Ensuring safe drinking water is essential for public health. Emerging contaminants, which include pharmaceuticals, personal care products, and industrial chemicals, pose new challenges for water safety. Detecting and testing for these contaminants requires specific methods and awareness. As regulatory frameworks evolve and analytical technologies improve, water utilities, environmental scientists, and concerned homeowners must stay informed about the latest approaches to identifying and managing these pollutants.

What Are Emerging Contaminants?

Emerging contaminants, also known as contaminants of emerging concern (CECs), are chemicals or microorganisms that are not yet routinely monitored in drinking water but have the potential to cause adverse health or ecological effects. Unlike legacy pollutants such as lead or arsenic, these substances often have no established maximum contaminant levels (MCLs) under the Safe Drinking Water Act. They include a broad range of compounds:

  • Pharmaceuticals and personal care products (PPCPs) – antibiotics, hormones, painkillers, sunscreen ingredients, and fragrances
  • Endocrine-disrupting chemicals (EDCs) – bisphenol A (BPA), phthalates, and certain pesticides
  • Per- and polyfluoroalkyl substances (PFAS) – used in nonstick cookware, firefighting foams, and water-repellent fabrics
  • Microplastics – tiny plastic particles from packaging, synthetic textiles, and degraded waste
  • Industrial chemicals – 1,4-dioxane, perchlorate, and flame retardants
  • Antibiotic-resistant bacteria and genes – emerging biological threats from agricultural and medical runoff

Because these compounds are often present at extremely low concentrations (parts per trillion or parts per billion), they require highly sensitive analytical methods for detection. Their long-term health effects are still being studied, but early evidence links some to hormonal disruption, developmental problems, and increased cancer risk.

Sources and Pathways of Emerging Contaminants

Wastewater Treatment Plants

Conventional wastewater treatment processes are not designed to remove many emerging contaminants. Pharmaceuticals and personal care products excreted by humans pass through treatment plants and are discharged into rivers and lakes, which often serve as drinking water sources. Studies have detected antidepressants, antibiotics, and birth control hormones in treated effluent.

Agricultural and Urban Runoff

Pesticides, herbicides, and veterinary pharmaceuticals from farms can leach into groundwater or be carried by stormwater into surface waters. Urban runoff contributes microplastics, tire wear particles, and lawn chemicals. Land application of biosolids (treated sewage sludge) can also introduce PPCPs and PFAS into soils and eventually into water supplies.

Industrial Discharges

Manufacturing facilities may release solvents, plasticizers, and PFAS into waterways. For example, 1,4-dioxane is a byproduct of plastics and cosmetics production and is highly mobile in groundwater. Legacy contamination from firefighting training sites has created widespread PFAS plumes near airports and military bases.

Improper Disposal of Household Products

Flushing unused medications down the toilet or pouring chemicals down drains sends them directly to sewage systems. Landfills that are not properly lined can leach contaminants into groundwater. Even septic systems, common in rural areas, can release PPCPs and microplastics into nearby aquifers.

Health and Environmental Significance

The health impacts of chronic exposure to low-level mixtures of emerging contaminants are not fully understood, but laboratory studies and epidemiological research raise concerns. Endocrine disruptors can interfere with reproductive development and thyroid function. PFAS have been linked to reduced immune response, high cholesterol, and some cancers. Antibiotic resistance genes in water could undermine medical treatments. Microplastics may carry toxic additives and accumulate in tissues.

Environmental effects include altered sex ratios in fish, reduced biodiversity, and the accumulation of persistent chemicals in food webs. These risks have prompted agencies like the U.S. Environmental Protection Agency (EPA) and the World Health Organization (WHO) to develop health advisories and research priorities for CECs.

Signs That May Indicate Emerging Contaminants

Most emerging contaminants are invisible, tasteless, and odorless at trace levels. However, some indicators can prompt further investigation:

  • Unusual tastes or odors – earthy or musty smells may indicate algal toxins or certain industrial chemicals
  • Change in water clarity or color – discoloration could suggest industrial discharge or high organic load
  • Foaming or suds – detergents or surfactants in well water
  • Location risk – proximity to farms, landfills, airports, or industrial zones increases likelihood
  • Known local contamination events – news reports or public health notices about PFAS or other CECs

Because symptoms are often absent, regular testing is the only reliable way to detect emerging contaminants before they accumulate to concerning levels.

How to Test for Emerging Contaminants

Sample Collection Best Practices

Proper sampling is critical to avoid false negatives or cross-contamination. Follow these steps:

  1. Use sample containers provided by a certified laboratory – typically glass or high-density polyethylene (HDPE) with Teflon-lined caps.
  2. Collect samples from a cold water tap that has been flushed for 2–5 minutes to ensure representative water from the main supply.
  3. Avoid touching the inside of the container or cap. Wear disposable gloves if possible.
  4. Fill the container completely to minimize headspace (air above the water), which can cause volatilization of certain compounds.
  5. Keep samples on ice or refrigerated during transport and deliver to the lab within the specified holding time (usually 24–48 hours).
  6. For microplastics, use stainless steel or glass containers and avoid synthetic clothing that could shed fibers.

