A crucial step towards understanding potential impacts of the Deepwater Horizon oil spill to marsh ecosystems was to quantitatively determine the toxicity of oil remaining in the sediment. The objective of this study was to assess the potential injury to benthic species using standardized toxicity bioassays. Sediments were collected from locations with differing degrees of oiling based on previous assessments. Less than 13% of the 315 toxicity tests resulted in toxicity to amphipods, mysid shrimp, or sea urchins. There was no relationship among toxicity test results, oiling category or measured total polycyclic aromatic hydrocarbons (PAHs). Equilibrium partitioning sediment benchmarks and additive toxic units (ESBTUs) were applied as an additional line of evidence to evaluate the potential adverse effects based on PAH concentrations in field sediments. The ∑ESBTUs based on 34 PAHs at the 64 nearshore sampling locations were <1, indicating PAHs in sediments were unlikely to cause adverse impacts.

了解“深水地平线”溢油对沼泽生态系统潜在影响的关键步骤是定量确定沉积物中残留油的毒性。这项研究的目的是使用标准化毒性生物测定法评估对底栖生物的潜在伤害。根据先前的评估，从不同注油程度的地点收集沉积物。315次毒性测试中，只有不到13％的毒性导致了对两栖类，虾类或海胆的毒性。毒性测试结果，上油类别或测得的总多环芳烃（PAH）之间没有关系。平衡分配的沉积物基准和附加毒性单位（ESBTU）被用作补充证据，以评估基于田间沉积物中PAH浓度的潜在不利影响。基于近64个采样点的34个PAHs的∑ESBTUs <1，表明沉积物中的PAHs不太可能造成不利影响。