成都市大气降尘放射性水平分析

本文介绍了成都市大气降尘放射性水平的监测结果。发现降尘中除有少量天然核素外,还尚存有以往大气层核试验释放的裂变核素９０Ｓｒ和１３７Ｃｓ。平均年沉降量９０Ｓｒ为１０２Ｂｑ·ｍ－２·Ｙ－１,１３７Ｃｓ为１３１Ｂｑ·ｍ－２·Ｙ－１。由大气９０Ｓｒ和１３７Ｃｓ沉降所致公众辐射剂量为１６８μＳｒ·ａ－１,是限值的２‰。所以,降尘中放射性造成的辐射影响是很小的。     

成都市在气降尘放射性水平分析

本文介绍了成都市大气尘放射性水平的监测结果。发现除尘中除少量天然核素外，还尚存在以往大气层柱试验释放的裂变核素＾９０Ｓｒ和＾１３７Ｃｓ。     

铀元件厂排污河流放射性污染与监测

本文报告了铀元件厂排污河流的放射性监测结果，并就污染水平和监测方法进行讨论。调查表明：采用监测河流底泥或水生物的方法可以提高监测灵敏度。     

沈阳市新开河底泥对水体黑臭的关键影响因子研究

对新开河沿河11个点位的底泥进行取样监测,并对监测数据进行分析,筛选底泥中对水体黑臭造成影响的关键因子.结果显示,底泥污染是黑臭水体的重要污染源之一,底泥的含水率是底泥处置的关键考虑因素;重金属和砷是底泥资源化利用的关键因子;总氮、总磷和有机质之间关系密切且有较好的同源性.     

基于SPSS相关性分析的地下水污染因果关系判定

为了查明某地麦田等作物利用地下水灌溉后出现生长缓慢及枯黄死亡等情况的原因,该地环保局对周边地下水井取样监测,对周边污染企业进行了排查。在确认某企业有非法排污行为后,对各监测水井中监测因子之间相关性进行拟合,运用SPSS软件对所有污染水井中含有的排污企业特征污染物因子和超标因子进行了相关性分析。结果表明:在污染地下水监测样品中非法排污企业的特征污染因子与超标因子呈显著相关,从而确认企业非法排污与下游地下水井污染存在因果关系。     

大沽排污河沉积物污染及生态风险性

利用HaKanson生态风险指数法,研究了大沽排污河底泥中重金属（和砷）污染物对水域的污染程度,及其对水域总体造成的潜在风险影响。     

滇池沉积物重金属污染状况评估

本文通过多年滇池底泥的采样监测数据,采用地积累指数法和对数衰减模型评估滇池的底泥质量状况,希望摸清底泥中重金属污染状况,并分析评价其对水生生物的风险,为底泥疏浚、截污护岸的滇池治理工程提供一定的科学依据。研究表明:以地积累指数法评价,(1)滇池监测断面底泥质量呈现轻度污染,镉出现一定程度富集,汞在个别监测断面也出现富集情况;(2)6种重金属污染排序为镉>汞>铅>铜>铬>砷;(3)从监测断面来看,海口西污染程度较重,滇池南底泥质量较好。采用对数衰减模型评价,(1)滇池监测断面沉积物重金属污染存在潜在生物风险,应引起重视;(2)从产生可以观察到毒性效果的可能性大小看,6种重金属潜在危害可能性排序为砷>铅>铜>铬>镉>汞;(3)从监测断面来看,白鱼口和观音山中潜在危害可能性大。从富集污染程度分析,海口西监测断面的底泥污染最重,可考虑在海口西监测断面附近进行一定的底泥疏浚工程。从而达到治标治本的目的。滇池监测断面沉积物重金属污染存在潜在生物风险,应引起重视,但在可控范围。     

混合化工污水处理工艺的试验研究

本文介绍了利用混凝沉淀一生物接触氧化法治理混合化工污水的试验工艺选择,对生化进水的预处理工作进行了初步的探索,在生化试验中,研究了水力停留时间和有机负荷对污水处理效果的影响,并观察了微生物的生长和发展规律,初步探讨了其动力学模型,试验证明：本法能有效地处理混合化工污水,在适宜的条件下,ＣＯＤｃｒ、ＢＯＤ５的去除率可达５５％和９０％以上,色度和ＳＳ的去除率分别可达８０％和５０％以上。     

浅析排污许可证制度执行中存在的不足及建议

排污许可证制度是依法规范管理各类企事业排污行为的基础性环境管理制度,通过排污许可制对所有固定污染源的全覆盖,实现以排污许可证为核心的“一证式”固定污染源管理模式。随着排污许可证制度的推进,在排污许可证执行中存在企业自查不到位、自行监测不全、台账记录缺失等问题。归纳了排污许可证制度执行过程中存在的不足,并有针对性地提出了相关建议,以期更好地推进排污许可证制度的实施与监管。     

