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QUALITY STANDARDS AND LIMIT VALUES
Quality Standards or Limit Values are widely used to protect the environment and human health from substances released by human activity. Generally speaking, they relate to doses or concentrations in the environment for specific chemicals, below which unacceptable effects are expected not to occur. Some standards are legally enforceable numerical limits, such as Environmental Quality Standards for List 1 chemicals in water, or forthcoming Annex X and VIII standards under the Water Framework Directive. Others are not mandatory, but are contained in guidelines, codes of practice as is the case for many soil and waste related limit values.
The ways in which standards and limit values are derived, and the frameworks within which they are used, differ between countries and regions. To some extent this diversity reflects genuine technical differences that must be taken into account in the development of numerical limits for different compartments (e.g., water, sediment and soil) or for different receptors (e.g., humans, livestock or flora and fauna). However, much standard-setting has been developed in a piecemeal fashion with little consistency between schemes in the levels of protection sought, the selection of chemicals for which standards may be needed, the methods used to derive them, or the methods used to monitor compliance. These differences can lead to the implementation of substantially different values from the same empirical data, which must mean that their application is either over- or under-precautionary in at least some situations.
WCA Environment has extensive expertise in deriving defensible standards and limit values for a range of environmental media, and fit for purpose frameworks in which they can be developed and used. We have done this for both aquatic and terrestrial systems, and for Government and business clients.
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