Identification and Prioritization of Management Practices to Reduce Methylmercury Exports from Wetlands and Irrigated Agricultural Lands

Abstract

The Sacramento–San Joaquin Delta’s (Delta) beneficial uses for humans and wildlife are impaired by elevated methylmercury (MeHg) concentrations in fish. MeHg is a neurotoxin that bioaccumulates in aquatic food webs. The total maximum daily load (TMDL) implementation plan aimed at reducing MeHg in Delta fish obligates dischargers to conduct MeHg control studies. Over 150 stakeholders collaborated to identify 24 management practices (MPs) addressing MeHg nonpoint sources (NPS) in three categories: biogeochemistry (6), hydrology (14), and soil/vegetation (4). Land uses were divided into six categories: permanently and seasonally flooded wetlands, flooded and irrigated agricultural lands, floodplains, and brackish-fresh tidal marshes. Stakeholders scored MPs based on seven criteria: scientific certainty, costs, MeHg reduction potential, spatial applicability, technical capacity to implement, negative impacts to beneficial uses, and conflicting requirements. Semi-quantitative scoring for MPs applicable to each land use (totaling >400 individual scores) led to consensus-based prioritization. This process relied on practical experience from diverse and accomplished NPS stakeholders and synthesis of 17 previous studies. Results provide a comprehensive, stakeholder-driven prioritization of MPs for wetland and irrigated agricultural land managers. Final prioritization highlights the most promising MPs for practical application and control study, and a secondary set of MPs warranting further evaluation. MPs that address hydrology and soil/vegetation were prioritized because experiences were positive and implementation appeared more feasible. MeHg control studies will need to address the TMDL conundrum that MPs effective at reducing MeHg exports could both exacerbate MeHg exposure and contend with other management objectives on site.

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References

  1. Ackerman JT, Eagles-Smith C (2010) Agricultural wetlands as potential hotspots for mercury bioaccumulation: experimental evidence using caged fish. Environ Sci Technol 44:1451–1457

    Article  CAS  Google Scholar 

  2. Alpers CN, Eagles-Smith CA, Foe C, Klasing S, Marvin-DiPasquale MC, Slotton DG, Windham-Myers L (2008) Mercury conceptual model. Sacramento (CA): Delta regional ecosystem restoration implementation plan. http://www.science.calwater.ca.gov/pdf/drerip/DRERIP_mercury_conceptual_model_final_012408.pdf

  3. Auer MT, Galicinao GA, Matthews DA, Todorova S, Driscoll DT, Chapra SC (2008) Enhanced natural recovery of mercury-contaminated lake sediments by electron acceptor augmentation. Tenth Annual Onondaga Lake Scientific Forum

  4. Bergamaschi BA, Fleck JA, Downing BD, Boss E, Pellerin B, Ganju N, Schoellhamer DH, Byington AA, Heim WA, Stephenson M, Fujiia R (2011) Methyl mercury dynamics in a tidal wetland quantified using in situ optical measurements. Limnol Oceanogr 56(4):1355–1371

    Article  CAS  Google Scholar 

  5. Bergamaschi BB, Krabbenhoft DP, Aiken GA, Patino E, Rumbold DG, Orem WH (2012) Tidally driven export of dissolved organic carbon, total mercury, and methylmercury from a mangrove-dominated estuary. Environ Sci Technol 46:1371–1378

    Article  CAS  Google Scholar 

  6. Byington AA (2007) Photo-degradation of methylmercury in the Sacramento-San Joaquin Delta Estuary, master of science thesis. Moss Landing Marine Laboratories at San Jose State University, San Jose

  7. Choe KY, Gill GA, Lehman RD, Han S, Heim WA, Coale KH (2004) Sediment-water exchange of total mercury and monomethyl mercury in the San Francisco Bay-Delta. Limnol Oceanogr 49(5):1512–1527

    Article  CAS  Google Scholar 

  8. (CVRWQCB) Central Valley Regional Water Quality Control Board (2010) Resolution No. R5-2010-0043 amendments to the water quality control plan for the Sacramento River and San Joaquin River Basins for the control of methylmercury and total mercury in the Sacramento-San Joaquin Delta Estuary. 44

