Comments on 'Polycyclic aromatic hydrocarbons (PAHs) in urban surface dust of Guangzhou, China: Status, sources and human health risk assessment'

摘要

Wang et al. (2011) analyzed 16 PAHs in the urban surface dust, in order to evaluate the incremental lifetime cancer risk (ILCR) from dust inhalation. The 95% UCL of calculated ILCR was 3.03 × 10~(-6) for children and for adults it was reported to be 2.92 × 10~(-6). However, we are concerned about the calculations, corresponding results, and subsequent interpretation. This is because upon calculating ILCR with the help of the same model and all related parameters mentioned in this manuscript, the results are different from that reported in the manuscript (a recalculated sheet ESM). To be concise in ESM, the ILCR values are re-calculated for ingestion rout of exposure. However, same trend was observed in the case of calculation regarding other routs of exposure (i.e. dermal and inhalation). It is observed that the model is accurate, and there is no possibility of any missing parameters because all the parameters have been described in the section under the heading "2.5. Risk assessment" with the formulas. This leaves a confusion regarding the calculations, which the corresponding author could better explain why this difference exists. In the same table, the values under the heading "Cancer risk" are unknown values, and there is no description where these values came from.