Long term effects of irrigation with petrochemical industry wastewater

Split plot designed field trials were conducted during 1988-1995 to study the long term effects of petrochemical industry wastewater on six crops and agricultural soils. It was observed that wastewater irrigation resulted in increased seed yield of all the crops selected, viz. wheat, triticale, chickpea, lentil and pigeonpea, except summer moong which showed a decrease in seed yield. Soil receiving the wastewater showed no significant changes in pH, total organic carbon, electrical conductivity, cation exchange capacity, micro- and macro-nutrients and SAR. Thus, it may be concluded that treated refinery wastewater met the irrigational quality requirements as its physico-chemical characteristics were within the permissible limits. The same could be said for the accumulation of heavy metals in the soil as well as in the grains making the latter safe for human consumption.