Influence of water treatment residuals on phosphorus solubility and leaching

Laboratory and greenhouse studies compared the ability of water treatment residuals (WTRs) to alter P solubility and leaching in Immokalee sandy soil (sandy, siliceous, hyperthermic Arenic Alaquod) amended with biosolids and triple superphosphate (TSP). Aluminum sulfate (Al-WTR) and ferric sulfate (Fe-WTR) coagulation residuals, a lime softening residual (Ca-WTR) produced during hardness removal, and pure hematite were examined. In equilibration studies, the ability to reduce soluble P followed the order Al-WTR > Ca-WTR = Fe-WTR > hematite. Differences in the P-fixing capacity of the sesquioxide-dominated materials (Al-WTR, Fe-WTR, hematite) were attributed to their varying reactive Fe- and Al-hydrous oxide contents as measured by oxalate extraction. Leachate P was monitored from greenhouse columns where bahiagrass (Paspalum notatum Flugge) was grown on Immokalee soil amended with biosolids or TSP at an equivalent rate of 224 kg P ha(-1) and WTRs at 2.5% (56 Mg ha(-1)). In the absence of WTRs, 21% of TSP and 11% of Largo cake biosolids total phosphorus (PT) leached over 4 mo. With co-applied WTRs, losses from TSP columns were reduced to 3.5% (Fe-WTR), 2.5% (Ca-WTR), and <1% (Al-WTR) of applied P. For the Largo biosolids treatments all WTRs retarded downward P flux such that leachate P was not statistically different than for control (soil only) columns. The phosphorus saturation index (PSI = [Pox]/ [Al(ox) + Fe(ox)], where Pox, Al, and Fe(ox) are oxalate-extractable P, Al, and Fe, respectively) based on a simple oxalate extraction of the WTR and biosolids is potentially useful for determining WTR application rates for controlled reduction of P in drainage when biosolids are applied to low P-sorbing soils.     

Estimates of health benefits due to reductions in ambient NO2 levels

A method is presented here by which the actual numbers of individuals in the U.S. population who would be expected to suffer respiratory illness as a result of exposure to ambient nitrogen dioxide (NO₂) concentrations in excess of the Federally-designated ambient air quality standard can be estimated. At the same time we have attempted to quantify how these adverse health effects would be alleviated by various degrees of reductions in current ambient concentrations. In addition, the health benefit expected to be derived by various NO_x emission control strategies will be examined utilizing the health benefit estimation method presented.It is estimated that there were approximately 33.2×10⁶ excess cases of respiratory illnesses in the U.S. in 1973 associated with ambient NO₂ concentrations in excess of the national ambient standard. A reduction of approximately 50 to 60 percent below 1973 NO₂ levels is needed to essentially eliminate excess respiratory illness associated with ambient NO₂ concentration.     

Alliances in winter flocks of willow tits; effects of rank on survival and reproductive success in male-female associations

Summary The value of being dominant in winter flocks of willow tits may not only be a matter of personal survival for males, although their survival probability was highest among flock members. Winter flocks of willow tits contain male-female subunits, and the dominant pair may be viewed as an alliance based on mutual benefits. Dominant males provide their mates with protection in winter, and females return the help in reproductive success. Survival was directly related to rank only within sexes. Mates of dominant males survived significantly better than low-ranked males even though these females were subordinate to these males in direct interactions. Mates of dominant males were relatively spared from costs of low rank as they were subject to aggression less often than expected. Presumably dominant males prevented such attacks, as they excluded other flock members from high tree sections where their mates fed. Males should gain from improving the survival probability of their mates since it was not always possible to replace lost mates in spring populations having a male-biased sex ratio. Dominance in avian winter flocks may thus have more indirect effects than merely to improve the personal survival probability through resource priority. The benefits of being a dominant suggest that subordinate willow tits join groups because there is no space available for them to take up a territory as dominants.     

