There is a growing threat to the aquatic environment by contaminants of emerging concern (CEC). A CEC is understood as compounds and chemicals whose presence in the environment was not previously monitored or thought to be of significant threat to the quality of freshwater sources. They were not easily detectable in drinking water given the technology previously available. With current technologies, CECs – with the potential of having adverse effects on humans and the ecosystem – are increasingly being detected in surface water. Some CECs have been confirmed to have carcinogenic and mutagenic effects. CECs are, however, not currently monitored or regulated in drinking water. Some countries across the globe have been proactively monitoring the fate of CECs in the environment, while others are docile in their approach. To this end, while actions are dragging towards addressing CECs in Canada, efforts are ongoing in some other jurisdictions to address CECs. For instance, the State of California established the Science Advisory Panel to assess the potential of CEC threats in recycled water. CECs, having different but similar pathways through which they get into the water bodies, are difficult to remove using the conventional water and wastewater treatment processes. Hence, the need to proactively swing into action to address the prevalence of CECs in the aquatic environment.
Introduction of CEC into the environment
CECs are ubiquitous in water and wastewater streams. Some examples include pharmaceuticals, personal care products, microplastics, illicit drugs, per- & polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), and Bisphenol A (BPA). Pharmaceuticals, for instance, get into the water bodies from industrial pharmaceutical discharge. Pharmaceuticals also get into the water through excreted metabolites (from urine and faeces). The excreted metabolites enter the wastewater stream as sewage. As conventional wastewater treatment plants were not designed to treat/remove this class of contaminants, pharmaceuticals eventually get into the water bodies, and thus into drinking water. Similarly, other CECs such as PFAS get into the environment through several other industrial activities. Anthracene – a PAH – gets introduced into water bodies through wood preservative effluents, and effluents from the manufacture of pigments and dyes. BPA gets introduced into the environment through industrial effluents from the production of epoxy resins, beverage cans, and plastics. As with other classes of contaminants, industrial effluents are the major pathway for introducing CECs into our environment. CECs limits are, however, not defined in drinking water regulations.
Trends, challenges, and regulatory gaps in addressing CECs
Water samples from St. Lawrence River and its tributaries were analysed using current analytical technologies. Twenty-one CECs were detected in significant concentrations. For example, acetaminophen (500 ng/L), tetracycline (700 ng/L), triclosan (34 ng/L) and BPA (90 ng/L) were detected; pharmaceuticals are bioactive at these low concentrations . Significant PFAS concentrations were also detected in Lake Ontario, Lake Erie, and Detroit River. A majority of the CECs have endocrine disrupting effects. They can imitate and impair the natural functions of the endocrine system in humans. European Union research identified about 900 endocrine disrupting compounds (EDCs) with the potential of causing some major health problems, such as, infertility, challenged infant mental development, and changing sexual behavior in aquatic animals. Endocrine disrupting effects of BPA exposure in concentration of 1-1000 μg/L in humans and marine life have been reported. While bioaccumulation of antibiotics through contaminated water ingestion can lead to antibiotic resistance, other CECs such as PAHs have been confirmed to have teratogenic, mutagenic, and carcinogenic effects. In Canada, regulations and policies seem to be lagging in addressing these challenges . Findings revealed a dearth of data on the amount of CECs discharged into the environment, making it difficult to quantify the magnitude of CECs in our environment, and to assess the harm to humans and the ecosystem. The lack of standardized analytical methods to detect and classify CECs in wastewater discharge were also noted.
While several other countries have been making efforts to address CECs, Canada seems a bit laid back. The European Union established a list of priority contaminants in 2008 which is updated biennially. The list, for the first time in 2015, comprised some CECs such as pharmaceuticals and synthetic hormones. There is also a similar list in Canada – list of toxic substances which conspicuously excludes CECs such as pharmaceuticals and personal care products. In the U.S., California established the Science Advisory Panel in 2009 to provide guidance on the assessment of potential CEC threats in recycled water. A drinking water CEC program was also instituted by the Minnesota Department of Health (MDH) in 2010. The program investigates exposure pathways and health risks of CECs in drinking water. In Canada, the Federal Contaminated Sites Action Plan (FCSAP) only recommended that when dealing with contaminants for which no guideline currently exists, academia, and research institutions with expertise in this area should be consulted for guidance. While other jurisdictions have been acting to analyze and review CECs, Canada seems too slow to act.
Options towards addressing CECs
Deciding not to take proactive actions toward addressing the growing issue may make a larger population of Canadians susceptible to emerging drinking water challenges from CECs; the resultant effect of which could increase the pressure on our health system. Given the slow response so far in addressing the risk of CECs, and the actions that other jurisdictions have taken, there are several options the government could take.
- Industries should be mandated to give a full disclosure of the chemicals they use. To ensure sincerity of disclosure, regulatory oversight could come in handy. Periodic sampling of industrial wastewater effluents at source by the regulatory authorities could provide more information regarding the CECs being released into the environment. Regulatory standards for CECs and other contemporary contaminants should, however, be defined with consideration to quantity, toxicity, and concentration.
- To adequately address CECs, governments should encourage research institutions to be more involved, and continue to drive initiatives to create more awareness regarding CECs, as well as emerging and advanced technologies for their effective removal in water. Although, investment in environmental issues might be perceived as non-revenue generating and may discourage investment in advanced water treatment technologies to remove CECs; a cost analysis as to the overall health benefit, and the burden such investment would lift on the health sector would be more rewarding. In the face of emerging health concerns through exposure to CECs, improved water quality would reduce money expended on sustaining the health of Canadians.
- Regulations to ensure that heavy industrial polluters (CECs in particular) pre-treat their wastewater before discharge. This would encourage industry-research institutions partnership towards finding an efficient and cost-effective means of treatment. To facilitate this approach, governments must urgently examine the costs and barriers of pre-treating wastewater. The government could provide reliefs in terms of research funding to further aid industry-research institutions partnership, thereby reducing the potential cost implication on industries. Research institutions, in this case, would provide technical and objective solutions to arrest CECs.