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To investigate associations among occupational exposure to coke oven emissions (COEs), oxidative stress, cytogenotoxic effects, change in the metabolizing enzyme glutathione S-transferase (GST), and internal levels of polycyclic aromatic hydrocarbons (PAHs) in coke oven workers, we recruited 47 male coke oven workers and 31 male control subjects from a coke oven plant in northern China. We measured the levels of 1-hydroxypyrene (1-OHP) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in urine, micronucleated binucleated cells (BNMNs) in peripheral blood lymphocyte, and GST in serum. Our results showed that the group exposed to COEs had significantly increased levels of 1-OHP [median 5.7; interquartile range (IQR), 1.4–12.0 μmol/mol creatinine] compared with the control group (3; 0.5–6.4 μmol/mol creatinine). In addition, the median levels (IQR) of 8-OHdG, BNMNs, and GST were markedly increased in the exposed [1.9 (1.4–15.4) μmol/mol creatinine; 6 (2–8) per thousand; 22.1 (14.9–31.2) U/L, respectively] compared with controls [1.3 (1.0–4.0) μmol/mol creatinine, 2 (0–4) per thousand; and 13.1 (9.5–16.7) U/L, respectively]. These results appeared to be modified by smoking. However, multivariate logistic regression analysis revealed that exposure to COEs had the highest odds ratio among variables analyzed and that smoking was not a significant confounder of the levels of studied biomarkers. Overall, the present findings suggest that COE exposure led to increased internal PAH burden, genetic damage, oxidative stress, and GST activity. The consequences of the changes in these biomarkers, such as risk of cancer, warrant further investigations.

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The Cenozoic Qilian Shan thrust belt is the northern margin of the Tibetan Plateau, which developed in part due to progressive India-Asia convergence during Himalayan-Tibetan orogeny. Available geologic observations suggest that this thrust belt started deforming shortly after initial India-Asia collision at 60-55 Ma, and thus its kinematic development is intrinsically related to the construction and evolution of the Tibetan Plateau. Here, we present new field observations from a geologic traverse across the Qilian Shan to elucidate the style of deformation across the active thrust belt. In particular, we infer protracted out-of-sequence deformation here that is consistent with this thrust system remaining a stationary northern boundary to the Tibetan Plateau since the early Cenozoic. We present a lithosphere-scale model for this region that highlights the following: (1) coupled distributed crustal shortening and underthrusting of the North China craton beneath Tibet, which explains the spatial and temporal distribution of observed crustal shortening and thickness, (2) this underthrusting exploited the south-dipping early Paleozoic Qilian suture paleo-subduction mélange channel, and (3) development of a lower-crustal duplex at the lithospheric underthrusting ramp. This last inference can explain the relatively high elevation, low relief, and thickened crust of the central Qilian Shan, as well as the comparative aseismicity of the region, which experiences fewer earthquakes due to less upper-crustal faulting. Both the northern and southern margins of the Himalayan-Tibetan orogen appear to have developed similarly, with continental underthrusting and crustal-scale imbrication and duplexing, despite vastly different climatic and plate-velocity boundary conditions, which suggests that the orogen-scale architecture of the thrust belt is controlled by neither of these forcing mechanisms. Instead, strength anisotropies of the crust probably control the kinematics and style of deformation, including the development of northern Tibet, where thrust systems are concentrated along pre-Cenozoic suture zones.