Treating the Disease, Not the Symptom: Beyond NSAIDs.

Mitigating inflammation is clearly important in cancer prevention and control. Traditionally, pharmaceuticals have taken the lead in this problem. In an attempt to 'head them off at the pass', this Forum takes a hard look at the concept of 'better living through chemicals' and limiting proinflammatory chemicals entering the body.

[Rubber granules on synthetic turf pitches: safe or not safe for children?] / Rubbergranulaat op kunstgrasvelden.

Rubber granules from old car tyres used in synthetic turf pitches contain a significant number of carcinogenic and endocrine-disrupting chemicals. In 2017 the Dutch National Institute for Public Health and the Environment (RIVM) and the European Chemical Agency (ECHA) concluded that the risks for children are negligible. However, their reports contain some scientific inaccuracies and omissions which may have led them to underestimate the risks for children. It is therefore premature to conclude that it is safe for children to play on synthetic turf pitches with rubber granules. It is now primarily up to the parents to decide whether or not playing sports is acceptable in these circumstances. The Dutch government should, in accordance with ECHA recommendations, advise parents that their children ought to avoid hand-and-mouth contact with these granules as much as possible.

[Occupational exposure to chromium(VI) compounds]. / Narazenie zawodowe na zwiazki chromu(VI).

This article discusses the effect of chromium(VI) (Cr(VI)) on human health under conditions of acute and chronic exposure in the workplace. Chromium(VI) compounds as carcinogens and/or mutagens pose a direct danger to people exposed to them. If carcinogens cannot be eliminated from the work and living environments, their exposure should be reduced to a minimum. In the European Union the proposed binding occupational exposure limit value (BOELV) for chromium(VI) of 0.025 mg/m³ is still associated with high cancer risk. Based on the Scientific Commitee of Occupational Exposure Limits (SCOEL) document chromium(VI) concentrations at 0.025 mg/m³ increases the risk of lung cancer in 2-14 cases per 1000 exposed workers. Exposure to chromium(VI) compounds expressed in Cr(VI) of 0.01 mg Cr(VI)/m3; is responsible for the increased number of lung cancer cases in 1-6 per 1000 people employed in this condition for the whole period of professional activity.

Human health risk assessment of synthetic turf fields based upon investigation of five fields in Connecticut.

Questions have been raised regarding possible exposures when playing sports on synthetic turf fields cushioned with crumb rubber. Rubber is a complex mixture with some components possessing toxic and carcinogenic properties. Exposure is possible via inhalation, given that chemicals emitted from rubber might end up in the breathing zone of players and these players have high ventilation rates. Previous studies provide useful data but are limited with respect to the variety of fields and scenarios evaluated. The State of Connecticut investigated emissions associated with four outdoor and one indoor synthetic turf field under summer conditions. On-field and background locations were sampled using a variety of stationary and personal samplers. More than 20 chemicals of potential concern (COPC) were found to be above background and possibly field-related on both indoor and outdoor fields. These COPC were entered into separate risk assessments (1) for outdoor and indoor fields and (2) for children and adults. Exposure concentrations were prorated for time spent away from the fields and inhalation rates were adjusted for play activity and for children's greater ventilation than adults. Cancer and noncancer risk levels were at or below de minimis levels of concern. The scenario with the highest exposure was children playing on the indoor field. The acute hazard index (HI) for this scenario approached unity, suggesting a potential concern, although there was great uncertainty with this estimate. The main contributor was benzothiazole, a rubber-related semivolatile organic chemical (SVOC) that was 14-fold higher indoors than outdoors. Based upon these findings, outdoor and indoor synthetic turf fields are not associated with elevated adverse health risks. However, it would be prudent for building operators to provide adequate ventilation to prevent a buildup of rubber-related volatile organic chemicals (VOC) and SVOC at indoor fields. The current results are generally consistent with the findings from studies conducted by New York City, New York State, the U.S. Environmental Protection Agency (EPA), and Norway, which tested different kinds of fields and under a variety of weather conditions.

Carcinogenic potential, levels and sources of polycyclic aromatic hydrocarbon mixtures in indoor and outdoor environments and their implications for air quality standards.

Both the World Health Organization and the UK Expert Panel on Air Quality Standards (EPAQS) have considered benzo(a)pyrene (BaP) as a marker of the carcinogenic potency of the polycyclic aromatic hydrocarbons (PAH) mixture, when recommending their respective guidelines for PAHs in outdoor air. The aim of this research is to compare the concentrations and relative abundance of individual PAH and their contribution to the overall carcinogenic potential of the PAH mixture in indoor and outdoor environments to assess the suitability of the UK air quality standard derived for outdoor air for use as a guideline for indoor environments. Samples were collected onto filters using active sampling in different indoor and outdoor microenvironments. The ratio of individual compounds to BaP, the BaP equivalent concentrations and the percentage contribution of each individual compound to the total carcinogenic potential of the PAH mixture were calculated. Mean concentrations were generally lower indoors (BaP=0.10 ng/m(3)) than outdoors (BaP=0.19 ng/m(3)), with the exception of indoor environments with wood burners (BaP=2.4 ng/m(3)) or ETS (BaP=0.6 ng/m(3)). The ratio of individual PAHs to BaP showed no significant differences between indoors (e.g. DahA/BaP=0.27) and outdoors (DahA/BaP=0.31). The relative contribution of BaP to the PAH overall carcinogenic potency is similar indoors (49%), outdoors (54%) and in the smelter environment (48%) used by EPAQS to derive the UK Air Quality Standard for ambient air. These results suggest the suitability of BaP as a marker for the carcinogenic potential of the PAH mixture irrespective of the environment. Despite small differences in PAH mixture composition indoors and outdoors, the level of protection afforded by the present EPAQS standard is likely to be similar whether it is applied to indoor or outdoor air.

