Synthetic chemicals risk assessment

The European system for regulating synthetic chemicals, described in Chapter 5, is predominantly risk-based . This means that restrictions on the manufacture or use of chemicals must be justified by reference to evidence that there is a risk of the chemical causing a specified type of harm. REACH (Registration, Evaluation, Authorization and restriction of Chemicals) does not define the term risk , but the directive on risk assessment of new substances defined it as the incidence and severity of the adverse effects likely to occur [...] due to actual or predicted exposure to a substance (Article 2 of Directive 93/67/EEC). In the first part of this chapter I look at how risks from chemicals are assessed. What does chemicals risk assessment in practice aim to achieve Can it provide the reliable evidence needed for agreement by all parties on whether or not a chemical poses a risk My answer to this second question is no there are multiple uncertainties in chemicals risk assessment which lead to protracted debates as to whether a chemical poses a risk or not. 

Chemicals risk assessment attempts to characterize the system — of a chemical in the environment or in the human body — and then estimate the risk of the chemical causing harm. A key question is whether the system can be adequately characterized to reliably estimate the probability of harm, or even to identify what harm the chemical may cause. Just as engineering systems have caused harm because they failed in ways that were not predicted, the most serious hazards of synthetic chemicals have often been unexpected, and not considered in risk assessments. 

The use of flame retardants came about because of concern over the flammabiUty of synthetic polymers (plastics). A simple method of assessing the potential contribution of polymers to a fire is to examine the heats of combustion, which for common polymers vary by only about a factor of two (1). Heats of combustion correlate with the chemical nature of a polymer whether the polymer is synthetic or natural. Concern over flammabiUty should arise via a proper risk assessment which takes into account not only the flammabiUty of the material, but also the environment in which it is used. 

A more fundamental problem is that risks can only be assessed where the possible harm has been identified. But the major types of harm caused by synthetic chemicals were unexpected no risk assessment of them could have been carried out. Insisting that regulation is risk-based will not help to prevent such future surprises. 

To help answer these questions I start this chapter with an examination of the various meanings of responsibility and discuss the nature of our responsibilities for things. I then examine how decisions about technology are currently made and point out the ways in which this leads to organized irresponsibility , particularly in the case of synthetic chemicals. Finally, I consider the limitations of risk assessment as a conception of responsible decision making. 

The chemical industry is facing a crisis in terms of its sustainability. Public trust in the industry needs to be restored in many EU countries and economic growth in the sector needs to be uncoupled from increased production volumes. REACH only begins to address these two issues. While REACH will generate information on chemical risks and will reset the frame of reference on what constitutes sufficient toxicological data for carrying out hazard assessments, it does not address how to control exposure levels. Apart from the authorisation process, REACH does not even propose specific mechanisms to control the increasing concentrations of synthetic chemicals in human blood and environmental media. 

Physical-Chemical Features of Synthetic Amorphous Silicas and Related Hazard and Risk Assessment... 

Not surprisingly, there are many synthetic chemicals and formulations commercially available. In Europe alone more than 100000 chemicals (not formulations) are on the European Inventory of Existing Commercial Chemical Substances (EINECS), which lists chemicals on the market before September 1981. This list differentiates between existing and all new chemicals produced since 1981 that have to be notified. During the period between 1981 and 2000 more than 2700 new substances were notified in Europe (Figure 1.3). For new substances, the obligatory notification system requires the manufacturer or importer to provide information suitable for risk assessment to be submitted to the competent authorities. The details required are dependent on the production volume or import quantities of the chemical. 

However the fear and anxiety of harm from synthetic chemicals saturates our psyches, and thus truth and realities are ignored in favor of the tenets of virtual toxicology. As the legal case history develops in support of this argument, it effectively becomes law. Is this the proper forum for risk assessment If hysteria and emotion are allowed to determine whether a chemical is toxic or not, society is doomed since the real hazards to our health, found in the natural world, are still there. I hope that this book can help dissuade this opinion. 

Abstract With increasing utilization of various synthetic chemicals, the adverse impact of these chemicals is of concern due to their occurrence in the environment. The subsequent transformation products pose considerable risk on the ecosystem and human health. However, for most currently used synthetic chemicals, the fate of their transformation products are yet to be elucidated, which forces most current risk assessment to focus on parent chemicals. In this article, general processes and principles of environmental fate of chemical transformation products are illustrated various influential factors such as phys-iochemical properties of transformatiou products aud couditious of the euviroumeutal media are described a mass balauce approach used to iuvestigate the euviroumeutal fate is discussed. 

---