Assessment of exposure to heavy metals and health risks among residents near Tonglushan mine in Hubei, China.

Heavy metal contamination due to mining activity is a global major concern because of its potential health risks to local inhabitants. In the present study, we investigated the levels of Cd, Cu, Pb and As in soil, crop, well water and fish samples collected from the vicinity of the Tonglushan mine in Hubei, China, and evaluated potential health risks among local residents. Results indicate that soils near the mine were heavily contaminated with Cd (2.59 mg kg(-1)), Cu (386 mg kg(-1)), Pb (120 mg kg(-1)) and As (35.4 mg kg(-1)), and exceeded the soil quality standard values of Cd and Cu contamination. The concentrations of Cd, Cu, Pb and As in crop samples grown in mine-affected soils were significantly higher than those of the reference soils. The concentrations of Cd and As in most vegetables grown in mine-affected soils exceeded the maximum allowable level (MAL). The Cd, Pb and As concentration in rice grain collected from mine-affected soils were 2.95, 1.85 and 2.07-fold higher than the MAL, respectively. The concentrations of Cd and As in fish muscle from the mine-affected area were above national MAL in 61% and 34% of analyzed samples, respectively. All measured heavy metals except Pb were significantly greater in well water in the mine-affected area than those in the reference areas. The average estimated daily intakes of Cd and As were beyond the provisional tolerable daily intake, respectively. The intake of rice was identified as a major contributor (⩾72%) to the estimated daily intake among the residents.

Effect of noxious stimulation on regional distribution of propofol in canine spinal cord / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the regional distribution of propofol in canine spinal cord under noxious stimulation.</p><p><b>METHODS</b>Twelve healthy hybrid dogs (12-18 months old, weighing 10-12 kg) were randomly divided into control group (n=6) and stimulation group (n=6). All the dogs were anesthetized with a single bolus dose of propofol (7 mg/kg) in 15 seconds followed by propofol infusion at a constant rate of 70 mg/kg/h via the great saphenous vein of the right posterior limb. In the stimulation group, the tails of the dogs were clamped for 5 min after 45 min of propofol infusion. Blood samples were taken from the internal carotid artery and internal jugular vein at 50 min after propofol infusion to detect plasma propofol concentrations by high-pressure liquid chromatography (HPLC). The dogs were then immediately sacrificed by decapitation and the frontal horn, posterior horn, intermediate zone, frontal funiculus, posterior funiculus and lateral funiculus of the spinal cord were dissected for determination of propol content by HPLC.</p><p><b>RESULTS</b>The plasma concentrations of propofol in the internal carotid artery and internal jugular vein were 5.07-/+0.23 and 5.03-/+0.10 microg/ml in the stimulation group, respectively showing no significant differences from those in the control group (5.09-/+0.03 and 5.08-/+0.03 microg/ml, P>0.05). In the control group, the propofol concentration was 5.09-/+0.08 microg/g in the frontal horm, 5.10-/+0.08 microg/g in the posterior horn, 5.05-/+0.19 microg/g in the intermediate zone, 5.06-/+0.14 microg/g in the frontal funiculus, 5.06-/+0.15 microg/g in the posterior funiculus and 5.06-/+0.41 microg/g in the lateral funiculus, showing no significant differences (P>0.05). The propofol concentrations in the frontal horn (7.65-/+0.47 microg/g) and posterior funiculus (7.06-/+0.82 microg/g) in the stimulation group were significantly higher than those in the other spinal cord tissues (P<0.05) and those in the control group (P<0.05).</p><p><b>CONCLUSION</b>At 50 min after intravenous injection of propofol at a constant rate of 70 mg/kg/h, plasma propofol concentrations in the internal carotid artery and internal jugular vein reaches equilibrium with a balanced distribution in all the spinal cord regions. Propofol concentration can be higher in the frontal horn and posterior funiculus under noxious stimulation.</p>