CICEET Progress Report for the period 3/01/09 Through 8/31/09

Project Title: Field Validation of General Methodology for Evaluating Narcosis Toxicity using the Sediment Profile Imaging and Micro-sampling System (SPIMS)
Principal Investigator(s): Marion Nipper
Additional Investigator(s): R. Scott Carr, Philip M. Gschwend
Project Start Date: 9/01/07
Report Compiled by: Marion Nipper

Contributing team members and their role in the project: Dr. R. Scott Carr – co-PI contributing to field work and toxicity assessments; Dr. Philip Gschwend – co-PI responsible for GC-MS chemical analyses. Jim Biedenbach has assisted with toxicity testing and field trips.  John MacFarlane has assisted with chemical analyses, design and preparation of passive samplers, and field trips. Dr. Joe Germano was responsible for sediment profile imaging.

Figures

Figure 1

Tables

Table 1

Table 2

Table 3

The project was managed and team collaboration was achieved through constant email communication and several conference calls between the teams in Texas and at MIT, and between Texas and Germano and Associates. Both the MIT team and Dr. Germano traveled to Texas on separate occasions to perform field work.

2) Development, refinement or demonstration of the technology or approach
a) Sediment profile imaging studies were performed at a gradient from the area suspected of containing higher concentrations of hydrophobic organic chemicals (HOCs) in Tabbs Bay and Corpus Christi Bay, using the REMOTS® camera.  Sediment profile images were also taken along a transect across Aransas Bay, for selection of the reference station.  A frame system with a long handle was devised for the deployment of polyethylene (PE) passive samplers in situ at water depths ranging from 1.5 to 3.5 m.
b) 1,2,4-trichlorobenzene (TCB) was selected as a low log Kow chemical for laboratory studies of loading and unloading of passive samplers. Films of polyethylene (PE), used as passive samplers, were loaded with a concentration series of TCB. Chemical analyses and toxicity tests were performed with the loaded PE.

3) Project evaluation
We evaluate the project as running smoothly and timely, within the approved 1-year extension.

4) Key findings

a) Sediment profile images were analyzed, and the main results of the analyses are presented in Table 1. Detailed methods and analyses data will be included in the final report. Black inclusions suspected of being PAHs were seen in profile images at several Tabbs Bay stations (Figure 1). As a result of the image analyses, Tabbs Bay was selected as the site for further studies and potential reference stations in Aransas Bay were also selected. Passive samplers were deployed for 15 days and sediments were collected for PE exposures in the laboratory.

b) Two experiments with a concentration series of TCB were performed, including chemical analyses and toxicity tests. The first experiment, using TCB-loaded PE as the source of the chemical in toxicity tests had inconclusive results due to problems with the dosing of the passive samplers with different doses of TCB. A second experiment was done with TCB dissolved in seawater using methanol as a solvent carrier. A good dose-response curve was observed (Table 2), resulting in a 48h-EC50 for sea urchin embryological development of 1686 µg/L, with 95% confidence interval of 1640 to 1734 µg/L. TCB loss in the absence of PE ranged from 8 to 27% during the 48-hour exposure.

5) Unanticipated issues
The change in plans to use the REMOTS® camera from Germano and Associates, Inc. instead of the SPIMS, as originally planned, caused some delay in the progress of the project. However, the project is back on track now and we do not anticipate further delays, so that we expect to have completed all the project objectives by the end of the approved one year no-cost extension.

B. Knowledge Dissemination Activities during this Reporting Period
Web pages for this project were created in both www.GulfBase.org, which is a website dedicated to the dissemination of information on Gulf of Mexico research, and the Marine Ecotoxicology Research Station’s website, www.sci.tamucc.edu/mers/. These pages can be viewed at http://www.gulfbase.org/project/view.php?pid=fvogmfentuspipsatt, which is linked to the pages of the Texas PIs (http://www.gulfbase.org/person/view.php?uid=mnipper and http://www.gulfbase.org/person/view.php?uid=rcarr), and at http://www.sci.tamucc.edu/mers/Project_Passive%20Sampler.htm), respectively.

C. Have the results/data gathered during this reporting period indicated that a change to your original approach is necessary?
No.

