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The present study has been performed to evaluate the prospective effects of toxic and potentially toxic elements (TPTEs) on different groups of sediments in mining area. Fractionation of metal and metalloid elements (As, Cd, Co, Cu, Fe, Mo and Zn) was studied using a modified Community Bureau of Reference (mBCR) sequential extraction procedure in the sediments collected at five sedimentary systems. Compared to natural background values the enrichment factor (EF) of TPTEs follow the order of Cu > Mo > Cd > Zn > Co > As > Fe. Comparison with sediments quality indicators (including: sediment pollution index (SPI), pollution load index (PLI), and modified contamination degree (mCd)) revealed, that leached sediment containing secondary phases (S5 and S6), sediments containing ferric compounds (S7 and S8) and then evaporitic deposits (S9) are considered as the most contaminated sediment with a high to ultra-high degree of contamination, Subsequently based on the average indices values for sedimentary systems, the descending order is as follows: S5> S4 > S2 > S3 > S1. This issue confirm that sedimentary systems of mining area are heavily contaminated by toxic and potentially toxic elements and were not found within the guideline acceptable values. The potential ecological risk index (PERI) revealed a very high risk level for Cu with a peak in sediments containing sulfide phases. Speciation results in the investigated sediments indicated that the labile form has a considerable role in the release of all TPTEs except for Mo, Fe, and to somewhat As. Accordingly, based on the risk of elements bioavailability, the descending order is as follows: S9 > S4 > S5 > S6 > S7 > S3 > S8 > S2 > S1. X-ray diffraction (XRD) analysis confirmed the presence of lithogenic minerals with low bioavailable elements in the samples (S1, S2, S3, S4, S7 and S8) and secondary minerals with high bioavailable elements in samples (S5, S6 and S9). Multivariate statistical analysis (Pearson's correlation analysis, PCA, and CA) suggested that the sources of TPTEs contamination were mainly anthropogenic along with the geogenic sources in the study area. [ABSTRACT FROM AUTHOR]

The Surgah Formation was studied in four sections (Kuh-e-Surgah anticline, Zifel, Sarkan, and Mal-e-kuh) from the NW-SE of the Zagros sedimentary basin. Forty-one planktonic foraminiferal species belonging to 20 genera were observed. The recorded species were used to subdivide the Surgah Formation into three biozones: Marginotruncana sigali-Dicarinella primitiva Zone, Dicarinella concavata Zone, and Dicarinella asymetrica Zone. Based on these data, the Surgah Formation was estimated to be of late Turonian to late Santonian age. The Coniacian/ Santonian boundary is placed at the Dicarinella asymetrica Zone. The base of the Santonian stage is identified on the FO of Globotruncana linneiana (pill box shaped), the FOs of Dicarinella asymetrica, Globotruncanita elevata and Globotruncana bulloides, and the LOs of Dicarinella primitiva, Dicarinella concavata and Muricohedbergella flandrini. [ABSTRACT FROM AUTHOR]

Eocene larger benthic foraminifera including orthophragmines, nummulitids and alveolinids from the Jahrum and Pabdeh formations in the Zagros region are presented. The studied 20-m-thick stratigraphic interval contains, Asterocyclina Gümbel 1870, Nemkovella Less 1987, Orbitoclypeus Silvestri 1907, Discocyclina Gümbel 1870, Nummulites Lamarck 1801, Assilina d’Orbigny 1826 and Alveolina d’Orbigny 1826. This larger benthic foraminiferal assemblage testifies for the shallow benthic zones (SBZs) 15 to 17, which ranges from the middle Lutetian up to the early Bartonian. Further micropaleontological analysis made on intercalated planktonic-rich levels helps calibrate the larger foraminifera biostratigraphy, demonstrating a correlation with the E11 biozone. This confirms that the chronostratigraphic calibration of the SBZs made by previous authors for the peri-Mediterranean area can, through the middle Lutetian to the early Bartonian, be applicable in the Middle East as well [ABSTRACT FROM AUTHOR]

