480
© Springer Nature Switzerland AG 2020
S. A. Murawski et al. (eds.), Deep Oil Spills,
https://doi.org/10.1007/978-3-030-11605-7_28
Chapter 28
A Synthesis of DWH Oil: Chemical
Dispersant and Chemically Dispersed Oil
Aquatic Standard Laboratory Acute
and Chronic Toxicity Studies
Carys L. Mitchelmore, Adriana C. Bejarano, and Dana L. Wetzel
Abstract In the event of an oil spill, like the Deepwater Horizon (DWH), a Natural
Resource Damage Assessment (NRDA) is mandated to document observable or
measurable adverse changes to a natural resource or predict a future impairment of
a natural resource. The assessment of health and integrity of estuarine and marine
aquatic resources following exposure to contaminants and/or other environmental
stressors relies on using established standard protocols and metrics for evaluating
chemical, biological, and toxicological status. One of the key tools available for
assessing environmental damage is the use of realistic laboratory- and mesocosmscale toxicity experiments to expose organisms to various concentrations of oil and/
or chemical dispersant employing an array of biological endpoints. However, widely
varying methods of laboratory testing have been used together with extrapolation
procedures that are not fully reliable for environmental assessments of oil spills
(NRC 2005; Coelho et al. 2013; Bejarano et al. 2014; Bejarano 2018). There is often
a severe lack of understanding in how to conduct aquatic toxicity tests correctly
with respect to the questions being asked (i.e., toxicological comparisons between
different oil mixtures, different species or life stages, or specific parameters unique
to a spill event). There are many examples of serious errors (i.e., under and overestimations of toxicity) resulting from using inadequate methods for experimental
design, chemical analyses of exposure media, and data analysis/interpretation.
Studies that evaluate biological responses and measureable adverse changes from
C. L. Mitchelmore (*)
University of Maryland Center for Environmental Science, Chesapeake Biological
Laboratory, Solomons, MD, USA
e-mail: mitchelmore@umces.edu
A. C. Bejarano
Research Planning Inc., Columbia, SC, USA
Shell Oil Company, Shell Health - Americas, Houston, TX, USA
e-mail: abejarano@researchplanning.com; Adriana.Bejarano@shell.com
D. L. Wetzel
Mote Marine Laboratory, Sarasota, FL, USA
e-mail: dana@mote.org
© Springer Nature Switzerland AG 2020
S. A. Murawski et al. (eds.), Deep Oil Spills,
https://doi.org/10.1007/978-3-030-11605-7_28
Chapter 28
A Synthesis of DWH Oil: Chemical
Dispersant and Chemically Dispersed Oil
Aquatic Standard Laboratory Acute
and Chronic Toxicity Studies
Carys L. Mitchelmore, Adriana C. Bejarano, and Dana L. Wetzel
Abstract In the event of an oil spill, like the Deepwater Horizon (DWH), a Natural
Resource Damage Assessment (NRDA) is mandated to document observable or
measurable adverse changes to a natural resource or predict a future impairment of
a natural resource. The assessment of health and integrity of estuarine and marine
aquatic resources following exposure to contaminants and/or other environmental
stressors relies on using established standard protocols and metrics for evaluating
chemical, biological, and toxicological status. One of the key tools available for
assessing environmental damage is the use of realistic laboratory- and mesocosmscale toxicity experiments to expose organisms to various concentrations of oil and/
or chemical dispersant employing an array of biological endpoints. However, widely
varying methods of laboratory testing have been used together with extrapolation
procedures that are not fully reliable for environmental assessments of oil spills
(NRC 2005; Coelho et al. 2013; Bejarano et al. 2014; Bejarano 2018). There is often
a severe lack of understanding in how to conduct aquatic toxicity tests correctly
with respect to the questions being asked (i.e., toxicological comparisons between
different oil mixtures, different species or life stages, or specific parameters unique
to a spill event). There are many examples of serious errors (i.e., under and overestimations of toxicity) resulting from using inadequate methods for experimental
design, chemical analyses of exposure media, and data analysis/interpretation.
Studies that evaluate biological responses and measureable adverse changes from
C. L. Mitchelmore (*)
University of Maryland Center for Environmental Science, Chesapeake Biological
Laboratory, Solomons, MD, USA
e-mail: mitchelmore@umces.edu
A. C. Bejarano
Research Planning Inc., Columbia, SC, USA
Shell Oil Company, Shell Health - Americas, Houston, TX, USA
e-mail: abejarano@researchplanning.com; Adriana.Bejarano@shell.com
D. L. Wetzel
Mote Marine Laboratory, Sarasota, FL, USA
e-mail: dana@mote.org