Health-based targets

Health-based targets - Consideration of local conditions... 

Health-based targets for chemicals (e.g, the guideline values in the WHO Guidelines for Drinking-water Quality - WHO, 2004 WHO, 2006) are concentrations that would generally not have a negative health impact if consumed over a lifetime. Therefore, the likelihood of a particular chemical occurring at concentrations that would cause health impacts is the most appropriate indicator that the chemical may be of concern in such situations. 

A full system assessment to determine whether an existing or planned drinking-water supply is capable of meeting health-based targets. 

For individual constituents of drinking-water, health-based targets are established. These targets represent a health risk from long-term exposure, in a situation where fluctuations in concentration are small or occur over long periods, It is important that such targets are defined by the relevant local authority, are realistic under local operating conditions and are set to protect and improve public health,... 

A health-based target specifies the agreed criteria for the quality of water delivered to the consumer, It is used to evaluate the adequacy of existing installations and to assist in verification (through inspection and analysis). 

Table 3.1 Health-based targets for application to microbial and chemical constituents of drinking-water...

For individual countries, guideline values are the first step towards establishing specific health-based targets for their particular circumstances, based on local and regional determinants. 

Various standards and guidelines have been developed for sulfur mustard. These values are applieable to occupational exposures, emergeney planning and response efforts, and remediation efforts. Airborne exposure limits (AELs) and health-based environmental sereening levels (HBESLs) for sulfur mustard have been developed by the US Army (USACHPPM, 1999, 2000). Most health-based criteria for sulfur mustard vapor exposure are based upon protection of the eyes and respiratory traet whieh are the most sensitive targets. 

This task consists of defining target levels for indoor and outdoor conditions based on requirements for laws and regulations, human health, production processes and equipment, and type of premises and construction. Target levels should also be defined for the ventilation system. For the decision tree, see Fig. 3.6. 

Estimates of exposure levels posing minimal risk to humans (Minimal Risk Levels or MRLs) have been made for methyl parathion. An MRL is defined as an estimate of daily human exposure to a substance that is likely to be without an appreciable risk of adverse effects (noncarcinogenic) over a specified duration of exposure. MRLs are derived when reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive health effect(s) for a specific duration within a given route of exposure. MRLs are based on noncancerous health effects only and do not consider carcinogenic effects. MRLs can be derived for acute, intermediate, and chronic duration exposures for inhalation and oral routes. Appropriate methodology does not exist to develop MRLs for dermal exposure. 

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