General Cleanup Technology

BioRefine: Availability of pollutants of contaminated soil for earthworms and soil microorganisms

The objective of the present project is to examine the percentage of PAH (Polycyclic Aromatic Hydrocarbon) and PHC (Petroleum-Derived Hydrocarbon)-pollution available in contaminated fallow lands for microorganisms and earthworms. These examinations serve to provide a realistic estimation of hazards from abandoned polluted areas, and thereby facilitate the reuse of these lands.

Summary

High clean-up costs due to soil contamination are often act an obstacle for the use of fallow lands, and thus contribute to increased land consumption. The objective of the joint research project "analysis of pollutants in land recycling and sustainable land management on the basis of availability/bio-availability (BioRefine)" was to assess contaminated lands not by totalling the pollutants, but by calculating the volume of pollutants that is actually available for organisms to absorb. The present sub-project examines the bio-availability of pollutants in the soil for soil microorganisms and earthworms. For this purpose, PHC- and PAH-contaminated soils were at first examined in terms of their habitat quality. In addition, tests were conducted to determine whether an extraction procedure (shake extraction test, 3-phases extraction) could provide information on a bio-available share of pollution levels. In case of mineral oils, besides the total fraction (chain length C10-C40), also the mobile fraction (C10-C22) was considered.

Results:

  • There is a correlation between the 3-phases extraction with HPCD and the Tenax extracted fraction respectively, and the available share of PHC for earthworms. Conclusions on microbial respiration coefficients can also be drawn from the 3-phases extraction, as well as from the leachate from shake test.
  • A pure water extraction cannot sufficiently simulate the pollutant absorption in earthworms.
  • In PAH-contaminated soils, only a very small percentage of pollutants is available for microbial degradation. Hence, no eco-toxicity is detectable for the test organisms employed.
  • Opposed to this, in PHC-contaminated soils, a large share of pollutants is available for degradation processes. The highest degradation rates are achieved in soils with a high percentage of mobile, short-chained PHC. The eco-toxicological effect can be detected in the earthworm reproduction test, as well as in the microbial respiration co-efficient.
  • The introduced variation of the 3-phases-extraction primarily provides significant results for PAH- and PHC-polluted soils in combination with the analysis of the corresponding total shares, which also include pollutant profiles.

More Project Informations

Project title:  Verbundprojekt: Bewertung von Schadstoffen in Flächenrecycling und nachhaltigen Flächenmanagement auf der Basis der Verfügbarkeit/Bioverfügbarkeit (BioRefine), Teilvorhaben 2: Aspekt Lebensraumfunktion und Abbaupotential

Project number: 0330765B

Project period: 2009 - 2010

Project region: Germany (North Rhine-Westphalia)

Project contact:

Frau Dr. Hund-Rinke

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Source: Technische Informationsbibliothek Hannover (TIB)