United States EPA-743-B-96-001
Environmental Protection September 1996
Agency
Office of Pollution Prevention anci Toxics'
O CDA AQUEOUS AND
^E-rrA SEMI-AQUEOUS
SOLVENT
CHEMICALS:
ENVIRONMENTALLY
PREFERABLE
CHOICES
IDE and WALL CHART
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Purpose of this Guide:
The U.S. Environmental Protection Agency
(EPA) developed this guide to provide
companies with information to help them make
responsible environmental choices for
chemicals used in metal cleaning.
EPA is aware of a general trend in industry to
reduce or eliminate use of halogenated solvent
cleaning systems, in addition, EPA knows
that many firms now use or may soon begin
using aqueous (water-based) and semi-
aqueous (partially water-based) cleaning
processes.
While use of these chemicals generally will be
better for the environment, the chemicals can
still be of concern when released to water.
EPA hopes this guide will help minimize such
adverse effects, and also focus solvent
selection on a thorough consideration of costs,
health effects, and effectiveness, as well as
the persistence and ecotoxicity factors which
are the focus of this guide.
Although metal-cleaning businesses often
have access to information on human health
effects, product effectiveness, and cost, more
limited information is readily available on the
environmental effects of alternative chemicals
used in aqueous and semi-aqueous cleaning
chemicals.
This guide and wall chart should help
companies make environmentally responsible
choices when choosing substitute cleaning
systems by providing environmental effect and
persistence information on some of the most
commonly used alternative chemicals. It also
refers the user to resources for health effects,
toxicity, and process change information.
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What This Guide Does:
This guide rates a number of aqueous and
semi-aqueous solvent chemicals, by toxicity
and persistence in the environment. The
toxicity rating indicates a level of potential
harm to aquatic organisms, such as fish and
algae, upon release of the chemical to surface
water. The persistence rating indicates how
long the chemical will remain in the water
before it degrades into stable components. In
general, chemicals which degrade into stable
components are less likely to pose
environmental problems.
How To Interpret The Ratings:
[Ratings are based on standard EPA hazard and
persistence criteria]
Ecological Toxicitv is based upon the effects
of the chemical on aquatic organisms, such as
fish and algae. The organisms are exposed to
varied concentrations of the chemical in water
over a 2-to 4- day period. The ratings are
determined by the chemical concentration at
which 50% of the aquatic organisms die. The
ratings are:
High - 50% of organisms die at 1 part per
million or less of the chemical.
Moderate - 50% of organisms die at > 1 part
per million, but < 100 parts per million.
Low - 50% of organisms die at > 100 parts per
million.
Persistence ratings are based upon how long
it takes the original chemical to completely
break up into stable components when it is
released to the environment. The ratings are:
High - longer than 6 months to completely
break up.
Moderate - breaks up in less than 6 months,
but longer than 1 month.
Low - breaks up in 1 month or less.
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Some Things To Consider When
Using This Guide:
' Determining which solvent chemicals to use
requires a careful balancing of the
environmental, health, cost, and other
factors with your needs for an effective
cleaning product. This guide focuses on
environmental factors only; check other
resources (see Resources section) to
ensure that you make a well-informed
decision and consider all factors.
* Toxicity is generally more important than
persistence.
* The percentage of each chemical in a
formulation also must be considered when
making substitution choices. For example,
a cleaner containing a small percentage of
a chemical with a high ecological toxicity
rating may be less harmful to the
environment than a cleaner with a large
percentage of a moderate ranked chemical.
* The toxicity ratings in this guide are based
on the specific chemical and do not
consider the potential effects of combining
more than one chemical in a formulation.
* The criteria for determining the ratings were
based on either measured and/or predicted
values for both ecological toxicity and
persistence.
If you are unsure about which chemicals you
are using, call your supplier for more
information. To be sure the information you
receive is correct, refer to the chemicals by
their Chemical Abstracts Service (CAS)
number, rather than chemical name, since
chemicals often have more than one name.
