[Decontamination of highly polychlorinated biphenyl contaminated indoor areas by complete removal of primary and secondary sources].

A new sanitization concept in a school highly contaminated with polychlorinated biphenyls (PCBs) is described. The maximum indoor air concentration was 13,100 ng/m3 PCB. Initially the average indoor PCB concentrations attained 6,000-7,000 ng/m3. A reduction to 226 +/- 89.1 ng/m3 (n = 24) was achieved. Ten months later the PCB concentration was 171 +/- 57.6 ng/m3 (n = 3). Primary sources were PCB-contaminated elastic sealants and the paint of radiators or heating elements. Also PCB-contaminated materials were walls, floors and ceilings. These secondary contaminations were also relevant for PCB indoor air concentrations. The primary sources were removed dust-free by manual procedures. Contrary to other sanitization concepts all secondary-contaminated PCB materials were also removed with a high-pressure water method specially developed for such cases. Because of the removal of all relevant primary and secondary PCB deposits, a lasting effect can be expected. By this sanitization concept, the use of new and less intensively explored products suppressing the diffusion of PCBs into the indoor air and whose toxicity is hardly known, may be prevented, thus avoiding the need for prolonged control measurements. Before using the above-mentioned new sanitization concept, another concept had been rejected for lack of efficiency, thus avoiding unnecessary costs. The companies performing sanitization should be compelled to accept a defined lowest PCB concentration.