Effect of treated sewage water on vegetative and reproductive growth of date palm

Abstract

The effect of treated sewage water on the vegetative and reproductive growth of date palms was assessed. Leaves and fruits samples were collected from locations irrigated with treated sewage (TSW), desalinised, and well water. Samples were analysed for their calcium (Ca), magnesium (Mg), iron (Fe), lead (Pb), copper (Cu), and zinc (Zn) content by atomic absorption spectro‐photometry and for sodium (Na) and potassium (K) by flame photometry. The Mg, Fe, and Zn content of fruits and Na in the leaves were not found to be significantly different. Treated sewage water from University campus utilities significantly increased the Na, K, and Cu and reduced Ca in leaves and Zn in fruits of date palms. But no significant effect was observed on the K, Ca, Mg, and Na contents in fruits of the same palms. The different concentrations of Ca, Mg, Fe, and Zn in the fruits of date palms grown along the same TSW line were attributed to variations in the soil; however, those in Pb content of leaves could be attributed to motor vehicle combustion. The general trend indicated that fruits contained higher K, Na, and Fe contents, but lower Ca, Mg, Cu, Zn, and Pb contents than the leaves. Furthermore, leaves of date palms irrigated with desalinised and well water contained higher Ca and Zn, but lower K, Mg, Na, Cu, Fe, and Pb contents than those of palms irrigated with treated sewage water. Desalinised water reduced the K, Ca, Na, and Zn contents, but it increased the Mg, Fe, Cu, and Pb content of leaves compared to well water. None of the examined metals were found to reach toxic level to man or plant.