This study investigated lead concentrations in < 250 µm and < 75 µm of deposited dust and< 2000 µm, < 250 µm, and < 75 µm of surface soils at undeveloped residential lands leased to auto-mechanic ...artisans for a minimum of ten years and estimated exposure risk for children that will reside on the polluted lands after the lease periods. Soil-Pb levels ranges obtained were between 40.0 - 411 mg/kg, 62.0 - 435 mg/kg , and 61.0 - 491 mg/kg for < 2000 µm, < 250 µm and < 75 µm fractions, respectively. Dust-Pb levels ranges were between 138 - 1819 mg/kg, and 128 - 1584 mg/kg for < 250 µm and < 75 µm fractions, respectively. The estimated daily intake were in the range of 0.17 - 1.22 µg Pb Kg-1 body weight BWd-1 and 0.39 - 5.11 µg Pb Kg-1 BWd-1 for soil and deposited dust, respectively. This study has highlighted possible risks to occupants of lands previously used for auto-mechanic and auto-welding activities.
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•A simple, robust and low-cost approach for generation of PM10 fraction is reported.•Approach applied to soil and mine waste samples from Mitrovica, Kosovo.•Fraction containing ...potentially harmful elements (PHEs) is applied in to a human risk assessment based on inhalation.•Average daily dose for Cd from the inhalation of suspended soil particles is reported.
A new simple, robust and low-cost wet laboratory method for the generation of the <10μm (PM10) particle size fraction is reported. A sedimentation method is directly compared with a centrifugation method for generation of the PM10 fraction. Both approaches are based on an integrated form of Stokes’ law. Subsequently the sedimentation method was adopted. The results from the sedimentation method were corroborated using particle size distribution measurements. This approach for the generation of the PM10 fraction was applied to soil and mine waste samples from Mitrovica, Kosovo as part of an investigation in to the human risk assessment from inhalation of the PM10 fraction containing potentially harmful elements (PHEs). The average daily dose for Cd from the inhalation of suspended soil particles was calculated to be 0.021 and 0.010μgkg−1BWd−1 for a child and an adult, respectively. This corresponded to an inhalation dose of 0.50 and 0.70μg Cdd−1 for a child (20kg) and an adult (70kg), respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A new simple, robust and low-cost wet laboratory method for the generation of the <10 mu m (PM sub(10)) particle size fraction is reported. A sedimentation method is directly compared with a ...centrifugation method for generation of the PM sub(10) fraction. Both approaches are based on an integrated form of Stokes' law. Subsequently the sedimentation method was adopted. The results from the sedimentation method were corroborated using particle size distribution measurements. This approach for the generation of the PM sub(10) fraction was applied to soil and mine waste samples from Mitrovica, Kosovo as part of an investigation in to the human risk assessment from inhalation of the PM sub(10) fraction containing potentially harmful elements (PHEs). The average daily dose for Cd from the inhalation of suspended soil particles was calculated to be 0.021 and 0.010 mu g kg super(-1) sub(BW)d super(-1) for a child and an adult, respectively. This corresponded to an inhalation dose of 0.50 and 0.70 mu g Cd d super(-1) for a child (20 kg) and an adult (70 kg), respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The adverse health effects resulting from exposure to contaminated soil on internally displaced populations in Mitrovica, Kosovo can be determined by how the potentially harmful elements are bound in ...the soils. Certainly this was the case for Pb, present at concentrations ranging from 624 to 46,900 mg/kg, and at bioaccessibilities ranging <5% to nearly 90%. To assess why the soil Pb might differ so markedly in terms of its bioaccessibility, computer controlled scanning electron microscopy (CCSEM) was employed to determine how the Pb was associated with other elements at the individual particle (IP) level in soils from the area. It was found that the Pb-bearing particle types were, for the most part, different in each sample. We consider these differences as the main control on Pb bioaccessibility in these soils. Pb solubility at the IP level was evaluated by examining Pb-particles from these soils in the electron microscope before and after successive immersions in a simulated gastric fluid. This analysis (differential IP analysis) confirmed the CCSEM characterization that Pb associated with other higher atomic number elements (Fe, Zn, Cu and Ni) was less soluble than when it was present as isolated phases (e.g., as carbonate) or when it was bound with lower atomic number elements (Na, Al, Si, K, Ca). The heterogeneity in solubility and composition of the Pb-particles suggested that the Pb originated from a range of different anthropogenic activities. The nature of these different anthropogenic activities created the wide differences in Pb-bioaccessibilty by producing Pb bound in many different forms in the soil particles. This type of Pb-particle characterization highlights the role CCSEM analysis, and IP acid extraction, can play in providing supporting evidence alongside bioaccessibility data for applications in human health risk assessment and management of contaminated soil.