Metal contamination of soil is primarily attributed to human activities and there is an increasing need to conduct risk assessments to characterize the nature and magnitude of risks to humans and ecological receptors from these contaminants. Trace metals (As, Sb, Cd, Cr, Pb, Co, Ni, V, Se, Zn, Fe) in soils from the Chelpu region of North East Iran were analyzed by ICP-OES to assess pollution using the geo-accumulation index (Igeo) and the enrichment factor (EF). The United States Environmental Protection Agency (USEPA) model was applied to calculate human health risk (HHR). Physicochemical and textural properties of the soil including pH, electrical conductivity (EC), organic matter (OM), calcium carbonate equivalent (CCE) were examined in 26 surface and subsurface soils and related to metal levels. Metal concentrations varied considerably [As (7.1–1448.8 mg/kg), Sb (7.7–74.4 mg/kg), Pb (0.6–26.5 mg/kg), Cd (1–2.6 mg/kg), Cr (67.5–527 mg/kg), Co (18.4–42.6 mg/kg), Ni (85.9–548.6 mg/kg), Sr (180.3–670.6 mg/kg), V (85.3–158.4 mg/kg), Se (0.4–3.10 mg/kg), Zn (44.6–104.9 mg/kg), and Fe (29,400–51,800 mg/kg)]. The Igeo indicated that soils were moderately polluted with As, Se, Ni, and Co but heavily to extremely contaminated with Sb and Cd compared with natural soils (USEPA). The enrichment factor (EF) values demonstrated that levels of As, Ni, and Co were moderately enriched but levels of Se, Cd, and Sb were substantially enriched. In contrast, Pb, Cr, Sr, V, and Zn levels were low. Using a human health risk assessment approach, non-carcinogen effects (HI >1) through ingestion of 13.04% of soil samples were determined. Carcinogenic effects through the ingestion pathway were observed for As and Cr in 13% and 3.9% of the soil samples, respectively. Organic matter (OM) content was significantly correlated with As (0.461, α = 0.05), Sb (0.605, α = 0.01), and Se (0.552, α = 0.01). [ABSTRACT FROM AUTHOR]

This study investigated the concentration of trace metals in surface sediments of Parishan Lake. Parishan Lake is one of the biggest freshwater lakes in the Middle East, situated in Kazerun area (Fars Province, Iran). This preliminary study concerns the mineralogy, enrichment level, and trace elements source identification in surface sediment of this lake. The geochemical Enrichment Factor (EF) and Geo-accumulation index (Igeo) and sedimentological approaches were applied to characterize the contamination by heavy metals, comparing with Average Shale. Multivariate statistical analysis was also used to identify probable studied elements sources in collected samples. The XRD and microscopic analysis show that main mineral of surface sediments is aragonite with small amounts quartz and nepheline. Chemical analysis of sediments showed that the mean concentrations of As, Cd, Cr, Cu, Ni, Pb, Zn, and Sr were 1.88, 27.2, 32.4, 18.6, 8.1, 38.4, and 3934.9 mg/kg, respectively, and average concentrations of Cd, Cu, and Sr exceeded the corresponding values of upper continental crust (UCC) values. The outcomes of this study indicate that geochemical indices (EF and Igeo) revealed an extremely high enrichment for Sr, whereas other elements had minimal enrichment. The levels of potential ecological risk index (RI) for studied trace elements in all sampling locations were 41.13 and 23.76, lower than baseline value (150), signifying that ecological risks displayed by those elements in sediments were moderate. The multivariate statistical analysis indicated that Sr had a geogenic source (natural source), while As and Cd came probably from Industrial source (chemical fertilizers), Ni and Cr were likely derived from vehicle emissions, particularly agricultural machinery, and Pb originated from exhaust and non-exhaust traffic emissions. [ABSTRACT FROM AUTHOR]

A letter to the editor in response to the article " Geogenic thallium and lead pollution in soils and potential risk of toxicity: A report from Iran" that was published in a previous issue of the periodical is presented.