Introduction

1. Mercury in Freshwaters and its Effect on Freshwater MusselsBy: Nicole Burke / Mentor: Aliyar MousaviNashua Community College Introduction Purpose Conclusion Continued Northwood Lake, Swain’s Lake and Umbabgog Lake have all had mercury contamination in the past which could have lead to a decline in aquatic species such as mussels. The EPA listed all three lakes as having impaired aquatic life in their most recent available assessments in their water body reports (US EPA, 2010). This could either be due to previous mercury contamination, as all were listed to have in December of 2007 or due to other factors related to supporting aquatic life, such as pH (US EPA,2010). While mercury was listed as an issue in these lakes there is no value given by the water body reports. PSNH was asked by the EPA Clean Air Act to implement new mercury scrubber equipment by 2013 which was estimated to drastically cut back mercury air emissions by 80 percent (US EPA, 2007). The reductions called for in the Clean Air Act and the closure of the Berlin chlor-alkali facility by the Department of Environmental Services have likely caused the mercury levels to be below our reporting limit. The closure of the chlor-alkali facility in Berlin in 1999 has drastically reduced the amount of mercury being emitted into the environment, however the water located directly around the facility is still deemed catch and release for its fish and other aquatic life (US EPA, 2014). This implies that mercury contamination is still a current problem in this area. However, the expanse of this mercury contamination is no longer as widespread, due to the closing of the plant preventing any further mercury emissions. Although the total mercury determination in water resulted in no detectable level, this does not mean that mussels would not result a detectable level. Hg in the water that has been metabolized by methylating bacteria into methylmercury which is taken in by zooplankton eating the bacteria. This zooplankton is a food source for mussels. Therefore, mussels not only ingest mercury from water directly, but also from the food chain.  This causes higher levels of bioaccumulation, especially that of methylmercury due to its higher permeability of biomembranes (Mousavi et al, 2011). Mercury (Hg) in freshwaters can have a substantial impact on the health of aquatic life it supports and anyone consuming affected aquatic life. Mercury can either be natural to the environment or from an anthropogenic source such as the burning of coal, chlor-alkali facilities, cement manufacturing, gold mining, production of sodium hydroxide (caustic soda) and polyvinyl chloride (PVC) production (Bespalova and Mousavi, 2013).These industrial sources release mercury into the atmosphere (EPA, 2014). Introduction of mercury into freshwaters by deposition via these anthropogenic sources allows the mercury to be processed by methylating bacteria from its original state (Hg2+) to methylmercury. Methylmercury has a high potential to bioaccumulate within a living organism due to its ability to more easily permeate biological membranes. Methyl mercury has neurotoxic ability and exposure to it can have a range of neurological and other systemic effects (Mousavi et al, 2011) . Freshwater mussels are a great indicator of mercury contamination due to their sensitivity to mercury levels. Freshwater mussels are also good indicators of a lake ecosystems overall health as they are sensitive to other environmental changes and contaminants (USGS, 2012). If mussels are not found where a healthy population existed before, there is likely an issue with pollutants or overall water quality (NH DES, 2005). As filter feeders, they draw in the water around them, including any pollution, in order to take in nutrition. A mussel’s diet is mostly phytoplankton and zooplankton; however other organisms are siphoned in through their gills. Not all of these organisms can be digested by the mussel and are expelled harm free from the mussel (Vaughn et al, 2008). Once methylmercury is drawn in and permeates the mussel’s biological membranes, it is then retained. This can cause significant health effects, including reproductive complications, altered health status and mortality (USGS, 2012). In lieu of collecting mussel samples as they were hard to come by and may be compromised in the areas of testing, water samples were utilized to determine the total mercury content of the waters in question. Total mercury determination takes into account all Hg species in the mercury cycle and therefore is a good measure of the amount or lack of contamination in a waterbody Methods • Four samples were taken from each lake for determination. • Two sites on each lake were utilized to obtain samples and two samples were taken per sample site • The method used for collecting samples was a surface water testing approach. • 500ml sample bottles were filled entirely and immediately put on ice to prevent any evaporation or loss of integrity. These