The effect of drilling fluids and crude oil on some chemical characteristics of soil and crops

A four-year pot trial was set up to determine, as precisely as possible, the influence of increased levels of total petroleum hydrocarbons (TPH) upon soil and plants grown. In eight treatments, clean soil and different doses of drilling fluids and crude oil were applied. The changes in some chemical parameters of soil, plant density and crop yields were investigated. The influence of the studied indicators on the achieved plant density and crop yield was strongest in the first trial year. Drilling fluids had a stronger impact on the chemical properties of the studied soil, while plant density and yield were more strongly affected by crude oil. Upon application of drilling fluids and crude oil, the soil pH, contents of organic matter (OM) and heavy metals (HM) varied very little throughout the trial period, whereas the soil levels of total petroleum hydrocarbons, mineral oils (MO) and polycyclic aromatic hydrocarbons (PAHs) were significantly reduced after the first trial year.