  9. Dahl TE (1990) Wetland losses in the United States 1780’s to 1980’s. U.S. Department of the Interior, Fish and Wildlife Service, Washington, United States Geological Survey. http://www.npwrc.usgs.gov/resource/wetlands/wetloss/summary.htm

  10. Davis JA, Greenfield BK, Ichikawa G, Stephenson M (2008) Mercury in sport fish from the Sacramento-San Joaquin Delta region, California. Sci Total Environ 391:66–75

    Article  CAS  Google Scholar 

  11. Dent S, Beutel M, Moore B, Shallenberger E (2011) Comprehensive evaluation of the impacts of hypolimnetic oxygenation on mercury cycling in the aquatic ecosystem of Twin Lakes, Washington. In: Presented at the 10th international conference on mercury as a global pollutant, July 24–29, 2011, Halifax, Nova Scotia, Canada

  12. Deverel S, Ackerman J, Bachand P, Bachand S, Baldocchi D, Brock B, Fleck J, Horwath W, Linquist B (2013) Annual progress report for Twitchell rice project, 2011. Prepared for CA Department of Water Resources, pp 84

  13. Driscoll CT, Mason RP, Chan HM, Jacob DJ, Pirrone N (2013) Mercury as a global pollutant: sources, pathways, and effects. Environ Sci Technol 47(10):4967–4983

    Article  CAS  Google Scholar 

  14. Eagles-Smith C (2012) CRP mercury study—study design and preliminary results. In: Presented at the Delta tributary mercury council, March 28, 2012. Galt, CA. http://www.sacriver.org/files/documents/dtmc-minutes/20120328.pdf

  15. Fleck JA, Gill G, Downing BD, Bergamaschi BA, Kraus TEC, Alpers CN (2014) Concurrent photolytic degradation of aqueous methylmercury and dissolved organic matter. Sci Total Environ 484:263–275. doi:10.1016/j.scitotenv.2013.03.107

  16. Foe C, Louie S, Bosworth D (2008) Methylmercury concentrations and loads in the central Valley and freshwater Delta. Final report submitted to the CALFED Bay-Delta Program for the project “Transport, cycling and fate of mercury and monomethylmercury in the San Francisco Delta and tributaries” Task 2. Central Valley Regional Water Quality Control Board. http://mercury.mlml.calstate.edu/wp-content/uploads/2008/10/04_task2mmhg_final.pdf

  17. Gilmour CC, Henry EA, Mitchell R (1992) Sulfate stimulation of mercury methylation in freshwater sediments. Environ Sci Technol 26:2281–2287

    Article  CAS  Google Scholar 

  18. Heim WA (2011) Best management practices to reduce methylmercury concentrations and exports from seasaonal wetlands in the Yolo Wildlife Area, California USA. In: Paper presented at the 10th international conference on mercury as a global pollutant, Halifax, Nova Scotia, Canada, July 24–29

  19. Heim W, Stephenson M (2012) Potential management practices to control methylmercury in discharges from non-point sources within the Sacramento-San Joaquin Delta. Appendix A3 in delta methylmercury TMDL nonpoint sources workgroup methylmercury control study collaborative workplan. April 19, 2013. http://delta-mercury-nps.org/documents/NPSWorkgroup_CollaborativeWorkplan_Draft_20130419.pdf

  20. Heim W, Coale KH, Stephenson M, Choe K-Y, Gill GA, Foe C (2007) Spatial and habitat-based variations in total and methyl mercury concentrations in surficial sediments in the San Francisco Bay-Delta. Environ Sci Technol 41:3501–3507

    Article  CAS  Google Scholar 

  21. Heim WA, Deverel S, Ingrum T, Piekarski W, Stephenson M (2009) Assessment of methylmercury contributions from Sacramento-San Joaquin Delta farmed Islands. Final report submitted to the Central Valley Regional Water Quality Control Board. Sacramento, CA

  22. Heim WA, Negrey J, Martenuk S, Bonnema A, Byington A, Masek J, Newman A, Stephenson M, Coale KH (2013) Using mesocosms to test the effect of land management practices on monomethylmercury production in freshwater seasonal wetlands. In: Paper presented at the AGU Fall Meeting, San Francisco

  23. Henneberry YK, Kraus TEC, Fleck JA, Krabbenhoft DP, Bachand PM, Horwath WR (2011) Removal of inorganic mercury and methylmercury from surface waters following coagulation of dissolved organic matter with metal-based salts. Sci Total Environ 409:631–637