Temporal induction pattern of hepatic cytochrome P450 1A in thermally acclimated dab (Limanda limanda) treated with 3,3′,4,4′-Tetrachlorobiphenyl (CB77)

Mature male dab (Limanda limanda) acclimated at 10° and 16°C were orally administered a single dose of 0.5 mg/kg 3,3′,4,4′-tetrachlorobiphenyl (CB77). At both temperatures, levels of cytochrome P450 1A (CYP1A) protein and 7-ethoxyresorufin O-deethylase (EROD) activity showed a two to six fold induction 40 days after CB77 treatment compared to control groups. Maximum responses of both EROD activity and CYP1A protein for the warm-acclimated fish were observed at 5 days after treatment. For the cold-acclimated fish a slow, progressive elevation for both EROD activity and CYP1A protein was observed and maximum responses were measured 40 days after treatment. Absolute EROD activity and CYPIA protein levels of fish from both temperatures were equally high at 40 days after treatment. Since in the control groups EROD activity and CYP1A protein levels were higher in the cold-acclimated fish, the magnitude of induction was higher in the warm acclimated ones. The highest concentrations of CB77 in muscle of fish from both temperatures were found at 5 and 10 days after treatment. The liver somatic index (LSI) showed 1.5 fold significantly higher values for the fish acclimated at 10°C.     

Cost-benefit ratio and empirical examination of the acceptance of heathland maintenance in the Lueneburg heath nature reserve

The cost-benefit ratio of heathland maintenance measures was assessed in the Lueneburg Heath nature reserve in North-West Germany. This nature reserve contains large areas of heathland and is of substantial ecological and historical importance. The heathland can only be preserved by regular maintenance. For this assessment the costs of the maintenance measures were traced and a survey of visitors was carried out. The willingness-to-pay of the visitors for the heathland maintenance was determined as an assessment of the benefit created. Furthermore, the social acceptance of each maintenance measure was examined as this variable can influence the economic data considerably. These aspects represent a basis for the assessment of the net costs and benefits and for the calculation of the net present value (NPV) provided by the maintenance of the area. The results show a substantial positive net benefit of the heathland maintenance as a whole and varying acceptance of the different maintenance measures.     

Removal of Phosphorus in Constructed Wetlands with Horizontal Sub-Surface Flow in the Czech Republic

The major processes responsible for phosphorus (P) removal in constructed wetlands with horizontal sub-surface flow (HSF CWs) are adsorption, precipitation and plant uptake if the biomass is harvested. The filtration materials frequently used in HSF CWs, i.e., gravel or crushed rock, provide only limited adsorption and plants are not regularly harvested. As a result, the removal of P in HSF CWs is usually low and typically amounts to only 40 to 60% during the treatment of municipal or domestic sewage. The average inflow and outflow P concentrations for vegetated beds of Czech HSF CWs were 6.6 mg L^-1 and 3.6 mgL^-1, respectively. The average P removal was 45.7%. Despite a wide fluctuation of inflow phosphorus loading rates in the Czech CWs (10.9 – 356 g P m^-2 a^-1) the retention of P is well predictable. The CWs in the Czech Republic are relatively new and therefore, it is not possible to evaluate long-time performance of P removal. However, results from systems that have been in operation for longer periods (maximum of 9 years) indicate that P removal decreases over years probably as a result of limited sorption capacity. The amount of P removed by aboveground Phragmites biomass is very low and usually does not exceed 5% of the total removed P in the beginning of operation. As the sorption decreases over years and macrophyte biomass increases at the same time the importance of P bound in biomass becomes higher but it rarely exceeds the level of 20% of the total P removed.     

两维缺陷分析:用于保护规划和实施生物多样性政策的有效手段

在景观水平的管理中,为了保护具有代表性和连接成片的生境网络,以达到维持生物多样性的目的,就必须在不同规模上将保护、经营和生境恢复等几项工作有机结合.我们认为将自然和社会科学融为一体的两维缺陷分析方法是实施生物多样性政策的有效工具.这个工具把与生物相关的"水平"生态学问题与"垂直"的制度体制和其它社会问题有机结合考虑.以森林生物多样性为例,本文将演示如何将与生物多样性保护有关的生态学和制度等方面的问题综合考虑,从而促进整个区域发展的环境可持续性.尤其,我们用区域性缺陷分析方法,即先确定对"绿色基础设施"起功能性连接作用的重点森林类型和生境模型,以此作为工具进行"水平"缺陷分析.就"垂直"范围而论,通过鉴别政策实施中的体制性障碍我们指出社会科学如何用于在实际景观范围内评估生物多样性政策实施是否成功.研究表明,多学科间的合作方法能应用于其它各类环境,包括其它陆生生物和水生生态系统,在这些生态系统中,重要栖息地的连接性、对栖息地丧失的非线性响应,以及社会和经济问题在同一景观内交织在一起.