Effects of fifteen PBDE metabolites, DE71, DE79 and TBBPA on steroidogenesis in the H295R cell line

Polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA) are brominated flame retardants that are produced in large quantities and are commonly used in construction materials, textiles, and as polymers in electronic equipment. Environmental and human levels of PBDEs have been increasing in the past 30 years, but the toxicity of PBDEs is not fully understood. Studies on their effects are relatively limited, and show that PBDEs are neurotoxins and potential endocrine disrupters. Hydroxylated (OH) and methoxylated (MeO) PBDEs have also been reported in the adipose tissue, blood and milk of wild animals and humans. In the present study, 15 PBDE metabolites, two BDE mixtures (DE71 and DE79), and TBBPA were studied individually to determine their effects on ten steroidogenic genes, aromatase activity, and concentrations of two steroid hormones (testosterone and 17beta-estradiol) in the H295R human adrenocortical carcinoma cell line. Exposure to 0.05 microM 2'-OH-BDE-68 significantly induced the expression of CYP11A, CYP11B2, CYP17, CYP21, 3betaHSD2, 17betaHSD1, and 17betaHSD4, and the expression of StAR was induced by 6-OH-BDE-90 at the three exposure concentrations. Exposure to DE71 and DE79 resulted in dose-dependent trend towards induction, but these effects were not significant. Exposure to 0.5 microM 2-OH-BDE-123 and 2-MeO-BDE-123 resulted in significantly greater aromatase activity. However, none of the compounds affected sex hormone production at the concentrations tested. Generally, OH-BDEs had a much stronger ability to affect steroidogenic gene expression than MeO-BDEs.     

Accumulation of perfluorinated compounds in captive Bengal tigers (Panthera tigris tigris) and African lions (Panthera leo Linnaeus) in China

The accumulation of perfluorinated compounds (PFCs) in the sera of captive wildlife species Bengal tigers (Panthera tigris tigris) and African lions (Panthera leo Linnaeus) from Harbin Wildlife Park, Heilongjiang Province, in China were analyzed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Perfluorooctanesulfonate (PFOS) was the predominant contaminant with a mean serum concentration of 1.18 ng mL(-1) in tigers and 2.69 ng mL(-1) in lions. Perfluorononanoic acid (PFNA) was the second most prevalent contaminant in both species. The composition profiles of the tested PFCs differed between tigers and lions, and the percentages of perfluorooctanoic acid (PFOA) were greater in lions than in tigers, indicating different exposures and/or metabolic capabilities between the two species. Assessments of the risk of PFC contamination to the two species were obtained by comparing measured concentrations to points of departure or toxicity reference values (TRVs). Results suggest no risk of PFOS exposure or toxicity for the two species.     

土壤中全氟和多氟烷基化合物的污染现状及环境行为

全氟和多氟烷基化合物（perfluoroalkyl and polyfluoroalkyl substances,PFASs）是一类新兴持久性有机污染物.土壤中PFASs可以通过淋溶作用进入地下水影响水质安全,或者通过陆生食物链的传递和生物放大作用危害生态系统和人类健康,有关土壤中PFASs的赋存状况、浓度水平与行为机制的研究已经成为环境化学领域的热点之一.目前土壤中可以准确测定的PFASs在含氟化合物总量中的占比不到1%,含量为ng/g水平.我国相关研究主要集中在东部及氟化工厂周边地区,其组分以全氟辛烷磺酸（Perfluorooctane sulfonic acid,PFOS）和全氟辛酸（Perfluorooctanoic acid,PFOA）等长链PFASs为主.不同类型土壤中PFASs的赋存特征主要受到物质种类与土壤理化性质及周边人类活动的影响.除了含氟化学品生产和使用过程中的直接释放和大气传输以外,PFASs前体物在土壤环境中的转化也是其重要来源.吸附-解吸是PFASs在土壤中的主要归趋方式,化合物碳链长度及官能团种类、土壤理化性质和生物种类等因素都会影响其在土壤中的迁移转化和富集能力.鉴于目前的研究现状,需要进一步优化土壤中PFASs的提取和分析方法,关注新型PFASs在土壤中的变化趋势及行为机制,开展土壤中PFASs的生物可给性和生物可利用性研究,进一步评估PFASs的生态与人体健康风险.      