    Article  CAS  Google Scholar 

  24. Henneberry YK, Kraus TEC, Nico PS, Horwath WR (2012) Structural stability of coprecipitated natural organic matter and ferric iron under reducing conditions. Org Geochem 48:81–89

    Article  CAS  Google Scholar 

  25. King JK, Harmon SM, Fu TT, Gladden JB (2002) Mercury removal, methylmercury formation, and sulfate-reducing bacteria profiles in wetland ecosystems. Chemosphere 46:859–870

    Article  CAS  Google Scholar 

  26. Krabbenhoft DP, Wiener JG, Brumbaugh WG, Olson ML, De Wild JF, Sabin TJ (1999) A national pilot study of mercury contamination of aquatic ecosystems along multiple gradients. In: Morganwalp DW and Buxton HT (eds), U.S. Geological survey toxic substances hydrology program. In: Proceedings of the technical meeting; Charleston 1999 Mar 8–12; vol 2 of 3—contamination of hydrologic systems and related ecosystems, U.S. Geol Surv Water-Resour Invest Rep 99–4018B, p 147–160

  27. Lund J, Hanak E, Fleenor W, Howitt R, Mount J, Moyle P (2007) Envisioning futures for the Sacramento-San Joaquin Delta. Public Policy Institute of California, San Francisco

    Google Scholar 

  28. Mailman M, Stepnuk L, Cicek N, Bodaly R (2006) Strategies to lower methyl mercury concentrations in hydroelectric reservoirs and lakes: a review. Sci Total Environ 368:224–235

    Article  CAS  Google Scholar 

  29. Marvin-DiPasquale M, Agee J (2003) Microbial mercury cycling in sediments of the San Francisco Bay-Delta. Estuaries 26:1517–1528

    Article  CAS  Google Scholar 

  30. Marvin-DiPasquale M, Windham-Myers L, Agee JL, Kakouros E, Kieu LH, Fleck JA, Alpers CN, Stricker CA (2014) Methylmercury production in sediment from agricultural and non-agricultural wetlands in the Yolo Bypass, California, USA. Sci Total Environ. doi:10.1016/j.scitotenv.2013.09.098

  31. Mehrotra AS, Sedlak DL (2005) Decrease in net mercury methylation rates following iron amendment to anoxic wetland sediment slurries. Environ Sci Technol 39(8):2564–2570

    Article  CAS  Google Scholar 

  32. Nichols FH, Cloern JE, Luoma SN, Peterson DH (1986) The modification of an estuary. Science 231:567–573

    Article  CAS  Google Scholar 

  33. Orlando JL, Kuivila KM (2004) Changes in rice pesticide use and surface water concentrations in the Sacramento River watershed, California. U.S. Geological Survey Scientific Investigations Report 2004–5097, p 28

  34. Parks JM, Johs A, Podar M, Bridou R, Hurt RA, Smith SD, Tomanicek SJ, Qian Y, Brown SD, Brandt CC, Palumbo AV, Smith JC, Wall JD, Elias DA, Liang L (2013) The genetic basis for bacterial mercury methylation. Science 339(6125):1332–1335

  35. Siegel S, Bachand P, Gillenwater D, Chappell S, Wickland B, Rocha O, Stephenson M, Heim W, Enright C, Moyle P, Crain B, Bergamaschi B, Pellerin B (2011) Final evaluation memorandum, strategies for resolving low dissolved oxygen and methylmercury events in Northern Suisun Marsh., vol SWRCB Project Number 06-283-552-0. Prepared for the State Water Resources Control Board, Sacramento, California

  36. Springborn M, Singer MB, Dunne T (2011) Sediment-adsorbed total mercury flux through Yolo Bypass, the primary floodway and wetland in the Sacramento Valley, California. Sci Total Environ 412:203–213

    Article  Google Scholar 

  37. Todorova SG, Driscoll CT, Matthews DA, Effler SW, Hines ME, Henry EA (2009) Evidence for regulation of monomethyl mercury by nitrate in a seasonally stratified, Eutrophic Lake. Environ Sci Technol 43(17):6572–6578

