Khan Yasir Karim, Toqeer Muhammad, Shah Munir H
Department of Chemistry, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
Department of Earth Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
Environ Geochem Health. 2023 May;45(5):1391-1412. doi: 10.1007/s10653-022-01270-4. Epub 2022 Apr 16.
The present study is based on the measurement of potentially toxic metal contents employing various extraction methodologies aimed at the evaluation of their mobility, bioaccessibility and bioavailability in the urban soil (n = 56) of Lahore, Pakistan. Selected metal levels in the soil were quantified using flame atomic absorption spectrometry. On the average basis, aqua regia and glycine extracts revealed comparatively higher contents for most of the metals; average concentrations of Fe, Mn, Zn, Pb, Cu, Cr, Co and Cd were found at 1566, 451.1, 114.8, 52.84, 39.15, 24.82, 12.59 and 3.953 mg/kg in aqua regia extract, while in glycine extract the metal levels were found at 579.6, 174.2, 74.72, 49.74, 19.28, 7.103, 4.692 and 3.357 mg/kg, respectively. However, Cd, Pb, Cu and Zn showed significantly higher mobility and bioavailability in the soil, while Co, Fe and Mn were least mobile/bioavailable. The pollution index was assessed in terms of enrichment factor and modified degree of contamination which revealed severe to significant contamination and anthropogenic enrichment of Cd, Pb, Cu and Zn. Multivariate analysis showed mostly anthropogenic contributions for Zn-Cu-Cr-Pb-Cd. Health risk assessment revealed relatively higher exposure of the metals through ingestion, while only minor contributions were noted for inhalation and dermal contact. Hazard quotient index was within the safe limit (< 1.0) in all soil extractions, thereby indicating no significant non-carcinogenic health risks. The incremental lifetime cancer risk for Cr (4.1E-06) through ingestion was comparatively higher than the safe limit which showed significant lifetime cancer risk to the local population.
本研究基于采用各种提取方法对潜在有毒金属含量进行的测量，旨在评估其在巴基斯坦拉合尔城市土壤（n = 56）中的迁移性、生物可及性和生物有效性。土壤中选定金属的含量通过火焰原子吸收光谱法进行定量。平均而言，王水和甘氨酸提取物显示大多数金属的含量相对较高；王水提取物中Fe、Mn、Zn、Pb、Cu、Cr、Co和Cd的平均浓度分别为1566、451.1、114.8、52.84、39.15、24.82、12.59和3.953mg/kg，而在甘氨酸提取物中，金属含量分别为579.6、174.2、74.72、49.74、19.28、7. l03、4.692和3.357mg/kg。然而，Cd、Pb、Cu和Zn在土壤中表现出显著更高的迁移性和生物有效性，而Co、Fe和Mn的迁移性/生物有效性最低。根据富集因子和修正污染程度评估了污染指数，结果显示Cd、Pb、Cu和Zn存在严重至显著的污染和人为富集。多变量分析表明，Zn-Cu-Cr-Pb-Cd主要来自人为贡献。健康风险评估显示，通过摄入途径接触这些金属的风险相对较高，而吸入和皮肤接触的贡献较小。所有土壤提取物中的危害商数指数均在安全限值（<1.0）内，因此表明不存在显著的非致癌健康风险。通过摄入途径，Cr的终生增量癌症风险（4.1E-06）相对高于安全限值，这表明当地人群存在显著的终生癌症风险。
