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Ecotoxicological information

Toxicity to soil microorganisms

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Description of key information

Except the high pH of GL, the general toxicity of GL to soil microorganisms is expected to be low, since the constituents of GL are very basic and ubiquitous elements/minerals in soil and soil pore water. In activated sludge respiration Inhibition test the substance was not specifically toxic to microbes, since the EC20 was  950 mg/l.

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Additional information

The high alkality, pH values reaching 13 or even above, is the major factor affecting soil microbial functions if GL is released to soil. The severity of an acute pH shock or longer term pH change of soil is dependent on load of the substance (pH load/m2), duration of exposure, soil buffer capacity (critical load).

Sulfides in GL may be another factor affecting heavily on soil microbes. Both of these factors, pH shock and toxicity of sulfides can be expected to be mainly as short term effects of relative high loads. Alkality is neutralized and sulfides are oxidized.

Microorganisms in soil (and water) are involved in oxidation-reduction reactions which oxidize hydrogen sulfide to elemental sulfur. Members of the generaBeggiatoa,Thioploca, andThiotrixfunction in transition zones between aerobic and anaerobic conditions where both molecular oxygen and hydrogen sulfide are found (USEPA 1986).

Except the high pH of GL and the effects of sulfides, the general toxicity of other constituents of GL to soil microorganisms is expected to be low, since these constituents are very basic and ubiquitous elements/minerals in soil and soil pore water. Based on the results of CSA assessment and on already existing exposure and effects information, it is currently not seen necessary to conduct any targeted ecotoxicological testing of GL