Title : Release of dye into McM Wastewater Type : Antarctic EAM NSF Org: OD / OPP Date : October 23, 1992 File : opp93082 DIVISION OF POLAR PROGRAMS OFFICE OF THE ENVIRONMENT 202/357-7766 MEMORANDUM Date: October 23, 1992 From: Environmental Officer, DPP Subject: Environmental Action Memorandum (Releases of Rhodamine WTþ Dye into McMurdo Wastewater Discharge at McMurdo Station Antarctica) To: Safety and Health Officer, DPP Head, Safety, Environment and Health Implementation Team, DPP Environmental Engineer, DPP Environmentalist, ASA Alan B. Crockett, INEL Files (S.7 - Environment) This Environmental Action Memorandum describes the need for, and location of, proposed actions to characterize the dispersal characteristics and dilution factors for McMurdo Station's domestic sewage effluent. The Environmental Officer posed a set of questions relating to the proposed project, and to the poten- tially affected environment. These questions were responded to by Mr. Alan B. Crockett of the U.S. Antarctic Program's (USAP) support contractor for Environmental Measurements and Assess- ments, Idaho National Engineering Laboratory, on October 23, 1992; the questions and responses are shown below: Environmental Assessment Queries and Responses Background The 1992 and 1993 Fiscal Year (FY) Environmental Sampling and Analysis Plans for the Wastewater Discharge at McMurdo Station, Antarctica, described this proposed activity. The 1992 FY plan could not be accomplished due to budget constraints within the USAP. The proposed action now would be accomplished during the current FY. A dye transport study would be conducted prior to water quality sampling to determine: 1) the horizontal and vertical extent of the domestic wastewater effluent plume; and, 2) dilution factors for selected constituents in the effluent. Rhodamine WT dye would be released into the wastewater effluent at a steady rate of about 1.25 milliliters per minute (mL/min) using a chemical metering pump. This rate is based on the U.S. Environmental Protection Agency's (USEPA) recommendation [EPA 1982] that concentration of dye in effluent should be about 0.2 parts per million (ppm). The dye would be released steadily for 12 hours on the ebb tide with in situ monitoring to begin after 6 hours. On average, 6 hours is recognized as sufficient time for the dye to travel about 275 meters (m) west of the outfall. While recent, reported current data (McFeters et al. 1992a and b) do not show any apparent tidal influence on current flow at the outfall, previous data and communications with Dr. James Barry (Monterey Bay Aquarium Research Institute) suggest that a relationship exists. The Raytheon data (Raytheon 1983) indicate that the ebb tide results in transport to the northwest which is generally the direction of net transport. The sampling grid for the subject dye study would be the same as that used for micro- bial studies being conducted at the same time by Dr. Gordon McFeters (Montana State University). A Turner Design Field Fluorometerþ with flow through cell would be used to determine the concentration of the dye through holes drilled in the ice with a Jiffyþ drill and augers. A battery- powered pump and garden hose would be used for pumping the dye from the selected depth through the fluorometer. Simultaneous in situ measurements of dissolved oxygen, pH, salinity, temperature, turbidity and depth would be made. These dye data will be used to identify the zone of potential greatest concentration outside the zone of initial dilution where sampling would be concentrated and will determine down current dilution factors. If a reason- able correlation between a water quality parameter and the dye is established, the dye would not have to be used during future water sampling efforts to locate the plume. Up to 3 or 4 releases would be made during the month of November 1992: one as an initial test of flow conditions and the others to coincide with other water sampling efforts. GENERAL 1. What is the specific purpose of the proposed activity? The dye is used regularly as a tracer to ensure that mandated down-current water quality sampling is actually conducted within a wastewater plume. The plume can change direction and location frequently, and the dye ensures that the plume is sampled. Rhodamine WT was used in a previous study of current patterns in the near shore area of McMurdo Station by Raytheon Service Company in 1982 (Raytheon 1983). What alternatives to the proposed activity have the Investigator considered? Consideration has been given to using such other parameters as turbidity, temperature, pH, and salinity that may be effective in locating the