浅谈我国农田土壤重金属污染现状及修复研究

农田土壤重金属污染导致农作物重金属含量超标,这些重金属随食物链进入人体内,对人体健康造成危害。了解农田土壤重金属污染现状、重金属污染对农作物的危害,以及污染农田的治理修复,对维护人体健康具有重要意义。本文综述了我国农田土壤重金属污染现状,分析了农田土壤重金属污染可能对农作物造成的影响,概括了目前农田土壤重金属污染的主要治理方式,并分析了这些治理方式的差异性和优缺点,对未来农田土壤重金属污染治理的方向作出了展望。为该领域初学者了解该领域研究方向、发展趋势和研究热点提供了指导,也为我国农田土壤重金属污染治理的进一步研究提供参考。     

Characterization of Influence of Manure Handling System and Feeding on the Level of Ammonia Release Using a Simple Method in Cow Houses

The effects of manure handling system and feeding of dairy cows were studied using a simple method to analyse the level of ammonia release in cow stables. Two ratios based on the balances of ammonia and sensible heat, and ammonia and carbon dioxide, respectively, in animal houses were determined and considered to give characteristic levels of the release of ammonia in relation to the animal density independently of the ventilation rate. This required measurements of ammonia, carbon dioxide and temperature with hand-held instruments in the buildings and in outside air. In total, 34 dairy herds were investigated in the south of Sweden. The results clearly demonstrated higher release of ammonia from free stall barn with liquid manure than from conventional tie stall barn with solid manure. There was a clear effect of the content of crude protein, gram per kg dry matter, in the total feed ration on ammonia release in tie stall barn with liquid manure.     

The potential contribution of separation technologies to the management of livestock manure

Separation processes have a distinct role in the management of livestock slurries, but it is important to recognise their limitations. Such technology can direct certain manure components into a small volume of a concentrated stream which is useful for the production of organic products in subsequent processes. Equipment generally falls into systems based either on mechanical screening (which can produce a fibrous and seemingly dry product), filtration processes (producing a cake), or sedimentation leading to a sludge product. Although physical separation can remove up to 80% of the total solids content from livestock manures, this will only include a relatively small part of the soluble nutrient and of the reactive organic matter; this is particularly so where separation is based on screens. The complete removal of all suspended matter (total clarification) of an effluent is theoretically possible by settling — a decanter centrifuge will accelerate the process. This can remove most of the phosphorous, especially if coupled with chemical pre-treatment to raise the pH. However, the clarified stream still retains a significant polluting potential in terms of the residual nitrogen content (as ammonia) and potassium. Only membrane separation can greatly reduce the potassium concentration, but such technology is rarely suitable for the farm situation.     

重庆地区饮用水源地污染现状及防治对策

结合重庆市饮用水源地的水质现状,分析了水质污染的主要原因。为实现重庆市饮用水源地的可持续利用,结合重庆市的实际情况提出了相应的防治对策,为重庆市的环境保护工作提供参考。     

饵料结构对河蟹养殖池塘氮、磷收支和污染强度的影响

通过调查走访和实验分析,比较了3种投饵结构下河蟹(Eriocheir sinesis)养殖池塘在氮、磷收支和实际污染强度方面的差异。1种饵料结构以冰鲜鱼为主,另2种含配合饲料,按照配合饲料使用量不同,分为低于1000kg/hm2组和高于1000kg/hm2组。结果显示,以冰鲜鱼为主的养殖池塘氮收支方程为:苗种3.02kg(1.10%)+饵料272.18kg(98.90%)=渔获物31.92kg(11.60%)+伊乐藻136.18kg(49.48%)+底泥沉积79.53kg(28.90%)+尾水排放27.57kg(10.02%),磷收支方程为:苗种0.26kg(0.42%)+饵料61.02kg(99.58%)=渔获物1.49kg(2.43%)+伊乐藻15.01kg(24.49%)+底泥沉积41.94kg(68.44%)+尾水排放2.84kg(4.63%);配合饲料使用量低于1000kg/hm2的养殖池塘氮收支方程为:苗种4.49kg(2.74%)+饵料159.09kg(97.26%)=渔获物45.55kg(27.85%)+伊乐藻136.18kg(83.25%)+底泥沉积-39.26kg(-24.00%)+尾水排...     

新开河入海河口的水质现状分析

根据对秦皇岛市新开河口实地采集水样 ,进行了重金属、总氮和总磷含量分析 ,发现新开河口水污染严重 ,多超过地表水IV类标准 ,主要污染物为氮、磷和油类 ,其他污染物含量均在II类标准以内 ,河口水体中氮、磷含量均达到水体富营养化危险负荷 ,可见陆源污染是秦皇岛近岸海域富营养化日趋严重、赤潮日趋增多的主要原因     

天津汉沽海域环境质量调查与分析

2009年5月7日到11日在天津汉沽海域进行了海上实际调查,通过采集样品的分析检测,掌握海域环境状况。根据所获资料分析了海水理化指标、叶绿素a和浮游植物的含量及分布特征。结果表明,海域各指标含量离岸递减,近岸高外海低,并且海域环境东部优于西部。同时运用N/P、单因子分析、富营养化指数、有机污染指数、生物评价法分析了汉沽海域环境质量,结果表明汉沽海域环境质量已经受到污染,应加强治理。     

东江湖水环境动态变化及评价

2006年3月至2007年1月对东江湖水质进行了监测和评价.结果表明,东江湖综合污染指数为0.45,水质总体良好,属于地表水的Ⅱ～Ⅲ类,但东江湖各断面水质在洪水前和洪水期差异显著;水质主要受控于重金属镉和总氮、总磷;东江湖周边氮磷污染源数多、面广、量大,洪水引起水体总磷、总氮迅速增大,水色变深,导致水体透明下降;东江湖现处于中营养水平.     

镰刀菌毒素DON和NIV研究进展

对脱氧雪腐镰刀菌烯醇（DON）和雪腐镰刀菌烯醇（NIV）的理化性质、污染状况、毒性作用和检测方法进行了综述,以期为同类研究提供参考。     

唐山附近海域春季表层沉积物重金属含量年际变化及污染评价

根据2006-2015年4个航次对唐山附近海域共70个采样站位的表层沉积物调查资料,分析了沉积物中Hg、Cu、Pb、Cd、Cr、Zn和As 7种重金属的含量和年际变化特征,并利用超标率统计法、地累积指数法和潜在生态风险指数法对其污染状况进行了评价.结果显示,调查海域表层沉积物中重金属含量总体水平较低,除个别站位的Cu和As超过第Ⅰ类标准值外,其他调查站位的重金属含量均符合第Ⅰ类标准.2006-2015年调查海域表层沉积物中7种重金属含量的年际变化略有不同,其中,Cu、Pb、Cd和Zn4种重金属含量相对比较稳定,Hg和Cr的含量表现为先升高后降低的趋势,而As的变化趋势不明显.地累积指数法评价结果显示,7种重金属的地累积指数(Igeo)多年平均值为Hg＞Cd＞Pb＞Cu＞As＞Cr＞Zn;而潜在生态风险评价结果显示,7种重金属的潜在生态风险系数(Eri)多年平均值为Hg＞Cd＞As＞Pb＞Cu＞Cr＞Zn;两种污染评价结果一致,均显示Hg是唐山附近海域表层沉积物的主要污染因子,潜在生态风险最大.综合潜在风险指数(RJ)年际变化范围为44.26-153.18,平均值为89.92,属于低生态风险水平;RI年际变化基本表现为先升高后降低的趋势,表明近年来调查海域表层沉积物重金属的污染状况有所改善.