Naphthalene Sulfonic Acids and Salts (NSAs) Group - information sheet

Overview

The Government of Canada conducted a science-based evaluation, called a screening assessment, to address the potential for harm to Canadians and to the environment from 6 substances in the Naphthalene Sulfonic Acids and Salts (NSAs) Group.
Under the Canadian Environmental Protection Act, 1999 (CEPA 1999), the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people and the environment. A substance may have hazardous properties; however, the risk to human health or to the environment may be low depending upon the level of exposure.
- More information on assessing risk can be found in the Overview of Risk Assessment and related fact sheets, particularly on Types of Risk Assessment Documents and the Risk Assessment Toolbox.
The ecological hazard and exposure potentials for one of the substances in the NSAs Group, naphthalenesulfonic acid, sodium salt (NaNSA), were classified using the Ecological Risk Classification of Organic Substances (ERC) Approach.
As a result of the draft screening assessment, the Government is proposing that 6 substances in the NSAs Group are not harmful to human health or to the environment at levels of exposure considered in the assessment.

The screening assessment focuses on 6 of 7 substances referred to collectively as the Naphthalene Sulfonic Acids and Salts (NSAs) Group under the Chemicals Management Plan (CMP):
- Naphthalenesulfonic acid, sodium salt (NaNSA)
- Naphthalenesulfonic acid, dinonyl- (DNNSA)
- Naphthalenesulfonic acid, dinonyl-, barium salt (BaDNNSA)
- Naphthalenesulfonic acid, dinonyl-, calcium salt (CaDNNSA)
- Naphthalenedisulfonic acid, dinonyl- (DNNDSA), and
- Naphthalenesulfonic acid, bis(1-methylethyl)-, compd. with cyclohexanamine (1:1) (CDINSA).
The remaining substance, naphthalenesulfonic acid, butyl-, sodium salt (CAS RN 25638-17-9), was determined to be of low concern to both human health and the environment through other approaches. Conclusions for this substance are provided in the Screening Assessment for the Rapid Screening of Substances with Limited General Population Exposure.
DNNSA, BaDNNSA, and DNNDSA were considered a priority for assessment based upon the results of the identification of risk assessment priorities process in 2015.
The 6 substances are commercially produced and do not occur naturally in the environment.
According to information gathered by the Government, in Canada, these substances may be used in fuels, lubricants, oil and natural gas extraction, paints and coatings, rubber materials, and water treatment processes.

Canadians may be exposed to DNNSA, CaDNNSA and DNNDSA mainly through drinking water.
Canadians may also be exposed to CaDNNSA through the use of a lubricant product available to consumers.
Exposure of Canadians to NaNSA is not expected, and exposure to BaDNNSA and CDINSA is expected to be negligible, based on the results of the Rapid Screening of Substances with Limited General Population Exposure approach.
The ecological exposure of DNNSA, BaDNNSA, CaDNNSA, DNNDSA, and CDINSA was considered as a group, due to the potential for these substances to be used interchangeably in industrial applications.
- They have the potential to be released to the aquatic environment during lubricant oil blending, use of metal working fluids, formulation and industrial use of paints and coatings, and formulation of oil and gas products.
- They also have the potential to be released to the environment through the application of biosolids to land.
According to the information considered under the ERC Approach, NaNSA was identified as having low ecological exposure potential.

There were limited health effects (hazard) data for DNNSA, CaDNNSA and DNNDSA; therefore, a comparative approach using similar chemicals, called read-across, was used for assessing potential health effects.
- Using data available on similar substances, the critical effect for characterizing the risk to human health from exposure to these substances were considered to be effects on the kidneys and thyroid.
The health effects of NaNSA, BaDNNSA, and CDINSA, were not investigated in this screening assessment as Canadians are not expected to be exposed to NaNSA, and exposure to BaDNNSA and CDINSA are considered to be negligible.
According to information considered under the ERC Approach, NaNSA was identified as having a low ecological hazard potential.
The ecological hazard of DNNSA, BaDNNSA, CaDNNSA, DNNDSA, and CDINSA was considered as a group, due to similarities in their chemical structures and ecological effects.These substances were considered as having moderate hazard to aquatic organisms and low hazard to benthic and soil organisms.

Considering all information presented, the risk to human health is considered to be low for NaNSA, BaDNNSA and CDINSA.
Based upon a comparison of levels to which Canadians may be exposed to DNNSA, CaDNNSA, and DNNDSA, and the levels associated with health effects, the risk to human health for these substances is considered to be low.
NaNSA is considered unlikely to be causing ecological harm, based upon the outcome of the ERC Approach.
Considering all information presented, it was determined that there is low risk of harm to the environment from DNNSA, BaDNNSA, CaDNNSA, DNNDSA, and CDINSA.
The Government of Canada published the Draft Screening Assessment for the Naphthalene Sulfonic Acids and Salts Group on July 4, 2020. The public are invited to comment on the assessment during the 60-day public comment period ending on September 2, 2020.

As a result of the draft screening assessment, the Government is proposing that NaNSA, DNNSA, BaDNNSA, CaDNNSA, DNNDSA, and CDINSAare not harmful to human health or to the environment at levels of exposure considered in the assessment.

Some of these substances may be found in products available to consumers. Canadians should follow any safety warnings and directions related to the product and dispose of products responsibly.
The screening assessment for the NSAs Group focused on potential risks of exposure to the general population of Canada, rather than occupational exposure. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System. For information concerning workplace health and safety and what steps to take in the workplace, Canadians should consult their employer and/or the Occupational Health and Safety Regulator in their jurisdiction.

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