Kinley Ciera M, Gaspari Daniel P, McQueen Andrew D, Rodgers John H, Castle James W, Friesen Vanessa, Haakensen Monique
Department of Forestry and Environmental Conservation, 261 Lehotsky Hall, Clemson University, Clemson, SC 29634, USA.
Department of Environmental Engineering & Earth Sciences, 300 Brackett Hall, Clemson University, Clemson, SC 29634, USA.
Chemosphere. 2016 Oct;161:491-500. doi: 10.1016/j.chemosphere.2016.07.050. Epub 2016 Jul 25.
Naphthenic acids (NAs) are problematic constituents in energy-derived waters, and aerobic degradation may provide a strategy for mitigating risks to aquatic organisms. The overall objective of this study was to determine the influence of concentrations of N (as ammonia) and P (as phosphate), and DO, as well as pH and temperatures on degradation of a commercial NA in bench-scale reactors. Commercial NAs provided replicable compounds necessary to compare influences of environmental conditions on degradation. NAs were quantified using high performance liquid chromatography. Microbial diversity and relative abundance were measured in treatments as explanatory parameters for potential effects of environmental conditions on microbial populations to support analytically measured NA degradation. Environmental conditions that positively influenced degradation rates of Fluka NAs included nutrients (C:N 10:1-500:1, C:P 100:1-5000:1), DO (4.76-8.43 mg L(-1)), pH (6-8), and temperature (5-25 °C). Approximately 50% removal of 61 ± 8 mg L(-1) was achieved in less than 2 d after NA introduction, achieving the method detection limit (5 mg L(-1)) by day 6 of the experiment in treatments with a C:N:P ratio of 100:10:1, DO > 8 mg L(-1), pH ∼8-9, and temperatures >23 °C. Microbial diversity was lowest in lower temperature treatments (6-16 °C), which may have resulted in observed slower NA degradation. Based on results from this study, when macro- and micronutrients were available, DO, pH, and temperature (within environmentally relevant ranges) influenced rates of aerobic degradation of Fluka NAs. This study could serve as a model for systematically evaluating environmental factors that influence NA degradation in field scenarios.
环烷酸（NAs）是能源衍生水体中的问题成分，好氧降解可能为降低对水生生物的风险提供一种策略。本研究的总体目标是确定氮（以氨形式存在）和磷（以磷酸盐形式存在）的浓度、溶解氧（DO）以及pH值和温度对实验室规模反应器中一种商业环烷酸降解的影响。商业环烷酸提供了可复制的化合物，用于比较环境条件对降解的影响。使用高效液相色谱法定量环烷酸。在处理中测量微生物多样性和相对丰度，作为环境条件对微生物种群潜在影响的解释参数，以支持分析测量的环烷酸降解。对氟化物环烷酸降解速率有积极影响的环境条件包括营养物质（碳：氮10:1 - 500:1，碳：磷100:1 - 5000:1）、溶解氧（4.76 - 8.43毫克/升）、pH值（6 - 8）和温度（5 - 25℃）。引入环烷酸后不到2天，61±8毫克/升的环烷酸实现了约50%的去除，在碳：氮：磷比例为100:10:1、溶解氧>8毫克/升、pH值约为8 - 9且温度>23℃的处理中，到实验第6天达到了方法检测限（5毫克/升）。微生物多样性在较低温度处理（6 - 16℃）中最低，这可能导致观察到的环烷酸降解较慢。基于本研究的结果，当大量和微量营养物质存在时，溶解氧、pH值和温度（在环境相关范围内）会影响氟化物环烷酸的好氧降解速率。本研究可作为系统评估影响现场环境中环烷酸降解的环境因素的模型。
