Correspondence/Rebuttal pubs.acs.org/est
Comment on “Appalachian Mountaintop Mining Particulate Matter Induces Neoplastic Transformation of Human Bronchial Epithelial Cells and Promotes Tumor Formation” he paper “Appalachian Mountaintop Mining Particulate Matter Induces Neoplastic Transformation of Human Bronchial Epithelial Cells and Promotes Tumor Formation” by S. Luanpitpong et al. reports that the second “main inorganic” element of the particulate matter (PM) is molybdenum. A quote from the abstract reads: “Chronic exposure to the main inorganic chemical constituent of PMMTM, molybdenum but not silica, similarly induced cell transformation and tumor promotion, suggesting the contribution of molybdenum, at least in part, in the PMMTM effects.” (PMMTM is the mountaintop mining PM sample, and PMCON is the control PM sample.) A quote from the Materials and Methods section reads: “In comparison with PMCON, Si and Mo were found to be the main inorganic chemical elements in PMMTM with the % weight-average of 48.15 ± 26.91% and 28.90 ± 4.16%, respectively, for Si and Mo versus 23.75 ± 15.07% and 0.00 ± 0.00% of the elements in PMCON...” In a letter of 1/5/15 to the primary author, I called the reported Mo results into question. The authors (ES&T 1/26/15) in a correction to the sentence quoted above stated: “In comparison with PMCON, Si and Mo were inorganic chemical elements found in PMMTM and were, therefore, further investigated in this study for their effects on cells.” This correction is insufficient, especially since the abstract still claims Mo to be a “main chemical constituent” of PMMTM, and the Results and Discussion section still focus on Mo, although the only quantitation for Mo was eliminated with the correction of 1/26/15. We routinely determine Mo concentrations for coals, and find them to be in the
