ARE ALL ARSENIC EXPOSURES TOXIC? Moving Selene* into Acton

Supporting Regional Risk Assessments through
Improved Arsenic Speciation Methodology

John T. Creed, P.A, Gallagher & C.A. Schwegel
Office of Research and Development, National Exposure Research Laboratory, Microbiological & Chemical Exposure Assessment Research Division, Cincinnati, OH

Environmental Issue: Arsenic Exposure

How does Arsenic Enter the Environment?

1. Naturally



T+ 1

2. Wood Perservative

4. Medicinal
Purposes

What are the Major Pathways for Human Exposure to Arsenic?

1. Drinking Water

Toxic I > Composed of All Toxic Arsenic
Toxic f

Non

Toxic

Toxic

Non
Toxic

Non
Toxic

Toxic

2. Seafood

> Composed of Toxic
and Non Toxic Arsenic

Recognizing that all chemicals are potentially Toxic depending on the dose, the term "Non Toxic" is very loosely used
to illustrate the fact that some forms of arsenic are not expected to present significant health risks at environmental
exposure levels, while other forms of arsenic do present health risks at environmental exposure levels.

What is the Problem?

1.	Traditional Analytical Methods do not Separate the Toxic forms of arsenic from the Non Toxic
forms. > NET EFFECT: Over Estimation of the Risk

2.	Seafood's total arsenic concentrations are high and contains both Toxic and Non Toxic forms.

3.	High seafood consumption rates in coastal regions produces a sub-population with the potential for
elevated arsenic exposures.

Scientific Approach

1. National Exposure Research
Laboratory (NERL) Scientists are
developing the scientific capability
to separate (i.e., speciate) the toxic
and non toxic forms of arsenic in
water, food and biologicals.

Traditional

2. This capability will allow the
amount of non toxic forms of
arsenic to be reported individually.

3. These separate concentrations
can then be used to better estimate
the risk associated with an arsenic
exposure.

Method

Ibtal Arsenic
(Noil Tbxic + Toxic)

Problem:

Must Assume
100% Toxic

Result: Over Estimation
of Risk Assessment

Non
Toxic

New
Speciation

Methodology



Toxic

35%

Toxic

To>cic



Improvement:
Preservation of
Chemical Form

65%

Non Toxic



Result: Improved
Risk Assessment

The Impact on the Issue

Acknowledgement

1.	Providing the Regions with analytical
methodologies capable of separating toxic arsenicals
in dietary and drinking water matrices allows them to
better define the magnitude of the risk associated
with a given exposure.

2.	It will allow Regional Scientists to provide
improved exposure/risk assessments associated with
fish advisories and human health.

We would like to thank Region 10 (Roseanne
Lorenzana, Isa Chamberlain and Stephanie Le) for the
seafood samples and collaborative work on this
project.

Pa Ttnering	to Protect	Human

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