1.4 Emerging contaminants and their impacts
2 min read•july 19, 2024
Emerging contaminants are newly recognized substances that pose potential risks to the environment and human health. These include , , endocrine disruptors, , and . They come from various sources like households, industries, and agriculture.
Managing emerging contaminants is challenging due to detection difficulties and limitations of conventional treatment methods. Advanced technologies are needed for effective removal, but they come with higher costs. Incomplete removal and formation of harmful byproducts during treatment are ongoing concerns.
Emerging Contaminants
Definition of emerging contaminants
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- Substances recently discovered or recognized as potential environmental or public health risks
- Not currently regulated or undergoing the process of establishing regulatory guidelines
- Examples include pharmaceuticals and personal care products (PPCPs) (antibiotics, hormones, painkillers, cosmetic ingredients), endocrine-disrupting compounds (EDCs) (BPA, phthalates, certain pesticides), microplastics (tiny plastic particles < 5 mm), and per- and polyfluoroalkyl substances (PFAS) (used in non-stick coatings, stain-resistant fabrics, firefighting foams)
Sources of emerging contaminants
- Domestic sources introduce emerging contaminants through human excretion of PPCPs and improper disposal of unused medications down the drain
- Industrial sources contribute via manufacturing processes that use or produce emerging contaminants and leaching from landfills containing industrial waste
- Agricultural sources add emerging contaminants through runoff from fields treated with pesticides and veterinary pharmaceuticals
- Pathways include direct release into sewer systems from households and industries, stormwater runoff carrying contaminants from surfaces into wastewater collection systems, and infiltration of contaminated groundwater into sewer lines
Impacts of emerging contaminants
- Environmental impacts involve accumulation in aquatic ecosystems, leading to adverse effects on aquatic life such as in fish and other organisms and developmental and reproductive issues in exposed wildlife
- and in the food chain result in higher concentrations of contaminants in top predators
- Human health impacts occur through exposure via drinking water, food, and direct contact with contaminated water
- Potential risks include endocrine disruption affecting hormone balance and development, antibiotic resistance due to exposure to low levels of antibiotics, and long-term effects of chronic exposure to mixtures of contaminants
Challenges in managing emerging contaminants
- Detection and monitoring challenges arise from low concentrations (parts per trillion or parts per billion) making detection difficult, lack of standardized analytical methods for many emerging contaminants, and a continuously evolving list of contaminants to monitor
- Removal challenges in wastewater treatment stem from conventional treatment processes not designed to remove emerging contaminants, with many contaminants persisting through primary and secondary treatment
- Advanced treatment technologies required for effective removal, such as , , , and , come with higher costs and energy requirements
- Incomplete removal may still result in the release of contaminants into the environment
- Formation of potentially harmful transformation products during treatment processes poses additional challenges
Key Terms to Review (23)
Activated Carbon Adsorption: Activated carbon adsorption is a process where contaminants in water adhere to the surface of activated carbon, effectively removing them from the water. This method is particularly useful for targeting organic compounds, including emerging contaminants and pharmaceuticals, making it an essential part of advanced wastewater treatment processes.
Advanced Oxidation Processes: Advanced oxidation processes (AOPs) are chemical treatment methods that involve the generation of highly reactive species, particularly hydroxyl radicals, to effectively decompose organic pollutants in water and wastewater. These processes address the limitations of conventional treatment methods, especially when dealing with emerging contaminants and micropollutants that are resistant to traditional techniques.
Bioaccumulation: Bioaccumulation refers to the process by which organisms accumulate substances, such as pollutants or toxins, from their environment faster than they can eliminate them. This phenomenon is crucial in understanding how contaminants, especially those found in wastewater, can build up in the tissues of living organisms over time, leading to harmful effects on ecosystems and human health.
Bioassays: Bioassays are experimental procedures that use living organisms or biological systems to assess the potency or effects of substances, such as contaminants or pharmaceuticals, on biological responses. These tests are crucial for understanding how emerging contaminants impact ecosystems and human health, as well as for evaluating the effectiveness of advanced treatment options in removing pharmaceutical compounds from wastewater.
Biomagnification: Biomagnification is the process where the concentration of toxic substances increases in the tissues of organisms as you move up the food chain. It occurs when predators consume prey that have accumulated these substances, leading to higher and more harmful concentrations in top predators. This phenomenon is especially concerning with emerging contaminants and pharmaceutical residues, as it highlights the potential for widespread ecological and health impacts due to human activities.
Degradation pathways: Degradation pathways refer to the series of biochemical and chemical processes that lead to the breakdown of contaminants, such as pharmaceuticals and other emerging pollutants, into simpler, less harmful compounds. Understanding these pathways is crucial for assessing the effectiveness of treatment methods and predicting the fate of these contaminants in the environment.
Drinking water standards: Drinking water standards are regulatory criteria established to ensure the safety and quality of water intended for human consumption. These standards are designed to protect public health by limiting the presence of harmful contaminants and ensuring that drinking water is safe, clean, and palatable. They play a critical role in guiding treatment processes and assessing the impact of emerging contaminants in water supplies, as well as in driving advancements in treatment technologies such as UV-based oxidation processes.
