典型污灌区土壤与作物中重金属健康风险评估

该文选取了国内外9个典型污灌区作为研究对象,分析了重金属在土壤及作物中的污染情况,评价了重金属对人体健康造成的风险.结果表明,总体而言同一灌区重金属在小麦中富集浓度高于玉米.其中超标最严重的是德国柏林（BL）地区的Cd,在玉米和小麦中浓度分别为1.62、7.50mg/kg,分别是WHO/FAO标准的8.1和37.5倍,这和BL灌区土壤中Cd浓度高有关.口食小麦对人体健康造成的风险分别在10^-6~10^-4a^-1之间.致癌性重金属Cd通过口食小麦途径对成人和儿童健康造成的风险分别占总风险的61.75~99.93%、60.78~99.84%.重金属在各种暴露途径下对儿童产生的风险大于成人.BL、津巴布韦的Harare（HR）、墨西哥的Mezquital（MQ）和沈阳珲浦（JP）灌区重金属对成人和儿童健康造成的总风险分别为5.12×10^-5~7.53×10^-4、5.71×10^-5~8.37×10^-4,超出USEPA和ICRP相关规定,其中污染最严重的地区是BL.     

基于网络分析法的海洋生态承载力评价及贡献因素研究

基于网络分析原理构建了能够处理指标之间存在关联影响关系的海洋生态承载力评价方法,并对我国沿海11省（区、市）在2006~2014年的海洋生态承载力指数和贡献因素进行了评价和分析。结果表明:沿海地区人口数量、地区海洋生产总值、海洋水产品产量、近岸海域一二类海水水质占比、直排海污染物排放量是对海洋生态承载力指数具有重要影响的指标;按承载力指数分布,广东、山东、浙江为高承载地区,福建、辽宁、上海为中承载地区,江苏、天津、河北、广西、海南为低承载地区,各类地区的海洋生态承载力指数近年总体上保持平稳发展趋势;按贡献因素分布,广东、广西、河北、江苏、辽宁、山东、浙江为社会压力主导型,上海、天津为生态本底主导型,海南为科技支撑主导型,福建为资源供给主导型。     

Community dynamics of ammonia oxidizing bacteria in a full-scale wastewater treatment system with nitrification stability

To determine whether the functional stability of nitrification was correlated to a stable community structure of ammonia oxidizing bacteria (AOB) in a full-scale wastewater treatment plant, the AOB community dynamics in a wastewater treatment system was monitored over one year. The community dynamics were investigated using specific PCR followed by terminal restriction fragment length polymorphism (T-RFLP) analysis of the amoA gene. The T-RFLP results indicated that during the period of nitrification stability, the AOB community structure in the full-scale wastewater treatment system was relatively stable, and the average change rate every 15 d of the system was 6.6%±5.8%. The phylogenetic analysis of the cloned amoA gene showed clearly that the dominant AOB in the system was Nitrosomonas spp. The results of this study indicated that throughout the study period, the AOB community structure was relatively stable in the full-scale wastewater treatment system with functional stability of nitrification.     

某工业园牛仔服装洗水废水集中处理工程实例

广东佛山市某工业园内污水处理厂采用混凝/生物接触氧化工艺对牛仔服装洗水废水进行集中处理,进水水量30 000 m3/d,水质ρ(COD)=411 mg/L、ρ(BOD5)=147 mg/L、ρ(SS)=313 mg/L、色度为239倍、pH=7～9,出水相应指标分别为ρ(COD)=53 mg/L、ρ(BOD5)=16 mg/L、ρ(SS)=32 mg/L、色度为8倍、pH为7.5,达到广东省地方标准DB 44/26—2001《水污染物排放限制》第二时段中的一级标准。此工艺具有工程投资少、运行稳定、处理效果好、成本低等优点。     

厌气条件下百菌清对土壤N2O和CH4排放的影响

在密闭、淹水、充N2的严格厌氧条件下对土壤进行了14d的培养试验,研究了杀菌剂百菌清在添加水平为田间施用量（FR）(5.5 mg·kg-1),20倍(20FR)和40倍田间施用量(40FR)时对强酸性、酸性、中性和碱性土壤N2O和CH4排放的影响.结果表明,20FR和40 FR的百菌清能够显著促进N2O向N2的还原,降低N2O排放,在酸性、中性和碱性土壤中培养14d后,对照处理的N2O排放量为0.076~0.46mg·kg-1,而20FR和40FR处理的N2O排放量为0.004~0.06mg·kg-1,降低了１个数量级.反硝化作用和有机氮矿化作用强的土壤中,百菌清减少N2O排放作用更明显.反硝化底物NO-3的存在对CH4的产生与排放具有显著的抑制作用.在加入百菌清未对NO-3浓度产生显著影响的土壤中,百菌清对CH4排放量没有明显影响,在对NO-3浓度产生显著影响的土壤中,CH4排放量随着NO-3的增加而减少,说明百菌清可能通过影响反硝化过程中NO-3的消耗而影响CH4排放.     

