Effect of treated sewage effluents on heavy metals contents of three dominant wild plants at Wadi Al Rummah, Qassim Region, Saudi Arabia

Abstract

A total of 132 plant samples from the aerial and underground parts of Halox-ylon salicornicum, Pulicaria undulata and Suaeda vermiculata, collected from Wadi Al Rummah, before and after Al Rass sewage Plant, were examined to assess their heavy metal contents. The results revealed highest Fe content and lowest Cd concentration in the three plant species examined. The aver-age metal concentration pattern in the aerial parts were: Fe> Mn> Zn> Cr> Cu> Ni> Pb> Cd. The concentrations of these eight elements in the aerial and underground parts were species dependant, but Mn was found to be pre-dominantly highly accumulated in the aerial parts, whereas Cu had the ten-dency to accumulate in the underground parts. The three plant species stud-ied, showed a decrease in Mn concentration and increased values in Zn, Cu, Fe, and Cr both in the aerial and underground parts after the Sewage Plant compared to their concentrations before the Sewage Plant (control.). The high accumulation of Cr in the plants examined (compared to typical concen-trations, suggested that the wild plants of the area should be used with cau-tion to feed livestock. The results also showed that P. undulata had the high-est accumulation of Zn, Cu, Ni, Fe, Mn and Cr, whereas the underground parts of H. salicornicum showed highest values for Pb and Cd.