Dynamics and Causation of Environmental Equity, Locally Unwanted Land Uses, and Neighborhood Changes

/ Why are some environmental risks distributed disproportionately in the neighborhoods of the minorities and the poor? A hypothesis was proposed in a recent study that market dynamics contributed to the current environmental inequity. That is, locally unwanted land uses (LULUs) make the host communities home to more poor people and people of color. This hypothesis was allegedly supported by a Houston case study, whereby its author analyzed the postsiting changes of the socioeconomic characteristics of the neighborhoods surrounding solid waste facilities. I argue that such an analysis of postsiting changes alone is insufficient to test the causation hypothesis. Instead, I propose a conceptual framework for analysis of environmental equity dynamics and causation. I suggest that the presiting neighborhood dynamics and the characteristics of control neighborhoods be analyzed as the first test for the causation hypothesis. Furthermore, I present theories of neighborhood change and then examine alternative hypotheses that these theories offer for explaining neighborhood changes and for the roles of LULUs in neighborhood changes. These alternative hypotheses should be examined when analyzing the relationship between LULUs and neighborhood changes in a metropolitan area. Using this framework of analysis, I revisited the Houston case. First, I found no evidence that provided support for the hypothesis that the presence of LULUs made the neighborhoods home to more blacks and poor people, contrary to the conclusion made by the previous study. Second, I examined alternative hypotheses for explaining neighborhood changes-invasion-succession, other push forces, and neighborhood life-cycle; the former two might offer better explanation.KEY WORDS: Environmental equity and justice; Locally unwanted lane uses; Siting; Market dynamics; Invasion-succession; Neighborhood changes     

Naphthalene and its biomarkers as measures of occupational exposure to polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAH) include compounds with two or more fused benzene rings, many of which are carcinogens. Industrial sources produce hundreds of PAH, notably in the coke- and aluminium-producing industries. Because PAH are distributed at varying levels between gaseous and particulate phases, exposure assessment has been problematic. Here, we recommend that occupational exposures to naphthalene be considered as a potential surrogate for occupational PAH exposure for three reasons. Naphthalene is usually the most abundant PAH in a given workplace; naphthalene is present almost entirely in the gaseous phase and is, therefore, easily measured; and naphthalene offers several useful biomarkers, including the urinary metabolites 1- and 2-hydroxynaphthalene. These biomarkers can be used to evaluate total-body exposure to PAH, in much the same way that 1-hydroxypyrene has been applied. Using data from published sources, we show that log-transformed airborne levels of naphthalene are highly correlated with those of total PAH (minus naphthalene) in several industries (creosote impregnation: Pearson r= 0.815, coke production: r= 0.917, iron foundry: r= 0.854, aluminium production: r= 0.933). Furthermore, the slopes of the log-log regressions are close to one indicating that naphthalene levels are proportional to those of total PAH in those industries. We also demonstrate that log-transformed urinary levels of the hydroxynaphthalenes are highly correlated with those of 1-hydroxypyrene among coke oven workers and controls (r= 0.857 and 0.876), again with slopes of log-log regressions close to one. These results support the conjecture that naphthalene is a useful metric for occupational PAH exposure. Since naphthalene has also been shown to be a respiratory carcinogen in several animal studies, it is also argued that naphthalene exposures should be monitored per se in industries with high levels of PAH.     

某铀矿工人头发中总α,总β,铀,钍放射性水平的调查

本文对某铀矿职业工人和非职业工人头发中的总β、总α放射性水平和铀、钍含量进行了分析测定.结果表明,该矿工人体内铀和钍的蓄积量均在正常放射性本底水平范围内,从头发中检验未观察到工人体内铀、钍放射性水平有明显的升高.     

金属对催化还原DDT的降解产物及其反应机制的研究

本报告介绍DDT经金属对处理后降解产物的分析鉴定和有关反应机制的初步研究。 降解产物主要是用气相色谱—质谱联用分析鉴定的。水溶液中的DDT用Cu-Zn金属对还原其降解产物经鉴定是DDD、DDMS、DDE_t,它们是DDT分子脱去烷基碳原子上不同数目的氯原子的产物。而在Cu-Fe金属对作用下,水溶液中的DDT的还原则是同时得到四种不同类型的产物。它们是DDT脱去烷基碳原子上的1个和3个氯原子的DDD和DDE_t;DDT脱氯、氧化产物DBP和DBH;DDT脱去HCI生成的DDE;两个DDT分子二聚脱氯的产物TTTB和TTDB。 实验证明金属对对DDT的作用是催化还原反应,金属对起着催化剂和还原剂双重作用。通过实验结果对DDT在金属对作用下的反应机制进行了初步探讨。     

我国淡水水域光合产物的气候生产力探讨

根据太阳辐射在水体中的有效分布、生长季水温和浮游植物光合生态特性等因子,模拟计算了我国大陆东部淡水水域的光合生产力、气候生产力及其季节变化的地理规律。从中得知,这些水域初级产物的年气候生产力主要呈纬向分布,由南向北递减,各地范围在 1.6-24.4gC/m²·a之间,长江以南是>15.0gC/m²·a的高值区,长城以北和四川盆地为<10.0gC/m²·a的低值区,因此,在气候生产力高值区有可能充分利用气候资源优势,开发低成本的自然淡水水域渔业;而在低生产力区,受自然资源的局限其自然捕鱼量需适量控制,因地制宜。     

某石化企业粉体料仓爆燃事故原因分析

本文以某企业HDPE料仓的一次爆燃事故为案例,通过分析事故的成因,提供了调查料仓事故的思路及整改方案的确定方法.     

“华夏古陆”考异

自葛利普创名“华夏古陆”以来,经过半个多世纪的论辩与考订,对其地质构造属性,至今仍然否定与肯定交迭起伏,莫衷一是,本文从推覆构造,陆地漂移等实际资料着手,加以论证,认为它是经历深刻改造和发生巨大位移的变质岩断片体,地质构造属性已非“华夏古陆”原义。     

废水中对—氨基苯酚的电位溶出法测定

采用Nafion修饰电极,以微分计时电位溶出法分析测定废水中对—氨基苯酚(PAP)。在选定的条件下,PAP的测定范围在1.0μ～0.5mmol/l之间;最低检测浓度为0.1μmol/l;标准偏差为1.6％:方法的回收率为92.5％～96.5％。     

复合氧化物汽车尾气净化催化剂抗SO2中毒机理研究

复合氧化物催化剂(ASC)具有较高的活性和良好的抗SO_2中毒性能.用IR、XPS、TPD等技术研究了该催化剂抗SO_2中毒机理,结果表明,与易失活催化剂相比,ASC经500h反应(反应气含SO_2约20ppm),其活性组分价态无显著变化,仅表面发生SO_2的化学吸附,经与约500ppm的SO_2作用20h后,发现仅有少量SO_4~(2-)形成.这是由于在ASC催化剂中添加了特殊助剂,而使催化剂活性组分得到保护的缘故.