plume. The correl- ation between the dye concentration and the above para- meters at the McMurdo Station site would be determined so that they can be used for future plume extent determinations rather than the dye. Have probable impacts of all alternatives been considered by the Investigator? Please explain how. Impacts have been judged to be minimal based on past experience and empirical investigation. The subject dye is used routinely for this purpose and is recommended as a water tracer in USEPA documents (EPA 1982). It is relatively non-toxic (see attached MSDS), would be released at low concentrations and would be diluted quickly to low ppb and ppt levels. The only adverse impact would be to research efforts that might be estimating fluorescence at the same wavelengths in components of the nearshore area at McMurdo Station in November 1992. Such research efforts have not been scheduled for the 1992-1993 science program. Should the chosen alternative involve potential impacts, how would these impacts be mitigated by the Investi- gator? There are no feasible or practical methods of mitigating potential impacts the dye may have after it is released. Should the proposed action be determined to be unaccept- able a less efficient and less scientifically defensible alternative, turbidity, would be used as a surrogate parameter for locating the plume. Have measures to assess the indirect costs of the proposed activity been identified or considered by the Investigator? Please explain how. There are no known indirect costs associated with the dye other than transport of the dye to Antarctica and appropriate disposal of any unused dye. LAND USE AND PLANNING 2. Where would the proposed activity be located, specifically? The dye would be released into the wastewater stream at the wastewater macerator building at McMurdo Station and the dye would travel with the plume along the nearshore area of McMurdo Station and within the McMurdo gyre. Have alternative locations been considered by the Investi- gator? If yes, which are they; if no, explain why. No. The intent is to study the outfall at its present location. 3. How would any aesthetic impacts to the area from the proposed activity be handled by the Investigator? The dye is reddish in color at high concentrations but with dilution becomes invisible. Only water at the melt hole may be visibly red and the color would disappear when the dye release is stopped. 4. Would the proposed activity have any other indirect impacts on the environment? If yes, what are they; if no, explain why none are expected. No. There are no known indirect impacts. The reason this particular dye is used by U.S. Geological Survey and the USEPA is its low toxicity and lack of adverse impacts. 5. Would the proposed activity change the traditional use(s) of the proposed (or chosen) site? If yes, how; if no, why. No. The release of the dye would not change the use of the outfall because it would have no affect on the discharge and would be diluted to non-detectable levels. The only impact anticipated would be to researchers estimating fluorescence that the dye might interfere with. Again, no such research has been planned for this season. 6. Are the physical and environmental characteristics of the neighboring environment suitable for the proposed activity? If yes, explain why; if no, explain why. The dye is designed for release to aqueous environments and the wastewater and ocean environment qualify on this account. IMPACT AND POLLUTION POTENTIAL AND ENVIRONMENTAL MANAGEMENT 7. How has protection of the environment and human health from unnecessary pollution or impact been considered for the proposed activity (includes such considerations as pollution abatement or mitigation, and waste management [e.g., of noise, dust, fuel loss, disposition of one-time-use mater- ials, construction wastes])? The dye would be released so that the concentration in the effluent stream would be about 0.2 ppm. Concentrations in drinking water are not to exceed 0.1 ppb. The dilution factor between the outfall and the drinking water intake is expected to exceed the necessary 2000 fold dilution. How- ever, to help ensure that the 0.1 ppb level is not exceeded in drinking water, the first dye release will be at a lower rate, and result in about 0.02 ppm in the effluent. Data from the first release will be used to determine the need and safety of the higher release rate as specified in regulatory guidance and the Sampling Plan and noted earlier is this document. Additionally, at the time of release, the ebb current is expected to transport the dye away from the drinking water intake. 