A review on sequential extraction of metals bound particulate matter and their health risk assessment

Sequential Extraction Procedure (SEP) is a method widely used to extract metals and metalloids from Particulate Matter (PM) based on their solubility in different reaction media. This extraction procedure is used to determine the actual mobility of metals present in the environment. A detailed discussion on the significance of sequential extraction analysis is also being given in this scientific document. This review includes different aspects related to the fractions obtained (exchangeable: F1, reducible: F2, oxidizable: F3, bound to organic matter: F4, and residual fraction: F5) during the SEP. The use of each reagent involved in the fractionation process of PM is also discussed briefly. Finally, the present up-to-date information given by different researchers in various fields of atmospheric chemistry along with the possible future developments is also part of this scientific review. The current review also focuses on the relation between SEP and mathematical expressions (bioavailability, source apportionment, and health risk assessment by the USEPA method). It is revealed from the previous studies that Cd and Zn are highly enriched, mobile as well as highly bioavailable in the environment and poses more risk to the human being. The Cr and As showed carcinogenic nature and hence pose carcinogenic diseases in humans. Whereas, Mn and As are non-carcinogenic in nature for children and adults and thereby both pose a non-carcinogenic disease threat to the population.