The increasing need for water in the arid areas of the world has resulted in the
emergence of wastewater application for agriculture and landscape. Using treated wastewater in
agricultural irrigation can provide more adequate supply of high quality water for human consumption,
but their heavy metal applications effect must be regulated to ensure no physiological problems for
both the plant and its consumer. The objective of the present research was to study the effects of
treated wastewater on soil chemical properties and plant growth characteristics as well as
accumulation of heavy metals in plant tissues. This research was conducted at Qatar university
greenhouse in the growing season of 2007. Treated wastewater was obtained from Abu Nakhala
pond in Doha City, Qatar. The soil was a mixture of sand and clay with ratio of (1:1). Two crop plants
were used in this study; grain sorghum (
Sorghum bicolor
L.) and Sunflower (
Helianthus annuus
L).
Plants were irrigated with four different mixtures of wastewater and sea water (1:0, 1:1, 3:1, and 0:1)
in addition to potable water as a control. The accumulation of salts and heavy metals in the soil as
well as concentration of the nutrients and heavy metal accumulation in the plant tissues were
determined at the end of the experiment. Cr, Mn and Zn showed significant differences between soil
irrigated with portable tap water and other irrigation treatments. On the other hand, Al, Fe, Ni, Co,
Cu, As, Cd and Pb did not show significant differences among the irrigation water treatments.
Sorghum soils have significantly less concentration of Co, Cu and As compared to that of Sunflower
soils. Sorghum was found to accumulate significantly higher concentration of Mn and Zn (72.47
and 92.00 mg/L, respectively) than that of Sunflower. On the other hand, Sunflower has significantly
higher concentration of Cr compared to that of Sorghum.