8. Would the proposed activity change ambient air quality at the proposed (or chosen) site? If yes, how; if no, why? The dye is not volatile and would not be released to the air. 9. Would the proposed activity change water quality or flow (drainage), at the proposed (or chosen) site? If yes, how; if no, why? Yes. The dye would temporarily impact the fluorescence characteristics of the water and water around the outfall should not be ingested because of the relatively high level of dye at the discharge point. This is not judged to be a problem as the water is salty and widely known to contain raw sewage. 10. Would the proposed activity change waste generation or management at the proposed (or chosen) site? If yes, how; if no, why? No. The dye release would create no wastes at the outfall but calibration standards would be prepared in the labor- atory. They can be discharged to the wastewater stream due to their low mass and toxicity. Any excess dye should be retained for possible future current and effluent dispersion studies. 11. Would the proposed activity change energy production or demand, personnel and life support, or transportation requirements at the site? If yes, how; if no, why. No. The chemical metering pump used to discharge the dye into the effluent requires very little power to operate. 12. Is the proposed activity expected to adversely affect scientific studies or locations of research interest (near and distant, in the short-term and in the long-term)? If yes, how; if no, why? No. No known studies in the McMurdo area will be impacted and any affects are not expected to be adverse and would be strictly short-term. The dye does not partition to sedi- ments so it will not build up to high levels in sediment compared to water and over time, any dye in sediment pore water will be released and diluted. Since the plume is initially buoyant, the highest concentrations of the dye should never contact the sediments. Dilution would reduce the dye to undetectable levels. 13. Would the proposed activity generate pollutants that might affect terrestrial, marine, or freshwater ecosystems within the environs of the station or inland camp? If yes, how; if no, why? The dye is the foreign material and would not generate any known contaminants. 14. Does the site of the proposed activity serve as habitat for any significant assemblages of Antarctic wildlife (for example, mosses, or lichens, or antarctic birds or marine mammals)? Yes. The sponge spicule mat and the diverse biological community at the sea water intake are unique but the impact of the wastewater discharge far exceeds any expected impact of the dye. HUMAN VALUES: 15. Would the proposed activity encroach upon any historical property of the site? If yes, how; if no, why? There are no known submerged historical properties in the nearshore area of McMurdo Sound. OTHER CONSIDERATIONS 16. What other environmental considerations may be potentially affected by the proposed activity at the proposed (or chosen) site? For example, have impacts associated with decommissioning of the activity been considered (and how). None. REFERENCES Environmental Protection Agency (EPA). 1982. Design of 301 (h) Monitoring Programs for Municipal Discharges to Marine Waters. EPA 430/9-82-010. Office of Water. U.S. Environmental Protection Agency, Washington, D.C. 134 p. McFeters, G. A., Howington, J. P., Smith, J. J. and J. P. Barry. 1992a. 1991 Annual Report to the Division of Polar Programs of the National Science Foundation, unpublished. McFeters, G. A., Barry, J. P. and J. P. Howington. 1992b. Distribution of Enteric Bacteria in Antarctic Seawater Surrounding a Sewage Outfall. submitted, draft manuscript. Raytheon Services Co. (Raytheon) 1983. Report on the McMurdo Station Water Quality Study. Performed for ITT Antarctic Services, Paramus, New Jersey. Raytheon Services Co., Middletown, Rhode Island. ATTACHMENT Material Safety Data Sheet for Rhodamine WT dye. Finding The Environmental Officer, after reviewing the information presented in this Environmental Action Memorandum believes that the proposed activity, poses less than potential minor and less than potential transitory impacts to the marine environment near McMurdo Station, Antarctica. There are recognized science and health benefits associated with completion of the proposed action: determination of the extent of the domestic wastewater effluent plume as it relates to the station's seawater intakes (seawater for scientific investigations and for production of potable water). The Investigator, Contractor and Program are authorized to proceed with the proposed activity. Sidney Draggan Attachment Materials Safety Data Sheet