Social Acceptability of Water Resource Management: A Conceptual Approach and Empirical Findings from Portland,Oregon1

Abstract: Surface water resources in urban areas serve multiple functions ranging from recreation to wildlife habitat. As a result, diverse values influence people’s views about resource protection, potentially leading to conflicting interests. In metropolitan Portland, Oregon, natural resource planning has recently focused on habitat restoration as well as stormwater and pollution mitigation, especially through the protection of riparian areas. Due to opposition over proposed regulations in the study region, this research examines public attitudes about an array of resource management efforts. The primary research question is: what is the extent of positive–negative attitudes about water resource protection, and what theoretical dimensions underlie diverse judgments? After empirical survey results are presented, I outline a conceptual approach for future assessments of environmental attitudes while highlighting important value‐based dimensions of judgments. Although flexible, the framework allows broad comparisons to advance knowledge about the social acceptability of varied water resource management approaches across diverse places and contexts.     

Dechlorination of polyvinyl chloride in NaOH/ethylene glycol solution by microwave heating

This study investigated the dehydrochlorination of flexible polyvinyl chloride (PVC) containing 59.2% PVC, 29.7% dioctyl phthalate (DOP), and approximately 12% stabilizers. Flexible PVC was treated with NaOH/ethylene glycol (NaOH/EG) solutions at NaOH concentrations in the range 0.5–4 mol/l and was heated in a microwave heater at a temperature between 100° and 160°C for 0–30 min. All chlorides were completely eliminated by internal heating at 160°C using microwaves for 10 min in a 1 mol/l NaOH/EG solution, and the residue was made up of hydrocarbons. The weight loss rate reached a maximum of 74.7% at a temperature of 160°C. It was discovered that the use of microwaves significantly shortened the reaction time compared to using conventional electric heaters or other external heating systems and also allowed the use of lower concentrations of NaOH. Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6     

The Effect of Masterbatch Addition on the Mechanical, Thermal, Optical and Surface Properties of Poly(lactic acid)

There has been considerable interest in the use of the biodegradable polymer poly(lactic acid) (PLA) as a replacement for petroleum derived polymers due to ease of processability and its high mechanical strength. Other material properties have however limited its wider application. These include its brittle properties, low impact strength and yellow tint. In an attempt to overcome these drawbacks, PLA was blended with four commercially available additives, commonly known as masterbatches. The effect of the addition of 1.5 wt% of the four masterbatches on the mechanical, thermal, optical and surface properties of the polymer was evaluated. All four masterbatches had a slight negative effect on the tensile strength of PLA (3–5% reduction). There was a four fold increase in impact resistance however with the addition of one of the masterbatches. Differential scanning calorimetry demonstrated that this increase corresponded to a decrease in the polymer crystallinity. However there was an associated increase in polymer haze with the addition of this masterbatch. The clarity of PLA was improved through the addition of an optical brightener masterbatch, but the impact resistance remained low. The glass transition and melting temperatures of PLA were not affected by the addition of the masterbatches, and no change was observed in surface energy. Some delay in PLA degradation, in a PBS degradation medium at 50 °C, was observed due to blending with these masterbatches.     

AHP-SWOT法在道路交通安全改善策略中的应用

针对交通事故的特点,探讨AHP-SWOT方法在道路交通事故评价中的具体应用。SWOT(优势—劣势,机会—威胁)分析法是一种综合考虑系统外部环境和内部条件的各种因素,对其进行系统评价并从中选择最佳策略的方法,但是它缺少定量分析的过程。AHP(层次分析法)具有定性分析和定量分析相结合的优势,采用SWOT和AHP相结合的方法进行评价更加合理和准确。将AHP-SWOT方法应用于道路交通安全评价系统,分析道路交通安全系统所面临的机会和威胁、所处的优势和劣势,可为正确评价道路安全水平、制定合理的道路交通安全改善策略提供理论指导。实例证明该方法可行有效。     

赤霉酸暴露对SD大鼠青春期发育的影响

赤霉酸是目前国内外使用极其广泛的一种植物生长调节剂,但是针对其发育毒性的数据依然较少。本文探讨了赤霉酸暴露对SD大鼠青春期发育的影响。参考国内外环境内分泌干扰物危害的评价方法,将144只初断乳SD大鼠按体重随机分为4组,分别为对照组和1、10、100 mg·kg-1bw剂量组,采用经口灌胃方式对雄鼠连续染毒28 d,雌鼠连续染毒21 d。暴露结束后检测大鼠的体重、食物利用率、雄鼠包皮分离时间/雌鼠阴道开口时间、血清生化指标、脏器系数及组织病理学的变化。研究结果表明,与对照组相比,仅10和100 mg·kg-1bw剂量组雄鼠的肌酐水平显著升高(P<0.01),100 mg·kg-1bw剂量组雌鼠谷丙转氨酶水平有显著升高(P<0.01)。而与对照组相比,所有剂量组均未观察到大鼠的体重、食物利用率、雄鼠包皮分离时间/雌鼠阴道开口时间、脏器系数等指标有显著性差异的改变(P>0.05),组织病理学结果亦显示大鼠重要器官无损害性改变。因此,在本试验给予的剂量范围内赤霉酸染毒不会对SD大鼠青春期发育产生显著影响。     