严格排污申报 促进环境监测

实施环境管理必须严格排污申报制度，排污申报又必须依赖环境监测，因此环境监测是环境管理的基础。国家环保局《关于进一步加强环境监测工作的决定》明确指出：“要依靠科学的，有权威的监测数据实施各项环境执法管理．进一步提高环境管理水平。”那么，如何加强环境监测工作呢？我们批市市是从狠抓排污申报这项工作开始的。我局以前环境监测工作没有依附在“排污中报”这项法律管理制度上，缺乏应有的法律依据。有时排污单位对监测结果持怀疑态度，甚至在监测站采样时，排污单位做手脚，掩盖排污实际，给监测工作造成了很大困难。监测站对…     

Tree-ring strontium-90 and cesium-137 as potential indicators of radioactive pollution

To examine whether tree rings can be used to detect or assess local historical 90Sr or 137Cs fallout, such as that resulting from the Hiroshima atomic bomb, radial distribution of 90Sr and 137Cs in trees was examined. We studied a gymnosperm [Japanese cedar, Cryptomeria japonica (L. f.) D. Don] and an angiosperm (Japanese persimmon, Diospyros kaki Thunb.) tree species from the vicinity of the atomic bomb hypocenter, and from other locations in Japan. A significant amount of 137Cs was detected in tree rings formed before 1945, indicating lateral migration of Cs. In contrast, the specific activity of 90Sr in the Hiroshima Japanese cedar showed the highest level in 1945, due to relatively immobile characteristics of Sr compared with Cs. Strontium-90 and Sr analyses in tree rings helped identify and distinguish between residual 90Sr activity from the Hiroshima atomic bomb and the atmospheric nuclear testing. This indicates the possibility of detecting or assessing previous local 90Sr pollution through with treering analysis.     

Determination of <Superscript>90</Superscript>Sr in milk and milk powder in Tehran and estimation of annual effective dose

Thirty-eight different milk and milk powder samples from Tehran-Iran were collected and analyzed for ⁹⁰Sr activity using a method in which the daughter product of ⁹⁰Sr decay (⁹⁰Y) was extracted by tributyl phosphate from ashed milk. ⁹⁰Y was then back extracted with water, and oxalate was precipitated . Following the sample analyzing, beta counting was performed with an ultralow-level liquid scintillation spectrometer. The quality control and assurance of the method were obtained by standard samples prepared with an IAEA-certified reference material. The mean determined ⁹⁰Sr activity concentration in the analyzed milk and milk powder (0.225 ± 0.042 and 0.216 ± 0.024 Bq kg⁻¹, respectively) showed that the radioactivity concentration in our samples was too low to induce biological hazards. These data can provide useful information of the background level of contamination, which in turn can be used in the following environmental monitoring programs.     

Sediment Quality Assessment in the Gulf of Gdańsk (Baltic Sea) Using Complementary Lines of Evidence

Sediments from Polish coastal environments were classified by a quality assessment approach that took into account trace metal and organic micropollutant concentrations, grain-size distribution, and organic carbon content. Generally, no benthic organisms were found at sites where sediments were classified as heavily polluted. However, areas characterized by a moderate contamination showed a variable composition of the benthic community and changing bioaccumulation patterns; therefore, no single species found in the Gulf of Gdańsk could be considered representative of the whole benthic environment. Although sediment monitoring must be considered a suitable tool to detect hot-spot pollution areas in coastal and inland waters, it should be complemented by bioaccumulation measurements to evaluate the actual risk posed by contaminants to benthic organisms. This “biological information” allows a better appreciation of the real benthic infaunal community exposure to chemicals and can usefully complement the existing sediment quality guidelines.     

90Sr、137Cs在某种包气带土壤中的迁移研究

本文叙述了放射性废物中具有代表性的裂变核素^90Sr、^137Cs在某种包气带土壤中的迁移情况研究。使用小型土柱的氚水淋洗实验研究土壤水力学性质，最后进行大型土柱实验研究核素在该包气带土壤中的迁移，并对实验情况进行了数学模拟。用该土壤原状土进行小型土柱的氚水淋洗试验，测得了土壤的水力弥散度为0．32cm，土壤有效孔隙度为0．35。经过290天的大型柱迁移试验表明，土壤对^90Sr的阻滞系数为220．4，在模拟实际降雨量的情况下，^90Sr的平均迁移速度为0．63cm/y，^137Cs在大型柱试验中没有明显迁移。数值模拟^90Sr、^137Cs迁移，得出经过上述大型柱试验相同的条件下，^90Sr、^137Cs迁移的峰位置基本和大型柱试验结果相同。     

Uptake of cesium-137 and strontium-90 from contaminated soil by three plant species; application to phytoremediation

A field test was conducted to determine the ability of three plant species to extract 137Cs and 90Sr from contaminated soil. Redroot pigweed (Amaranthus retroflexus L.), Indian mustard [Brassica juncea (L.) Czern.], and tepary bean (Phaseolus acutifolius A. Gray) were planted in a series of spatially randomized cells in soil that was contaminated in the 1950s and 1960s. We examined the potential for phytoextraction of 90Sr and 137Cs by these three species. Concentration ratios (CR) for 137Cs for redroot pigweed, Indian mustard, and tepary bean were 2.58, 0.46, and 0.17, respectively. For 90Sr they were substantially higher: 6.5, 8.2, and 15.2, respectively. The greatest accumulation of both radionuclides was obtained with redroot pigweed, even though its CR for 90Sr was the lowest, because of its relatively large biomass. There was a linear relationship between the 137Cs concentration in plants and its concentration in soil only for redroot pigweed. Uptake of 90Sr exhibits no relationship to 90Sr concentrations in the soil. Estimates of time required for removal of 50% of the two contaminants, assuming two crops of redroot pigweed per year, are 7 yr for 90Sr and 18 yr for 137Cs.     