Always follow the laboratory's specific instructions, as methods vary by analyte.

Analytical Techniques Used by Certified Laboratories

Emerging contaminants require advanced instrumentation because of their low concentrations. Common methods include:

  • Liquid chromatography-tandem mass spectrometry (LC-MS/MS) – highly sensitive for nonvolatile and polar compounds such as pharmaceuticals, pesticides, and PFAS
  • Gas chromatography-mass spectrometry (GC-MS) – suitable for volatile and semi-volatile organic chemicals like flame retardants and phthalates
  • High-resolution mass spectrometry (HRMS) – used for suspect screening and non-targeted analysis to identify unknown contaminants
  • Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy – applied to microplastic identification and characterization
  • Enzyme-linked immunosorbent assay (ELISA) – a quicker, less expensive screening tool for specific compounds like atrazine or certain antibiotics

Most homeowners and small water systems will order test panels through a state-certified drinking water laboratory. Typical tests for PFAS, for example, cost between $200 and $600 and detect 14–18 individual compounds. For pharmaceuticals, a broader screen may exceed $1,000.

Interpreting Test Results

Because no federal MCLs exist for most emerging contaminants, interpretation requires context. Laboratories often report results alongside health advisory levels established by the EPA or state agencies. For instance, the EPA has proposed a maximum contaminant level for six PFAS compounds, and many states have set their own limits. An experienced water quality consultant or your local health department can help you understand what the numbers mean for your specific situation.

Key questions to ask:

  • Do any detected levels exceed state or federal health advisories?
  • Are there synergistic effects from multiple contaminants present?
  • What is the likely source of contamination, and can it be mitigated?
  • How often should retesting occur?

Advanced Treatment Technologies for Emerging Contaminants

If testing reveals elevated levels of CECs, standard treatment methods like chlorination and sand filtration are often insufficient. More advanced technologies are required:

Granular Activated Carbon (GAC)

GAC effectively adsorbs many organic contaminants, including PFAS, pesticides, and pharmaceuticals. However, its effectiveness depends on contact time, carbon type, and the specific compound. GAC filters must be replaced regularly to avoid breakthrough.

Reverse Osmosis (RO)

RO systems force water through a semipermeable membrane that rejects a wide range of contaminants, including some PFAS, pharmaceuticals, and microplastics. Point-of-use RO units under the kitchen sink can significantly reduce emerging contaminants but also remove beneficial minerals.

Ion Exchange Resins

Ion exchange is particularly effective for PFAS removal. Specialized resins can target perfluorinated compounds, and the process can be regenerated or disposed of after saturation.

Advanced Oxidation Processes (AOPs)

Combining ozone, hydrogen peroxide, or UV light creates hydroxyl radicals that break down even persistent organic compounds. AOPs are used at municipal water treatment plants and some large-scale in-home systems to degrade pharmaceuticals and endocrine disruptors.

Nanofiltration and Ultrafiltration

Membrane technologies with pore sizes between RO and conventional microfiltration can remove many CECs while retaining more natural minerals than RO. They are gaining traction for both central and residential treatment.

Homeowners should consult a water treatment professional to select a system certified by NSF International for the specific contaminants of concern.

Prevention and Mitigation Strategies

At the Household Level

  • Dispose of medications properly – take advantage of drug take-back programs offered by pharmacies and law enforcement; do not flush or pour down drains.
  • Use eco-friendly household products – choose cleaning agents, cosmetics, and pesticides that are free of phthalates, parabens, and nonylphenol ethoxylates.
  • Reduce microplastic shedding – wash synthetic clothing in a Guppyfriend bag or install a washing machine filter; avoid single-use plastics.
  • Maintain septic systems – pump tanks regularly and avoid using garbage disposals excessively, which can overload the system with organic matter and chemicals.

Community and Policy Approaches

  • Upgrade wastewater treatment – municipalities can invest in tertiary treatment with ozone or activated carbon to remove CECs before effluent is released.
  • Strengthen source water protection – enforce buffer zones around wells and surface water intakes, limit agricultural runoff through best management practices, and monitor upstream industrial discharges.
  • Support regulatory action – states and the EPA are developing new rules for PFAS, 1,4-dioxane, and other CECs. Public engagement can accelerate these efforts.
  • Advocate for extended producer responsibility – hold manufacturers accountable for the lifecycle of chemicals in their products, encouraging safer alternatives.

Staying Informed and Taking Action

The landscape of emerging contaminants evolves rapidly as analytical methods improve and new chemicals enter commerce. Consumers can stay up to date by:

  • Reviewing annual water quality reports from their utility (consumer confidence reports) for any mention of CEC monitoring.
  • Subscribing to alerts from EPA Water Research or their state environmental agency.
  • Participating in community water testing programs or citizen science initiatives that track PFAS or microplastics.
  • Engaging with local watershed groups to advocate for comprehensive monitoring and pollution prevention.

Testing for emerging contaminants is an investment in long-term health and environmental stewardship. While the science continues to develop, taking proactive steps to identify, treat, and prevent these pollutants can significantly reduce risks. By combining household vigilance, certified laboratory testing, and community action, we can work toward a future where drinking water remains safe and pure for generations to come.