D. Collaboration activities with target stakeholders during this period.
There were no specific collaboration activities with target stakeholders during this reporting period.

E. Project Objectives for Next Reporting Period:
a) Objectives: 1) To verify if passive samplers exposed to sediments in situ and in the laboratory behave similarly relative to absorption of HOCs; 2) To continue experiments of loading and unloading dynamics of passive samplers using a chemical with higher log Kow than TCB; 3) To present data at national and international scientific conferences, which will promote interactions with target stakeholders.

b) Work Plan to Meet Objectives: 1) Chemical analyses and toxicity tests with the passive samplers exposed to the sediments in situ and in the laboratory will be performed; 2) PE loading and unloading experiments will be performed with a concentration series of 4-methyl phenanthrene; 3) To participate and present data obtained in this project within the last year at two meetings: the Aquatic Toxicity Workshop, in Canada, and the 30th Annual Meeting of the Society of Environmental Toxicology and Chemistry, in New Orleans, LA, USA.

Additional Relevant Information
The overall project timeline has changed as a result of problems described previously. The updated timeline for years 2 and 3 of the project is presented in Table 3.

G. End User/Producer/Adopter Advisor(s) Feedback:

End User Advisor: Robert M Burgess
Organization: U.S. EPA Office of Research and Development/NHEERL
Location: Atlantic Ecology Division - Narragansett
Phone number: 401-782-3106
E-mail: burgess.robert@epa.gov

At this stage, what are the potential applications for this research? Please discuss how you and others could potentially use the technology.

The project appears to be on course and the researchers are communicating their interim findings to the appropriate audiences.  Right now, and at this stage of the project, it is too early to address potential applications of the research.  When completed and field validated, the results of this work will be very applicable in a wide range of environmental management uses including the relatively inexpensive mapping of the distribution and bioavailability of organic contaminants in sediments.  This application could be very interesting to U.S. EPA programs like Superfund.

What are the key challenges to application of this technology?  Please consider the technology itself as well as issues related to regulation, politics, socio-economic pressures, trends in the field etc.

For the technology being developed and field validated in this project, the key challenges to application are likely to be generating a tool that is scientifically robust with regard to the data it produces but user friendly (and inexpensive) such that it is readily adopted by environmental managers.  Successful field validation of the methodology discussed in the proposal will make this adoption more likely.

Specifically, a key challenge is developing the appropriate passive sampler configuration that results in exposures that emulate actual sediment exposures. 

Has anything changed about this project's potential applicability since the last reporting period (not applicable to the first Progress Report)?

No.

Questions/comments/ suggestions for the researchers?

(1) General comment: This progress report presents some very interesting results. I look forward to the next update.

(3) Section A.4.a:  Are there any plans to analyze the sediments from the site in Figure 1 for PAH concentrations in order to confirm your visual conclusions?

(4) Section A.4.b: Some more details regarding the “problems with the dosing of the passive samplers” would be interesting.  Was there insufficient uptake by the polyethylene or too much, excessive variability?

H. PI Response to End User Advisor Feedback by Comment/Question Number:

(2) Section A.2.a:  The depths noted at the end of the paragraph are water depths. This information has been added to the text.

(3) Section A.4.a:  We have not sampled the sediments in a manner that will allow us to say whether those dark spots are PAHs.  That would require coring and explicit sectioning to isolate those horizons.  Based on past SPI studies, those dark spots are consistent with past inputs of weathered oils, supporting our contention that this station is polluted.  Sediments from the stations found relevant to the current study based on toxicity test results will be analyzed for HOC concentrations, which include PAHs, to confirm the visual conclusions.  GC/MS analyses will be performed by MIT and in the samples deemed of most interest will then be analyzed by GC x GC at WHOI.

(4) Section A.4.b: The reasons for the problems with the dosing of the passive samplers are not clear at this stage.  Toxicity tests using the passive samplers dosed with a gradient of TCB did not produce the expected dose-response curve. Measured concentrations of TCB in the dosed filtered seawater (which was exposed to the dosed passive samplers for 24 hours) were lower than expected (based on theoretical calculations). We believe the source of the latter problem was volatilization during shipping from Texas to Massachusetts.  Different vials are currently in use for shipment of these materials. Further information should be available for the next progress report.