Detecting Water Pollution with Optical Biosensors: An Overview
Written on
Credit: This article draws from the scientific work “Optical Biosensors and Their Applications for the Detection of Water Pollutants” by Marcela Herrera-Domínguez et al. (Full citation and link available at the end of the article)
Access to clean drinking water is essential for survival, as humans can only last approximately three days without it. Alarmingly, around 1.2 billion individuals worldwide experience water scarcity, a situation exacerbated by environmental challenges like climate change and pollution.
Contaminated water poses severe risks, affecting ecosystems and wildlife. For instance, pollutants from sunscreen can harm marine life (see further reading: Beware: Our Sunscreen Can Affect And Kill Marine Animals). Even treated water can still harbor pollutants, leading to unintended consequences such as accelerated fish growth (see further reading: How Waste Water Can Make Fish Go Big). To tackle water pollution effectively, it’s vital to detect and quantify the contaminants present.
Optical biosensors represent a promising solution for identifying and measuring pollutants in water. These devices gauge chemical reactions between substances, with the frequency of these reactions indicating the concentration of pollutants: a higher reaction rate signifies a greater pollutant presence.
The benefits of using biosensors for pollution detection are numerous, including:
- Minimal sample preparation required prior to testing.
- Quick measurement times for pollutants.
- Detailed insights into pollutant behavior, concentration, and molecular interactions.
- High sensitivity, capable of detecting even low levels of contaminants.
- Versatility in analyzing various pollutant types.
- Precise measurements that can accurately identify the specific pollutants present.
The following pollutants can be identified using optical biosensors:
Pesticides
Optical biosensors can detect pesticides, which are chemicals used in agriculture to protect crops from harmful organisms. Unfortunately, these substances often leach into groundwater due to irrigation and rainfall (see further reading: How Lasers Can Reduce The Need For Pesticides).
Detection of pesticide contamination can be achieved through interferometry, where a light beam is split into two. One beam interacts with the pollutants, while the other remains unaltered. The difference between the two beams provides information on pesticide presence.
Pharmaceuticals
Pharmaceuticals, which can enter water systems through improper disposal or human excretion, are another type of pollutant that biosensors can identify. These chemicals can accumulate in the environment and pose risks to health, including contributing to antibiotic resistance.
Surface Plasmon Resonance methods can be employed to detect pharmaceutical pollution. In this technique, a light beam interacts with a metal layer on glass, leading to changes in the reflection angle when pharmaceuticals bind to the metal, indicating their presence.
Organic Compounds
Optical biosensors can also identify organic compounds, which are large molecules found in various products like plastics and fuels. A notable harmful organic compound is bisphenol A (BPA), prevalent in certain plastics.
BPA contamination can be detected through fluorescence, where fluorescent materials interact with pollutants, leading to detectable changes in brightness that correlate with pollutant concentration.
Microorganisms and Toxins
Microorganisms and their toxins can also be identified by optical biosensors, which are crucial for ensuring safe drinking water.
Detection can be accomplished using grating techniques, where light interactions with specific surface patterns reveal the presence of harmful microorganisms through changes in light behavior.
Heavy Metals
Heavy metals such as copper, mercury, lead, and cadmium are particularly hazardous due to their persistence in the environment and potential to cause serious health issues, including Parkinson’s disease (see further reading: How Heavy Metal Pollution Contributes to Parkinson’s Disease).
Detection of heavy metal pollution can utilize optical resonators, which trap and manipulate light particles, allowing for the measurement of changes in light frequencies that indicate heavy metal presence.
Conclusion
Optical biosensors serve as effective tools for detecting various water pollutants, including pesticides, pharmaceuticals, organic compounds, microorganisms, and heavy metals. Different detection methods such as interferometry, Surface Plasmon Resonance, fluorescence, grating, and optical resonators can be employed.
How We Can Take Action
Here are some practical steps to minimize water pollution:
- Limit the use of chemicals for household cleaning, opting for natural alternatives like vinegar.
- Unclog drains through physical removal instead of using chemical solutions.
- Choose organic pesticides over chemical ones.
- Properly dispose of medications by returning them to a pharmacy.
Which of these actions can you incorporate into your daily routine? Do you have additional suggestions for reducing water pollution? Your contributions could inspire others, so please share your thoughts in the comments!
Credit
This article is based on: Herrera-Domínguez, M., Morales-Luna, G., Mahlknecht, J., Cheng, Q., Aguilar-Hernández, I., & Ornelas-Soto, N. (2023). Optical Biosensors and Their Applications for the Detection of Water Pollutants. Biosensors, 13(3), 370.