background: soil and sediment serve as major reservoir for contaminants as they possess ability to bind various chemicals together. in this study the concentrations of heavy metals cd, cr and cu were analyzed in surface sediments of agh gel wetland in west of iran. methods: the sediment samples were taken from 10 stations. the samples were subjected to bulk digestion and chemical partitioning a...

For a spanning tree T in a nontrivial connected graph G and for vertices u and v inG, there exists a unique u−v path u = u0, u1, u2, . . ., uk = v in T . A u− v T -path in G is a u− v path u = v0, v1, . . . , vl = v in G that is a subsequence of the sequence u = u0, u1, u2, . . . , uk = v. A u− v T -path of minimum length is a u− v T -geodesic in G. The T distance dG|T (u, v) from u to v in G i...

Four heavy metals were measured in forty-nine topsoil samples collected fromagricultural areas in Siakh-Darengoun, Iran. The goals were to investigate soil spatialdistribution patterns of metals; their potential ecological risk; and sources. The Hakansonpotential ecological risk index and index of geo-accumulation (Igeo) were used forevaluating t...

Objective: Metal concentrations in 53 soil samples of Shahr-e-Babak were determined.  Methods: Assessment of enrichment factor and geo-accumulation index revealed higher degree of contamination of Cd, Pb, and Cu in soil samples. Moreover, results of metal fractionation study revealed high amount of Cd and Pb are associated in weakly bounds may lead to environmental risk of these metals.  Result...

The structures of three xGeO(2)-(1- x)P(2)O(5) glasses, where x = 0.98,0.88, and 0.81, have been studied by neutron and x-ray diffraction experiments that yield well resolved P-O and Ge-O bond distances. The Ge-O coordination number (N(GeO)) increased from 4.0 ± 0.2 to 4.5 ± 0.2 with the decrease in x from 0.98 to 0.81. The increase in N(GeO) is consistent with a structural model that assumes t...

mahallat hot springs located in the northeast of mahallat, in central iran. there are 6 main hot springs namely shafa, abejoush, donbeh, soleimanie, hakim and soda. in this research, geology, physico-chemical characteristics and petrography of basement rocks of these hot springs have been investigated. the results show that hot springs have an average temperature of 45°c and acidic to neutral p...