Ecotoxicological assessment of soil-like mixtures made of drill cuttings

The purpose of this study is to determine the possibilities to use drill cuttings in soil formation processes on sandy substrates. The ecological and toxicological assessment of drill cuttings of various genesis and mixtures based on them is applied for the purpose. Acute toxicity of mixtures consisting of various drill cuttings, sand and peat was estimated using soft wheat seeds (Triticum aestivum) using the eluate method. Subacute toxicity experiments were carried out using creeping trefoil (white clover) seeds (Trifolium repens), rye seeds (Secale cereale), and garden radish seeds (Raphanus sativus L.). Drill cuttings of the West Siberian oil-and-gas basin generated as a result of drilling on clay-polymer drilling fluids can be used as a component of soil-like mixtures in the reclamation of sand fills. Patterns of the selective stimulation of seed growth by components of drilling fluids (xanthate and bentonite) were revealed. It was found that the addition of bentonite and xanthan (0.05% by weight of the cuttings each) reduces the suppression of seed growth occasioned salt content by 21.1% and 24.0%, respectively. Soil degradation and desertification is a serious and widespread problem. The restoration of the fertile layer can be launched by application of the artificial soil-like mixtures based on drill cuttings of a certain origin to the disturbed lands.