Strategy for risk assessment and remediation former tannery sites in consideration of production techniques

Findings and proposed measures are based upon the historical investigation and analysis of soil and groundwater samples. The main contaminants identified have been chromium, arsenic and naphthalene. The polymerase chain reaction method has also been subject to further development, in order to allow the identification of anthrax spores, even at low concentrations.

Due to several techniques with pollutants former tannery sites contain chemical and microbiological contamination. Especially microbiological contaminations are related to the treatment of raw skins from animals which were infected by Bacillus anthracis. The assessment of the risk potential of these hazardous subjects is yet fragmentary. High chemical contaminations and the suspection of pollution by Bacillus anthracis often hinder a reuse of these sites.

Based on the historical utilization of several tannery sites, areas, of different contamination were located. In addition techniques of leather production in the past, including special chemical additives, were differentiated and attached to single lists of pollutants related to each technical process. Five representative sites were selected for technical investigations. The differ strictly according to their production period, processes (vegetabilic tannery - chromatic tannery) and in risks of contaminations by Bacillus athracis.

Results:

• The main suspected contaminated subareas of a tannery site are production area, purification basin, irrigation fields, area of deposits of production residues and riverlowlands downstream of the tannery site. The results of risk assessment based on soil- and groundwater investigations, determined main contamination by chromium, arsenic and naphthalin. Chromium is adsorbed at organic material of soil and therefore immobile in contact to arsenic which was examined also in groundwater.
  
  
• According the development of potential remedial technologies laboratory experiments showed that chromium polluted substrates and soil can't remediate by soil washing. Deposition experiments of contaminated substrates and soil by chromium and arsenic in relation to saturated and unsaturated conditions showed a mobilisation of arsenic.
  
  
• Using the PCR method (polymerase chain reaction), it has been possible to detect anthrax spores, even at very low concentrations.

In order to enhance the suitability of the comprehensive results obtained for practical application, guidelines for the “Analysis of the sites of former tanning works” have been prepared and published as a separate document to the research report.




Source Of Supply: The final report and the guidelines (call numbers F 98 B 408(1)(2) or rather F 99 B 243, in German) can be borrowed from:
Technische Informationsbibliothek (TIB) Hannover
Welfengarten 1B
30167 Hannover





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