Oil shale, thermal processing waste

Endpoint summary

Additional information

The long-term effects of oil shale thermal processing residue to terrestrial organisms was evaluated in a long-term test (21 d) with earthworm (Eisenia fetida) according to OECD 222 and GLP. The No Observed Effect Concentration (NOEC) for mortality, growth, reproduction and feeding activity of the earthworm Eisenia fetida was determined to be 1000 mg test item/kg soil, i.e. the highest concentration tested.

Based on the available data, no toxicity of oil shale thermal processing residue to terrestrial organisms is expected.

As a natural raw material oil shale mainly contains silica (10-76% w/w SiO2 by weight). The remainder chiefly are oxides as Al2O3, Fe2O3, CaO and MgO. Oil shale thermal processing residues are most common in soils. Oil shale itself may even be a natural component of the earth crust or rather build up own soil horizons. The man made intake of BOS constituents into soil compartment will by far not result in concentrations higher than the natural concentration in soils.

It should be noted, that the active substance has to be treated carefully to prevent uncontrolled emission into environment. Industrial activities are primarily considered to be indoor processes. It is assumed that the production of burned oil shale must be a strictly moisture free process to avoid unintentional hardening. Consequently, the release rate from manufacturing is 0% representing a water-free process. An indirect contamination of the soil compartment via sludge application is considered negligible. The main environmental issues associated with oil shale thermal processing residues are emissions to air. Based on the physical-chemical properties of the substance significant volatilisation is not expected. To reduce the emission of particles to the air the cyclones, wet scrubbers or bag filters are used. The efficiency of processes is maximized. Assuming that air filter techniques are implemented in accordance to national regulations (e.g. for Germany: TRGS, GefStoffV, BImSchG), air emissions cause no substantial contribution to environmental concentrations.

Based on this information, toxicity to terrestrial organisms is not expected to be of concern, and consequently, no further testing is required.

As the test substance is not classified as toxic or harmful, the substance is not considered to cause toxic effects in predators. Additionally, the bioaccumulation potential is low and thus the test substance is considered to cause low hazard to predators. Thus, a study with birds is not needed due to animal welfare reasons.