不同暴露途径下有机污染物对大鼠急性毒性的相关性研究

不同暴露途径下有机物在生物体内的吸收分布不同,导致毒性效应亦不同,研究化学品在不同暴露途径下对生物体的毒性,对化学品的安全性评价有实际意义。本文通过研究静脉注射、腹腔注射、肌肉注射与经口灌胃4种暴露途径下527个有机物对大鼠的急性毒性数据相关性,比较了不同暴露途径下大鼠对有机污染物的敏感度顺序,结果为:静脉注射>腹腔注射>肌肉注射>经口灌胃途径,静脉注射途径下log1/LD50与其他几种注射途径下的log1/LD50有较显著的相关性,但是与灌胃途径下毒性值之间的相关性较差,相关系数r的范围为0.82~0.97。通过逐项分析研究不同暴露途径下化合物对大鼠的急性毒性与生物利用度、吸收速率、消除速率以及代谢过程的关系,结果表明,导致这种差异的原因主要是有机污染物在大鼠体内的吸附动力学过程不同所致。     

Pesticide residue removal in classic domestic processing of tomato and its effects on product quality

This study was undertaken to evaluate the effectiveness of several household practices (washing with water or acidic, alkaline, and oxidizing solutions, and peeling) in minimizing pesticide residue contamination of tomatoes, as well as the impact on the quality of the treated fruit. Tests were performed using two systemic fungicides (azoxystrobin and difenoconazole) and one contact fungicide (chlorothalonil). Solid-liquid extraction with low temperature partition (SLE/LTP) and liquid-liquid extraction with low temperature partition (LLE/LTP) were used to prepare the samples for pesticides determination by gas chromatography. Washing the tomatoes with water removed approximately 44% of chlorothalonil, 26% of difenoconazole, and 17% of azoxystrobin. Sodium bicarbonate (5%) and acetic acid (5%) solutions were more efficient, removing between 32 and 83% of the residues, while peeling removed from 68 to 88% of the pesticides. The washing solutions altered some fruit quality parameters, including acidity and chroma, and also caused weight loss. Acetic acid (0.15 and 5%) and hypochlorite (1%) solutions had the greatest effect on these parameters.     

Advantages and risks of using steel slag in preparing composts from raw organic waste

It had been reported that iron and manganese oxides in steel slag enhanced the production of humic acid (HA) from low-molecular-weight compounds, such as phenolic acids, amino acids, and saccharides. In the present study, this function of steel slag was applied to the composting of raw organic wastes (ROWs). The degree of humification of HAs is an important factor in evaluating compost quality. Thus, HAs were extracted from the prepared composts and the humification parameters were determined, in terms of elemental compositions, acidic functional group contents, molecular weights, spectroscopic parameters from UV–vis absorption and ¹³C NMR spectra. The timing for adding steel slag affected the degree of humification of HAs in the composts. The weight average molecular weight of a HA when slag was added initially (29 kDa) was significantly higher than when slag was added after elevating the temperature of the compost pile (17–18 kDa). These results show that ROWs are decomposed to low-molecular-weight compounds after the pile temperature is elevated and the presence of slag enhances the polycondensation of these compounds to produce HAs with a higher degree of humification. Because the slag used in the present study contained several-tens ng g^?1 to several μg g^?1 of toxic elements (B, Cu, Cr, and Zn), leaching tests for these elements from the prepared composts were carried out. Levels for leaching boron from composts prepared by adding slag (0.2–0.4 mg L^?1) were obviously higher than the corresponding levels without slag (0.05 mg L^?1).     

Glutamine synthetase and protease enzyme activities and growth response of ruminal bacterium Prevotella ruminicola strain B14 to nitrogen source and concentration

Abstract

The objective of this study was to determine the effects of varying nitrogen sources and concentrations upon glutamine synthetase and protease activities in Prevotella ruminicola strain B₁4. Based on growth response it appears that ammonium chloride or pepticase limited P. ruminicola becomes nitrogen limited when nitrogen concentration is at 0.5 mM. However, when casein was provided as the sole source of nitrogen P. ruminicola becomes nitrogen limited at 2.5 mM. Glutamine synthetase activity was measured from mid‐log phase cells grown in either nitrogen‐limited or non‐limited conditions. No activity was detectable in the non‐limited treatments. However, in the N‐ limited treatments, pepticase had the highest activity (20.76 units), followed by ammonium chloride (18.72 units) and casein (14.42 units). Protease activity assays indicated that nitrogen‐limited cultures had higher proteolytic activity than non‐limited cultures. Moreover, these activities appeared to follow the same response pattern as the previously observed glutamine synthetase activities. The results of this study indicate that P. ruminicola strain B, 4 protease activity may be influenced by nitrogen concentration such that activity increases when nitrogen availability decreases.