كليدواژه :
ذرات خروجي از وسايط نقليه , سرب , كشاورزي , Lead , Sequential extraction , emission , Highway , Automobile , بزرگراه , عصاره گيري متوالي
چكيده لاتين :
Lead gasoline additive, is one of the most significant contributors to atmospheric and soil pollution. Soil lead pollution by on road vehicle emission was investigated in Rasht-Anzaly (Anzaly), Kelachay-Ramsar (Ramsar), Tehran-Karaj (Karaj), and East and West sides of Tehran-Esfahan (Deliejan-E, Deleijan-W) highways. Soil samples was collected from the 0-5 cm soil surface along a 100 meter transect perpendicular to road. The soil samples were analyzed for total lead content, and lead in exchangeable, oxide, carbonate, organic, and residual fractions forms using a sequential extraction method. The lead exchangeable and organic-matter fraction were low in all areas. The dominated form of lead in Anzally, Ramsar and Delijan-W was in residual, in Karaj area was carbonate and in Deleijan-E was oxide form. Soil lead content increased by increasing vehicle traffic on highways, and relative soil lead content in carbonate and oxid forms increased comparative to other forms.The relative lead content in oxid and carbonate form decreased and the residual form increased further away from the highways.The residul, and carbonate forms were dominated in low and highly polluted area, respectively. Comparison of the results with the standard permissible and critical lead content indicated that, Ramsar and Deleijan-W, Anzally and Deleijan-E, and Karaj are the least, medium, and mostly polluted area,respectively. The lead fraction in different chemical form depend on traffic density and the total soil lead content resulted from the on road vehicle emission.
