Remediation measures in a residential area highly contaminated with PCDD/PCDF, Arsenic and heavy metals as a result of industrial production in the early 19th century

Soil from a residential area, which was established on a past chemical production site, was found to be highly contaminated with PCDD/Fs (~1-10 kg TEQ load), arsenic (12 to 80 tons load) and heavy metals. The contamination resulted from a LeBlanc chemical sodium carbonate decahydrate (sal soda or washing soda) production facility, which operated during the 19th century. The discovery of PCDD/F levels up to 100,000 ng/kg TEQ on the residential site resulted in extensive remediation and monitoring measures which are accompanied by extensive monitoring and safety measures. This case demonstates for the first time that PCDD/Fs were formed at high concentrations during production processes of inorganic chemicals involving chloride/chlorine already in the early phase of industrialization at the beginning of the 19th century, i.e. several decades before the first chloroalkali electrolysis started around 1890. The case further demonstrates that these contaminated sites can be of contemporary relevance including contamination of humans and the environment.