Solutions sought for addressing emerging substances of concern
Multilateral regional and national co-operation is required for solving today’s complex water quality challenges
Chemicals are part of everyday life, and the chemicals sector contributes a sizable portion to the economy. However, if not properly managed, some chemicals may end up in the environment, posing a human health risk. The current water quality challenges confronting the world are unparalleled, as they are complex and dynamic in nature, calling for fundamental shifts in the way we use, manage and even think about water.
Recently, there has been increasing concern over the presence of so-called “emerging substances of concern” within the aquatic ecosystem. Emerging substances of concern can be defined as substances, both of chemical or biological nature, or of natural or synthetic origin, that have been detected in the environment, but which are currently not included in routine monitoring programmes and whose fate, behaviour and (eco)toxicological effects are not well understood. These substances can further be categorised as global organic contaminants; pharmaceuticals and personal care products; endocrine disrupting compounds (EDCS); nanoparticles; industrial chemicals (new and recently recognised); and biological metabolites and toxins, as well as emerging pathogens.
The presence of these substances in aquatic environmental systems such as wastewater, surface water, groundwater and drinking water presents a new water quality challenge and adds more pressure to the world’s water resources, with unknown long-term effects on human health and ecosystems. Thus, addressing water quality challenges due to the presence of emerging substances of concern in water requires a shift from the traditional and fragmented sectoral approach to water quality management to a more integrated and co-ordinated approach as part of one urban water cycle, ensuring that all water users are aware of their responsibility for the protection
of water resources and are accountable for the impacts.
One subset of these substances, namely endocrine disrupting chemicals (EDCS) have been known to interfere with hormone actions, thereby increasing the risk of adverse health outcomes, including cancer, reproductive impairment, cognitive deficits and obesity. Current consensus is that EDCS pose a significant long-term environmental risk to the wellbeing of both humans and wildlife.
These potentially harmful pollutants were the topic of discussion during one of the sessions at the 5th Water Research Commission (WRC) Symposium that took place virtually from 20 to 22 September. To date, thousands of chemicals have been identified as potential EDCS. In 2005, a Wrc-led co-ordinated programme on EDC research was launched. Since then, EDCS and other emerging substances of concern have been studied in a number of WRC projects commissioned as part of the Water Quality and Health Programme.
The main aim of the Symposium session was to share research accomplishments under this programme and to track progress towards informing policy- and decision-making on minimising human and environmental exposure to EDCS. Current Wrc-funded initiatives include the development of a knowledge hub on emerging substances of concern, tracking the occurrences, sources and levels of these substances and strengthening capacity for risk assessment (including the use of effect-based methods as a proxy) and management.
The sources of EDCS include personal and household care products, industrial, agricultural and pharmaceutical wastes, among others. Routine water quality monitoring for tracking the entry of EDCS into the aquatic environment, managing the risks thereof, including adoption of appropriate water treatment technologies and imposing and enforcement of related water quality regulations, has proven to be challenging
for most countries worldwide, including South Africa. This is because of the large numbers of contaminants that have been detected to date.
To put this into perspective, more than 100-million chemical substances are currently registered in the Chemical Abstracts Service (a division of the American Chemical Society) and about 4 000 new substances are registered every day. This number is expected to continue to increase exponentially, presenting a significant cost and analytical challenges for the monitoring and regulation of these substances in water resources.
Water resources are an important component of sustainable development, thus most problems related to water quantity and quality require co-ordinated national and regional solutions. In this regard, it is important that there is multilateral co-operation for the attainment of environmental management principles and developmental goals, as a means for solving complex water quality challenges due to the presence of EDCS.
Moreover, such solutions should also incorporate a wide range of social, ecological and economic factors in order to account for the roles and responsibilities of human activities on water quality management. Apart from having the right policies in place, active water quality surveillance is a fundamental tool in the management of freshwater resources.
In the developed world, forensic approaches are increasingly being applied as part of an early warning strategy for water quality changes, as means for chemical pollution control and to enforce compliance to environmental quality regulations. In South Africa, an integrated water quality management model has been adopted, but there is need to strengthen the implementation of this model, in order to give impetus to the national water quality monitoring programmes established under the National Water Act (Act 36 of 1998), as well as to balance the need for water to achieve
developmental needs and for maintaining a healthy environment.
Tracking the emergence of new pollutants into the environment requires the use of rapid and highly sensitive analytical technologies, stakeholders heard at the Symposium. Thus, improvements in laboratory analytical methods are necessary for the timeous and accurate identification of these substances, also aiding risk management. Additionally, there is a need to improve and harmonise methods for sampling and analysis for a number of emerging substances of concern, in order to be able to compare and extract meaningful information from analyses.
For example, methods for microplastics analysis are still at its infancy, requiring further research and harmonisation. As environmental risk cannot be meaningfully assessed for the vast majority of emerging substances of concern, there has been an increased research interest towards the use of effect-based methods (EBMS) complemented by chemical screening and/or impact modelling for water quality risk assessment and establishment of health-based targets for water quality for different uses.
The main goal of water quality risk assessment is protecting humans and ecological communities in the aquatic environment. Thus, adoption of EBMS as part of a risk-based approach may serve as an alternative method for assessing the cumulative risks from combined exposures to several stressors, including mixtures of emerging substances of concern.
Policymakers are advised to take a precautionary approach when dealing with the issue of potential EDCS. Scientific research is ongoing and will continue for many years into the future. We need stricter legislative control over these substances, and we need to start looking for safer alternatives to avert risks of serious or irreversible harm to humans and the environment.