Sponsor:
German Environmental Agency, Dessau (FKZ 200 24 33)
Realisation:
Hydrotox GmbH, Stefan Gartiser (project management), Elke Urich
Project duration:
April 2000 –October 2001
Summary:
In Germany about 32 billion m3/a cooling water are discharged from industrial plants and power industry. These are conditioned partly with biocides, scaling and corrosion inhibitors. Within the research project the significance of cooling water chemicals was evaluated, identifying the chemicals from product information, calculating their loads from consumption data of more than 180 cooling plants and investigating the basic data needed for an environmental hazard assessment. Additionally, the effects of cooling water samples and products were determined in biological test systems. Batch tests were performed under defined conditions in order to measure the inactivation of cooling water biocides.
Generally the cooling water samples only showed low ecotoxicity, considering the inactivation time of the biocides. With systematic backtracking, the genotoxicity of the cooling water from one company in the umu-test could be attributed to one biocide with Isothiazolinones and Bronopole as ingredients. The inactivation of biocides, as measured with the luminescent bacteria toxicity test, showed a strong correlation with the inoculum concentration and enabled a better estimation of the importance of the elimination factors degradation and adsorption. The balance of chemical loads confirmed that the principal amounts came from open recirculation cooling systems, whereas only <10% of the plants with once-through cooling water used conditioning chemicals at all. The extrapolation of consumption data for Germany resulted in total loads of about 4.000 t/a oxidative and 125 t/a non oxidative biocides. Additionally an input of about 1.500-2.200 t/a phosphonic acids, 45-135 t/a molybdate and 113-216 t/a zinc was calculated. Basic substance data sheets were documented for all chemicals applied, enabling first assessments of environmental relevance using several approaches of hazard assessment.
Further information:
The final report (209 pages) has been published in the 
UBA-Texte series No 70/02. A not authorised English translation of the main report can be downloaded 
here together with the annex with data sheets on 89 chemicals.
Contact Person
Dr. Stefan Gartiser (
gartiser(at)hydrotox.de, Tel: +49-(0)761-45512-24)