ABSTRACT

Pharmaceuticals and personal care products (PPCPs) are a contaminant class of worldwide concern and a potential source of global change. To better understand the impact of low levels of PPCPs on stream biofilm structure and function, we conducted laboratory mesocosm experiments in which biofilms cultivated in streams draining areas of different land use (natural, agricultural, and urban) were exposed to low levels (5 µg L⁻¹) of several common pharmaceuticals. We performed several functional assays and assessed differences in biofilm bacterial community composition among pharmaceutical treatments and streams. Pharmaceutical treatments altered the functional capacity and diversity of biofilms, but had no significant effect on carbon uptake or photosynthetic potential. Biofilm bacterial communities differed with land use, and pharmaceutical treatments decreased the relative abundances of Alcanivorax and Halioglobus and increased the relative abundance of Pseudomonas, indicating a shift to more drug-tolerant groups. Overall, our results provide evidence that PPCPs may act as ecological disruptors even at low levels, altering biofilm structure and some aspects of ecosystem function, and potentially influencing important biogeochemical processes in streams.

摘要

药品和个人护理产品 (PPCP) 是全球关注的一类污染物，也是全球变化的潜在来源。为了更好地了解低水平 PPCPs 对河流生物膜结构和功能的影响，我们进行了实验室中观实验，其中在不同土地利用（自然、农业和城市）排水区的河流中培养的生物膜暴露于低水平（5 µg L ^-1) 几种常见药物。我们进行了几种功能分析，并评估了药物处理和流之间生物膜细菌群落组成的差异。药物治疗改变了生物膜的功能容量和多样性，但对碳吸收或光合作用潜力没有显着影响。生物膜细菌群落因土地利用而不同，药物治疗降低了Alcanivorax和Halioglobus的相对丰度并增加了假单胞菌的相对丰度，表明转向更耐受药物的群体。总体而言，我们的结果提供证据表明，即使在低水平下，PPCPs 也可能充当生态破坏者，改变生物膜结构和生态系统功能的某些方面，并可能影响河流中的重要生物地球化学过程。