Bioaccessibility of Airborne Particulate-Bound Trace Elements in Shanghai and Health Risk Assessment

Xian Huang,Rajasekhar Balasubramanian,Jinping Cheng,Raghu Betha,Dandan Bo

doi:10.3389/fenvs.2016.00076

Abstract

Increased concentrations of airborne particulate matter in megacities within China, caused by rapid economic growth, urbanization and industrialization, have become a major health concern. High energy consumption, emissions from a large fleet of on-road vehicles and intense industrial activities all contributed to the deterioration of urban air quality in China. In this study, we investigated the bioaccessibility of twelve particulate-bound trace elements (Al, Co, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, and Zn) using simulated lung fluids (Gamble’s solution (pH = 7.4) and artificial lysosomal fluid (ALF) (pH = 4.5)) following the collection of PM in Shanghai, a megacity in China, to gain a better understanding of their fate upon inhalation by adults and children. All the trace elements showed higher bioaccessibility in ALF, compared to that in the Gamble’s solution, due to lower pH and higher ionic strength of the former over the latter. In most cases, the kinetic response of trace elements in terms of their solubility followed a curvilinear pattern and approached near steady-state characteristics after a protracted period of incubation in the lung fluids. Health risk assessment was conducted for adults and children based on the measured bioaccessible fractions of trace elements, which showed significant excess lifetime cancer risk to both children and adults.

Highlights

The rapid urbanization and industrialization since the introduction of the economic reform in 1970s in China brought tremendous economic growth, and caused severe air pollution problems (Chan and Yao, 2008; Tie and Cao, 2009)
The possible reasons of the low total suspended particles (TSP) concentration reported in the current study include a short sampling duration (12 selected days over a period of 2 months) and the frequent rain events during the sampling period, leading to the washout of the airborne PM through wet deposition
Airborne particles in the urban atmosphere of Shanghai were collected during August and September 2014 for the measurement of bioaccessibility of particulate-bound trace elements using simulated lung fluids (SLFs) and for health risk assessment

Summary

Introduction

The rapid urbanization and industrialization since the introduction of the economic reform in 1970s in China brought tremendous economic growth, and caused severe air pollution problems (Chan and Yao, 2008; Tie and Cao, 2009). The energy consumption tripled from 1973 to 2002 with nearly 70% of the energy generated by coal-fired power plants (Chan and Yao, 2008; Tie and Cao, 2009) Such a high consumption of coal in the energy sector has resulted in the emission of SO2 and particulate-bound trace elements with high levels into the ambient air in the megacities of China such as Beijing, Shanghai, Guangzhou, Tianjing, Xi’an, etc (Bi et al, 2007; Wang et al, 2008; Lü et al, 2012; Wang D. et al, 2014). A number of research studies on the physical, chemical, and toxicological properties of PM and related socioeconomic effects have been conducted in China, especially during the last decade (e.g., Chan and Yao, 2008; Tie and Cao, 2009; Tan and Zhao, 2014; Andersson et al, 2015)

Methods

Results

Discussion

Conclusion