A continuous pilot plant for the degradation of polychlorinated biphenyls (PCBs) by the palladium on carbon (Pd/C)-catalyzed hydrogenation in the presence of triethylamine was designed and constructed. Both undiluted PCBs obtained from a capacitor and diluted PCBs with desulfurized trans oil were smoothly decomposed at ambient temperature and pressure. Desulfurization of the trans oil was found to be essential for the efficient degradation due to the possible deactivation of the Pd/C by catalysis poisoning due to the sulfur-containing materials in the oil. The combined use of the present degradation method and the catalytic desulfurization technology for the purification of gasoline and kerosene could be used in practical applications.
Fibrates, which are widely used lipidaemic-modulating drugs, are emerging environmental pollutants. However, fibrate concentrations in the environment have not been thoroughly surveyed. Here, we determined concentrations of the most commonly used fibrates and their metabolites in source water and drinking water samples from ten drinking water treatment plants in Shanghai and Zhejiang, China, using solid-phase extraction and liquid chromatography–tandem mass spectrometry. All the target compounds were detected in at least some of the source water samples, at concentrations ranging from 0.04 ng/L (fenofibrate) to 1.53 ng/L (gemfibrozil). All the compounds except fenofibrate were also detected in at least some of the drinking water samples, at recoveries ranging from 35.5% to 91.7%, suggesting that these compounds are poorly removed by typical drinking water treatment processes. In a peroxisome proliferator-activated receptor α agonistic activity assay, the target compounds showed no significant activity at nanogram per litre concentrations; therefore, our results suggest that the fibrate concentrations in drinking water in Shanghai and Zhejiang, China do not significantly affect human health. However, because of the increasing westernization of the Chinese diet, fibrate use may increase, and thus monitoring fibrate concentrations in aquatic environments and drinking water in China will become increasingly important.
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