Comparison of solid-phase and eluate assays to gauge the ecotoxicological risk of organic wastes on soil organisms

Development of methodologies to assess the safety of reusing polluted organic wastes in soil is a priority in Europe. In this study, and coupled with chemical analysis, seven organic wastes were subjected to different aquatic and soil bioassays. Tests were carried out with solid-phase waste and three different waste eluates (water, methanol, and dichloromethane).Solid-phase assays were indicated as the most suitable for waste testing not only in terms of relevance for real situations, but also because toxicity in eluates was generally not representative of the chronic effects in solid-phase.No general correlations were found between toxicity and waste pollutant burden, neither in solid-phase nor in eluate assays, showing the inability of chemical methods to predict the ecotoxicological risks of wastes. On the contrary, several physicochemical parameters reflecting the degree of low organic matter stability in wastes were the main contributors to the acute toxicity seen in collembolans and daphnids.     

Comparison of solid-phase bioassays and ecoscores to evaluate the toxicity of contaminated soils

Five bioassays (inhibition of lettuce germination and growth, earthworm mortality, inhibition of springtail population growth, avoidance by springtails) were compared, using four coke factory soils contaminated by PAHs and trace elements, before and after biotreatment. For each bioassay, several endpoints were combined in an ‘ecoscore’, a measure of test sensitivity. Ecoscores pooled over all tested bioassays revealed that most organisms were highly sensitive to the concentration of 3-ring PAHs. When four soils were combined, behavioural tests using the springtail Folsomia candida showed higher ecoscores, i.e. they were most sensitive to soil contamination. However, despite overall higher sensitivity of behavioural tests, which could be used for cheap and rapid assessment of soil toxicity, especially at low levels of contamination, some test endpoints were more sensitive than others, and this may differ from a soil to another, pointing to the need for a battery of bioassays when more itemized results are expected.     

School building condition,school attendance,and academic achievement in New York City public schools: A mediation model

Little is known about how the condition of school facilities affects academic outcomes. This study examines the role of school attendance as a mediator in the relationship between facilities in disrepair and student grades in city and state tests. Data on building condition and results from English Language Arts (ELA) and Mathematics (Math) standardized tests were analyzed using a sample of 95 elementary schools in New York City. Variables relevant to academic achievement such as ethnicity, socioeconomic status, teacher quality, and school size were used as covariates. In run-down school facilities students attended less days on average and therefore had lower grades in ELA and Math standardized tests. Attendance was found to be a full mediator for grades in ELA and a partial mediator for grades in Math. This study provides empirical evidence of the effects of building quality on academic outcomes and considers the social justice issues related to this phenomenon.     

Fractionation and Biotoxicity of Heavy Metals in Urban Dusts Collected from Hong Kong and London

Samples of urban dusts, road site dusts and car park dusts, were collected at two selected sites each in Hong Kong and London. Sequential extraction was used to characterise the chemical compositions of these urban dusts. Copper, lead, zinc, pH, electrical conductivity and organic content were measured. Biotoxicity tests of urban dusts were conducted on higher plants (Brassica chinensis and Lolium perenne), a dinoflagellate green alga (Dunaliella tertiolecta) and luminescent bacteria (Photobacterium phosphoreum). A significant correlation was found between total lead (r =; – 0.70, p < 0.01) and zinc (r =; – 0.74, p < 0.05), and the 20 min – EC50 using P. phosphoreum. In addition, there was a significant correlation (r = – 0.72, p < 0.01) between the exchangeable lead content in dust and the 48 h- EC30 using D. tertiolecta. No specific trend was obtained for higher plants. Total lead and zinc contents were higher in dusts from London while the percentage of exchangeable fraction of metal contents was higher in those from Hong Kong.     

