Evaluation of heavy metals pollution in crops and agricultural soils in south Tehran.

World population increase needs to more production in one hand and scarse of water resources and unsuitable use of water especially in arid and semiarid regions and also waste volume of waste water in the citis in the other hand needs a suitable program to use it in the agriculture sector and to change the ground water. The heavy metals in a small concentrations are dangerous for human,animal and plant due to not breaking down.cadmium, lead and nikel are the contaminated sources of soil, water and plant. The may penetrate in nutrition change of humans and animals and would have the dangerous effects. In this project 2000 hectares of agricultural area which irrigated by Firozabad canal is selected to study. The results decal arced that more than 11 % of the soils head less than 20 and the 89 % of them had more than 20 mg/kg of available phosphorous which is due to over estimated application of phosphorous fertilizers. The soil mean particle size included 39% of clay, 42% of silt and 19% of sand which indicat the most soil had medium to heavy texture. Regarding these data it is essential to have a proper program for preventing the accumulation irrigation and fertilization of the soils in this area. The mean total cadmium concentration of soil samples were 0.27 mg/kg with zero and 0.82 mg/kg for minimum and maximum rates respectively the mean concentration of soil samples lead were 58 mg/kg with zero and 125 mg/kg for minimum and maximum respectively. The mean concentration rate of nike of soil samples were 83 mg/kg while the minimum and maximum concentration rates were zero and 164 mg/kg. The absorbation rates of lead by plant were 0-12 mg/kg which were lees than the critical level. The absorbtion were of nikel by plant were 0-2.67 mg/kg which were less than the critical level. The absorbtion rates of cadmium and arsenic by plant were egligible and less them critical level 0-0.5 mg/kg this means the fixation capacity of the soil is very high so the plant cannot abserb them. The water more than the vertical level bicarbonate concentration in water samples were 0-451 mg/l which in irrigation water(91.5 mg/l). 28 The results dead that indicated that on behalf of wan safety, pointed on the national standard No. 12968 of standard org animation calcium contamination in corn forage, wheat seed, rice and the stuble of wheat weren't seen. The 15% of fresh vegetables had cadmium contamination. The contamination of lead were seen 100 % in forage corn, wheat stuble and fresh vegetable 20% in wheat seed and 60% in rice. Keys: contaminated,heavy metals