Why Drugs and Other Pharmaceuticals Are Found in Our Water
Many people assume that once wastewater enters a treatment plant, any chemical or medicinal residue is completely removed. However, most municipal wastewater treatment facilities were not designed to filter out the complex molecular structures of pharmaceutical compounds. As a result, small but detectable amounts of prescription and over-the-counter medications, hormones, and other personal care products can pass through treatment and enter rivers, lakes, and, eventually, our drinking water supplies.
There are several pathways through which pharmaceuticals enter the water system:
- Human Excretion: When a person takes a medication, their body absorbs a portion of it, and the rest is excreted through urine and feces. This makes its way into the sewage system, which is not designed to remove these persistent compounds.
- Improper Disposal: Historically, and still today, many people flush expired or unused medications down the toilet. This sends the drugs directly into the wastewater stream.
- Agricultural Runoff: Antibiotics and hormones used in livestock and other agribusiness can enter surface water and groundwater through runoff from fields and animal-feeding operations.
- Hospital and Industrial Waste: While regulated, residue from hospital and pharmaceutical manufacturing facilities can also contribute to the overall load of micropollutants in water.
The Limitations of Conventional Water Treatment
Conventional water treatment processes, which typically involve coagulation, sedimentation, and chlorination, are effective at removing pathogens and larger particles. However, they are largely ineffective against the tiny, dissolved molecules of pharmaceutical residue. Some studies show that standard treatment may only reduce these contaminants by about 50 percent. This leaves a significant portion to pass through and potentially reach consumers' taps.
For most individuals, the levels of pharmaceuticals found in drinking water are measured in nanograms per liter, or parts per trillion, and the World Health Organization suggests that appreciable adverse impacts are unlikely at these concentrations. However, the long-term effects of chronic exposure to a mixture of different compounds are not fully understood, leading many to seek more advanced filtration options.
Advanced Filtration Methods That Can Be Filtered Out of Water
For those who want to ensure their drinking water is as free of pharmaceuticals as possible, several advanced filtration methods offer high removal rates. These are typically point-of-use systems installed under a kitchen sink or in a specific location for drinking water.
Reverse Osmosis (RO)
Reverse osmosis is one of the most effective methods for removing pharmaceuticals and other trace contaminants. It works by forcing water through a semi-permeable membrane that has pores small enough to block particles at the molecular level. RO systems can achieve removal rates of 99% or higher for many pharmaceutical compounds. They are often paired with activated carbon filters to enhance performance.
Activated Carbon Filtration
Activated carbon (AC) filters, especially high-quality activated carbon block systems, use a process called adsorption to trap chemicals and organic compounds. The highly porous nature of the carbon creates a large surface area for contaminants to bind to. While effective, the removal rate can vary depending on the specific drug and the filter's quality. Combining activated carbon with other methods, like RO, provides the most comprehensive protection.
Nanofiltration
Nanofiltration (NF) is similar to reverse osmosis but uses a slightly larger pore size. It is highly effective at removing larger organic molecules, including many pharmaceuticals, while allowing beneficial minerals to pass through. NF systems also boast high removal efficiencies, with some studies showing rates over 95% for certain compounds.
Ozonation
Ozonation is a powerful oxidizing process that can be used at the municipal level or in some advanced home systems. It breaks down complex organic molecules, including pharmaceuticals, into simpler, non-toxic compounds. After treatment, the ozone naturally decomposes into oxygen, leaving no harmful by-products.
Comparison of Filtration Methods
| Filtration Method | Mechanism | Effectiveness Against Drugs | Typical Use | Advantages | Disadvantages |
|---|---|---|---|---|---|
| Reverse Osmosis (RO) | Uses a semi-permeable membrane to block particles at the molecular level. | Excellent (>99% for many compounds). | Point-of-use (e.g., under-sink). | High removal efficiency, removes a wide range of contaminants. | Produces some wastewater, removes beneficial minerals, slow flow rate. |
| Activated Carbon (AC) | Adsorption; porous carbon surface traps contaminants. | Good, but effectiveness varies depending on the compound and filter type. | Point-of-use (pitcher, faucet mount, under-sink). | Cost-effective, improves taste and odor. | Not effective for all drugs, filters require regular replacement. |
| Nanofiltration (NF) | Membrane filtration with slightly larger pores than RO. | Excellent (>95% for many organic molecules). | Point-of-use or whole-house. | High removal efficiency, retains beneficial minerals. | Can be more expensive than AC, may have a slower flow rate than standard filters. |
| Ozonation | Strong oxidation breaks down organic compounds. | Excellent (>99% at treatment plants). | Municipal wastewater treatment or advanced home systems. | Highly effective, leaves no harmful byproducts. | Not commonly found in simple home filtration setups. |
| Distillation | Boiling water and condensing the steam to leave contaminants behind. | Excellent, removes many types of contaminants. | Point-of-use. | Removes dissolved solids, biological and many chemical contaminants. | Slow process, high energy consumption, can remove beneficial minerals. |
Proper Disposal of Medications: A Crucial First Step
While advanced home filtration is an effective solution for cleaning drinking water, it is not the only one. The U.S. Environmental Protection Agency (EPA) and other organizations emphasize the importance of proper medication disposal as a key strategy for reducing micropollutants in the water supply.
Drug take-back programs are the safest and most recommended way to dispose of unwanted or expired medications. These programs are often available at pharmacies, police stations, and specific drug take-back events. The collected medications are typically incinerated, which safely destroys the chemical compounds and prevents them from entering the environment.
Conclusion: Taking Control of Your Water
For those concerned about the presence of pharmaceuticals and other micropollutants in their drinking water, effective solutions are available. While conventional municipal treatment is not designed to remove these trace contaminants, advanced point-of-use filters like reverse osmosis and high-quality activated carbon systems can provide excellent removal rates. Combining this personal protection with proper medication disposal practices helps address the problem at its source. By staying informed and utilizing the right technologies, individuals can take proactive steps to ensure their water is as clean and safe as possible. For more information on environmental contamination and water quality, consider visiting the U.S. Environmental Protection Agency website.
