A Guide to Trace and Ultra-Trace Mercury Testing in Water · • Typically Trace (low level) Mercury = results between 5 - 50 ng/L (ppt). • Typically Ultra-Trace Mercury = results

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A Guide to Trace and Ultra-Trace Mercury Testing in Water

Blair Easton

General Manager – ALS Environmental Calgary


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Presentation Overview

• Mercury Sources

• Mercury Cycle

• Anthropogenic Mercury Sources in Alberta

• Relative Mercury Concentrations

• Regulatory Limits

• Sampling Considerations

• Dissolved Mercury Sampling

• Field & Transport Blanks

• Mercury Analysis


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Mercury Sources


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Mercury Cycle


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Anthropogenic Mercury Sources - Alberta

Mercury is of particular concern in the northern rivers of Alberta.

Where Coal Power Generation Plants are a source of Anthropogenic Mercury.


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Anthropogenic Mercury Sources - Alberta

Both bitumen and oil sands tailing ponds are known to contain

traces of mercury.


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Relative Levels of Mercury Concentration

• Typically Trace (low level) Mercury =

results between 5 - 50 ng/L (ppt).

• Typically Ultra-Trace Mercury = results

between 0.1 – 5 ng/L

One part per trillion (1 ppt) is a proportion equivalent to a drop of water diluted into 400Olympic-size swimming pools.

1ppt = 0.001 ppb = 0.000001 ppm


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Mercury Regulatory Limits

• The lowest AB Tier I Ground Water

Remediation Guideline = 5 ng/L

(i.e. the Aquatic Life guideline).

• AB Regional Aquatics Monitoring

Program (RAMP) has the lowest

reported result for Total Mercury

at 0.2 ng/L and the average

result is ~3 ng/L.


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Sampling Considerations

• The potential for contaminating ambient water samples

with the mercury and interfering substances cannot be

overemphasized.


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Contamination Sources

Sources of contamination can include:

Metallic sampling equipment

In-appropriate & Un-tested Sample

containers

Sampling gloves (e.g. powdered gloves)


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Contamination Sources

Atmospheric inputs such as dust and dirt from:

Automobile exhaust

Roads, bridges, wires and poles

Cigarette smoke

And, the Sampler – e.g. older dental work


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Historic Mercury Sampling Containers

• Until recently, the most

common container type

and preservative used for

routine or low level

mercury analysis of

waters was:

The High Density Polyethylene (HDPE) plastic container with nitric acid (U.S. EPA Method 245.1, 1972).


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New Trace Level Mercury Sampling Requirements

• Pre-cleaned Borosilicate

glass container with

Teflon®

lined cap with 1:1

Hydrochloric acid (HCl).

EPA Method 245.7 (2005)


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Ultra-Trace Level Mercury Sampling Requirements

• Pre-cleaned borosilicate glass or Teflon®

container with 1:1 Hydrochloric acid (HCl).

EPA Method 1631 E (2002).

The EPA further recommends the use of the

"clean hands/dirty hands" technique during

field sampling.

Some labs recommend no preservation with

(1:1) hydrochloric acid as it acts as a strong

magnet for contamination.


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Clean Hands Dirty Hands Procedure

• EPA 1631 E recommends

to follow the US EPA

“clean hands / dirty

hands” (EPA 1669)

sampling protocols when

conducting ultra-trace

mercury analyses.

EPA Method 1669: Sampling Ambient Water for Determination of Trace Metals at EPA Water Quality Criteria Levels (Sampling Method).


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Dissolved Mercury Sampling

• Filtration for dissolved

Hg should be conducted

within one hour of

sample collection using

a suitable in-line filter or

0.45 μm syringe filter.


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Field & Transport Blanks

Field Blank

A sample prepared in the field using

analyte free water and incorporate all

aspects of sampling operations.

Transportation Blank

A sample in which the analytes of

interest are absent is prepared by the

laboratory and shipped with sample

containers.

It travels to the sampling site and returns

with the collected samples.

Transport Blank


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Mercury Analysis

• Mercury Instruments

Some instruments use

enclosed samplers to

prevent sample

contamination.

• Mercury Analysis Labs

Dedicated rooms for ultra-

trace mercury analysis

prevent cross

contamination from

routine level samples.

Open Air Sampler Enclosed Sampler


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Questions

Documents

A Guide to Trace and Ultra-Trace Mercury Testing in Water · • Typically Trace (low level) Mercury = results between 5 - 50 ng/L (ppt). • Typically Ultra-Trace Mercury = results