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891.
The objective of this study was to describe the ambient levels of particulate matter (PM) and its influence to air quality situation on the dry Mediterranean island of Cyprus. From October 2002 to August 2003 PM10 and PM2.5 samples were collected at 31 different sampling sites in Cyprus. In addition, continuous measurements of PM10 were carried out from 2003 to 2007 at a traffic and a rural site. It can be recognised that at all traffic and at some residential and urban background sites, the actual EU limit values have been exceeded. Special events e.g. long-range transport of Sahara dust storms were recorded over urban as well as rural areas in the order of 6–8 events per year, with a major frequency in summer and spring periods. The comparison of the PM10 concentrations in Cyprus cities with values of other European cities demonstrates the PM10 problem in Cyprus, especially in the dry summer season, when no rain is cleaning the air and the dry surfaces. This underlines the necessity of PM abatement strategies.  相似文献   
892.
893.
Different aspects of bacterial degradation of organic contaminants in soil, and how to improve the efficiency and reproducibility is discussed in this review. Although bioremediation in principle includes the use of any type of organism in improving the condition of a contaminated site, most commonly bacteria are the degraders and other organisms, such as soil animals or plant roots, play a role in dissemination of bacteria and, indirectly, plasmids between bacteria, and in providing nutrients and co-substrates for the bacteria active in the degradation process. There are a number of different procedures that have been tested more-or-less successfully in attempts to improve reliability, cost efficiency and speed of bioremediation. The methods range from minimal intervention, such as mere monitoring of intrinsic bioremediation, through in situ introduction of nutrients and/or bacterial inocula or improvement of physico-chemical conditions, all the way to excavation followed by on site or ex situ composting in its different varieties. In the past the rule has been that more intervention (leading to higher costs) has been more reliable, but novel ideas are continuously tried out, both as a means to come up with new truly functional applications and also as a line of studies in basic soil microbial ecology. Both approaches generate valuable information needed when predicting outcome of remediation activities, evaluating environmental risks, deciding on cleaning-up approaches, etc. The emphasis of this review is to discuss some of the novel methods for which the value has not been clearly shown, but that in our view merit continued studies and efforts to make them work, separately or in combination.  相似文献   
894.
Previous studies have demonstrated that pesticides could induce cytotoxicity and genotoxicity in vivo and in vitro, and that oxidative stress may be an important factor involved. However, investigations comparing the capability of different organophosphorous (OP) compounds to induce cytotoxicity, genotoxicity and oxidative stress are limited. Hence, the aim of this paper was to access the cytotoxic and genotoxic effects of five OPs or metabolites, Acephate (ACE), Methamidophos (MET), Chloramidophos (CHL), Malathion (MAT) and Malaoxon (MAO), and to clarify the role of oxidative stress, using PC12 cells. The results demonstrated that MET, MAT and MAO caused significant inhibition of cell viability and increased DNA damage in PC12 cells at 40 mg L?1. MAO was more toxic than the other OPs. ACE, MET, MAT and MAO increased the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), and decreased the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) at 20 mg L?1 and 40 mg L?1 to different degrees. Pre-treatment with vitamin E(600 μM)caused a significant attenuation in the cytotoxic and genotoxic effect; pre-treatment reversed subsequent OP-induced elevation of peroxidation products and the decline of anti-oxidant enzyme activities. These results indicate that oxidative damage is likely to be an initiating event that contributes to the OP-induced cytotoxicity.  相似文献   
895.
Field studies were conducted at USDA Beltsville Agricultural Research Center, Beltsville, Maryland, in 1984 and 1985 using open-top chambers to acquire information on the responses of 12 soybean (Glycine max L. Merr.) cultivars to O3 stress and to examine the interactions between maturity groups and O3 stress. Cultivars representing Groups III, IV, and V were exposed for approximately 3 months to charcoal-filtered air (CF) and nonfiltered air plus 40 nl litre(-1) O3 (NF + O3). Ozone was added 6 h d(-1), 5 d week(-1) for 13 weeks. The CF effectively reduced the accumulative oxidant exposure (AOX) to less than 1.0 microl litre(-1) h and the NF + O3 treatment approximately doubled the ambient AOX (16.7 microl litre(-1) h) to about 30 microl litre(-1) h. The AOX estimates the total O3 exposure above 30 nl litre(-1) during an entire growing season. Plant growth rates and relative growth rates were reduced by 17.0 and 14.4%, respectively, when averaged over cultivars. Based on growth rates, the Group III cultivars were the most affected by O3 stress. Averaged over cultivars, leaf expansion rates, leaf conductance, and transpiration rates were lower in the NF + O3 treatment compared to the CF control; however, wide variation was found with the stomatal results from field observations. Combined over years and cultivars, grain yield was reduced by an average of 12.5% by O3 stress with 3 of 12 cultivars showing significant reductions. Grain protein content was increased by 0.7% by O3 stress, but cultivar differences were equal to the differences caused by the O3 treatments. Grain oil content was unchanged by the O3 treatments. Group IV cultivars showed the greatest decrease in grain yield due to O3 stress. Multiple regression analyses were calculated using the difference between the CF and NF + O3 treatment as a measure of O3 stress. Significant positive relationships were found among net assimilation rates, plant growth rates, relative growth rates, and leaf expansion rates, which suggest that growth analysis characteristics would be useful in addition to yield in air pollution tolerance improvement studies with soybeans.  相似文献   
896.
