Rowe Christopher L, Mitchelmore Carys L, Baker Joel E
University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Solomons, MD 20688, USA.
Sci Total Environ. 2009 Oct 1;407(20):5344-55. doi: 10.1016/j.scitotenv.2009.06.036. Epub 2009 Jul 24.
Snapping turtle (Chelydra serpentina) eggs were exposed to two concentrations of chemically- or physically-dispersed water accommodated fractions of weathered Arabian light crude oil (Low=0.5 and High=10 g oil/L water). Solutions were passed through nest substrate to simulate alterations in composition during percolation to egg depth. Hatchlings were raised for 13 months during which numerous endpoints were measured. Prior to percolation, total PAH ("tPAH"; the sum of 52 PAHs measured) in physically-dispersed oil fractions were similar (High, 43; Low 67 mg/L). Following percolation, tPAH was also similar in physically-dispersed fractions (High, 14; Low 24 mg/L). Addition of dispersant increased tPAH prior to percolation in the High treatment (302 mg/L) relative to Low (13 mg/L), but percolation resulted in nearly equal concentrations in both treatments (High, 30; Low, 22 mg/L) due to physical trapping of dispersed oil by the nest substrate. In both chemically- and physically-dispersed fractions, percolation reduced low molecular weight (MW) compounds such that embryos were exposed to primarily mid- to high MW compounds. Total PAH in eggs differed 15-fold between the chemically-dispersed High and physically-dispersed High treatments (560 and 36 microg/kg respectively), the former characterized by higher MW compounds than the latter. While eggs accumulated up to 560 microg/kg tPAH, we observed no effects on hatching success or hatchling/juvenile traits (DNA integrity, survival, growth, metabolism, energy storage, or behavior), our results demonstrate that PAH profiles are altered during percolation, suggesting that experiments with subsurface organisms should be designed to account for compositional changes that occur as the solutions percolate through the substrate.
将麝香龟（Chelydra serpentina）的卵暴露于两种浓度的经化学或物理分散的风化阿拉伯轻质原油的水溶组分中（低浓度 = 0.5 g油/升水，高浓度 = 10 g油/升水）。溶液通过巢穴基质，以模拟在渗透至卵深度过程中成分的变化。幼龟饲养13个月，在此期间测量了许多指标。在渗透之前，物理分散油组分中的总多环芳烃（“tPAH”；所测52种多环芳烃的总和）相似（高浓度组为43 mg/L，低浓度组为67 mg/L）。渗透后，物理分散组分中的tPAH也相似（高浓度组为14 mg/L，低浓度组为24 mg/L）。相对于低浓度组（13 mg/L），在高浓度处理中添加分散剂会使渗透前的tPAH增加（302 mg/L），但由于巢穴基质对分散油的物理截留，渗透后两种处理中的浓度几乎相等（高浓度组为30 mg/L，低浓度组为22 mg/L）。在化学和物理分散的组分中，渗透都会减少低分子量（MW）化合物，从而使胚胎主要暴露于中等到高分子量的化合物。化学分散高浓度处理组和物理分散高浓度处理组的卵中总PAH相差15倍（分别为560和36微克/千克），前者的特征是高分子量化合物比后者多。虽然卵中积累的tPAH高达560微克/千克，但我们未观察到对孵化成功率或幼龟/幼体特征（DNA完整性、存活率、生长、代谢、能量储存或行为）有影响，我们的结果表明，在渗透过程中PAH谱会发生改变，这表明针对地下生物的实验设计应考虑到溶液渗透过基质时发生的成分变化。
