这些问题的外部和内部因素。针对"一切照常"和"水位调控"两种情景,预测了湿地未来的变化趋势,并指出了当前研究中的不确定性问题。研究认为:鄱阳湖秋冬季的低枯水位,对水质、湿地植被、水鸟栖息地以及鱼类食物资源和"三场"(即:产卵场、洄游通道、索饵场)产生了一定不利影响。建议通过模型模拟和情景预测来分析不同调控方案的影响效果,优化调控方案、将生态系统的负面影响降到最低。     

大型水利水电工程实施占用耕地补偿制度的思考

本文在分析长江三峡工程用地特点的基础上。对大型水利水电工程实施耕地补偿制度中的问题和困难进行调查研究，认为应从新的视角来认识大型水利水电工程的耕地占补平衡问题。进而探索耕地补偿制度实施的新途径和新方式。应在耕地总量动态平衡政策适当调整的基础上．将“以地补地”和“缴费补地”的方式相结合。既通过土地整理．在提商土地质量的前提下增加耕地的有效面积：又要落实耕地开垦费．扶持库区的土地整理。从而使库区的耕地占补制度顺利实施。     

河流综合水质评价方法比较研究

为探讨综合水质评价结论的科学合理性,对典型的7种河流综合水质评价方法,包括单因子评价法、污染指数法、模糊评价法、灰色系统评价法、层次分析法、人工神经网络法、水质标识指数法,在归类分析其特性的基础上,针对代表性的评价样本,进行了综合水质评价比较研究。主要结论为：①单因子评价法以最差水质指标所属类别作为综合水质类别,评价结论表现为过保护;②污染指数法能够直观判断综合水质是否达到功能区目标,但是不能判断综合水质类别;③对模糊数学法、灰色系统评价法、层次分析法、BP人工神经网络法和水质标识指数法等5种典型评价方法,当综合水质为Ⅰ~Ⅴ类水情形时,这几种方法评价结论基本一致,证明这5种典型评价方法对Ⅰ~Ⅴ类水的评价结论具有科学合理性;④当综合水质为劣Ⅴ类水时,模糊数学法、灰色系统评价法、层次分析法、BP人工神经网络法的评价结论偏保守,而水质标识指数法解决了劣Ⅴ类水质的连续性描述问题,能够对劣Ⅴ类水进行科学合理评价,并对Ⅰ~Ⅴ类水、劣Ⅴ类水不黑臭、劣Ⅴ类水黑臭进行全面、科学合理的定性与定量评价.     

丰水期鄱阳湖氮磷含量变化及来源分析

通过系统测定丰水期鄱阳湖湖水、主要支流水、长江水及部分农田水、地下水及城市污水的氮磷含量,对其氮磷含量变化及来源进行了分析,结果表明,鄱阳湖水体中主要的氮素形式是硝酸盐氮（090 mg/L）,赣江是其主要贡献者。鄱阳湖五大支流氮磷含量存在着较大的差异,赣江NO-3 N含量明显高于鄱阳湖其它主干流,而NH+4 N和TN含量以饶河的最高,TP以信江的最高。农田水、城市废水以及地下水含有较高的氮磷含量,是鄱阳湖及其五大支流氮磷的主要来源。农田水TN和TP含量最高,分别为1347、2863 mg/L。高含量的NO-3 N（735 mg/L）和NH+4 N（548 mg/L）分别出现在地下水和城市污水中。鄱阳湖水体氮负荷较大,N/P比值远大于7〖DK〗∶1。受滞留区及赣江和修水补给的影响,鄱阳湖主河道氮含量变化从上游至下游呈总体上升趋势。鄱阳湖湖体氮含量以下游最高,滞留区次之,上游主河道最低,TP含量呈相反的趋势变化。底层沉积有机物的降解和扰动导致鄱阳湖水体底层NO-3 N、NH+4 N、TN、TP的含量高于表层。