The risks posed by a substance are determined by both its hazardous properties (potential to cause adverse human health or ecological effects) and the amount or extent of exposure to people or the environment.
When needed, the Government implements risk management measures under CEPA 1999 and other federal acts to help prevent or reduce potential harm.
The Government is concluding that the substances in this group do not present a risk to human health or to the environment at levels of exposure considered in the assessment. However, there may be a concern if exposures of some NSAs were to increase.
About these substances
The screening assessment focuses on 6 substances referred to collectively as the 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).
These 6 substances are further organized into a low solubility subgroup (DNNSA, BaDNNSA and CaDNNSA) and a high solubility subgroup (NaNSA, DNNDSA, CDINSA).
NaNSA, CaDNNSA and CDINSA were prioritized for assessment as they met categorization criteria under subsection 73(1) of CEPA or were considered a priority on the basis of other human health or ecological concerns. DNNSA, BaDNNSA, and DNNDSA were prioritized for assessment based upon the results of the identification of risk assessment priorities process in 2015.
These 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.
Human and ecological exposures
The screening assessment indicated that 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.
Substances in the NSAs Group 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, formulation of oil and gas products and formulation of fuels. 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.
Key health and ecological effects (hazard)
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 effects 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 low solubility NSAs and high solubility NSAs were considered separately, due to differences in their physical-chemical properties and hazard to aquatic organisms. Low solubility NSAs were found to have high hazard to aquatic organisms, while high solubility NSAs were found to have moderate hazard to aquatic organisms. Both low solubility and high solubility NSAs were found to have moderate hazard to sediment organisms and to soil organisms.
Consideration of subpopulations who may be more susceptible or highly exposed
There are groups of individuals within the Canadian population who, due to greater susceptibility or greater exposure, may be more vulnerable to experiencing adverse health effects from exposure to substances.
Certain subpopulations are routinely considered throughout the screening assessment process, such as infants, children, and people of reproductive age. For instance, age-specific exposures are routinely estimated and developmental and reproductive toxicity studies are evaluated for potential adverse health effects.
Risk assessment outcomes
Considering the available information, 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 the available information, it was determined that there is low risk of harm to the environment from DNNSA, BaDNNSA, CaDNNSA, DNNDSA, and CDINSA at levels of exposure considered in the assessment, however there may be a concern if exposures to low solubility NSAs were to increase.
Screening assessment conclusions
The Government concluded that NaNSA, DNNSA, BaDNNSA, CaDNNSA, DNNDSA, and CDINSA are not harmful to human health or to the environment at levels of exposure considered in the assessment.
Preventive action and risk reduction
Although NSAs are not considered to be harmful to the environment at exposure levels estimated at the time of the assessment, DNNSA, BaDNNSA and CaDNNSA are considered to have ecological effects of concern due to their toxicity to aquatic organisms. There may be a concern if exposure levels were to increase.
Therefore, the Government intends to apply the Significant New Activity (SNAc) provisions of CEPA 1999 to these 3 substances. The SNAc provisions would require that the Government be notified of proposed new activities related to the substances, and that the new activities be assessed before being undertaken.
Use the Substances Search tool to find substances that are referenced in certain legislative or regulatory instruments or on Government of Canada websites.
Information about SNAc provisions applied to substances, including new notices and orders, and those already published, can be found in the SNAc publications dataset.
Related resources
CaDNNSA 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.
