The work presented in this article focuses on the environmental impact of hydraulic fluids used in forestry. Migration and biodegradability of three biolubricants and a mineral lubricant were monitored in two forest soils and in a liquid medium. These studies proved that biolubricants were easily degradable products and showed ultimate biodegradability rates significantly higher than those of the fluid of mineral origin, specially in a soil environment. This superiority was even greater when fluid behaviour was observed after 1000h of use. Ecotoxicity test enabled the classification and comparison of biolubricants and showed that toxicity levels of the biolubricants were never high however, even after use, as compared to petroleum-based fluid.

The methyl ester of oleic acid, a plant oil derivative, can be used as an additive oil for pesticides. We compared the biodegradability in soil of this oil with that of a mineral oil by means of laboratory experiments using lysimeters of 70 cm height x 20 cm diameter. The migration in soil of the oils and of the metabolites of the plant ester over 120 days was examined by gas chromatography and liquid chromatography. The plant oil and its metabolites were completely degraded within 60 days, whereas degradation of the mineral oil required 90 days. The molecules did not migrate far into the soil and therefore presented no risk of contaminating groundwater.

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