纵向排烟与集中排烟下烟气控制效果的对比研究

以某特长公路隧道为研究背景,采用缩尺寸试验测试、数值模拟的方法分别对纵向排烟和集中排烟模式下隧道内火灾烟气的蔓延特性进行了研究,并对比分析了两种排烟系统在火灾工况下对烟气的控制效果。结果表明,纵向排烟模式将火灾烟气控制在火源下游并从隧道出口排出,高温烟气蔓延范围较长;集中排烟模式通过排烟阀将烟气抽离行车道,有效地控制了烟气蔓延和沉降,高温烟气维持在行车道的上部空间,主要通过竖井排出隧道。采用纵向排烟模式的坡度隧道烟气控制受烟囱效应影响较大,而在设置排烟道的坡度隧道中,将排烟阀开启进行自然排烟就能有效地减弱烟囱效应。因此,采用集中排烟模式的防灾安全性能要优于采用纵向排烟模式。     

Regulating post-implantation fetal sex selection: a UK perspective

This article reviews the current and potential laws relevant to post-implantation fetal social sex selection and considers whether they could provide an effective deterrent and control of the practice, if the United Kingdom decided that such control were desirable. It concludes that enacting, drafting and enforcing of any legislation throws up many difficult practical and ethical issues. These issues need to be debated and further information collected before any legislation is rushed into. Copyright © 2006 John Wiley & Sons, Ltd.     

Combating the Illegal Trade in African Elephant Ivory with DNA Forensics

Abstract:  International wildlife crime is burgeoning in this climate of global trade. We contend that the most effective way to contain this illegal trade is to determine where the wildlife is being removed. This allows authorities to direct law enforcement to poaching hot spots, potentially stops trade before the wildlife is actually killed, prevents countries from denying their poaching problems at home, and thwarts trade before it enters into an increasingly complex web of international criminal activity. Forensic tools have been limited in their ability to determine product origin because the information they can provide typically begins only at the point of shipment. DNA assignment analyses can determine product origin, but its use has been limited by the inability to assign samples to locations where reference samples do not exist. We applied new DNA assignment methods that can determine the geographic origin(s) of wildlife products from anywhere within its range. We used these methods to examine the geographic origin(s) of 2 strings of seizures involving large volumes of elephant ivory, 1 string seized in Singapore and Malawi and the other in Hong Kong and Cameroon. These ivory traffickers may comprise 2 of the largest poaching rings in Africa. In both cases all ivory seized in the string had common origins, which indicates that crime syndicates are targeting specific populations for intense exploitation. This result contradicts the dominant belief that dealers are using a decentralized plan of procuring ivory stocks as they became available across Africa. Large quantities of ivory were then moved, in multiple shipments, through an intermediate country prior to shipment to Asia, as a risk-reduction strategy that distances the dealer from the poaching locale. These smuggling strategies could not have been detected by forensic information, which typically begins only at the shipping source.     

An overview of short‐term tests for the mutagenic and carcinogenic potential of pesticides

Abstract

In the last few years, marked progress has been made in the development of methods for evaluating the mutagenic and carcinogenic potential of pesticide chemicals. The correlation of genetic and related biological activity in short‐term tests with carcinogenic activity in whole animals allows the utilization of short‐term mutagenicity bioassays to prescreen chemicals for effects related to mutation induction and presumptive carcinogenicity. In addition, bioassays now available can measure directly the chemical transformation of normal cells in culture into cells capable of producing tumors when injected into animals.

This paper will review briefly the major types of relevant short‐term tests and will develop a rationale for a phased approach to the evaluation of the mutagenic and carcinogenic potential of environmental chemicals. This approach involves the sequential application of bioassays which are organized into a three‐level matrix emphasizing first detection, then confirmation, and finally hazard assessment. Chemicals demonstrating positive results in the short‐term detection systems and confirmatory bioassays are pursued in higher level whole animal tests. A core battery of tests is proposed to operationally define a negative result. The phased approach should facilitate a cost effective utilization of limited testing resources and provide protection for human health in proportion to the anticipated hazard.

Results obtained in evaluating a series of thirty‐eight pesticide chemicals according to the phased approach are discussed in detail.     

原子荧光光谱法测定水中砷的方法比对试验

通过试验分析确定了原子荧光光谱法测定水样中砷的检测条件,并在优化试验条件下与现行砷的国家标准分析方法GB 7485-87进行了样品分析比对实验,试验表明,该方法操作简单方便,历时短,可大大提高检测效率,完全可以代替分析操作复杂繁琐的现行国家标准分析方法。