用清洁生产的理念防治农业污染的初步探讨

农业发展面临的农业污染问题,已成为制约农业可持续发展的＂瓶颈＂.农业污染问题已经成为影响农村经济发展,以及农村社会和谐发展的重要因素之一.在论述农业清洁生产涵义的基础上,探讨了农业清洁生产防治农业污染问题.以新疆绿洲农业为例,论述了农业污染现状及发展农业清洁生产的必要性,分析探讨了发展农业清洁生产存在的问题和障碍,并提出了对策和建议.     

樊庆生红球菌菌剂制备优化及其重金属修复促进效果研究

目前,土壤重金属污染形势严峻,而微生物辅助植物修复的措施以其绿色友好的特性备受关注,其中,研发高效的微生物菌剂对提高修复效率至关重要.针对一种能代谢植物激素脱落酸（ABA）的微生物—樊庆生红球菌（Rhodococcus qingshengii）进行菌剂制备研究,并验证其对超积累植物东南景天提取重金属镉（Cd）、铜（Cu）、镍（Ni）和锌（Zn）能力的强化效果.结果表明,该菌种制备优化条件为：80%麦麸∶15%锯末∶5%活性炭;料水比1∶2、pH=9;接菌量40%;培养温度30℃、培养时间3 d、烘干温度40℃.优化后,固体菌剂有效活菌数可达2×10¹²CFU·g^-1,与土壤混合后其有效活菌数峰值达1×10¹¹CFU·g^-1,是接种相同活菌数液体菌剂的4倍,30 d保有的有效活菌数是液体菌剂的23倍.与未配施的空白相比,该菌剂配施于不同重金属污染土壤中,可使东南景天的Cd含量提高110%～260%,Ni和Zn含量分别提高约100%和90%;生物富集因子（BCF）则提高50%～500%,转运系数（TF）...     

鄱阳湖河湖交错区软体动物重金属富集与迁移特征分析

河湖交错区是鄱阳湖流域重金属污染物进入湖泊的主要通道,也是重金属富集的场所.本文通过在鄱阳湖河湖交错区采集软体动物样品,分析样品的肌肉和内脏中铁（Fe）、锰（Mn）、铜（Cu）、锌（Zn）、铬（Cr）、镍（Ni）、砷（As）、镉（Cd）、铅（Pb）和锑（Sb）的含量,利用生物-沉积物累积因子和碳氮稳定同位素对鄱阳湖软体动物重金属的富集特征及营养结构和食源关系进行研究,并利用综合目标危险系数进行健康风险评估.结果表明：①鄱阳湖软体动物重金属含量存在显著的种间和组织间的差异,且受体长体重的稀释作用,与所在栖息地的关系不大,但与区域背景环境存在明显的对应关系,均低于水产限量标准值.软体动物对重金属Cu、Zn和Cd具有明显的富集能力,蚌（圆顶珠蚌、三角帆蚌、背瘤丽蚌和褶纹冠蚌）易从环境中富集更多的Mn和Cd,而螺（铜锈环棱螺和大沼螺）则易富集Cu和Zn;②软体动物δ¹³C值为-29.84‰~-21.13‰,δ¹⁵N值为4.09‰~11.51‰,螺和蚌存在明显不同的食物来源.软体动物中的重金属并不随δ¹⁵N值的变化表现出显著的改变,但与δ¹³C值存在显著的线性关系;其中Cu和Zn与δ¹³C值表现为显著的正相关关系,而Mn、Cr、As、Cd、Pb和Sb表现为显著的负相关关系;③健康风险评估结果表明,不论是成人还是儿童,综合目标危险系数（TTHQ） 均大于1,表明鄱阳湖河湖交错区软体动物重金属的富集会对人群食用产生较为显著的健康风险,其中Mn和As是主要的贡献者,且食用蚌的风险略高于螺.研究结果可为鄱阳湖水生态安全、水生生物多样性保护及食品安全评估提供科学依据和理论支撑.     

长江三角洲跨界流域生态产品交易机制——以天目湖流域为例

生态价值多元化实现是落实区域一体化生态保护格局的经济政策保障。针对当前生态产品交易制度不完善与市场活跃度问题,以天目湖流域水质净化服务产品为例,提出一条生态保护市场化与生态产品增值的双向促进道路：基于长序列监测数据与水文水质过程模型,提出流域生态保护基准概念及其约束下生态产品交易边界,精准核算基准年水质净化产品的可交易量为1.37 t,基准价格为1186.71万元/t/年;面向近10年产品实际供需主体的内在联系,揭示了“三类五种”生态产品交易机制类型,并选择设计了低端产品退出—高端产品激励的典型交易模式。生态产品交易实施为研究区生态价值实现提供市场化路径,为国内同类地区一体化生态保护格局保障提供思路。     

Effects of artificially induced complete mixing on dissolved organic matter in a stratified source water reservoir

Naturally complete mixing promotes the spontaneous redistribution of dissolved oxygen(DO), representing an ideal state for maintaining good water quality, and conducive to the biomineralization of organic matter. Water lifting aerators(WLAs) can extend the periods of complete mixing and increase the initial mixing temperature. To evaluate the influence of artificial-induced continuously mixing on dissolved organic matter(DOM) removal performance, the variations of DOM concentrations, optical cha...     

