Safety assessment of sandalwood oil (Santalum album L.).

Sandalwood (Santalum album L.) is a fragrant wood from which oil is derived for use in food and cosmetics. Sandalwood oil is used in the food industry as a flavor ingredient with a daily consumption of 0.0074 mg/kg. Over 100 constituents have been identified in sandalwood oil with the major constituent being alpha-santalol. Sandalwood oil and its major constituent have low acute oral and dermal toxicity in laboratory animals. Sandalwood oil was not mutagenic in spore Rec assay and was found to have anticarcinogenic, antiviral and bactericidal activity. Occasional cases of irritation or sensitization reactions to sandalwood oil in humans are reported in the literature. Although the available information on toxicity of sandalwood oil is limited, it has a long history of oral use without any reported adverse effects and is considered safe at present use levels.     

Exposure to dioxin-like pollutants via different food commodities in Swedish children and young adults

The dietary intake of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) in terms of toxic equivalents (TEQs) was investigated in Swedish children and young adults. Exposure was estimated from concentration data of six groups of individual food commodities (meat, fish, dairy products, egg, edible fats and other foodstuff) combined with food intake data from a 7-day record book obtained from 670 individuals aged 1–24 years. The results showed that Swedish boys and girls, up to the age of ten, had a median TEQ intake that exceeded the tolerable daily intake (TDI) of 2 pg TEQ/kg body weight. Children exceeding the TDI varied from almost all individuals among the youngest children to about 20% among young men and women. Dairy and fish products were the main sources of exposure for the average child, accounting for 59% of the total TEQ intake. The individuals most highly exposed were, on the other hand, characterized by a high consumption of fish. Since children constitute a vulnerable group, results obtained from the present study show that it is essential to perform age specific dietary intake assessments of pollutants and more carefully consider sensitive and/or highly exposed groups in the population in the risk management processes.     

Species differences in contaminants in fish on and adjacent to the Oak Ridge Reservation, Tennessee

Risks to humans and other organisms from consuming fish have become a national concern in the USA. In this paper, we examine the concentrations of 137Cs, arsenic, beryllium, cadmium, lead, mercury, and selenium in three species of fish from two river reaches adjacent to the US Department of Energy's Oak Ridge Reservation in Tennessee. We were interested in whether there were species and locational differences in radiocesium and metal concentrations and whether concentrations were sufficiently high to pose a potential health risk to humans or other receptors. Striped bass (Morone saxatilis) were significantly larger than white bass (M. chrysops), and crappie (Pomoxis spp.) were the smallest fish. Lead was significantly lower in striped bass, mercury was significantly higher in striped bass, and selenium was significantly higher in white bass compared to the other species. There were no other species differences in contaminants. White bass, the only species that was sufficiently abundant for a comparison, had significantly higher concentrations of cadmium, lead, and selenium in fillets from the Clinch River and significantly higher concentrations of mercury in fillets from Poplar Creek. The low concentrations of most contaminants in fish from the Clinch River do not appear to present a risk to humans or other consumers, although mercury concentrations in striped bass ranged as high as 0.79 ppm, well above the 0.5-ppm action level for human consumption of some US states.     

The limits of regulatory toxicology

The Acceptable Daily Intake (ADI) has been used by regulatory and public health organizations (e.g., the U.S. Food and Drug and Administration, and the World Health Organization) for chemicals for more than 50 years. The ADI concept was also initially employed at the U.S. Environmental Protection Agency at its inception in 1971, although with the adoption of newer terminology, it later became known as the Reference Dose (RfD). It is clear from the literature that both were first devised as instruments of regulatory policy. In the intervening years, it has become common to use language that implies that these standards are statements of scientific fact. Similarly, some of the discretionary or default values that are used to derive regulatory standards are represented as scientific assumptions when in fact they also represent regulatory policy. This confusion impedes both the best use of the available science and informed public participation in policy making. In addition, the misconception of the ADI or the RfD as statements of scientific fact may impede the consideration of alternative means to reduce exposure to chemicals that may be harmful, including regulatory measures that do not involve prescribing a regulatory concentration limit.     

The impact of on-site hospital wastewater treatment on the downstream communal wastewater system in terms of antibiotics and antibiotic resistance genes

This study quantified antibiotic and antibiotic resistance gene (ARG) concentrations in hospital and communal wastewaters as well as the influents and effluents of the receiving urban wastewater treatment plants (UWWTP) in two Dutch cities. In only one city, hospital wastewater was treated on-site using advanced technologies, including membrane bioreactor treatment (MBR), ozonation, granulated activated carbon (GAC) and UV-treatment.On-site hospital wastewater (HWW) treatment reduced gene presence of hospital-related antibiotic resistance genes and antibiotic concentrations in the receiving urban wastewater treatment plant. These findings support the need for on-site treatment of high-risk point sources of antibiotic resistance genes.13 antibiotic resistance genes, Integrase Class 1 and 16S rRNA concentrations were quantified using multiplex quantitative real-time PCR (qPCR) assays and the presence and/or concentration of 711 antibiotics were analyzed.Hospital wastewater contained approximately 25% more antibiotics and gene concentrations between 0.4 log to 1.8-fold higher than communal wastewater (CWW). bla_KPC and vanA could be identified as hospital-related genes and were reduced to under the limit of detection (LOD) during on-site treatment. Advanced on-site treatment removed between 0.5 and 3.6-fold more genes than conventional biological urban wastewater treatment (activated sludge). Advanced on-site treatment was able to eliminate 12 out of 19 detected antibiotics, while urban waste water treatment eliminated up to 1 (out of 21 detected). Different advanced treatment technologies were able to target different pollutants to varying extents, making sequential alignment more effective. MBR treatment was most efficient in antibiotic resistance gene reduction and ozonation in antibiotic reduction.bla_KPC could only be detected in the influent of the urban wastewater treatment plant receiving untreated hospital wastewater. Similarly, vanA was only consistently detected in this treatment plant. These results indicate a positive effect of on-site treatment of hospital wastewater on the communal sewage system.     