    Article  CAS  Google Scholar 

  38. Ulrich PD, Sedlak DL (2010) Impact of iron amendment on net methylmercury export from tidal wetland microcosms. Environ Sci Technol 44(19):7659–7665

    Article  CAS  Google Scholar 

  39. Whipple A, Grossinger RM, Rankin D, Stanford B, Askevold R (2012) Sacramento-San Joaquin Delta historical ecology investigation: exploring pattern and process. San Francisco Estuary Institute, Richmond

    Google Scholar 

  40. Windham-Myers L, Ackerman JT (2012) A synthesis of mercury science to support methylmercury control studies for delta wetlands and irrigated agriculture. Appendix A2 in Delta methylmercury TMDL nonpoint sources workgroup methylmercury control study collaborative workplan. April 19, 2013. http://delta-mercury-nps.org/documents/NPSWorkgroup_CollaborativeWorkplan_Draft_20130419.pdf

  41. Windham-Myers LM, Marvin-DiPasquale M, Fleck J, Alpers CN, Ackerman J, Eagles-Smith C, Stricker C, Stephenson M, Feliz D, Gill G, Bachand P, Brice A, Kulakow R (2010) Methylmercury cycling, bioaccumulation, and export from agricultural and non-agricultural wetlands in the Yolo Bypass. Final report

  42. Windham-Myers L, Ackerman JT, Fleck JA, Heim WA, and McCord SA (2013a) A synthesis of mercury studies in California’s Sacramento San-Joaquin Delta, 1998-2008: Scientific support towards a landscape-level management plan for controlling mercury exposure. Abstract T128. In: International conference on mercury as a global pollutant. Edinburgh, July 28–Aug 2, 2013

  43. Windham-Myers L, Marvin-DiPasquale M, Stricker CA, Agee JL, Kieu LH, Kakouros E (2013b) Mercury cycling in agricultural and managed wetlands of California, USA: experimental evidence of vegetation-driven changes in sediment biogeochemistry and methylmercury production. Sci Total Environ. doi: 10.1016/j.scitotenv.2013.05.028

  44. Windham-Myers L, Ackerman JT, Fleck J, Marvin-DiPasquale M, Stricker CA, Bachand P, Eagles-Smith CA, Feliz D, Gill G, Heim WA, Stephenson M, Alpers CN (2014) Mercury cycling in agricultural and managed wetlands: a synthesis of observations from an integrated field study of methylmercury production, hydrologic export, and bioaccumulation. Sci Total Environ, http://ca.water.usgs.gov/pubs/2014/WindhamMyersEtAl2014.html

  45. Wood ML, Foe C, Cooke J, Louie SJ (2010) Sacramento—San Joaquin Delta Estuary TMDL for methylmercury: Staff report, Regional Water Quality Control Board—Central Valley Region, Sacramento, California, April 2010, p 234 http://www.swrcb.ca.gov/rwqcb5/water_issues/tmdl/central_valley_projects/Delta_hg/april_2010_hg_tmdl_hearing/index.shtml

  46. Zillioux EJ, Porcella DB, Benoit JM (1993) Mercury cycling and effects in freshwater wetland ecosystems. Environ Toxicol Chem 12:2245–2264

    Article  CAS  Google Scholar 

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Acknowledgments

Partial funding for the NPS Workgroup was made available from the Central Valley Regional Water Quality Control Board and administered through the Sacramento River Watershed Program. Funding for this project was provided in part through an agreement with the State Water Resources Control Board and EPA under the Federal Nonpoint Source Pollution Control Program (Clean Water Act Section 319(h)). Thoughtful reviews were provided by Josh Croft, Janis Cook, Tom Maurer, and Lisamarie Windham-Myers. Other members of the Steering Committee and organizations participating in the NPS Workgroup as Cooperating Entities can be found on the Workgroup’s website (http://delta-mercury-nps.org/).

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Correspondence to Stephen A. McCord.

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McCord, S.A., Heim, W.A. Identification and Prioritization of Management Practices to Reduce Methylmercury Exports from Wetlands and Irrigated Agricultural Lands. Environmental Management 55, 725–740 (2015). https://doi.org/10.1007/s00267-014-0425-5

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Keywords

  • Irrigated agriculture
  • Management practices
  • Mercury
  • Methylmercury
  • Prioritization
  • Wetlands