Determination of lead in groundwater samples of three aquifers of a coal mining area at various depths using advance extraction methodology

ABSTRACT

A simple and novel ultrasonically modified dual-cloud point extraction (Um-DCPE) method has been developed to preconcentrate a toxic heavy metal, lead (Pb²⁺), in aquifer water of different depths in the region of Thar coalfield, Pakistan, prior to analysed by flame atomic absorption spectrometry (FAAS). The Pb²⁺ in water samples have been complex with 8-hydroxyquinoline followed by the entrapping in the hydrophobic non-ionic surfactant (Triton X-114). The second step of Um-DCPE involved the addition of 0.5 to 2.0 mol L⁻¹ of HCl/HNO₃ (2 mL) and subjected to shaking and centrifugation, separate upper aqueous layers, and subjected for analysis. To check the performance of the proposed method a certified reference material (CRM) of water and spiked standard in a real sample were applied successively. Both LOD and LOQ achieved by the proposed method for Pb²⁺ were 0.023 and 1.70 μg L⁻¹, respectively. The optimised Um-DCPE method was applied effectively to selected aquifer water samples. The results obtained from the proposed method indicated that the aquifer water samples of different depths have 2 to 3 folds higher Pb²⁺ values than recommended values of the world health organisation.

KEYWORDS:

• Ultrasound energy
• non-ionic surfactant
• lead
• aquifer water

Acknowledgments

The authors would like to thank National Centre of Excellence in Analytical Chemistry (NCEAC) University of Sindh Jamshoro for providing laboratory facilities for scholars to carryout research work.

Disclosure statement

No potential conflict of interest was reported by the author(s).