Trace contamination with dioxin-like chemicals: evaluation of bioassay-based TEQ determination for hazard assessment and regulatory responses

Many recent dioxin contamination events have been traced back to poisoned animal feed or feed ingredients. Therefore, enforcement authorities placed limits on the levels of dioxins in food and feed or implemented strict monitoring and control programs. The levels in force are generally expressed as TEQ values, which inherently accepts the underlying hypothesis that the effects of dioxin-like chemicals are additive. TEQ determination involves either chemo-analysis, with high-resolution gas chromatography in combination with high-resolution mass spectroscopy, or bio-analysis. Bio-analytical methods, more particularly the reporter gene expression method CALUX, are advantageous due to their high throughput rate and low cost. Moreover, the CALUX methodology detects the overall dioxin-like toxicity, rather than the limited number of compounds investigated by chemo-analysis. Bioanalytical methods such as CALUX also differ from chemo-analysis in that the contribution of antagonistic as well as synergistic effects, which violate the additivity principle, can be detected. The application of bio-analytical methods can facilitate a broader assessment of public health risks by intensifying the current monitoring programs in terms of both sample numbers and types. Bio-analysis provides information on the total dioxin-like activity of the samples under study (hazard assessment); however, chemo-analysis is still needed to identify the predominant contaminants (congener identification) for risk management.     

Disruption of thyroid hormone binding to sea bream recombinant transthyretin by ioxinyl and polybrominated diphenyl ethers

A number of chemicals released into the environment share structural similarity to the thyroid hormones (THs), thyroxine (T(4)) and triiodothyronine (T(3)) and it is thought that they may interfere with the thyroid axis and behave as endocrine disruptors (EDs). One of the ways by which such environmental contaminants may disrupt the TH axis is by binding to TH transporter proteins. Transthyretin (TTR) is one of the thyroid hormone binding proteins responsible for TH transport in the blood. TTR forms a stable tetramer that binds both T(4) and T(3) and in fish it is principally synthesized in the liver but is also produced by the brain and intestine. In the present study, we investigate the ability of some chemicals arising from pharmaceutical, industrial or agricultural production and classified as EDs, to compete with [I(125)]-T(3) for sea bream recombinant TTR (sbrTTR). Ioxinyl, a common herbicide and several polybrominated diphenyl ethers were strong inhibitors of [I(125)]-T(3) binding to TTR and some showed even greater affinity than the natural ligand T(3). The TTR competitive binding assay developed offers a quick and effective tool for preliminary risk assessment of chemicals which may disrupt the thyroid axis in teleost fish inhabiting vulnerable aquatic environments.     

Anaerobic abiotic transformations of cis-1,2-dichloroethene in fractured sandstone

A fractured sandstone aquifer at an industrial site is contaminated with trichloroethene to depths greater than 244 m. Field data indicate that trichloroethene is undergoing reduction to cis-1,2-dichloroethene (cDCE); vinyl chloride and ethene are present at much lower concentrations. Transformation of cDCE by pathways other than reductive dechlorination (abiotic and/or biotic) is of interest. Pyrite, which has been linked to abiotic transformation of chlorinated ethenes, is present at varying levels in the sandstone. To evaluate the possible role of pyrite in transforming cDCE, microcosms were prepared with groundwater, ～40 mg L^?1 cDCE + [¹⁴C]cDCE, and crushed solids (pure pyrite, pyrite-rich sandstone, or typical sandstone). During 120 d of incubation, the highest level of cDCE transformation occurred with typical sandstone (11–14% ¹⁴CO₂, 1–3% ¹⁴C-soluble products), followed by pyrite-rich sandstone (2–4% ¹⁴CO₂, 1% ¹⁴C-soluble products) and even lesser amounts with pure pyrite. These results indicate pyrite is not likely the mineral involved in transforming cDCE. A separate experiment using only typical sandstone compared the rate of cDCE transformation in non-sterilized, autoclaved, and propylene-oxide sterilized treatments, with pseudo-first order rate constants of 8.7, 5.4, and 1.0 yr^?1, respectively; however, transformation stopped after several months of incubation. Autoclaving increased the volume of pores, adsorption pore diameter, and surface area in comparison to non-sterilized typical sandstone. Nevertheless, autoclaving was less disruptive than chemical sterilization. The results provide definitive experimental evidence that cDCE undergoes anaerobic abiotic and biotic transformation in typical sandstone, with formation of CO₂ and soluble products.     

Fly-ash-amended sand as filter media in bioretention cells to improve phosphorus removal.