Comments on article "Toxicity and carcinogenicity of chromium compounds in humans" by Costa and Klein.

The recent article by Costa and Klein (2006) contains several inaccuracies about the federal drinking water standard for chromium. The federal drinking water standard for chromium is 100 ppb, not 50 ppb as stated by Costa and Klein, and it is based on non-carcinogenic effects, not a one in one million cancer risk level. The question of whether or not hexavalent chromium is carcinogenic via the oral route is the focus of much current interest and has major implications for regulation of chromium in drinking water and soil. The chronic drinking water study of hexavalent chromium currently being conducted by the National Toxicology Program will provide further information that will be useful in addressing this question.

Approaches to determining regulatory values for carcinogens with particular reference to bromate.

There are challenges in developing standards for substances that are carcinogenic in laboratory animals. In general, acceptable levels of substances that are shown to act through a mechanism that involves direct genotoxicity are determined by applying a mathematical model to extrapolate the risk at high doses to the risk at low environmental exposures. Most such models assume linearity at the low doses, which is not experimentally verifiable. Levels for substances that act through an indirect mechanism for which there is an experimentally verifiable threshold, such as cytotoxicity and regenerative hyperplasia, are generally determined by applying an uncertainty factor to a no effect level or a benchmark dose. Bromate is a potentially important contaminant in hypochlorite, and also as a consequence of the use of ozone in drinking water treatment. Although it has been used for many years as a flour improver it is known to cause cancers of the kidney, tunica vaginalis testis and thyroid in laboratory rodents. There are species differences in the sensitivity to bromate and differences in the tumours observed. The mechanism by which bromate causes cancer in laboratory animals is uncertain. There is evidence that bromate is a genotoxin but there is also indication that the dose response is not linear at low doses and that bromate may act through an intermediate mechanism. There is also evidence to suggest that bromate may be inactivated by antioxidants in the gastrointestinal tract and blood and so may not reach the sensitive tissues at low doses. Bromate has been considered by WHO, USEPA and Canada with slightly differing outcomes depending on the assumptions made. Because the acceptable levels determined are close to or below the concentrations that can be practically achieved in drinking water, even small differences have become very important. Determining whether it is appropriate to use a linear assumption and which is the most relevant tumour site are important steps in refining the risk assessment to for drinking water disinfection with hypochlorite and ozone.

Observations at the interface of mutation research and regulatory policy.

Between 1970 and 1975 developments in environmental mutagenesis proceeded with amazing speed. These developments were both structural and conceptual in nature. A new infrastructure was built and new concepts about how best to protect consumers from exposures to mutagens emerged. The internal dynamics within the Food and Drug Administration played an important role and is discussed with regard to modifications in testing protocols as well as changes in the overall approach used to protect consumers. It is clear that this exciting period in the early days of environmental mutagenesis has provided a base for growth and development of the field and continues to affect and guide future developments.

Standards for environmental, non-threshold, carcinogens: a comparison of the approaches used for radiation and for chemicals.

Environmental standards for ionising radiation and for chemical carcinogens have been developed independently of each other. Radiation standards have been derived by deciding upon what is an acceptable risk, and then finding the corresponding dose from the exposure/risk relationship-quantitative risk assessment (QRA). The extent and the quality of the exposure/risk data for radiation, and the authority of the recommendations of the International Commission on Radiological Protection (ICRP), have resulted in universally accepted guidance and standards. This is not the case for chemical, non-threshold carcinogens. Their carcinogenicity ranges from doubtful to well-established, the exposure/response data are generally of poor quality, and there is no authoritative international body analogous to the ICRP. For some of these carcinogens, some organisations have used QRA to derive environmental standards. Others consider the data inadequate for such an approach and have used more pragmatic methods. The problems associated with the various approaches used and the prospects of an integrated approach for both radiation and chemical carcinogens are discussed.

Valor de referência tecnológico (VRT): a nova abordagem do controle da concentraçäo de benzeno nos ambientes de trabalho / Technological Reference Value (TRV): a new approach to benzene concentration control in the work environment

A finalidade deste artigo é apresentar um novo conceito de controle da concentração de benzeno nos ambientes de trabalho, adotado recentemente no Brasil com a concordância de empregadores, trabalhadores e governo. Trata-se do Valor de Referência Tecnológico (VRT). O artigo apresenta um breve histórico do processo de concepção e adoção do VRT no país, seguido da discussão conceitual de "Limite de Tolerância" adotado legalmente no Brasil, que atribui aos valores definidos o caráter de segurança e proteção à saúde do trabalhador, mesmo tratando-se de substâncias reconhecidamente cancerígenas, como o benzeno. Apresenta também o conceito estabelecido para o VRT que incorpora a classificação da carcinogenicidade do benzeno e a necessidade da redução permanente de seu valor, indicando-o como "guia" para as ações de prevenção em higiene ocupacional. Por fim conclui que a concepção adotada introduz na realidade brasileira a participação dos trabalhadores na discussão do risco decorrente do uso de um produto químico tão importante como o benzeno.

Problems and perspectives in the identification of new occupational carcinogens.

Occupational studies have played a major role in the identification of chemical carcinogens. There still remain, however, substances and occupations that deserve further evaluation. The more careful control of potentially hazardous exposures in most developed countries has necessitated a change in the conduct of epidemiologic investigations. The lowering of exposures and the lack of a simple correspondence between specific exposures and one or a few jobs underscores the need for careful reconstruction of historical exposures. The most successful reconstructions will include the integration of monitoring data, historical information on work histories and work practices, and use of biochemical markers.