Valuing wetland conservation: A contingent valuation analysis among Iranian beneficiaries

Wetland ecosystems conservation is a critical environmental policy and practice challenge. Though policy protection mechanisms ostensibly establish a commitment to long-term protection, the level and types of wetland threats are growing. Management of sustainable wetland resources requires community commitments to protection amongst predominantly rural stakeholders that draw upon wetland ecosystem services for their livelihoods and is vital to forming a policy strategy. This empirical study uses contingent valuation methodology with rural residents around four key wetlands areas in the ecologically fragile Khuzestan province in Iran. We find that 65% of the residents are willing to pay an amount of personal income to protect wetland ecosystems. The estimated Logit model with 84% prediction accuracy showed the variables of education and job relationship with the wetland had a positive effect on the probability of price acceptance, and the variables of living costs and marital status had a negative effect on the probability of price acceptance. In total, the conservation value of wetlands is estimated at 103351.52 USD. Finally, we assess the policy-relevance of our findings towards community windfall payments, tax disbursements, community resource management schemes, public participation, and social outreach programs to improve social learning buy-in to long-term conservation practices.     

活化硅藻精土处理低浓度污水的试验研究

采用混凝搅拌试验,对影响活化硅藻精土处理低浓度污水的各项因素进行分析。实验表明,在最佳参数条件下,该工艺对污水中悬浮固体(SS)的去除率为95%、化学需氧量(COD)去除率为67%、氨氮(NH_3-N)去除率为16%、总磷(TP)去除率为91%,是一种优良的城市污水强化一级处理工艺。     

Fate of inoculated Escherichia coli in hay

AIMS: To monitor the fate of inoculated Escherichia coli in dry and moist hay of various types, under laboratory conditions. METHODS AND RESULTS: Wheat, vetch and clover hay were used as received or wetted to 250-300 g kg(-1) moisture. The hay was inoculated at about 10(6) CFU g(-1) with a kanamycin-resistant E. coli strain that expresses the green fluorescence protein, and was stored in small open glass jars that were covered with aluminium foil. Three jars per treatment were sampled on days 1 and 3, or 4 and 7, or 8, 20 and 50, respectively, after the initiation of the experiments, and the numbers of E. coli in the hay were determined. The results indicated that E. coli disappeared from both dry and moist hay by 7-8 days after inoculation. However, in a few cases colonies that were presumed to be E. coli developed after incubation in Luria broth medium. CONCLUSIONS: The tagged E. coli strain usually disappeared rapidly from both the dry and the moist hay, in spite of the high level of inocula used. However, in some cases a few, possibly injured E. coli might have persisted, and could be detected after incubation in a rich growth medium. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is part of a risk assessment associated with sewage irrigation of forage crops in Israel. The results indicate that E. coli added to the hay is not likely to pose a health risk to cattle or to humans. Nevertheless, more research with natural strains of E. coli and other enteric pathogens that might be more adapted to forage conditions is warranted in order to ensure the safety of sewage-irrigated crops.     

Biological Degradation of Crude Oil Refinery Sludge with Commercial Surfactant and Sewage Sludge by Co-Composting

This study determined the potential of surfactant and sewage sludge in enhancing degradation of oil sludge. A mixture of oil sludge, surfactant, and sewage sludge was co-composted for 24 weeks in the laboratory. Physical and chemical parameters in the compost were measured every four weeks. Isolated microorganisms were characterized by molecular techniques. The pH in all experiments remained between 8 and 6.4. CO₂ evolution reached 5503 µg/dwt/day by the twenty-fourth week. The dominant bacterial species were Acinectobacter, Rodococcus, mycobacterium, Pseudomonas, Bacillus, Arthrobacter, and Staphylococcus species and fungi were Pleurotus, Penicillium, and Aspergillus sp. TPH was reduced by 92% in the sewage sludge and surfactant treatment, 75 and 81% in other treatments, and 44.2% in the control. PAH concentrations were reduced by between 75 and 100%. The results indicate that a careful application of surfactant and sewage sludge could enhance oil sludge degradation in a compost system.     

Trace Elements in Edible Rocky Shore Species: Effect of Sewage Discharges and Human Health Risk Implications

Sewage pollution is a worldwide concern and can result in increasing levels of trace elements in the environment that can pose serious risks both to wildlife and human health. This highlights the importance of studying the role of sewage discharges in the contamination of aquatic systems, especially in rocky shores, since part of our food resources is directly collected from coastal waters. For this purpose, the accumulation of trace elements (Cu, Zn, Pb, Ni, Co, Cd, Fe, Mn, and As) by edible molluscs (Mytilus galloprovincialis, Patella ulyssiponensis, and Phorcus lineatus) was compared between one sewage-impacted area and two reference areas.