This study identified material with high phosphorus sorption suitable for bioretention filter media. Materials examined were fly ash, two expanded shales, peat moss, limestone, and two common Oklahoma soils--Teller loam and Dougherty sand. The peat moss was a phosphorus source, while the two soils, limestone, and one expanded shale had only modest sorption capacity. One expanded shale and the fly ash had significant phosphorus sorption. Fly ash is unsuitable for use in a pure form, as a result of its low permeability, but phosphorus sorption on the sand was increased significantly with the incorporation of small amounts of fly ash. Column leaching experiments found that the sand with 2.5 and 5% fly ash and the better expanded shale had linear, non-equilibrium transport retardation factors of 272, 1618, and 185, with first-order rate coefficients of 0.153, 0.0752, and 0.113 hour(-1), respectively. Desorption experiments showed that the phosphorus sorption on the sand/fly ash mixture is largely nonreversible. Transport simulation assuming a 1-m-deep sand/fly ash treatment layer, with 5% of the watershed area, showed that the sand/fly ash filter media could effectively treat 1 mg/L influent for 12 years in a paved watershed and 34 years in a grassed watershed before exceeding Oklahoma's scenic rivers' phosphorus criterion of 0.037 mg/L. Significant phosphorus removal would continue for over 100 years.     

Book reviews

Deregulation in the European Union: environmental perspectives. U. Collier (Ed.), 1998, London, Routledge, ISBN 0 415 15694 7, £47.50 (hbk)

Protecting the European Environment: enforcing EC environmental law. H. Somsen (Ed.), 1996, London, Blackstone Press, ISBN 185 431 6044, £19.95

Green Parties and Politics in the European Union. Elizabeth Bomberg, 1998, London, Routledge, ISBN 0 415102 650, £15.99 (pbk)

British Environmental Policy and Europe. Philip Lowe & Stephen Ward (Eds), 1998, London, Routledge, ISBN 0 415155 010, £16.99 (pbk)

Wolf in the Garden: the land rights movement and the new environmental debate. Philip D. Brick & R. McGreggor Cawley (Eds), 1996, Lanham, MD, Rowman & Littlefield, ISBN 08476 8184 X, US$67.50 (hbk) ISBN 08476 8185 8, US$24.95 (pbk)

Fresh Water. E. C. Pielou, 1998, Chicago, IL, University of Chicago Press, ISBN 0 226 66815 0, US$24/£19.25 (hbk)

Environment and Politics. Timothy Doyle & Doug McEachern, 1998, London, Routledge, ISBN 0415 14776, £10.99

Eat Your Genes: how genetically modified food is entering our diet. S. Nottingham, 1998, London, Zed Books, ISBN 1 85649 577 9, £32.95 (hbk) ISBN 1 85649 578 7, £11.95 (pbk)

Working for Better Environmental Performance in SMEs. PACTE programme of the European Commission, 1997, Project of Berlin, Bristol, Copenhagen and Vienna¹ (no charge)

Love Canal, the Story Continues. Lois Marie Gibbs, 1998, Gabriola Island, BC, New Society Publishers, ISBN 0 86571 382 0, US$16.95/Can$19.95 (pbk)     

Ricin as a weapon of mass terror — Separating fact from fiction

In recent years there has been an increased concern regarding the potential use of chemical and biological weapons for mass urban terror. In particular, there are concerns that ricin could be employed as such an agent. This has been reinforced by recent high profile cases involving ricin, and its use during the cold war to assassinate a high profile communist dissident. Nevertheless, despite these events, does it deserve such a reputation? Ricin is clearly toxic, though its level of risk depends on the route of entry. By ingestion, the pathology of ricin is largely restricted to the gastrointestinal tract where it may cause mucosal injuries; with appropriate treatment, most patients will make a full recovery. As an agent of terror, it could be used to contaminate an urban water supply, with the intent of causing lethality in a large urban population. However, a substantial mass of pure ricin powder would be required. Such an exercise would be impossible to achieve covertly and would not guarantee success due to variables such as reticulation management, chlorination, mixing, bacterial degradation and ultra-violet light. By injection, ricin is lethal; however, while parenteral delivery is an ideal route for assassination, it is not realistic for an urban population. Dermal absorption of ricin has not been demonstrated. Ricin is also lethal by inhalation. Low doses can lead to progressive and diffuse pulmonary oedema with associated inflammation and necrosis of the alveolar pneumocytes. However, the risk of toxicity is dependent on the aerodynamic equivalent diameter (AED) of the ricin particles. The AED, which is an indicator of the aerodynamic behaviour of a particle, must be of sufficiently low micron size as to target the human alveoli and thereby cause major toxic effects. To target a large population would also necessitate a quantity of powder in excess of several metric tons. The technical and logistical skills required to formulate such a mass of powder to the required size is beyond the ability of terrorists who typically operate out of a kitchen in a small urban dwelling or in a small ill-equipped laboratory. Ricin as a toxin is deadly but as an agent of bioterror it is unsuitable and therefore does not deserve the press attention and subsequent public alarm that has been created.