Quality of Wastewater Used for Conventional Irrigation in the Vicinity of Lahore and its Impact on Receiving Soils and Vegetables

The quality of wastewater was evaluated from Rohi Nullah, Lahore, Pakistan, for one year (2008-2009) from those points where it is used for irrigation of crops on both sides of Nullah. The quality of wastewater was evaluated for pollution load including pH, sulphide, phenol, methylene blue active su...

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Bibliographic Details
Published in:Pakistan journal of scientific and industrial research. Series A: physical sciences 2014-05, Vol.57 (2), p.86-94
Main Authors: Bashir, Farzana, Tariq, Muhammad, Khan, Rauf Ahmad, Shafiq, Tahira
Format: Article
Language:English
Subjects:
Environmental aspects
Evaluation
Irrigation water
Wastewater
Water quality
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Summary:The quality of wastewater was evaluated from Rohi Nullah, Lahore, Pakistan, for one year (2008-2009) from those points where it is used for irrigation of crops on both sides of Nullah. The quality of wastewater was evaluated for pollution load including pH, sulphide, phenol, methylene blue active substances, chemical oxygen demand (COD), biochemical oxygen demand (BOD), irrigation quality (electric conductivity, total dissolved solids, total suspended solids, sodium adsorption ratio, residual sodium carbonate and chlorides) nutritional value (total nitrogen, total phosphorus and total potassium) and for metal concentration. The metals analysed were cadmium, nickel, chromium, zinc, manganese, cobalt and copper. With respect to pollution load BOD, COD and sulphide concentration was above the National Environmental Quality Standard (NEQS) limit. Nitrogen and phosphorus were contained at levels of concern in wastewater but the level of potassium was below crop requirements. The concentration of nickel, chromium, manganese and copper was above the FAO standards, while the concentration of cadmium, zinc and cobalt fell within FAO standards. Considering NEQS standards, the metals concentration was within limits. Temporal variations were prominent in some parameters and mostly higher values were observed in summer and lower in winter season. There was accumulation of heavy metals in soils receiving wastewater for irrigation. The metal contents in soils follow the order Mn> Co> Zn> Cr>Ni> Cu > Cd. It was observed that the concentration of all studied toxic metals in edible part of the vegetables was above the critical level. Finally, it was concluded that the practice of using wastewater in irrigation for growing vegetables and other crops is non-sustainable. Keywords: wastewater, irrigation quality, COD, BOD, SAR, metal ions
ISSN:2221-6413
2223-2559
DOI:10.52763/pjsir.phys.sci.57.2.2014.86.94