Mercury in the Onondaga Lake Remedy Betsy Henry May 22, 2008

Current Global Mercury Cycle

Fish Consumption Advisories (in US based on mercury as of 2006) 3,080 advisories in 48 states, one territory, and two tribes 3,080 advisories in 48 states, one territory, and two tribes 14,177,175 lake acres and 882,963 river miles 14,177,175 lake acres and 882,963 river miles 23 states including New York have issued statewide advisories for mercury in freshwater lakes and/or rivers 23 states including New York have issued statewide advisories for mercury in freshwater lakes and/or rivers

Mercury Study Report to Congress

Mercury Bioaccumulation

Methylmercury Timeline

“…(mercury) is rather inert chemically and insoluble in water, hence it is unlikely to occur as a water pollutant.” McKee and Wolf (1963) 1963 California Water Quality Criteria

Improved Sampling and Analysis “Reduces” Mercury Concentrations in Uncontaminated Surface Waters

Mercury Transformation Processes in Aquatic Systems Methylation Hg 2+ + CH 3 – CH 3 Hg + biological, chemical, photochemical Demethylation CH 3 Hg + + H + CH 4 + Hg 2+ biological, photochemical Reduction/Volatilization Hg e – Hg 0 biological, chemical, photochemical Oxidation Hg 0 Hg e – chemical

Mercury Transformation Processes in Aquatic Systems

Onondaga Lake, New York

a LCP purchased plant in 1979 and operated it until closure in Allied Mercury Cell Chlor-Alkali Operations Chlor-alkali products Chlor-alkali products –Chlorine –Caustic potash (KOH) –Caustic soda (NaOH) Bridge Street plant (1953–1979 a ) Bridge Street plant (1953–1979 a ) Willis Avenue plant (1947–1977) Willis Avenue plant (1947–1977) In 1970, mercury releases were reduced from 10 kg/day to less than 0.5 kg/day In 1970, mercury releases were reduced from 10 kg/day to less than 0.5 kg/day

Mercury Cell Electrolysis Source:

More than 6,000 samples of lake and tributary water, lake sediment, shoreline groundwater, wetlands, fish, plankton, benthic macroinvertebrates, and plants Onondaga Lake Remedial Investigation 1992—2000

Methylmercury in the Aquatic Food Web of Onondaga Lake, New York in 1992

Note: Units are g/May-Sept 92. First number is total mercury, second is methylmercury. Mercury Mass Balance in Onondaga Lake

Harbor Brook Semet Ponds Willis Ave Ballfield Ninemile Creek Tributary 5A Geddes Brook Dredge Spoils Area Town of Van Buren Town of Geddes Town of Camillus Town of Salina Town of Geddes Liverpool Syracuse MetroMetro Onondaga Lake Carousel Mall Ley Creek NYS Fairgrounds LCP Groundwater Collection and Treatment Former LCP Plant Honeywell owned sites Sites owned by others Remediation of plants and tributaries Cleanup of Mercury Sources to Onondaga Lake Settling Basins Settling Basin 11 Settling Basins 9 & 10 Former Main Plant West Flume Mathews Ave Settling Basin B East Flume

Former Allied Operations

Former LCP Plant Cleanup West Flume Mathews Ave NYS Fairgrounds Cutoff Wall Geddes Brook LCP Town of Geddes Town of Camillus Former LCP Plant Primary source of lake mercury stopped

Former LCP Site Mercury Soil Washing 24˝ 2,204 lb Container Nearly 8 tons of mercury recycled Innovative Soil Washing Technology 8,500 Tons of Soil Cleaned

Former LCP Site Cut off Wall Installation 3,277 ft long, encompassing 17 acres 3,277 ft long, encompassing 17 acres 35–70 ft deep 35–70 ft deep

Key project completed for lake cleanup LCP Wetland Restoration Completed fall 2007 Completed fall 2007 Nearly 12,000 trees and wetland plants Nearly 12,000 trees and wetland plants More than 20 native species More than 20 native species Consultation with SUNY-ESF, TES, and Audubon Consultation with SUNY-ESF, TES, and Audubon

Route 690 Groundwater Collection System/Barrier Wall Harbor Stops, collects and treats groundwater

Barrier wall construction begins Barrier wall construction begins –1.5 mile underground wall –Being constructed in three phases –Will prevent contamination from reaching lake –Groundwater cleaned at Willis Ave plant to state standards Lake cleanup has begun Groundwater Collection Phase 1

Groundwater Collection Phase 2 Access Road I-690 Fair Grounds Access Road I-690 Clay Marl Install Collection Trench Groundwater Restored Shoreline Groundwater to Treatment Facility Soil Barrier Wall Onondaga Lake Semet Barrier Wall Completed 12/06

