Technische Universität Berlin, Department of Applied Geosciences, Hydrogeology Research Group, Ernst-Reuter-Platz 1, 10587 Berlin, Germany.
Sci Total Environ. 2012 Nov 1;438:113-21. doi: 10.1016/j.scitotenv.2012.08.041. Epub 2012 Sep 13.
In this study a laboratory column experiment under water saturated conditions was conducted to investigate the transport behaviour of the pharmaceutical compounds sulfamethoxazole, carbamazepine, diclofenac, and ibuprofen under varying nitrate concentrations. Organic rich sediment (f(OC)=0.01) and surface water from a formerly investigated field site were used. The water was spiked with the four compounds and the specific redox conditions in the column (0.351 m height) were varied throughout the experiment by adding nitrate in the influent water. Stepwise controlled decreasing influent nitrate concentrations between 131 and 20 mg L(-1) were applied in the course of the experiment which lasted 71 days. This established temporarily denitrifying conditions in the column during the reduction of nitrate. Sulfamethoxazole was severely influenced by this process. During denitrification sulfamethoxazole concentrations in the effluent water decreased rapidly and significantly. This experiment demonstrates the strong dependency of sulfamethoxazole transformation specifically on nitrate reducing redox conditions and therefore may help to explain the wide ranges of reported degradability for this compound. Ibuprofen was more stable under denitrifying redox conditions. Both for carbamazepine and diclofenac apparent retardation was observed. For carbamazepine this was attributed to sorption and also to degradation. For diclofenac nitrate controlled degradation seems the dominating process for the apparent retardation of this compound.
本研究采用水饱和条件下的实验室柱状实验，研究了在不同硝酸盐浓度下，磺胺甲恶唑、卡马西平、双氯芬酸和布洛芬这四种药物化合物在有机丰富沉积物（f(OC)=0.01）和地表水（来自先前调查的现场）中的运移行为。在实验过程中，通过在进水口添加硝酸盐，改变了柱内特定的氧化还原条件（0.351 米高）。实验持续了 71 天，期间逐步控制进水硝酸盐浓度从 131 到 20 毫克/升。这在柱内建立了暂时的反硝化条件，从而导致了硝酸盐的还原。磺胺甲恶唑受到这一过程的严重影响。在反硝化过程中，磺胺甲恶唑在出水中的浓度迅速且显著下降。该实验证明了磺胺甲恶唑的转化强烈依赖于硝酸盐还原的氧化还原条件，因此可以帮助解释该化合物报道的降解率差异较大的原因。布洛芬在反硝化氧化还原条件下更稳定。对于卡马西平和双氯芬酸，均观察到明显的阻滞现象。对于卡马西平，这归因于吸附和降解。对于双氯芬酸，硝酸盐控制的降解似乎是该化合物出现阻滞的主要过程。
