Source-specific risk assessment for cadmium in wheat and maize: Towards an enrichment model for China

Cadmium (Cd) pollution of agricultural soil is of public concern due to its high potential toxicity and mobility. This study aimed to reveal the risk of Cd accumulation in soil and wheat/maize systems, with a specific focus on the source-specific ecological risk, human health risk and Cd enrichment model. For this we investigated more than 6100 paired soil and grain samples with 216 datasets including soil Cd contents, soil pH and grain Cd contents of 85 sites from China. The results showed that mining activities, sewage irrigation, industrial activities and agricultural practices were the critical factors causing Cd accumulation in wheat and maize cultivated sites. Thereinto, mining activities contributed to a higher Cd accumulation risk in the southwest China and Middle Yellow River regions; sewage irrigation influenced the Cd accumulation in the North China Plain. In addition, the investigated sites were classified into different categories by comparing their soil and grain Cd contents with the Chinese soil screening values and food safety values, respectively. Cd enrichment models were developed to predict the Cd levels in wheat and maize grains. The results showed that the models exhibited a good performance for predicting the grain Cd contents among safe and warning sites of wheat (R² = 0.61 and 0.72, respectively); while the well-fitted model for maize was prone to the overestimated sites (R² = 0.77). This study will provide national viewpoints for the risk assessments and prediction of Cd accumulation in soil and wheat/maize systems.     

苏州河市区段非点污染源及防治对策

通过对苏州河市区段的实地调查，结果认为，苏州河市区段主要非点污染源为垃圾和粪便码头，其次为船泊通行、垃圾堆、装卸吊车以及居民点。文章还提出初步防治对策。     

区域源解析模式的建立

运用数值分类学手段建立了一种迭代的(iterative)、分裂的(divisive)、不加权的(non-weighting)、非交迭(nonoverlapping)的运算程式(IDNN模式),从实测原始数据中提取可近似作为纯源的样品和相应的性状,通过分析这些近似纯源样品及与之关系密切的其它特征样品的采样参数和成分特征可鉴别或识别源的类型,运用化学质量平衡法(CMB)求解受体样品的定量来源.在对模拟数据的验证处理中,IDNN模式显示了初步成功.     

REAUTHORIZING THE CLEAN WATER ACT: LOOKING TO TANGIBLE VALUES1

ABSTRACT: The degree of progress achieved under the 1972 Clean Water Act is reviewed by reference to traditional measures of program implementation, and to evidence of tangible, or “real-world” progress, such as beach closures, drinking water contamination, fishing bans and advisories, species health, and habitat degradation. Significant progress has been made in reducing pollution from point sources, but large point source releases of toxic and other pollutants remain. Little progress has been made in addressing runoff pollution, and in protecting aquatic habitats. Clean Water Act reauthorization should focus on pollution prevention to reduce further the release of toxics by point sources, a new program of mandatory but flexible controls on sources of runoff, and watershed protection programs to promote habitat protection and restoration. Economic factors should be considered in Clean Water Act programs, but must be balanced against scientific and governmental factors as well.     

秦皇岛市环境噪声变化趋势分析与防治对策

以秦皇岛市2001-2010年的噪声监测资料为依据,通过对环境噪声变化趋势的分析,发现秦皇岛市环境噪声源主要为社会生活噪声、交通噪声、工业噪声,并提出了相关防治对策。     

沉积盆地地下水无机氮来源示踪及其演化模式

以我国沉积型盆地三江平原的典型农业区抚远地区为例，采用水化学法和GIS技术分析区域水化学成因作用及无机氮素的污染特征，利用氮氧双稳定同位素分布特征及稳定同位素解析模型（SIAR）确定氮素来源及各污染源贡献比，基于对影响氮素浓度变化的多项因素的认识，建立区域氮素的水化学演化模式.结果表明：研究区地下水中氨氮超标率为56.52%，毫克当量百分数平均值占无机氮总量的55.50%，是地下水无机氮素中污染影响程度最大的指标；土壤有机氮、厩肥污水和氨态化肥是径流补给区氮素的主要污染来源，各污染端元贡献比由大到小依次为40.49%、30.24%和29.27%.地下水补给区是氨氮污染最重的区域，排泄区是硝酸盐氮污染相对严重的区域，氧化还原条件是影响氮素浓度的关键因素；在氮素的时空演化过程中，除二级阶地仍保持天然水化学状态外，一级阶地和漫滩区的氮素浓度均有不同程度的升高.     

中美能源结构的战略分析

通过对世界能源资源储备、能源消费状况和中美能源结构分析,提出各国需要建立能源基金,合理调整能源结构的战略构想。     

由两起事故谈多能源设备的能源隔离措施

分析了两起因能量意外释放导致的伤害事故,制定了具备多能源设备的锁定和挂牌的安全作业流程,并提出预防事故的措施.     

太湖流域农村公众环境意识案例研究

环境意识属上层建筑范畴,对环境行为具有指导意义。针对太湖流域日益严重的农业非点源污染,提高农村公众环境意识是控制该区水污染的主要措施之一。首次选取无锡市大浦镇14个行政村2.7万人为抽样框进行农村公众环境意识调查。结果表明：①居民对水环境污染的原因有了初步的认识,但与实际有明显偏差;②浅层次的局部的“日常生活环保型”环境意识依然存在;③居民在环保行为上为“政府依赖型”,整体参与环保意识不强;④居民获取环保信息渠道单一,政府对主要的信息发布渠道重视不足;⑤2003年该镇居民总支付意愿为55.3～98.2万元。     

东北三省工业废水污染物排放的时空变化规律研究

采用等标污染负荷法和GIS空间分析方法,针对改革开放和产业结构大调整前后的4个典型年份,从工业污染源空间特征出发分析了东北三省工业废水污染物排放的变化趋势,并详细讨论了重点污染物排放的时空演变规律. 结果表明:东北三省工业污染源主要分布在哈大铁路和高速公路沿线以及辽宁省中部及沿海地区,且有不断集中的趋势;工业废水排放总量以及污染物排放总量都呈不断减少的趋势;东北三省主要污染物为挥发酚,COD_Cr,石油类及汞;有机污染物排放量高于无机污染物,其中挥发酚、石油类的主要排放区域变化很大,污染物排放区域转移趋势明显;COD_Cr和汞的主要排放区域变化不大,有新污染城市出现; 20年间东北三省废水排放量比例变化不大,污染物等标污染负荷排名却变化很大.