The health orientation value (HOV) is drawn on for the evaluation of materials in drinking water with insufficient data records. Should experimental data be lacking, then "as a substitute ... the rating of the contaminants in the overall range >0,1 µg/l to 3 µg/l is then recommended, if scientifically appropriate resilient expectation statements about the relationship between structure and biochemical toxicological potential of the contaminants are present. ("Structure/activity relationship") original emphasis: Bundesgesundheitsbl.- Gesundheitsforsch - Gesundheitsschutz 2003, 46:249-251 (German Environmental Protection Agency and Commission for Drinking Water Safety).

Evaluation of Chemicals

The usage of chemical substances assumes reliable data about their properties such as solubility, volatility, polarity, dispersal, stability and biodegradability. Data about their toxicity (e.g. carcinogenicity, mutagenicity, immuno and neuro toxicity, endocrine effect, and fish, daphnia, algae and bacterial toxicity), about their metabolism and their decomposition products as well as their behaviour in the environment are indispensable, however frequently not available or available too late. Computer-based methods, such as those available to EDC, allow for the quick development of the necessary knowledge without the need to conduct tedious and expensive experiments.


Drinking water is a fundamental foodstuff. Possible contamination is therefore rightly given attention by the general public and the media. In such situations, however, it can lead to excessive public discussion about water quality. This can be avoided when information about the detected substances is made available as quickly as possible, which at least enables an initial assessment of the potential hazard for the consumer and targeted measures of risk management. This information, however, is often missing.
An orienting hazard assessment is quickly possible with computer-based methods. This assessment can then accordingly be rapidly communicated. Thus gains are also made for a deeper-reaching substance evaluation which may become necessary. Furthermore this method can also be used for a quick assessment as to whether the respective hazardous material can, for example, be removed by means of sorption on activated carbon.


In drinking water purification, in addition to the sorption on activated carbon, oxidative technical procedures for the removal of hazardous materials play a role such as in the ozonation or the treatment with UV light. With this process, however, secondary products can emerge, which have unknown toxicological properties. The evaluation of such materials is complicated by the fact that sufficient quantity for an experimental analysis is rarely available. Here also structural property relationships are offered for evaluation.


A large number of contaminated sites emerged at the beginning of the 1970s which in part contained hazardous materials. In addition to the materials themselves decomposition and other reaction products of these substances are often detected. For the same reasons as with the secondary products of the oxidative drinking water purification, often no experimental data are available for these secondary products for the assessment of the hazards. In part significant hazards arise for the protected areas of water, soil and air. The effective and economical evaluation and possible remediation of a contaminated area needs exact knowledge about the type and scope of the hazardous material inventory, the degree of discharge of these contaminants in the protected areas as well as the transport behaviour of the contaminants within a protected area. Structural property and structure activity relationships are excellently suited for the fast and economical collection of data required for this purpose.


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© EDC Chemical Consulting | Wed, October 27th, 2021