Onondaga Lake Barrier Wall (Phase 1 – 2007) Collection trench and wells (Phase 1 – 2007) Pumping station Storage tanks Treatment facility (Operational 2006) I-690 Treated water to lake Groundwater Plant is Now Operating Groundwater Collection and Treatment Systems

Storage tanks Treatment plant Internal equipment Groundwater Treatment and Storage

The Onondaga Lake Remedy Consent decree signed October 11, 2006 by Attorney General, DEC, and Honeywell, lodged January 4, 2007 Consent decree signed October 11, 2006 by Attorney General, DEC, and Honeywell, lodged January 4, 2007 Pre-design investigation begun in 2005 to expedite schedule Pre-design investigation begun in 2005 to expedite schedule Design has begun—remedial design work plan submitted early Design has begun—remedial design work plan submitted early Extensive community outreach by both DEC and Honeywell, supportive public Extensive community outreach by both DEC and Honeywell, supportive public Commitment to aggressive 5 year schedule Commitment to aggressive 5 year schedule

Sediment Management Units

Note: Units are g/May-Sept 92. First number is total mercury, second is methylmercury. Mercury Mass Balance in Onondaga Lake

Sediment Remediation Nearshore (littoral) sediment Nearshore (littoral) sediment –Dredging an estimated 2.65 million cubic yards of the most contaminated sediment –Isolation cap an estimated 425 acres—all areas exceeding sediment criteria in littoral area Deep basin (profundal) sediment Deep basin (profundal) sediment –Monitored natural recovery (MNR) Natural processes reduce chemical concentrations, exposure, and mobility Natural processes reduce chemical concentrations, exposure, and mobility Refinement of MNR model used to predict future concentrations Refinement of MNR model used to predict future concentrations Long-term monitoring with thin layer cap as contingency Long-term monitoring with thin layer cap as contingency –Thin layer capping Application of thin (e.g., 4 to 6 inches) cap over sediment not expected to meet the sediment cleanup goals within 10 years following remediation Application of thin (e.g., 4 to 6 inches) cap over sediment not expected to meet the sediment cleanup goals within 10 years following remediation

Onondaga Lake Groundwater Collection Near Shore Barrier Wall Groundwater Contaminated Sediments Removed During Dredging Cap Chemical Isolation Layer Mixing Layer Contaminated Sediment Habitat Restoration Layer Erosion Protection (Where Needed) Capping/Dredging and Habitat Restoration/ Enhancement In Onondaga Lake

Natural recovery is already occurring in SMU 8 sediments DEPTH (cm DEPTH (cm ) TOTAL MERCURY (mg/kg) Natural Recovery in Deep Basin Sediment Surface concentrations reflect ongoing inputs to the lake Surface concentrations reflect ongoing inputs to the lake Higher concentrations are permanently buried by cleaner sediment Higher concentrations are permanently buried by cleaner sediment

Gas Ebullition Resuspension Littoral Sediment EPILIMNION HYPOLIMNION Methylmercury Production Profundal Sediment Methylmercury Bioaccumulation Oxygen Depth Internal Source of Methylmercury Methylmercury produced under anoxic conditions by sulfate-reducing bacteria Methylmercury produced under anoxic conditions by sulfate-reducing bacteria Oxygen limits methylmercury production Oxygen limits methylmercury production

Nitrate Control of Methylmercury Production Nitrate concentrations in Onondaga Lake increased when Metro started year-round nitrification in 2004 Nitrate concentrations in Onondaga Lake increased when Metro started year-round nitrification in 2004 In 2005, Syracuse University and Upstate Freshwater Institute (SU/UFI) observed that nitrate increase delayed sulfate reduction In 2005, Syracuse University and Upstate Freshwater Institute (SU/UFI) observed that nitrate increase delayed sulfate reduction They hypothesized that this delay would result in decreased methylmercury concentrations in the lake They hypothesized that this delay would result in decreased methylmercury concentrations in the lake

Sequence of Redox Reactions

Time Series of Metabolic Indicators, 2006 and 2007 (Volume-weighted hypolimnetic averages)

Comparison of Maximum Masses of Methylmercury in the Hypolimnion

Mercury in the Onondaga Lake Remedy Eliminate external sources of mercury Eliminate external sources of mercury Dredging/capping Dredging/capping Monitored natural recovery Monitored natural recovery Oxygen/nitrate addition Oxygen/nitrate addition Designed to meet the remedial goal of reducing mercury concentrations in Designed to meet the remedial goal of reducing mercury concentrations in –sediment, –water, and –fish to levels that are protective of human health and the environment. to levels that are protective of human health and the environment.

Progress... Lake agreement Lake agreement Mercury source at LCP Bridge Street eliminated Mercury source at LCP Bridge Street eliminated Groundwater barrier wall and treatment in progress Groundwater barrier wall and treatment in progress – Lake design work plan – Phase 2 barrier wall...on the Cleanup of Onondaga Lake