Emerging contaminants research program: The emerging contaminants research program focuses on the study of substances that are not commonly monitored in the environment but may pose significant risks to human health and ecosystems. These contaminants often include pharmaceuticals, personal care products, and industrial chemicals that enter water systems through various pathways. The program aims to assess the effects of these contaminants, develop detection methods, and explore treatment solutions to mitigate their impact on water quality and public health.
Endocrine disruption: Endocrine disruption refers to the interference of chemicals, often found in various environmental contaminants, with the hormonal systems of organisms. This disruption can lead to adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife. The presence of such chemicals in the environment raises concerns about their accumulation and potential impacts on ecosystems and human health.
EPA Guidelines: EPA guidelines refer to the set of regulations and recommendations established by the Environmental Protection Agency to protect human health and the environment from pollutants. These guidelines provide a framework for managing and reducing contaminants in water, including emerging pollutants and advanced treatment technologies.
Exposure Assessment: Exposure assessment is the process of estimating or measuring the intensity, frequency, and duration of human or ecological contact with environmental contaminants. This concept is critical for understanding how contaminants, including emerging pollutants and pharmaceuticals, may affect health and the environment. It combines information on contaminant sources, pathways of exposure, and populations at risk to determine the potential impacts on human health and ecosystems.
Liquid chromatography-mass spectrometry: Liquid chromatography-mass spectrometry (LC-MS) is an analytical technique combining the physical separation capabilities of liquid chromatography with the mass analysis capabilities of mass spectrometry. This powerful method allows for the identification and quantification of various compounds, including emerging contaminants and micropollutants in wastewater. Its high sensitivity and specificity make it a vital tool for assessing the presence and impact of pollutants, as well as for developing advanced technologies for their removal.
Membrane Filtration: Membrane filtration is a physical separation process that uses semi-permeable membranes to separate particles and contaminants from liquids. This technology is crucial in advanced wastewater treatment as it effectively removes suspended solids, microorganisms, and various dissolved substances, playing a significant role in addressing emerging contaminants and ensuring water quality.
Microplastics: Microplastics are tiny plastic particles less than 5 millimeters in size that originate from the breakdown of larger plastic debris or are manufactured as small particles for various applications. These small particles pose significant challenges in wastewater treatment processes, as they are often not effectively removed and can lead to environmental contamination, particularly in water systems.
National Water Quality Assessment: The National Water Quality Assessment (NWQA) is a comprehensive program aimed at evaluating the quality of surface and groundwater resources across the United States. This program is crucial for identifying trends in water quality, assessing the impact of various pollutants, including emerging contaminants, and guiding water management and policy decisions to protect public health and the environment.
Ozonation: Ozonation is a water treatment process that uses ozone gas (O₃) to oxidize and break down pollutants, including emerging contaminants and micropollutants. This powerful oxidative technique is effective in disinfecting water and improving overall water quality, which aligns with regulatory drivers and design considerations for advanced treatment processes.
Persistence: Persistence refers to the ability of a substance, particularly contaminants, to remain in the environment for an extended period without significant degradation or removal. This property is critical when assessing the long-term effects of pollutants, especially in water systems, as persistent substances can accumulate, posing risks to ecosystems and human health.
Personal Care Products: Personal care products are items used for personal hygiene, grooming, and enhancement of appearance, including cosmetics, shampoos, lotions, and deodorants. These products often contain a variety of chemicals that can contribute to environmental pollution when they are washed down the drain, leading to concerns about their impact on water quality and aquatic ecosystems.
PFAS: PFAS, or per- and polyfluoroalkyl substances, are a group of human-made chemicals that have been widely used in various industrial applications and consumer products since the 1940s. These substances are known for their ability to repel water and oil, making them valuable in products like non-stick cookware, water-resistant clothing, and firefighting foams. Due to their persistence in the environment and potential health risks, PFAS are recognized as emerging contaminants that pose significant impacts on water quality and human health.
Pharmaceuticals: Pharmaceuticals are chemical substances used for the diagnosis, treatment, or prevention of diseases and medical conditions in humans and animals. They have gained attention as emerging contaminants in water systems due to their persistence and potential harmful effects on ecosystems and human health when they enter wastewater treatment systems and natural water bodies.
Risk Communication: Risk communication refers to the process of conveying information about potential hazards and their associated risks to stakeholders, including the public, policymakers, and other relevant parties. It plays a crucial role in decision-making by providing clear, accurate, and timely information that helps individuals understand risks related to health, safety, and the environment, particularly in the context of emerging contaminants and their impacts. Effective risk communication fosters trust and empowers communities to make informed choices about managing risks.
Stakeholder involvement: Stakeholder involvement refers to the active engagement of individuals, groups, or organizations that have an interest or stake in a particular issue, project, or decision-making process. This concept is essential in understanding how decisions related to emerging contaminants are made, as it ensures that diverse perspectives are considered, and fosters collaboration among affected parties, which can lead to more effective and sustainable outcomes.
Toxicological Evaluation: Toxicological evaluation is the systematic assessment of the potential harmful effects of substances, particularly in relation to human health and the environment. This evaluation is crucial when considering emerging contaminants, as it helps determine their toxicity levels, exposure risks, and overall impacts on ecosystems and public health. By identifying harmful substances and their effects, toxicological evaluation aids in regulatory decision-making and risk management related to wastewater treatment processes.