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AQUEOUS AND SEMI-AQUEOUS SOLVENT CHEMICALS:
ENVIRONMENTALLY PREFERABLE CHOICES
WALL CHART
Chemicals Used in Cleaners,
Grouped by Functional Type
Other/Common Names
Acid Agents and Acids
Citric acid
Ethylenetetraacetic acid, sodium salt1
Ethylenediaminetetraacetic acid1
:ormic acid
Glucoheptonic acid
Gluconic acid, sodium salt
Gluconic acid
Hydrochloric acid
Phosphoric acid3
Sulfuric acid
2-Hydroxy-1 ,2,3-propane carboxylic acid
Sodium EDTA
EDTA
Methanoic acid
Glucosemonocarboxylic acid
Sodium gluconate
D-Gluconic acid
Muriatic acid
Orthophosphoric acid
Hydrogen sulfate
CAS
Numbers
Ecological
Toxicity
Environmental
Persistence
77-92-9
7379-28-4
60-00-4
64-18-6
23351-51-
527-07-1
526-95-4
7647-01-0
7664-38-2
7664-93-9
Moderate
Moderate
Moderate
Low
Low
Low
Low
Low
High
Low
Low
Moderate
Moderate
Low
Low
Low
Low
I
J
2
Alkalies
vlonoethanolamine
Potassium hydroxide
Sodium tripolyphosphate
Sodium hydroxide
Sodium carbonate
Sodium sulfate
Sodium metasilicate
Tetrapotassium pyrophosphate3
Tetrasodium pyrophosphate3
Triethanolamine
Trisodium phosphate
2-Aminoethanol
Caustic potash
STPP
Caustic soda
Soda ash
Sulfuric acid disodium salt
Sodium silicate
Potassium pyrophosphate
Sodium pyrophosphate
TEA
Sodium phosphate
141-43-5
1310-58-3
7758-29-4
1310-73-2
497-19-8
7757-82-6
6834-92-0
7320-34-5
7722-88-5
102-71-6
7601-54-9
Moderate
Low
High
Low
Low
Low
Moderate
High
High
Low
High
Low
2
2
2
2
2
1
B
2
Low
2
Surfactants
Polyethoxylated nonylphenol
Sodium xylene sulfonate
Nonyl phenol ethoxylate
Dimethylbenzenesulfonic acid, sodium salt
9016-45-9
1300-72-7
Moderate
Lo\y
Low-Moderate
Low-Moderate
I Hydrocarbon Solvents
Dipentene
n-Hexane
d-Limonene
l-a-Pinene, d-a-pinene, p-pinene5
Terpene processing byproducts
Hexane
p-metha-1,8-diene
Pinenes
68956-56-
110-54-3
5989-27-5
See Notes
High
High
High
High
Low
Low
Low
Low
Non-Hydrocarbon Solvents
Ethanol, 2-butoxy
Ethanol 2- (2- butoxyethoxy)
Ethanol
Methanol
N-methyl-2-pyrrolidone
1-Nonanol
EGBE
DGBE
Ethyl alcohol
Methyl alcohol
NMP
Nonyl alcohol
111-76-2
112-34-5
64-17-5
67-56-1
872-50-4
143-08-8
Low
Low
Low
Low
Moderate
Moderate
LOW
Low
Low
Low
Low
Low
Other Chemical Classes Used "
Fatty acids7
Alkyl aryl sulfonates7
Sulfated ethoxy phenols
Ethoxylated alkyl phenols7
Naphthalene sulfonates
Various
Various
Various
Various
Various
Various
Various
Various
Various
Various
Low to High
Low to High
Low
Low to High
Low
Low-Moderate
Low-Moderate
Low
Varies
Low
How To Interpret
the Ratings
Ecologjcal
Toxlcitv is based
upon the effects of
the chemical on
aquatic organisms,
such as fish and
algae. The
organisms are
exposed to varied
concentrations of
the chemical in
water over a 2- to
4- day period. The
ratings are
determined by the
chemical
concentration at
which 50% of the
aquatic organisms
die. The standard
EPA hazard and
persistence criteria
are:
High - 50% of
organisms die at 1
part per million or
less of the
chemical.
Moderate - 50% of
organisms die at
>1 part per million,
but <100 parts per
million.
Low - 50% of
organisms die at
>100 parts per
million.
ratings are based
upon how long it
takes the original
chemical to
completely break
up into stable
components when
it is released to the
environment. The
ratings are:
High - longer than
6 months to
completely break
up-
Moderate - breaks
up in less than 6
months, but longer
than 1 month.
Low - breaks up in
1 month or less.
Notes
1. In moderately hard water (120.0 - 150.0 mg/L as CaCO3), the toxicity of EDTA is mitigated about 30 times by Calcium (Ca) and Magnesium (Mg) ions.
2. In this chart, environmental persistence ratings are only applied to organic compounds.
3. The concern for inorganic phosphates is their high potential to increase the growth of freshwater green algae, whose eventual death will reduce the
available oxygen for aquatic life.
4. The ecological toxicity and persistence for this chemical are moderate and low-moderate; however, there is a high toxicity concern, and a moderate-high
persistence concern for the chemicals that the product eventually breaks down to in the environment.
5. The CAS numbers for the pinenes are:
7785-26-4,
7785-70-8, and
127-91-3
6. Due to the large number of chemicals used to make aqueous and semi-aqueous cleaners in each of these live categories, the individual chemicals could
not be listed.
7. The toxicity for the chemicals in these three categories ranges from low to high toxicity. For additional information on the toxicity rating lor chemicals in
these categories, please call the number for the TSCA Hotline at (202) 554-1404.
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Resources You Should Consult to
Help Make Your Decisions.
\Note. these are only a few sources; many other
good references exist]
* The Integrated Solvent Substitution Data
System (ISSDS), part of Enviro$en$e, a
multi-part World-Wide Web resource site
[http://es.inel.gov/ssds/ssds.html], which
provides solvents and alternatives
information, links to health and toxicity
information, material safety data sheets
(MSDSs), and more.
* The Solvents Alternative GuidE (SAGE) [on
the Control Technology Center bulletin
board, at (919) 541-5742 (via modem); also
part of ISSDS], a system that evaluates
your current cleaning operation and needs,
and identifies possible surface cleaning
alternative solvents and processes that best
suit operating and material requirements.
EPA TSCA Hotline ((202) 554-1404) for:
* Background documents explaining the
ecological toxicity and persistence ratings of
this guide.
* Answers to questions about how to use this
guide.
* Details about the human health effects of
listed chemicals and for chemicals that are
not on this list.
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