Impact of spreading olive mill waste water on agricultural soils for leaching of metal micronutrients and cations.
Olive mill waste water (OMWW) is an acidic (pH 4-5), saline (EC ∼ 5-10 mS cm-1), blackish-red aqueous byproduct of the three phase olive oil production process, with a high chemical oxygen demand (COD) of up to 220,000 mg L-1. OMWW is conventionally disposed of by uncontrolled dumping into the environment or by semi-controlled spreading on agricultural soils. It was hypothesized that spreading such liquids on agricultural soils could result in the release and mobilization of indigenous soil metals. The effect of OMWW spreading on leaching of metal cations (Na, K, Mg, Mn, Fe, Cu, Zn) was tested in four non-contaminated agricultural soils having different textures (sand, clay loam, clay, and loam) and chemical properties. While the OMWW contributed metals to the soil solution, it also mobilized indigenous soil metals as a function of soil clay content, cation exchange capacity (CEC), and soil pH-buffer capacity. Leaching of soil-originated metals from the sandy soil was substantially greater than from the loam and clay soils, while the clay loam was enriched with metals derived from the OMWW. These trends were attributed to cation exchange and organic-metal complex formation. The organic matter fraction of OMWW forms complexes with metal cations; these complexes may be mobile or precipitate, depending on the soil chemical and physical environment.
['Aharonov-Nadborny|R|R|', 'Tsechansky|L|L|', 'Raviv|M|M|', 'Graber|E R|ER|']
D000383:Agriculture D057919:Biological Oxygen Demand Analysis D002412:Cations D008670:Metals D018977:Micronutrients D031658:Olea D012987:Soil D012989:Soil Pollutants D062065:Waste Water D014874:Water Pollutants, Chemical
Metals OMWW Cation exchange Complex formation Olive mill wastewater Soil spreading