Dosing low-level ferrous iron in coagulation enhances the removal of micropollutants, chlorite and chlorate during advanced water treatment

Drinking water utilities are interested in upgrading their treatment facilities to enhance micropollutant removal and byproduct control. Pre-oxidation by chlorine dioxide (ClO₂) followed by coagulation-flocculation-sedimentation and advanced oxidation processes (AOPs) is one of the promising solutions. However, the chlorite (ClO₂^–) formed from the ClO₂ pre-oxidation stage cannot be removed by the conventional coagulation process using aluminum sulfate. ClO₂^– negatively affects the post-UV/chlorine process due to its strong radical scavenging effect, and it also enhances the formation of chlorate (ClO₃^–). In this study, dosing micromolar-level ferrous iron (Fe(II)) into aluminum-based coagulants was proposed to eliminate the ClO₂^– generated from ClO₂ pre-oxidation and benefit the post-UV/chlorine process in radical production and ClO₃^– reduction. Results showed that the addition of 52.1-µmol/L FeSO₄ effectively eliminated the ClO₂^– generated from the pre-oxidation using 1.0 mg/L (14.8 µmol/L) of ClO₂. Reduction of ClO₂^– increased the degradation rate constant of a model micropollutant (carbamazepine) by 55.0% in the post-UV/chlorine process. The enhanced degradation was verified to be attributed to the increased steady-state concentrations of HO^· and ClO^· by Fe(II) addition. Moreover, Fe(II) addition also decreased the ClO₃^– formation by 53.8% in the UV/chlorine process and its impact on the formation of chloro-organic byproducts was rather minor. The findings demonstrated a promising strategy to improve the drinking water quality and safety by adding low-level Fe(II) in coagulation in an advanced drinking water treatment train.     

Microwave-assisted continuous flow phytosynthesis of silver nanoparticle/reduced graphene oxide composites and related visible light catalytic performance

The creation of an environmentally friendly synthesis method for silver nanomaterials (AgNPs) is an urgent concern for sustainable nanotechnology development. In the present study, a novel straightforward and green method for the preparation of silver nanoparticle/reduced graphene oxide (AgNP/rGO) composites was successfully developed through the combination of phytosynthesis, continuous flow synthesis and microwave-assistance. Oriental persimmon (Diospyros kaki Thunb.) extracts were used as both plant reducing and capping agents for fast online synthesis of AgNP/rGO composites. The experimental parameters were optimized and the morphologies of the prepared materials were investigated. The characterization results reveal that spherical AgNPs were quickly synthesized and uniformly dispersed on rGO sheets using the proposed online system. Fourier transform infrared spectroscopy analysis confirmed that phenols, flavonoids, and other substances in the plant extracts played a decisive role in the synthesis of AgNP/rGO composites. Using sodium borohydride (NaBH₄) degradation of p-nitrophenol (4-NP) as a model, the catalytic activity of the prepared AgNP/rGO materials was evaluated. The complete degradation of 4-NP was achieved within 12 min through the use of AgNP/rGO materials, and the composite had a much better catalytic activity than the bare AgNPs and rGO had. Compared with the conventional chemical method, our online method is facile, fast, cost-efficient, and environmentally friendly.     

Evidence on the causes of the rising levels of CODMn along the middle route of the South-to-North Diversion Project in China: The role of algal dissolved organic matter

As the biggest inter-basin water transfer scheme in the world,the South-to-North Water Diversion Project（SNWD） was designed to alleviate the water crisis in North China.The main channel of the middle route of the SNWD is of great concern in terms of the drinking water quality.In this study,we tested the hypothesis that the dissolved organic matter（DOM） derived from the planktonic algae causes the rising levels of COD_Mn along the middle route by monitoring data on water quality（2015-20...     

长江三角洲地表水环境污染规律及调控对策

根据野外实地考察和定点观测数据 ,结合历年环境监测资料 ,初步揭示了长江三角洲地表水环境污染的现状与近十年来的时空演变规律 :河网干流水质基本良好 ,中小河流污染突出 ;城市河流有机污染严重 ,普遍出现水体黑臭现象 ;湖泊氮磷含量逐年增高 ,水体富营养化加剧 ;市郊小城镇河网水质急剧恶化 ,已成为新的水环境污染中心。造成长江三角洲地表水环境污染的主要物源包括工业废水和生活污水、畜禽粪便、农田化肥、底泥等。针对上述污染规律和成因机制 ,提出了相应的调控对策。     

肥料调控强化象草对重度Cd污染农田修复效果

象草（Pennisetum purpureum Schumach.）因适应能力强、生长迅速和生物量大,且具有一定的经济效益,在重金属污染土壤植物修复中有很好的应用前景.通过田间试验,研究不同肥料（有机肥、复合肥和追施氮肥）联合施用强化象草修复重度Cd污染农田的效果.结果表明：①不同肥料调控处理降低了土壤pH值,提高了土壤有机质含量,根际土壤总Cd含量较修复前降低了8.3%~23.3%,土壤有效态Cd含量较对照降低了11.7%~34.6%;②不同肥料调控处理显著促进了象草生长和对Cd的吸收累积,象草地上部生物量增加29.2%~368.2%,象草Cd总累积量增加了37.8%~283.9%,其中有机肥+复合肥+追施氮肥处理（F3N）象草Cd总累积量达到了145.48 g·hm^-2;③不同肥料联合对提高象草Cd累积量的效果为：有机肥+复合肥+追施氮肥>有机肥+复合肥>单一复合肥.因此,在重度Cd污染农田植物修复中,肥料调控可以强化象草对土壤中Cd的富集移除效果,进而加快对污染农田的修复.