Alleviation of Toxic Effects of Untreated Wastewater on Selective Vegetables Using Soil Organic Amendments

Abstract

In this work, a pot experiment was conducted to evaluate theeffect of organic amendments in alleviation of toxicity ofuntreated domestic wastewater to okra (Abelmoschusesculentus) and purslane (Portulaca oleracea). Threeorganic amendments including farm yard manure (FYM),poultry manure (PM) and bagasse ash (BGA) at the rate of1% and 3% were applied to the soil to evaluate their positiveimpact on vegetable plants. Results showed that untreatedwastewater impeded the growth of both vegetables andincreased uptake of heavy metals (HMs) (i.e. Cu, Ni, Pb andZn) by plants whereas organic amendments significantlyimproved the growth of plants and decreased the uptake ofHMs. Shoot and root lengths and dry weights of plants wereboosted by the FYM and PM, while chlorophyll a and b andcarotenoids were enhanced by PM and BGA amendments.Interestingly, reduced HMs uptake was found where 3% ofBGA or FYM were applied. Overall the results of this studyshowed that all three organic amendments were useful forimproving growth of vegetables and alleviating thephytotoxicity of untreated wastewater and uptake of HMs byplants. Our findings suggest that these organic materialscould be useful for improving agricultural productivity inuntreated wastewater irrigated areas.