are local, near-ground emissions of mercury and copper significant sources of water pollution? geoff...
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Are Local, Near-Ground Emissions of Mercury and Copper Significant Sources of Water Pollution?
Geoff Brosseau, BASMAA
Doug Steding/Christopher Conaway, UCSC – Mercury
Mark Schlautman, Clemson University – Copper
WRPPN Annual P2 Conference - 2003
Funding
USEPA Great Waters Program (National Estuary Program) – Air Deposition Initiative Grant
BASMAA (Bay Area Stormwater Management Agencies Association)
SFEP (San Francisco Estuary Project)
In the Beginning…
The Development and Legacy of 70s Environmental
Protection Regulations
Lost in the Translation?
Clean Water Act POCs / PBTs
Heavy metals Pesticides Toxics (OCs, PCBs,
PAHs, Dioxins/Furans)
Sediment
Clean Air Act HAPs / TACs
Ozone, VOCs NOx, SOx Nutrients
PM (Particulate matter)
Lost in the Translation? (Cont’)
Dimensions ppm, ppb, ppt (ng/l) Aquatic life-driven
Discharges Point / Non-Point
Watershed
Dimensions ppm (ng/m3) Human health-driven
Emissions/Deposition Stationary / Mobile /
Fugitive Airshed
Air Quality / Water Quality – Previous National Work
National studies concentrated on Chesapeake Bay and Great Lakes
Continental / Regional impacts First federally-funded air quality / water
quality studies west of the Mississippi began in 1999
San Francisco Bay – Previous AQ/WQ Work
Loading of Toxic Contaminants, AHI, 1987 Status and Trends, SFEP, 1991 Site-specific water quality objectives, San Jose, 1991 State of the Estuary, SFEP, 1992 Metals Control Measures Plan, SCVURPPP, 1997 Scoping Study of Air Deposition Monitoring
Information Relevant to Water Quality, BASMAA, 1998
BASMAA Scoping Study of Air Deposition Monitoring Information
Relevant to Water Quality
Prompted by increasing concern about air pollution being a “source” of POCs
Conducted preliminary review of both air pollution monitoring and air quality / water quality work
Showed that air monitoring network was unsuited for water quality POCs and source control work
Air Quality / Water Quality West Coast Studies
Deposition San Francisco Estuary Institute (SFEI) Southern California Coastal Water Research
Project (SCCWRP) Emissions – BASMAA and SFEP – Develop
and implement a monitoring program for specific emission sources to storm water in San Francisco Bay Area watersheds
BASMAA / SFEP Study – Scoping
Candidate Pollutants of Concern
Selection criteria Defined problem (303(d), WQO exceedances) Storm water identified as significant pathway Air emissions / deposition identified as significant pathway Source identification/ characterization information needed
Emissions – Near-ground Mercury in tailpipe exhaust Copper in brake pads
• Copper
• Diazinon
• PAHs
• PCBs
• Dioxin
• Mercury
BASMAA / SFEP Study – Scoping (Cont’)
Mercury Diesel exhaust was estimated source of 33% of mercury
to South San Francisco Bay and 80% of mercury in urban runoff (SCVURPPP, 1997)
Sample and analyze fuels and lubricating oils Copper
Brake pads were estimated source of 42% of copper to South San Francisco Bay and 80% of copper in urban runoff (SCVURPPP, 1997)
Characterize physical and chemical properties of brake pad wear debris
California Air Resources Board Mobile Laboratory
Sampling Plan
39 total fuel samples 20 Diesel 19 Gasoline
13 Regular gasoline 6 Premium gasoline
Semi-random locations Refineries Transfer stations Service stations
Sampling Plan (cont’)
25 samples – other automotive fluids Motor oils Lube oils Gear oils
Semi-random distribution of types and weights
Analysis
Fuels Mercury – Cold Vapor Atomic Fluorescence
Spectrometry Full suite of other metals – ICP/OES (direct
injection)
Oils – Thermal decomposition method?
Results – Mercury in fuels
Fuel Type Concentration
average (ppb)
Standard
dev. (ppb)
No. of Samples
Diesel 0.142 0.064 20
Regular gasoline
0.542 0.444 13
Premium gasoline
0.474 0.331 6
Results – Other metals, Oils
Other metals in fuels – Most of the metals were below the detection limits with the exception of Ni and Pb in a few samples and Cu in one sample
Oils – Mercury appears to be less than 10 ppb BUT analyses were problematic, probably because of product formulation
Changing Load Estimates – Mercury
Diesel exhaust – 33% of load to South San Francisco Bay (SCVURPPP, 1997)
Atmospheric deposition – 7% of load to San Francisco Bay (RWQCB, 2003)
Gas / diesel fuel consumption (BASMAA / SFEP, 2003 draft) 6% of atmospheric deposition 0.4% of load to San Francisco Bay
So, where’s the rest of the Hg in air coming from?
Regional – Bay Area plus surrounding Cos. Medical waste incineration Portland cement manufacturing Municipal waste combustion Carbon black production Crude oil refining?
International – Trans-Pacific fluxes from Asia plus local smog
City of Palo Alto / BASMAA Brake Pad Wear Debris Testing
Sample – One copper containing brake pad Development of microwave digestion
techniques for brake wear debris Analyses
Determination of sample heterogeneity and minimum sample size for representative results
Total copper concentration determinations for brake wear debris
Specific surface area analysis Copper solubility/leaching tests for model test
conditions and for environmentally-relevant aqueous environments
Preliminary Results – Copper in Brake Pads
Wear debris particles are fine particulate matter (~72% is 10 μm or smaller – PM10)
Highly irregular shapes
Upon initial release, about 47% of the material was released into the air; about 49% fell to the ground
SEMs of Brake Wear Debris
Source: Brake Manufacturers Council Product Environmental Committee, 2001
Preliminary Results – Copper in Brake Pads (cont’)
Copper content depends on individual pad
About 40% increase in copper use in pads between 1998 and
2000, with some probable increase between 1996 and 1998
If results from one pad are typical, copper from vehicle
brake pads probably behaves in the environment like copper
from other environmental copper sources
Copper solubility in brake wear debris is probably due to the
high surface area of brake pad wear debris and the chemical
form of the copper in the wear debris
Copper in Brake Pads – Next Steps
Proposition 13 Grant – Brake Pad Partnership Chemical and physical characterization work Environmental transport and fate modeling
Source loading Air deposition modeling Watershed modeling Receiving water modeling
Environmental monitoring
Original Question
Are Local, Near-Ground Emissions of Mercury and Copper Significant
Sources of Water Pollution?
Mercury – NoCopper – Yes, probably
Contact Info.
Geoff Brosseau
BASMAA
(Bay Area Stormwater Management Agencies Association)
(510) 622-2326