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•Individual particle data collected by computer controlled SEM.•Generation of a detailed classification scheme for Pb-bearing particles.•Lead particle solubility investigated by Differential Individual Particle Analysis.•Pb associated with higher atomic number elements had lower bioaccessibilities.•Complexity at the individual particle level not observable by bulk chemical analysis.
CCSEM-EDS was used to collect particle composition data to better refine risk-based assessments and site management strategies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Aim: The aim of this study is to generate and investigate oral bioaccessibility based on the health risk of polycyclic aromatic hydrocarbon (PAHs) in fly ash from waste tyres and petroleum products ...in Rivers State, Nigeria.
Study Design: Crude oil, crude oil asphalt, artisanal diesel, refined diesel, waste engine oil and waste tyres samples were collected and incinerated. The different fly ash samples were analyzed with GC-MS.
Place and Duration of Study: Rivers State is a state that is rich in oil in the Niger Delta area of Nigeria. The State has been experiencing the release of soot into the environment for more than five (5) years now. This soot is noticeable to all residents of Port Harcourt and its environment with soot covering both indoor and outdoor objects such as clothes, cars, houses, floors, soil, water body, etc. The five (5) petroleum products and waste tyres samples were collected and incinerated for six (6) weeks (22nd of June to 7th of August 2021).
Methodology: The petroleum products and waste tyres samples were collected and incinerated. The different fly ash samples were collected after combustion daily. The total and oral bioaccessible PAH concentrations were determined using GC-MS. The oral bioaccessibility of PAHs in the fly ash was evaluated using the physiologically-based extraction test method (PBET) to determine the bioaccessible concentrations of 16 priority US Environmental Protection Agency (USEPA) PAHs in fly ash samples. The results obtained for PAHs were used for health risk assessment.
Results: A wider range of total PAH concentrations were observed in the six (6) fly ash samples from 49.71 to 926.62 mg/kg. The PAHs concentrations were significantly higher in higher molecular weight PAHs (with benzene of 4-5-6 rings) than lower molecular weight PAHs (benzene of 2-3 rings). Naphthalene, acenaphthylene, acenaphthene, and fluorene with 2-3 ring structures had the highest bioaccessible concentrations in both gastric and gastrointestinal phases of all the six fly ash samples studied. Flourene had the maximum percentage bioaccessibility of 91.30 % in the gastric phase from locally refined diesel fly ash whilst acenaphthene had a maximum percentage bioaccessibility of 98.75% in the gastrointestinal phase from crude oil asphalt fly ash.
Conclusion: Data obtained from this study indicated that crude oil fly ash is a potential point source of toxic polycyclic aromatic hydrocarbons with significant levels of health risk to humans.
Removal of Zn, Pb, Cu and Fe ions from unspent and spent engine oil was studied using Termite soil. Process parameters such as contact time and adsorbent dosage were varied. Values from contact time ...were used for predicting kinetics equation of their uptake. At optimum time of 40 minutes, percentage adsorption was of the order Fe>Zn>Cu>Pb for both spent and unspent engine oil. Kinetics equation such as Elovich, Intra-particle, Pseudo-first order and Pseudo-second order were tested. Results obtained shows that their sequestering pattern fit into the pseudo-second order kinetics. Initial reaction rates, h (mg/g.min) and α (mg. g-1min-1) for all metal ions obtained from Pseudo-second order and Elovich kinetic models followed the trends Zn>Fe>Cu>Pb and Zn>Fe>Pb>Cu respectively in spent engine oil while for unspent engine oil, the trend was Fe>Zn>Cu>Pb for h (mg/g.min) and Zn>Fe>Pb>Cu for α (mg. g-1min-1). Electrostatic attraction existing on the surface of the adsorbent assisted in the high initial reaction of Zn and Fe ions, implying good affinity of the ions for the adsorbent. Desorption constant ᵦ (g/mg) was of the trend Cu>Pb>Fe>Zn and Cu>Pb>Zn>Fe for spent and unspent engine oils respectively. Intra-particle diffusion constant kid (mgg-1min-1/2) followed a similar pattern, revealing strong binding between Zn and termite soil than any of the metal ion. This pilot research has been able to suggest a kinetic process for uptake of the studied ions from spent and unspent engine oil.
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