Contamination, enrichment and translocation of heavy metals in certain leafy vegetables grown in composite effluent irrigated soil

Abstract

The present investigation was carried out to determine the contamination, enrichment and translocation of heavy metals in vegetables viz., spinach (Spinacia oleracea L.), fenugreek (Trigonella foenum-graecum L.) and coriander (Coriandrum sativum L.) grown in the composite effluent (mixture of industrial and domestic wastewater) irrigated soil. The composite effluent of Hindon River was significantly (P<0.05/P<0.01) loaded with different physical (TDS, EC), chemical (pH, BOD₅, COD, Cl ^–, TKN, PO₄^3-, SO₄^2-, Na⁺, K⁺, Ca²⁺, Mg²⁺), heavy metals (Cd, Cr, Cu, Fe, Mn, Pb, Zn) and microbial  (total bacteria, total fungi, total coliform and yeast) parameters in comparison to the ground water. The composite effluent irrigation significantly (P<0.05) altered the soil characteristics like EC, pH, PO₄^3-, K⁺, Cd, Cr, Cu, Fe, Mn and Pb in the soil used for the cultivation of S. oleracea, T. foenum-graecum and C. sativum. The composite effluent irrigation significantly increased the contents of Cd, Cr, Cu, Fe, Mn, Pb and Zn in the S. oleracea, T. foenum-graecum and C. sativum. The enrichment factor of Cd, Cr, Cu, Fe, Mn, Pb and Zn in vegetables was recorded to be plant part specific after irrigation with composite effluent. The enrichment factor of Cd, Cr, Cu, Fe, Mn, Pb and Zn were recorded in the order of Cd>Zn>Pb> Fe>Cr>Mn>Cu for S. oleracea, Cd>Zn>Fe>Mn>Pb>Cr>Cu for T. foenum-graecum and Cd>Zn>Pb>Fe>Cu>Mn>Cr for C. sativum after irrigation with composite effluent. Therefore, disposal of sewage and industrial effluents in the Hindon River must be strictly prohibited to save the existence of the Hindon River and irrigation practices using composite effluent should also be banned to prevent the possible health hazards due to consumption of contaminated vegetables.