Effects of environmental factors on organochlorine pesticide residues in soils of the Guanting Reservoir area, China

Topsoil samples from 56 sites around the Guanting Reservoir, China, were measured for HCH and DDT concentrations. The total soil HCH content (including alpha-, beta-, gamma-, and delta-isomers) in these soil samples ranged from 0 to 7.33 ng x g(-1), with a mean of 0.69 ng x g(-1). These levels were considerably lower than those of the total DDT soil contents (including pp'-DDE, pp'-DDD, op'-DDT, and pp'-DDT), which ranged from 0 to 76.01 ng x g(-1), with a mean of 9.46 ng x g(-1). DDT was also found to be the major pollutant in the soil samples, accounting for approximately 93% of the total organochlorine pesticide (OCP) contents. Several environmental factors including land use, soil texture, soil taxonomy, and microbial biomass were considered to be responsible for the OCP levels observed. The data provide some insight into the effects of environmental conditions such as soil formation, agricultural cultivation, nutrient enrichment, and other anthropogenic activities on the degradation of OCPs in soils. Although the OCP residues currently are below the maximum limits set for use on agricultural land in China, and only rarely would such levels pose significant ecological concern, OCPs are highly persistent in soil and bioaccumulative. The data provided in this study are considered crucial for reservoir remediation, especially since the Guanting Reservoir will serve as one of the main drinking water sources for Beijing in the foreseeable future.     

Modeling human exposures to air pollution control (APC) residues released from landfills in England and Wales

Human exposures to air pollution control (APC) residues released from 6 landfills were modeled and assessed. Following a qualitative risk characterisation, direct and indirect exposures were quantified. Site-specific air dispersion modeling was conducted for PM(10), PCDDs/PCDFs, Pb, Cd, As and Cr(VI) concentrations at the closest residential points of exposure for 4 landfill sites accepting, in total, 75% w/w of the APC residues disposed of in 2000-2001 (UK). Inhalation risks, assessed by reference to air quality standards at residential exposure points, were assessed as insignificant. Preliminary modeling suggested that indirect exposures from PCDDs/PCDFs at the 95th percentile level for the site where APC deposition rates were highest could potentially exceed the tolerable daily soil intake (TDSI) but this warrants further study given the model limitations. These results offer an initial screen of the significance of potential risks from APC disposal, which is of value in addressing concerns about the uncertainty of potential risks to human health from bulk APC disposal at strategic locations.     

Monitoring seasonal distribution of an endangered anadromous sturgeon in a large river using environmental DNA

Monitoring dynamic distribution is crucial to conservation management of anadromous sturgeons, but traditional survey methods are less efficient for low-density populations in a large river. Natural propagation of Chinese sturgeon has been monitored annually mainly at the spawning ground using netting for eggs and hydroacoustics for broodstock. However, absence of spawning was observed sporadically in recent years, indicating further crises for the declining population. We analyzed eDNA of water samples collected from 24 sites across 1360 km of the migratory route of anadromous Chinese sturgeon in the middle and lower reaches of the Yangtze River. Chinese sturgeon was detected at 9 sites during the spawning season and 14 sites after the spawning season. We found that positive eDNA detection rates remained constant in the middle reaches but dramatically changed in the lower reaches, reflecting seasonal migration pattern of Chinese sturgeon. Invasive sturgeons were detected in the river, indicating their possible escape from aquaculture facilities. This study established a protocol for the use of eDNA to monitor distribution of Chinese sturgeon and could be valuable in making better policies for the conservation of this endangered species.     

PHAST软件预测火炬的气体扩散和热辐射

简述了PHAST（Process Hazard Analysis Software Tool）软件中APIRP521计算模型计算火炬喷射火的要点，以某企业的液化天然气接收站火炬为例，详细说明了计算步骤，给出了计算结果，并作出简要分析。     

环境监测实验室废液处理的讨论

环境监测作为环境保护工作的基础,并随着环境保护事业的发展而发展。近年来,我国环境监测水平大幅提高,监测能力不断增强,但随着工作量的加大,环境监测实验室所产生的废物数量及种类都在增多,这些废物如不经无害化处理直接排放,将会严重危及人们的健康。本文从防止污染环境的立场出发,分类讨论了环境监测实验室日常产生的废液处理方法。     

Water-saving Technologies,Solar Green House and Ecological Rehabilitation in Minqin Oasis of Gansu Province,China

Land degradation and desertification have become severe environmental problems in arid areas due to excessive use of water resources. It is urgent to reduce agricultural water use for ecological rehabilitation, which may result in a decrease in agricultural production and farmer＇s welfare. This paper focused on the impacts of some main measures including extensions of watersaving irrigation, expanding solar green house and increasing off-farm employment, which are generally recognized to be important to alleviate water shortage and poverty. A bioconomic model is applied taking Minqin Oasis in Gansu Province as a case study site. Simulation results showed that the effect of expanding solar greenhouse was more positive than other ones so it drew more attention. On the view of the different effects between each irrigation zone, mixed policy patterns suitable for them are suggested. In Baqu, expanding solar greenhouse should be the most important, auxiliary with encouraging pipe irrigation. Inversely, with regard to Quanshan, the major attention should be paid to subsidy for pipe irrigation and it would be better to supply the off-farm employment opportunities to the households in Huqu, where the expanding of solar greenhouse should also be summoned. Finally, it should be noted that farmer＇s income would only resume to 90% of the current level in the short run by putting more effort into local policies. Thus, the ecological compensation is needed to ensure farmer＇s welfare.     

从炼厂含油污泥中回收油及残渣无害化治理的研究

通过对某油田石化厂的含油污泥中回收油及其残渣无害化治理问题的研究，确定了用热洗加离心分离实现污油回收及残渣无害化。根据实验室数据，处理此种含油污泥可达到如下结果：油回收率９５％，残渣中油及主要污染物含量基本符合ＧＢ４２８－８４标准，工艺污水符合进入污水场的要求。采用此法，按照２ｔ／ｈ的处理量计算，预计设备投资４５．７万元。     

黄河下游泥沙灾害初步研究

基于黄河下游对泥沙运动与泥沙灾害发生的关系问题进行了分析。认为下游泥沙灾害类型主要包括洪水、河岸侵蚀、土地沙化、水涝和土地盐碱化, 并认为改造下游泥沙灾害环境应通过改变泥沙堆积分布入手。