Chemical fragmentation and Bioavailability for Lead in some calcareous soils from the city of Mosul

Abstract

Abstract The first two sites were selected from the Aden district and geographically defined by coordinates N36° 21′ 21.5″ E43° 12′ 39.1″ In the course of valley Al-Danfili in the city of Mosul, which pours its cargo in the Tigris River at the site of the Al-Mazara district, which is geographically defined by coordinates N36° 19′ 50.2″ E43° 09′ 49.05″ We classified the soil suborder (Argids, Orthents) Respectively. The total content of the Lead was separated by extracting the soil in a sequential manner in order to identify the nature of its distribution within the different soil phases according to the following context: Water extraction and then (0.005M) (DTPA) Which is associated with carbonates with diluted hydrochloric acid solution (0.1M). The H2O2 extraction stage is 20% equilibrium for the purpose of determining organic matter content then associated with non-crystalline iron oxides (AFeOx) Amorphous Fe Oxides using a mixture solution (0.25M NH2OH. HCl + 0.25M HCl) (10: 1) (solution: soil), This was followed by the final phase, which included mechanical separation of sand, silt and clay digest each separately by using a wet digestion method to determine residual content(sand, silt and clay). Lead was measured in the solutions and extracts in the solutions above using the (GBC 933plus) atomic absorption device The results indicated the following: The water soluble fraction ranged from (0.33 to 0.34) mg.kg−1 and by (0.10%), exchange from (15.14 to 7.01) mg.kg−1 and by(3.31%), associated with oxides from (14.20 to 76.29) mg.kg−1 and by (13.51%), which is related to the organic matter from (29.60 to 23.00) mg.kg−1 and by (7.85%), associated with carbonates from (261.20 to 87.50) mg.kg−1 and by (52.04%), and associated with clay from (43.84 to 10.77) mg.kg−1 and by (8.15%), and associated with silt from (22.23 to 3.59) mg.kg−1 and by (3.85%) and associated with sand from (44.46 to 30.50) mg. kg−1 and (11.19%) of the total content from the Aden(clay) and the Al-mazara (sandy clay loam) districts Respectively. The physiochemical pathway for the distribution of Lead in the calcareous conditions prevailing in the following area is explained: Solid carbonates > Oxides > Sand > clay > Organic Matter> Silt > Exchange > Soluble.