Applications of Numerical Sediment Quality Targets for Assessing Sediment Quality Conditions in a US Great Lakes Area of Concern

Contaminated sediments are receiving increasing recognition around the world, leading to the development of various sediment quality indicators for assessment, management, remediation, and restoration efforts. Sediment chemistry represents an important indicator of ecosystem health, with the concentrations of contaminants of potential concern (COPCs) providing measurable characteristics for this indicator. The St. Louis River Area of Concern (AOC), located in the western arm of Lake Superior, provides a case study for how numerical sediment quality targets (SQTs) for the protection of sediment-dwelling organisms can be used to support the interpretation of sediment chemistry data. Two types of SQTs have been established for 33 COPCs in the St. Louis River AOC. The Level I SQTs define the concentrations of contaminants below which sediment toxicity is unlikely to occur, whereas the Level II SQTs represent the concentrations that, if exceeded, are likely to be associated with sediment toxicity. The numerical SQTs provide useful tools for making sediment management decisions, especially when considered as part of a weight-of-evidence approach that includes other sediment quality indicators, such as sediment contaminant chemistry and geochemical characteristics, sediment toxicity, and benthic macroinvertebrate community structure. The recommended applications of using the numerical SQTs in the St. Louis River AOC include: designing monitoring programs, interpreting sediment chemistry data, conducting ecological risk assessments, and developing site-specific sediment quality remediation targets for small, simple sites where adverse biological effects are likely. Other jurisdictions may benefit from using these recommended applications in their own sediment quality programs.     

RUNOFF AND SEDIMENT RESPONSES TO CONSERVATION PRACTICES: LOESS PLATEAU OF CHINA1

ABSTRACT: Soil erosion is the most significant threat to land productivity and environmental quality on the Loess Plateau of China. The annual total sediment load of the Yellow River is 1.6 billion tons, with about 90 percent coming from soil erosion from the Loess Plateau. To reduce soil erosion from the Loess Plateau, conservation practices, including tree planting, ridge construction between fields and around gullies, terrace and ditch construction perpendicular to the main slope, and dam construction are being implemented. An evaluation of these conservation practices is required before they are implemented at the large scale. The objective of this study is to evaluate the effectiveness of conservation practices to control runoff and sediment yield from paired watersheds in the hilly gully region of the Loess Plateau. The advantage of the paired watershed approach is its sensibility in detecting differences in runoff and sediment transport by monitoring both watersheds during two periods, an initial period with no conservation practices and a treatment period with only one watershed subjected to conservation practices. Implementation of the conservation practices resulted in (1) cumulative runoff and sediment yield that were, respectively, 25 and 38 percent less from the treatment watershed than from the control, (2) a decrease in the number of rainfall events producing runoff and sediment transport (94 in the control versus 63 in treatment), and (3) a reduction in the maximum discharge and maximum suspended sediment concentration.     

Antibiotic Transport via Runoff and Soil Loss

Research has verified the occurrence of veterinary antibiotics in manure, agricultural fields, and surface water bodies, yet little research has evaluated antibiotic runoff from agricultural fields. The objective of this study was to evaluate the potential for agricultural runoff to contribute antibiotics to surface water bodies in a worst-case scenario. Our hypothesis was that there would be significant differences in antibiotic concentrations, partitioning of losses between runoff and sediment, and pseudo-partitioning coefficients (ratio of sediment concentration to runoff concentration) among antibiotics. An antibiotic solution including tetracycline (TC), chlortetracycline (CTC), sulfathiazole (STZ), sulfamethazine (SMZ), erythromycin (ERY), tylosin (TYL), and monensin (MNS) was sprayed on the soil surface 1 h before rainfall simulation (average intensity = 60 mm h(-1) for 1 h). Runoff samples were collected continuously and analyzed for aqueous and sediment antibiotic concentrations. MNS had the highest concentration in runoff, resulting in the highest absolute loss, although the amount of loss associated with sediment transport was <10%. ERY had the highest concentrations in sediment and had a relative loss associated with sediment >50%. TYL also had >50% relative loss associated with sediment, and its pseudo-partitioning coefficient (P-PC) was very high. The tetracyclines (TC and CTC) had very low aqueous concentrations and had the lowest absolute losses. If agricultural runoff is proven to result in development of resistance genes or toxicity to aquatic organisms, then erosion control practices could be used to reduce TC, ERY, and TYL losses leaving agricultural fields. Other methods will be needed to reduce transport of other antibiotics.