Interprovincial trade driven relocation of polycyclic aromatic hydrocarbons and lung cancer risk in China

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous organic contaminants which poses an adverse health impact on environment and humans. This study assesses the PAHs environmental contamination and associated lung cancer risk attributable to interprovincial trade in goods and services in China. Virtual trade driven PAHs flow mainly from well-developed and industrialized provinces to less-developed provinces that provide energy and raw materials. In 2007, Shanxi (with a net PAHs outflow of 3743 tons) and Hebei (with a net PAHs outflow of 851 tons) account for 66.8% of total PAH emission outflow attributable to interprovincial trade. The largest single net PAHs flow was from Shanxi to Zhejiang (399 tons), followed by Shanxi to Jiangsu (371 tons), and Hebei to Zhejiang (194 tons). Our results also reveal a switching from outflow to inflow of industrial products with high PAH emissions in some provinces from 2007 to 2012 due to the changes in their industrial structure. The estimated incremental lifetime cancer risk (ILCR) based on modeled benzo [a]pyrene (BaP) concentrations and considering trade driven emissions shows that excess nonoccupational lung cancer cases associated with trade related industrial BaP emissions totaled 2176 in 2007, accounting for 42% of lung cancer cases induced by all Chinese BaP emissions. Without interprovincial trade, Chinese lung cancer cases would increase to 3677 in 2007, indicating that interprovincial trade reduces lung cancer cases in well-developed and populated coastal provinces and increases cases in less populated and less developed provinces, which reduces the overall number of Chinese lung cancer cases. It is recommended that well-developed provinces in eastern and southern China should subsidize those inland provinces providing goods and services to eastern and southern China, in addition to the interprovincial trade.