Faculty of Environmental Science & Engineering, Kunming University of Science & Technology , Kunming 650500, P. R. China.
The affiliated Hospital of Kunming University of Science and Technology , Kunming, 650500, China.
Environ Sci Technol. 2018 Feb 6;52(3):1054-1061. doi: 10.1021/acs.est.7b05453. Epub 2018 Jan 24.
The mining and burning of low-rank coal in Xuanwei, China have attracted a great deal of research attention because of the generated polyaromatic hydrocarbons (PAHs) and the high incidence of lung cancer in this region. Given the abundant transition metals in the allitic soil, we hypothesized that environmentally persistent free radicals (EPFRs) are formed in this region and the potential risk had not been addressed. Strong electron paramagnetic resonance (EPR) signals of 3.20 × 10 - 3.10 × 10 spins/g were detected in environmental samples, including chimney soot, coal, soil and total suspended particles (TSP). These EPR signals did not significantly change after 18-months storage and had g-values in the range of 2.0039-2.0046, suggesting typical organic free radicals. Similar strong EPR signals were observed in PAH (anthracene and pyrene as model compounds) degradation on simulated soil particles and lasted over one month even when the applied PAHs were 100% degraded. Based on g-value and bond width, we propose that EPR signals detected in TSP and soot originated from both coal combustion and PAH photodegradation. Further research is thus urgently required to investigate EPFR generation, exposure and risk in Xuanwei to better understand the cause of high lung cancer incidence.
中国宣威的低阶煤开采和燃烧因其产生的多环芳烃（PAHs）和该地区肺癌高发而引起了大量研究关注。鉴于明矾土中丰富的过渡金属，我们假设在该地区形成了环境持久性自由基（EPFRs），但尚未解决其潜在风险。在环境样品（包括烟囱烟灰、煤、土壤和总悬浮颗粒物（TSP））中检测到 3.20×10 - 3.10×10 自旋/g 的强电子顺磁共振（EPR）信号。这些 EPR 信号在 18 个月的储存后没有明显变化，g 值范围在 2.0039-2.0046 之间，表明存在典型的有机自由基。在模拟土壤颗粒上的 PAH（作为模型化合物的蒽和芘）降解中也观察到类似的强 EPR 信号，即使施加的 PAHs 降解了 100%，这些信号也能持续一个多月。基于 g 值和键宽，我们提出在 TSP 和烟尘中检测到的 EPR 信号源自煤燃烧和 PAH 光降解。因此，迫切需要进一步研究宣威的 EPFR 生成、暴露和风险，以更好地了解肺癌高发的原因。
