【摘要】 三氯生（Triclosan, TCS）和三氯卡班（Triclocarban, TCC）是典型的药品与个人护理用品,在土壤生态系统中被广泛检出,且存在增加土壤微生物抗药性及抑制土壤呼吸的潜在风险,但目前有关TCS和TCC对土壤氮转化过程及氧化亚氮（N₂O）排放的影响尚不清楚。基于此,采用室内培养实验和15N稀释-富集法,结合氮转化数值模型,研究了不同浓度梯度下TCS(2和5mg·kg^-1)和TCC(1和2 mg·kg^-1)的单独及联合存在对水稻土氮初级转化速率以及N₂O排放的影响。结果表明,1mg·kg^-1TCC及5mg·kg^-1TCS+2mg·kg^-1TCC处理对水稻土氮素的矿化-同化无显著影响,其余TCS和TCC处理均显著促进了氮的矿化-同化循环。此外,TCS和TCC处理显著降低了自养硝化速率、硝态氮的微生物固定速率以及硝酸盐异化还原成铵（Dissimilatory nitrate reduction to ammonium, DNRA）速率(2 mg·kg^-1TCS处理及5mg·kg^-1TCS+2mg·kg^-1TCC对DNRA速率无显著影响)。值得关注的是,TCS和TCC单一和联合处理均显著增加了N₂O的累积排放量,其累积排放量为对照的1.13倍～1.44倍。本研究表明,TCS和TCC改变了水稻土好氧氮转化过程,可能对稻田生态系统氮循环产生不利影响;TCC和TCS对水稻土N₂O排放的促进作用也增加了稻田生态系统对温室效应和臭氧层破坏的潜在贡献,因此,未来评价TCS和TCC土壤生态风险时,应考虑其对氮转化过程和N₂O排放的潜在影响。更多还原

【Abstract】 【Objective】Triclosan（TCS） and triclocarban（TCC）, are typical pharmaceutical and personal care products（PPCPs） that are extensively detected in soil, posing potential risks of raising soil microbes’ drug resistances and inhibiting soil respirations. However, so far little is known about their influences on soil gross N transformation processes and N₂O emissions in soil. 【Method】 In view of this,an indoor incubation experiment was carried out using the 15 N diluting-enriching method coupled with a N transformation numerical model to investigate influences of TCS and TCC, applied alone or in combination,at varying rates on preliminary N transformation rate and N₂O release rate in paddy soil. 【Result】Results show that the treatment of applying 1 mg·kg^-1 TCC or 5 mg·kg^-1 TCS+2 mg·kg^-1 TCC did not have much influence on N mineralization-assimilation in the paddy soil, but all the other treatments did quite reversely（P<0.05）. Besides, all the TCC and TCS treatments significantly inhibited autotrophic nitrification,microbial immobilization of nitrate and dissimilatory nitrate reduction to ammonium（Dissimilatory nitrate reduction to ammonium, DNRA）, except for the treatment of applying 2 mg·kg^-1 TCS or 5 mg·kg^-1 TCS+2 mg·kg^-1 TCC. It is noteworthy that all the treatments（P<0.05） increased cumulative emission of N₂O significantly or by 1.13～1.44 folds as compared with the control. 【Conclusion】All the findings in this study suggest that TCS and TCC alter aerobic N transformation processes, which may bring about adverse effects on N recycling in the paddy field ecosystem, and promote N₂O emission, which may enhance the potential contribution of the paddy field ecosystem to greenhouse effect and damage of the ozone layer.Therefore, in evaluating soil ecological risks of TCS and TCC in future, it is essential to take into account their potential influences on N transformation and N₂O emission.更多还原