Exposure of human fetal penile cells to different PCB mixtures: transcriptome analysis points to diverse modes of interference on external genitalia programming

The effects exerted by three mixtures of Polychlorinated Biphenyls (PCBs) were evaluated on human fetal corpora cavernosa cells, as a model for male external genitalia development. The three mixtures feature congeners grouped according to potentially shared modes of action: one dioxin-like (DL) (Mix2) and two non dioxin-like (NDL) mixtures featuring congeners defined as estrogenic (Mix1) and highly persistent-cytochrome P-450 inducers (Mix3). Congeners concentrations used were derived from human internal exposure data. Toxicogenomic analysis revealed that all mixtures modulated critical genes involved in genitourinary development, however displaying three different expression profiles. The DL Mix2 modulated actin-related, cell-cell and epithelial-mesenchymal communication morphogenetic processes; Mix1 modulated smooth muscle function genes, whereas Mix3 mainly modulated genes involved in cell metabolism (e.g., steroid and lipid synthesis) and growth. Our data indicate that fetal exposure to environmentally relevant PCB levels modulates several patterns of genitourinary programming; moreover, NDL congener groups may have specific modes of action.     

Potential effects of environmental contaminants on P450 aromatase activity and DNA damage in swallows from the Rio Grande and Somerville, Texas

Cliff swallows (Petrochelidon pyrrhonota) and cave swallows (P. fulva) were sampled during the breeding season at several locations in the Rio Grande, Texas, to evaluate the potential effects of environmental contaminants on P450 aromatase activity in brain and gonads and DNA damage in blood cells. The tritiated water-release aromatase assay was used to measure aromatase activity and flow cytometry was used to measure DNA damage in nucleated blood cells. There were no significant differences in brain and gonadal aromatase activities or in estimates of DNA damage (HPCV values) among cave swallow colonies from the Lower Rio Grande Valley (LRGV) and Somerville. However, both brain and gonadal aromatase activities were significantly higher (P < 0.05) in male cliff swallows from Laredo than in those from Somerville. Also, DNA damage estimates were significantly higher (P < 0.05) in cliff swallows (males and females combined) from Laredo than in those from Somerville. Contaminants of current high use in the LRGV, such as atrazine, and some of the highly persistent organochlorines, such as toxaphene and DDE, could be potentially associated with modulation of aromatase activity in avian tissues. Previous studies have indicated possible DNA damage in cliff swallows. We did not observe any differences in aromatase activity or DNA damage in cave swallows that could be associated with contaminant exposure. Also, the differences in aromatase activity and DNA damage between male cliff swallows from Laredo and Somerville could not be explained by contaminants measured at each site in previous studies. Our study provides baseline information on brain and gonadal aromatase activity in swallows that could be useful in future studies.     

Refining the threshold of toxicological concern (TTC) for risk prioritization of trace chemicals in food

Due to ever-improving analytical capabilities, very low levels of unexpected chemicals can now be detected in foods. Although these may be toxicologically insignificant, such incidents often garner significant attention. The threshold of toxicological concern (TTC) methodology provides a scientifically defensible, transparent approach for putting low-level exposures in the context of potential risk, as a tool to facilitate prioritization of responses, including potential mitigation. The TTC method supports the establishment of tiered, health-protective exposure limits for chemicals lacking a full toxicity database, based on evaluation of the known toxicity of chemicals which share similar structural characteristics. The approach supports the view that prudent actions towards public health protection are based on evaluation of safety as opposed to detection chemistry. This paper builds on the existing TTC literature and recommends refinements that address two key areas. The first describes the inclusion of genotoxicity data as a way to refine the TTC limit for chemicals that have structural alerts for genotoxicity. The second area addresses duration of exposure. Whereas the existing TTC exposure limits assume a lifetime of exposure, human exposure to unintended chemicals in food is often only for a limited time. Recommendations are made to refine the approach for less-than-lifetime exposures.     

室内空气污染与改善

建筑环境受到人们的重视，尤其是室内环境，随着建筑业的进一步发展，由室内环境引起的病态建筑的问题成为研究的热点，去除室内环境中的低浓度有害物质避免“病态建筑综合征”的方法很多，该文具体分析了影响建筑室内空气品质的污染物种类，系统阐述了当前室内空气的改善措施，提出净化室内空气的研究方向。