samples were then transported directly to the laboratory where they were preserved with sulfuric acid and placed in cold storage until testing could be performed. • Total mercury determination was performed on the water samples by Alpha Analytical in Mansfield, MA. The process by which the total mercury determination was completed was by procedure EPA 7474 and the used instrumental method of analysis is Atomic Fluorescence Spectrometry. Results Background on Chosen Lakes References and Acknowledgements • Knowing the anthropogenic causes of mercury contamination, three lakes were picked in accordance to their proximity to these sources. • Two of which were within a thirty mile radius of coal burning power plants: Northwood Lake and Swain’s Lake are between both of Public Services of New Hampshire’s currently coal burning power stations: Merrimack station and Schiller station. • The third was located within thirty to thirty five miles from a closed chlor-alkali plant. Lake Umbagog was chosen because of its proximity to a closed chlor-alkali facility in Berlin, NH. Mousavi, Aliyar , Chávez, Rose D. , Ali, Abdul-Mehdi S. and Cabaniss, Stephen E.(2011) 'Mercury in Natural Waters: AMini-Review', Environmental Forensics, 12: 1, 14 — 18 Ruessler, D.S., N.J. Kernaghan, C.M. Wieser, J.J. Wiebe, and T.S. Gross. "Contaminants Effect Mussels." Contaminants Effect Mussels. United States Geological Survey, 14 Dec. 2012. Web. 29 June 2014. <http://fl.biology.usgs.gov/posters/Ecotoxicology/Contaminants_Effect_Mussels/contaminants_effect_mussels.html>. Vaughn, Caryn C., S. Jerrine Nichols, and Daniel E. Spooner. "Community and Foodweb Ecology of Freshwater Mussels." . The North American Benthological Society, 22 Apr. 2008. Web. 28 July 2014. <http://vmpincel.ou.edu/download/publications/VaughnetalJNABS08.pdf>. Yulia Aleksandrovna Bespalova & Aliyar Mousavi (2013) Mercury (Hg) Levels in the Caspian Sea Kilka Fish: A Communication, Environmental Forensics, 14:3, 179-181, DOI: 10.1080/15275922.2013.814183 "Basic Information about Mercury (inorganic) in Drinking Water." Home. United States Environmental Protection Agency, 5 Feb. 2014. Web. 11 July 2014. <http://water.epa.gov/drink/contaminants/basicinformation/mercury.cfm>. "Energy Choices - Northeast Utilities." Energy Choices - Northeast Utilities. Public Service Company of New Hampshire, n.d. Web. 29 July 2014. <http://www.nu.com/energy/stations/psnh.asp>. "Find New England Sites - CHLOR-ALKALI FACILITY." Find New England Sites - CHLOR-ALKALI FACILITY. United States Environmental Protection Agency, 25 Mar. 2014. Web. 9 June 2014. <http://yosemite.epa.gov/r1/npl_pad.nsf/701b6886f189ceae85256bd20014e93d/94dd5df1d9c0ab95852570c20063f11a!OpenDocument>. "Freshwater Mussels in New Hampshire: Hidden Treasures of Our Lakes ." . New Hampshire Department of Environmental Services, 20 Mar. 2005. Web. 5 June 2014. <http://des.nh.gov/organization/commissioner/pip/factsheets/bb/documents/bb-55.pdf>. "How People are Exposed to Mercury." EPA. Environmental Protection Agency, 10 Mar. 2014. Web. 6 June 2014. <http://www.epa.gov/hg/exposure.htm>. "Northeast Regional Mercury TDML - October 2007."EPA . United States Environmental Protection Agency, n.d. Web. 4 Aug. 2014. <http://www.epa.gov/region1/npdes/merrimackstation/pdfs/ar/AR-412.pdf>. "2010 Waterbody Report for Northwood Lake, Northwood." Waterbody Quality Assessment Report | WATERS | US EPA. . United States Environmental Protection Agency, 1 Jan. 2010. Web. 10 June 2014. <http://iaspub.epa.gov/tmdl/attains_waterbody.control?p_list_id=NHLAK700060502-08-01&p_cycle=&p_report_type=>. "2010 Waterbody Report for SWAINS LAKE, STN A, BARRINGTON, PWS." Waterbody Quality Assessment Report | WATERS | US EPA. . United States Environmental Protection Agency, 1 Jan. 2010. Web. 10 June 2014. <http://iaspub.epa.gov/tmdl_waters10/attains_waterbody.control?p_list_id=NHLAK600030903-03&p_cycle=&p_report_type=>. "2010 Waterbody Report for UMBAGOG, LAKE, STN 2, ERROL." Waterbody Quality Assessment Report | WATERS | US EPA. United States Environmental Protection Agency, 1 Jan. 2010. Web. 10 June 2014. <http://iaspub.epa.gov/tmdl/attains_waterbody.control?p_list_id=NHLAK400010602-04&p_cycle=2010&p_report_type=>. Conclusion Samples from Northwood , Swain’s and Umbagog lakes resulted in no detectable level of mercury. The reporting limit was 5.0x10-2 µg/L. This reporting limit is below the value approved for drinking water, which is 2 µg/L (2 ppb) , fresh water and salt water which are, 2.1 µg/L and 1.8 µg/L respectively( US EPA, 2014; Mousavi, et al). This implies these lakes have a very minute amount of mercury in the water itself. This does not imply that there is no mercury content in these lakes, surface freshwater values range between 0.2 ng/L – 7.2 ng/L (Mousavi, et al). The lower end of these values is below the labs reporting limit for total mercury. Acknowledgements – This research was supported with funding from the National Science Foundation’s grant to NH EPSCoR (IIA-1101245).