An optimization model for the economic control of reservoir eutrophication

An interdesciplinary attempt to formalize and numerically solve problems of the management of reservoir eutrophication is presented. A dynamic ecosystem model is treated by means of a generalized penalty optimization technique to calculate the combination of control actions that minimize cost under the condition that given water-quality indices are preserved.     

Sulfur Metabolism in Polluted Sphagnum Peat Bogs: A Combined 34S–35S–210Pb Study

The size and isotopic behavior of sulfur pools in²¹⁰Pb-dated peat cores were investigated to obtain aninsight into retention mechanisms of pollutant S in twomountain-top peatlands of the Northern Czech Republic, CentralEurope. The bogs were situated 40 km apart in an area whichbetween the years 1985 and 1995 received as much as 130 kg Sha^-1 yr^-1 from the atmosphere. Vertical peataccretion was faster at Pod Jelení horou (JH) than atVelký moál (VM). Organic carbon-bonded S was themost abundant sulfur pool, constituting 77 and 65 wt. % at JHand VM, respectively. At JH both the S concentration maximumand the highest annual S deposition rate were displaceddownward by more than 20 years (from 1987 to the 1960s)indicating that the buried S is vertically mobile. At VM the Sconcentration was the highest in the topmost 2-cm section eventhough atmospheric S deposition peaked in 1987. Differentmechanisms of S isotope redistribution prevailed in thetopmost peat layers at JH, where a negative ³⁴Sshift occurred, and at VM, where a positive ³⁴Sshift occurred. Bacterial sulfate reduction was responsiblefor the negative ³⁴S shift at JH. One possibleexplanation of the positive ³⁴S shift at VM isrelease of ³²S-enriched products of mineralization duringpeat diagenesis. There was a strong positive correlationbetween the abundance of total and pyrite S along the profiles.The presence of pyrite S at VM (526 ± 60 ppm) suggestedthat even at VM bacterial sulfate reduction occurred. Ananaerobic incubation of JH peat indicated sulfate reductionrate of 600 nmol g^-1 day^-1. The turnover times forinorganic S pools were shorter than for the organic S pools.Cumulative S contents in the Czech peat bogs were found to besignificantly lower than in similar sites in the NortheasternU.S., even though the atmospheric S inputs were more thanthree times higher at the Czech sites. Possible causes of suchdiscrepancy are discussed.     

Radioactive contamination of wood and its products

This paper presents research on radioactive contamination of the three most common kinds of wood in Croatia--beech, oak and fir as well as acorn. Gamma-spectrometric measurements carried out on the samples of bark and wood of beech, oak, fir and acorn have shown radioactivity contents ranging from 1.6 +/- 0.1 to 37.3 +/- 0.5 Bq/kg from deposited 137Cs, whose concentrations in the soil of Croatia have increased after the Chernobyl accident. Measurements have also shown the radioactivity originating from 40K and 214Bi, which are part of the natural composition of the soil. The distribution of the radionuclides in wood has been discussed, as well as the impact of radioactive contamination of wood by the artificial radionuclide 137Cs upon the forest ecosystem. According to the corresponding model, it has been calculated that a 10 h daily stay in a typical family house increases the annual radiation dose of the population, due to the deposited 137Cs in the structure or furniture, by 343 microSv.     

Application of impregnated filters to determination of smoke and ammonia

Whatman No. 1 filters impregnated with a 3% solution of oxalic acid in ethanol which are used for elimination of ammonia from the air stream before entering the absorber for collecting SO₂, were tested for a possible application (a) in the spectrophotometric determination of ammonia with Nessler's reagent and (b) in the reflectometric determination of smoke. It was shown that impregnated filters were as suitable for the determination of ammonia as absorbing solution and as applicable for smoke measurement as untreated filters. Further, the advantage of using impregnated filters for sampling ammonia lies in avoiding the interference of organic vapours which may occur, if absorbing solution is used.     

How to Preserve Coastal Wetlands,Threatened by Climate Change-Driven Rises in Sea Level

A habitat transition model, based on the correlation between individual habitats and micro-elevation intervals, showed substantial changes in the future spatial distributions of coastal habitats. The research was performed within two protected areas in Slovenia: Se?ovlje Salina Nature Park and ?kocjan Inlet Nature Reserve. Shifts between habitats will occur, but a general decline of 42 % for all Natura 2000 habitats is projected by 2060, according to local or global (IPCC AR4) sea level rise predictions. Three different countermeasures for the long-term conservation of targeted habitat types were proposed. The most “natural” is displacement of coastal habitats using buffer zones (1) were available. Another solution is construction of artificial islets, made of locally dredged material (2); a feasible solution in both protected areas. Twenty-two islets and a dried salt pan zone at the desired elevations suitable for those habitats that have been projected to decease in area would offer an additional 10 ha in the Se?ovlje Salina. Twenty-one islets and two peninsulas at two different micro-altitudes would ensure the survival of 13 ha of three different habitats. In the area of Se?ovlje Salina, abandoned salt pans could be terrestrialized by using permanent, artificial sea barriers, in a manner close to poldering (3). By using this countermeasure, another 32 ha of targeted habitat could be preserved. It can be concluded that, for each coastal area, where wetland habitats will shrink, strategic plans involving any of the three solutions should be prepared well in advance. The specific examples provided might facilitate adaptive management of coastal wetlands in general.     

