Chemical partitioning of fine particle-bound As, Cd, Cr, Ni, Co, Pb and assessment of associated cancer risk due to inhalation, ingestion and dermal exposure

Abstract

The bioavailability and human health risks of As, Pb, Ni, Co, Cr and Cd in fine particulate matter (PM_2.5) at an urban site on a National highway in Agra, India were investigated. Inductively coupled plasma-optical emission spectrometer was used for metal analysis in sequentially extracted samples to ascertain the highly mobile, reducible, bioavailable and immobile fractions of the metals. Cancer risk resulting from inhalation, dermal and ingestion exposure to each metal in these fractions was calculated according to US EPA models. The average mass concentration of PM_2.5 was 87.16 ± 62.51 μg/m³. Cr, Ni and Pb were the most abundant metals. The results showed that Pb and Cr were higher in the mobile fraction. Cd and Co had high bioavailability. Ingestion is the major exposure pathway for all heavy metals except Cr to infants, children and adults followed by inhalation and dermal contact. The cumulative risk for Cr(VI) due to dermal and inhalation routes exceed the maximum acceptable limit for children of age 1–7 years, 8–15 years and adults when total concentration is considered, but the estimated risks are within the acceptable limit when the bioavailable, water soluble and mobile fraction are taken into account. Hence the study shows that children and adults living in the vicinity of this site are more susceptible, hence more attention should be paid to protect them from pollution hazards. The study indicates the importance of metal speciation in assessing associated human health risks.

Keywords:

• PM_2.5
• chemical partitioning
• metals
• cancer risk
• ingestion
• inhalation
• dermal exposure

Acknowledgements

We are grateful to Dr. Tarun Gupta and Mr. Amit Kumar Singh, IIT Kanpur for their help in analyzing samples by ICP-OES. We are thankful to Director and Head, Department of Chemistry, Dayalbagh Educational Institute, Agra, for providing us the necessary facilities.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This work was supported by UGC-BSR [Grant No. ETP/UGC Res.Fellowship/3089] and Department of Science and Technology [Project No. SB/S4/AS-150/2014].