title: Risk assessment of total and bioavailable potentially toxic elements (PTEs) in urban soils of Baghdad-Iraq.
abstract: The solubility of soil-associated potentially toxic elements (PTEs) in surrogate biological fluids provides valuable information about their potential health hazard. This work addresses the concentrations and bioaccessibility of nine PTEs (As, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn) in thirty eight agricultural land and playground soils collected from a semi-arid urban area of Baghdad-Iraq. Two surrogate biological fluids (SBFs), macrophage vacuole (MS) and gastric (GS) solutions, were used to extract the metals to simulate the biological availability of the PTEs via inhalation and ingestion exposure routes. ICP/AES was used to quantify PTEs in both strong acid digests (for total concentration), and in the SBF extracts. Soil contamination factors showed that some sites exhibited elevated levels of As (36 ± 10 mg/kg), however, these levels of As are not likely to have significant human health impacts whether the particulate arsenic is ingested or/and inhaled. Soil-geochemical variables (including: pH, EC, CO3(=), soil organic carbon (SOC)) and major elements (e.g. Al, Ca, and Fe) were used to interpret the lability of PTEs in the soils. Hazardous index (HI) based non-cancer risk of inhalation and ingestion of PTEs was estimated to be 2-fold higher for that based on total element concentrations compared with that for bioavailable fractions for both children and adults. A similar conclusion was reached for the estimated cancer risk (which was lower than the threshold level of concern for children and adults). A sensitivity analysis showed that there is a 97% chance for children and 90% for adults to have hazardous indices of the total PTEs >1 (the acceptable value); the corresponding metrics for the bioavailable fraction of the elements were 39% for children, and 3% for adults; these results were sensitive to the concentrations of "airborne" soil particles.
authors.affiliation: Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park Str., Madison, WI 53706, USA. Electronic address: shamad@wisc.edu.
authors.forename: Samera H
authors.initials: SH
authors.lastname: Hamad
authors.affiliation: Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park Str., Madison, WI 53706, USA; Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA; Wisconsin State Laboratory of Hygiene, 2601 Agricultural Drive, Madison, WI 53718, USA. Electronic address: jjschauer@wisc.edu.
authors.forename: James J
authors.initials: JJ
authors.lastname: Schauer
authors.affiliation: Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park Str., Madison, WI 53706, USA; Wisconsin State Laboratory of Hygiene, 2601 Agricultural Drive, Madison, WI 53718, USA. Electronic address: mmshafer@wisc.edu.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Shafer
authors.affiliation: Iraqi Ministry of Science and Technology, Al-Jadria, Baghdad, Iraq. Electronic address: esam3a76@yahoo.com.
authors.forename: Esam Abd
authors.initials: EA
authors.lastname: Al-Rheem
authors.affiliation: Wisconsin State Laboratory of Hygiene, 2601 Agricultural Drive, Madison, WI 53718, USA. Electronic address: pamela.skaar@slh.wisc.edu.
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Skaar
authors.affiliation: Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park Str., Madison, WI 53706, USA. Electronic address: jongbaeheo@gmail.com.
authors.forename: Jongbae
authors.initials: J
authors.lastname: Heo
authors.affiliation: Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park Str., Madison, WI 53706, USA. Electronic address: mitejedo@facstaff.wisc.edu.
authors.forename: Isabel
authors.initials: I
authors.lastname: Tejedor-Tejedor
mesh_terms: D004781:Environmental Exposure / Q000032:analysis / Q000706:statistics & numerical data*; D004787:Environmental Pollution / Q000706:statistics & numerical data*; D015386:Hazardous Substances / Q000032:analysis* / Q000633:toxicity; D007493:Iraq; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000633:toxicity
chemical_list: D015386:Hazardous Substances; D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants
keywords: Bioavailability; Potentially toxic elements; Surrogate biological fluids; Urban area—Baghdad/Iraq