The Frequency of Micronuclei among Newborns from Kragujevac, Central Serbia, after NATO Bombing in the Spring of 1999

Kragujevac, as an important industrial and economic center of the region, is now placed on the top of the list of environmentally endangered cities in our country. The aim of this biomonitoring study was to evaluate cytogenetic damage in a sample of newborns from Kragujevac after contamination of the environment entailed by the intensive bombing of the industrial zone of this city in the spring of 1999. The frequency of micronuclei (MN) in peripheral blood lymphocytes in a total of 61 phenotypically healthy newborns was analyzed before and after the NATO bombing. Analysis of micronuclei has been performed using the cytokinesis-block technique (CB MN test). Average MN frequency in lymphocytes of newborns before the bombing (N = 25) was 5.77 ± 0.85/1000 analyzed cells. After the bombing (N = 36), the average frequency of MN increased by a factor of 1.4 (8.11 ± 0.85), compared to the control frequency before the bombing. Statistical difference (p < 0.05) was established by Student's t-test. Our data suggest that such changes in genetic material were a direct consequence of contamination of the living environment.     

Seasonal trend of ambient PCDD/Fs in Tianjin City, northern China using active sampling strategy

The spatial concentrations, seasonal trends, profiles and congener pairs of ambient polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were investigated within a seasonally active sampling scheme during Jun 2008 and Jan 2009 in Tianjin City, northern China. The PCDD/F concentrations ranged 14.2-172 fg I-TEQ/m³ (average 69.3 fg I-TEQ/m³) in summer and (89.8-1.01) × 10³ fg I-TEQ/m³ (average 509 fg I-TEQ/m³) in winter, respectively, except for the E-waste dismantling site where much higher values were observed (1.04 × 10³ fg I-TEQ/m³ in summer and 7.123 × 10³ fg I-TEQ/m³ in winter). The results indicated a significantly seasonal trend with higher TEQ values in winter as compared with summer, which could be related to increased emission sources and seasonal variations of the atmospheric boundary layer height. 2,3,4,7,8-PeCDF was the dominant contributor to the total PCDD/F toxic equivalents, and 2,3,7,8-TCDD was detected at almost all the sampling sites in winter. Most of the similarly substituted PCDD/F congener pairs exhibited high correlations, suggesting that they might have similar environmental fate or sources. But different seasonal and spatial distributions of PCDD/F concentrations indicated that the emission sources might be intermittent.     

重庆三峡库区非点源污染评价与影响因子分析

选取重庆三峡库区4个行政建制镇进行非点源污染监测与调查,以COD、TN、TP、Cu、Zn等指标为主要研究内容对库区农村环境进行污染特性分析并且利用等标污染负荷法对其生活污水、生活垃圾、畜禽养殖、水产养殖、化肥流失、农药流失、水土流失等污染源进行非点源污染评价。结果表明:COD、TN、TP、Cu、Zn的平均排放浓度分别为22.15 mg/L、6.37 mg/L、1.49 mg/L、47.73 g/kg、85.24 g/kg,库区主要污染物依次为TN、TP、COD、Cu、Zn等,主要污染源依次是畜禽养殖、化肥流失、生活污水、生活垃圾、农药流失、水土流失、水产养殖等。采用SPSS软件对影响库区环境污染的季节、收入水平、地域、畜禽养殖规模、环境基础设施完善程度等因子进行了分析,结果显示:COD主要影响因子是地域和畜禽养殖规模,TN主要影响因子是季节、地域和畜禽养殖规模,TP主要影响因子是环境基础设施完善程度、畜禽养殖规模和地域,Cu、Zn主要影响因子均是畜禽养殖规模。该研究可为重庆三峡库区生态修复、城乡统筹下的城乡规划及产业布局提供理论基础。     

纳米二氧化钛与镉对斜生栅藻(Scenedesmus obliquus)生长的拮抗效应及其作用机制

人工纳米材料（MNMs）进入水环境将改变传统环境污染物的环境归趋及其毒性作用,两者的相互作用及其机制一直是环境科学领域的热点问题.迄今为止,已有大量MNMs与现存污染物联合毒性作用的研究成果发表,但其潜在的作用机制,尤其是联合作用下的生物响应机制仍未清楚.本文以典型MNMs——纳米二氧化钛（nTiO₂）与重金属镉（Cd²⁺）为研究目标,以斜生栅藻（Scenedesmus obliquus）为受试生物,考察在等效剂量（毒性比1 ∶1）下不同浓度组合nTiO₂和Cd²⁺对斜生栅藻的联合毒性作用模式及其分子机制.结果表明,等效剂量下Cd²⁺和nTiO₂的72h EC₅₀值对比单独暴露时均有显著升高,呈拮抗效应.进一步开展转录组学分析发现,nTiO₂存在下斜生栅藻能量代谢所涉及的光合作用、叶绿素代谢以及淀粉与蔗糖代谢通路发生了显著上调,与藻细胞抗逆效应相关的精氨酸与脯氨酸代谢通路同样呈正向刺激表现.本文首次报道了nTiO₂与Cd²⁺等效剂量联合暴露下,浮游植物通过改变藻细胞抗逆能力与加强能量代谢来降低毒性的生物响应机制.本研究结果为深入理解MNMs与现存污染物的复合环境健康效应提供重要参考和研究基础.