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

gabrosseau@attbi.com