Seasonal variation of nitrogen and phosphorus in Xiaojiang River—A tributary of the Three Gorges Reservoir

A yearlong monitoring program in the backwater area of Xiaojiang River (XBA) was launched in order to investigate the eutrophication of backwater areas in tributaries of the Yangtze River in the Three Gorges Reservoir (TGR) in China, starting after the impoundment water level of the TGR reached 156 m. From March 2007 to March 2008, the average concentration of total nitrogen (TN) and total phosphorus (TP) were (1553±484) μg·L⁻¹ and (62±31) μg·L⁻¹, respectively. The mean value of chlorophyll was (9.07±0.91) μg·L⁻¹. The trophic level of XBA was meso-eutrophic, while the general nutrient limitation was phosphorus. The results indicated that XBA has a strong ability to purify itself and has non-point source pollution from terrestrial runoff. The variation of TN/TP ratio was caused by a variation in TN rather than in TP when TN/TP < 22. N-fixation from cyanobacteria occurred and became an important process in overcoming the nitrogen deficit under a low TN/TP ratio. When TN/TP ⩾ 22, the variation of TP affected the TN/TP ratio more significantly than TN. The increase of TP in XBA was caused mainly by particulate phosphorus, which could originate from a non-point source as adsorptive inorganic forms after heavy rainfall and surface runoff. An increase in the river’s flow could also contribute to an unstable environment for the growth of phytoplankton.     

壬基酚初级生物降解产物的辨认

为分析污水生物处理过程中壬基酚的去除机制,采用混合基质加标对照培养活性污泥、单一基质培养优势菌群2种生物降解实验,结合气相色谱-质谱谱图解析,从分子水平分析了壬基酚初级代谢产物和代谢途径.研究结果表明,活性污泥降解壬基酚的初级代谢产物主要为C4-C6烷基取代苯酚,烷基链的结构差异与其母体壬基的异构方式有关,烷基上的支链主要为甲基;优势降解菌群代谢壬基酚的初级产物除烷基苯酚外,还有苯乙酸等.污水生物处理过程中壬基酚可能的初级生物代谢途径是壬基上的长支链断裂为短的甲基链,生成一系列带有不同分支结构的短链烷基酚类代谢产物,进一步的代谢产物有苯乙酸.根据烷基酚类物质的内分泌干扰特性,短链烷基酚仍然具有雌激素活性,因此在壬基酚污染防治过程中应给与足够的重视.     

基于SSD网络的电梯内电动自行车检测研究*

为减少因电动自行车违规操作而造成的消防安全事故,杜绝电动自行车进电梯的违规行为,基于深度学习SSD目标检测网络,使用VGG16、EfficientNet、MobileNet 3种主干网络,研究SSD网络对电梯内电动自行车检测的可行性,分析比较3种网络的检测效果,并提出基于双摄的检测方法,进一步提高电梯场景下检测准确度,减少误检误报警。研究结果表明:SSD检测网络对电梯内电动自行车检测效果良好,其中SSD_MobileNet网络更适用于工业领域,双摄检测方法的检测准确率均大于90%。     

Effects of herbicides on Odonata communities in a rice agroecosystem

The effects of the five herbicides propanil, quinclorac, molinate/propanil, 2,4-D amine, and bensulfuron on Odonata diversity and abundance at the experimental rice plots was investigated. A total of 13 Odonata morphospecies belonging to two families have been identified. Treated plots exhibited higher species richness (up to 12 species) than the control plot (8 species). Ishnura spp. was the most abundant species in the treated plots with a mean density of 194.2 individuals per m², (ind m^?2) followed by Brachythemis contaminata (152 ind m^?2) and Agriocnemis spp. (124 ind m^?2). In the control plots, Agrocnemis spp. was the dominant species (153 ind m^?2) followed by Ishnura spp. (143 ind m^?2) and Neurothemis fluctuans (59 ind m^?2). In the propanil-treated plot, the highest number of odonate species (10 species) was recorded followed by the plots treated with quinclorax and molinate/propanil (9 species). On the 2,4-D amine or bensulfuron-treated plots as well as the control plot, only eight odonate species were recorded. This study revealed that herbicide application had a positive effect on Odonata diversity. This seems reasonable as Odonata are non-target organisms for herbicides. Furthermore, the decomposed weeds resulting from herbicide application would enrich the water with necessary organic matter.     

Ecology,ecological poverty and sustainable development in Central Himalayan region of India

The people inhabiting the mountains of the Central Himalayan region of India are heavily dependent on their immediate natural resources for their survival. However, this resource-poor mountain ecosystem is gradually becoming unable to provide a minimum standard of living to its continually growing population. In this ecosystem, human population is doubling every 27–30 years, against the declining resource base, particularly forests. Forest are disappearing both quantitatively and qualitatively. Against the requirement of 18 ha of forest land to maintain production in 1 ha of cultivated land, the ratio of forests to cultivated land is only 1.33: 1. The present production from grasslands supports 8 units of livestock, against the ideal 2 units, and the gap between the demand and deficit of fodder is more than 5-fold. Loss of vegetative cover is resulting in drying up of water resources, compelling the women to walk longer distances to collect water. This ecological deterioration, apart from human growth and interference, is compounded by mountain specificities such as inaccessibility, fragility, marginality, diversity, niche and adaptability. The specificities manifest in isolation, distance, poor communication, limited mobility, etc., resulting in limited external linkages and replication of external experiences, and slow pace of development. They, therefore, restrict options for economic growth, effecting poverty and affecting the quality of life of the people of the region. Poverty, in this mountain ecosystem cannot be understood and assessed independent of ecological wealth and would better be termed as ecological poverty. The development efforts to be effective in alleviating poverty here, should take into account mountain specificities and incorporate options which have larger human dimensions, such as mechanisms for population control, socio-economic and cultural conditioning, indigenous knowledge systems of the local people and simple technologies that are already in practice or have potential and are based on least external inputs.