This study suggests that the concentrations of trace elements in the soft tissues of the selected molluscs can be affected by the presence of sewage discharges, and that limpets seem to be the best bioindicator. Moreover, the sewage pollution increased the concentrations of As in the mollusc species, emphasizing its potential damaging effects on natural systems and on edible species.     

温度对赤子爱胜蚓堆肥处理有机垃圾混合剩余污泥效率的影响

为了探讨环境温度对蚯蚓的生物量及其堆肥效率的影响,进行了不同培养温度条件下赤子爱胜蚓堆肥处理有机垃圾混合剩余污泥的研究。试验结果表明,在其他生态因子保持不变的情况下,赤子爱胜蚓的生长和繁殖具有一个适宜的温度范围,可能在20℃左右,温度太高或太低都对蚯蚓的生长和繁殖不利。赤子爱胜蚓对有机垃圾混合剩余污泥的堆肥效率在20℃达到最高,而在其他温度时较低,特别是低温(5℃、10℃)情况下堆肥效率显著降低,但温度较高(30℃、35℃)时其堆肥效率下降不显著。从产业应用的角度,如果同时考虑蚯蚓维持种群繁衍的再生产能力以及蚯蚓堆肥效率这两个因素,环境温度维持在20℃附近可能最适宜赤子爱胜蚓处理有机垃圾混合剩余污泥。     

Comparative study of seasonal and intradiurnal variation of airborne herbaceous pollen in urban and rural areas

The content of herbaceous pollen in the atmosphere depends on the vegetal cover, climate and the weather and geographical conditions. The aim of the study reported here was to compare aerobiological data obtained from pollen monitoring stations located at sites differing with respect to their flora and microclimate – i.e. a town and a rural area. A volumetric method was used for sampling. In each microscopic preparation 12 vertical strips corresponding with 2-h intervals were analysed. A 90% method was used to determine the pollen season. The results were statistically verified using the u test and the Kolmogorov-Smirnov, Spearman and Wilcoxon tests. Higher values of the Seasonal Pollen Index (SPI), higher daily average concentrations and higher peak values were recorded in the rural area. An analysis of intradiurnal variations of airborne pollen showed that apart from the Poaceae the number of pollen grains in the air began to increase earlier in the day in the rural area; in the case of Rumex and Ambrosia, the maximum values also appeared a few hours earlier. For all the taxa investigated, the analysis of correlation showed a significant association between the daily average concentrations at both sites. The weakest association occurred for Plantago lanceolata; for all other taxa, the determination coefficients (R ²) were high. The results of the Wilcoxon test showed that, despite the strong positive association between daily concentrations of the pollen types investigated, there were differences in mean pollen concentrations in the overlapping pollen season. Mean concentrations of Poaceae and Rumex airborne pollen were significantly higher in the rural area in both years, and those of Urtica and P. lanceolata were significantly higher only in 2002.     

城市污泥应用于陆地生态系统研究进展

随着城市化进程加快和人口剧增,城市污泥已成为世界许多城市面临的主要环境问题之一,且不合理的管理可引发严重的环境污染.城市污泥含有大量、微量元素和有机质,可能对土壤及其生产力有利,特别对退化土壤能进行有机修复,并改善土壤理化特性,譬如土壤结构和营养含量.目前,污泥作为一种有机肥料已成为普遍措施.但来自工业及生活污水的污泥常含有重金属、病原物及有毒有机物等,潜在的毒性可能对生态系统构成危险,因此必须经过污泥预处理才可安全施用.评述了近年来国内外污泥应用于陆地生态系统4个方面的主要研究进展:(1)污泥处理与处置方法;(2)污泥应用于农田、草地及森林生态系统;(3)污泥对土壤生态系统的影响,包括污泥对土壤理化性质、土壤酶及微生物的影响;(4)污泥应用的环境效应.提出未来我国污泥处置及利用需要重视的研究领域和方向.     

Production of PHB and P (3HB-co-3HV) biopolymers by <Emphasis Type="Italic">Bacillus megaterium</Emphasis> strain OU303A isolated from municipal sewage sludge

Bacillus megaterium strain OU303A isolated from municipal sewage sludge was selected for the study of biosynthesis of polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-hydroxyvalerate P (HB-co-HV) copolymer. The strain yielded a maximum of 62.43% DCW polymer in the medium containing glycerol as carbon source, which was followed by 58.63% DCW polymer in glucose containing medium. We found that this strain was capable of producing 2.5% hydroxyvalerate copolymer from a single carbon substrate, glucose. The strain showed an increase in the amount of HV monomer content, when the precursor for the copolymer was included in the fermentation medium. The characterization of the biopolymers was carried out using FTIR, GC-MS, H¹ NMR and DSC. This is the first report of B. megaterium strain producing HV copolymer, without the addition of any precursor in the fermentation medium.