Heavy metal contamination in the seaweeds of the Venice lagoon   总被引:8,自引:0,他引:8  
The concentrations of heavy metals (Fe, Zn, Cu, Cd, Ni, Pb, Cr, As) were determined in seven seaweeds of environmental and commercial relevance (Ulva rigida C. Ag., Gracilaria gracilis (Stackhouse) Steentoft, L. Irvine and Farnham, Porphyra leucosticta Thuret, Grateloupia doryphora (Montagne) Howe., Undaria pinnatifida (Harv.) Suringar, Fucus virsoides J. Agardh, Cystoseira barbata (Good. et Wood.) Ag.) collected in four sampling sites in the lagoon of Venice, in spring and autumn 1999. Metals were extracted using hot concentrated acids in a Microwave Digestion Rotor and analysed by absorption spectrophotometry using a flame mode for Fe and Zn and a graphite furnace for Pb, Cr, Cd, Cu, Ni and As. High contamination levels, especially for Pb, were detected in Ulva and to a lesser extent in Gracilaria. Brown seaweeds, especially Cystoseira was highly contaminated by As. The least contaminated genera with all metals except As were Porphyra and Undaria. A concentration decrease for Zn and Cd was observed from the inner parts of the central lagoon, close to the industrial district, towards the lagoon openings to the sea.  相似文献   
897.
The accumulation of trace metals in aquatic organisms may lead to serious health problems through the food chain. The present research project aims to study the accumulation and potential sources of trace metals in aquatic organisms of the Pearl River Estuary (PRE). Four groups of aquatic organisms, including fish, crab, shrimp, and shellfish, were collected in the PRE for trace metal and Pb isotopic analyses. The trace metal concentrations in the aquatic organism samples ranged from 0.01 to 2.10 mg/kg Cd, 0.02 to 4.33 mg/kg Co, 0.08 to 4.27 mg/kg Cr, 0.15 to 77.8 mg/kg Cu, 0.17 to 31.0 mg/kg Ni, 0.04 to 30.7 mg/kg Pb, and 8.78 to 86.3 mg/kg Zn (wet weight). High concentrations of Cd were found in crab, shrimp and shellfish samples, while high concentration of Pb was found in fish. In comparison with the baseline reference values in other parts of the world, fish in the PRE had the highest elevated trace metals. The results of Pb isotopic compositions indicated that the bioaccumulation of Pb in fish come from a wide variety of food sources and/or exposure pathways, particularly the anthropogenic inputs.  相似文献   
898.
Abstract

Soil samples obtained from the former polybrominated biphenyls (PBB) manufacturing site in Michigan were analyzed by gas chromatography and gas chromatography with mass spectrometric detection. The results indicate significant degradation of the PBB residue in the soil sample. The soil sample with the highest concentration of PBB has the greatest degree of degradation. Principal degradation products include 2,3’,4,4’,5‐pentabromo‐biphenyl, 2,2’,4,4’,5‐pencabromobiphenyl and two unidentified tetrabromobiphenyls.

The degradation pattern observed supports a photochemical decomposition mechanism. These degraded residues may be more toxic than the original Firemaster residues. The implications of the results are discussed.  相似文献   
899.
The aim of this study was to investigate the pollution characteristics of typical veterinary antibiotics in manure and soil of livestock farms in Jiangsu province. This investigation employed solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A total of 53 manure and 50 amended soil samples from 16 livestock farms in Jiangsu province were collected for analysis. In the manure samples, the highest detected frequencies and concentrations were those of tetracyclines (TCs, 54.1 ± 5775.6 μgkg?1), followed by fluoroquinolones (FQs, 8.4 ± 435.6 μgkg?1), sulphonamides (SAs, 3.2 ± 5.2 μgkg?1) and macrolides (MACs, 0.4 ± 110.5 μgkg?1). Statistical analysis was used to illuminate the pollution characteristics of 23 veterinary antibiotics for various animal types and different regions in Jiangsu province. The results showed that the pollution level in cow manure was relatively lower compared with pig and chicken manure due to the relative restriction of medication. Furthermore, contamination was serious in amended soil from chicken farms. The pollution level in manure among different regions was higher to the south and north compared with the centre of the region. The same outcome was found for soil. Antibiotic residues in organic fertilizer were also investigated in this study. We found that although the detected concentration was lower in organic fertilizer than in fresh manure, detection frequencies (10–90%) were high, especially for roxithromycin (90%) in MACs (30–90%). This finding suggests attention should be paid to the pollution levels in organic fertilizer. This study is the first extensive investigation of the occurrence and distribution of many kinds of typical veterinary antibiotics in manure and soil from livestock farms of Jiangsu province. This investigation systematically assesses veterinary antibiotics usage and related emissions in southeast China.  相似文献   
900.
浙江省生态环境可持续发展评价指标体系的建立   总被引:8,自引:0,他引:8  
生态环境的可持续发展评价是生态安全与生态建设中的重要内容。本研究应用主成分分析法,收集浙江省1990~2000年的数据,对评价指标进行初步筛选.同时采用德尔斐法进行专家咨询,得到评价指标的分层排序。最后从初选的54个评价指标中,根据主成分分析法、专家咨询法的指标筛选结果,结合有关国家及地方生态环境建设规划,建立了由40个指标组成的浙江省生态环境可持续发展评价指标体系。  相似文献   
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