PLASTIC PARTICLES
1. Context
A litre of bottled water can contain more than one lakh particles of micro- and nano-plastics, with 90% of those being the latter, a new study has reported. Nanoplastics are minute, with dimensions ranging from 1 nanometre to 1 micrometre. The new findings indicate bottled water contains a much greater concentration of of these minuscule plastics particles than previously expected.
2. How was the study conducted?
- Nanoplastics pose a challenge for analysis primarily due to their small size and the limitations of existing diagnostic methods in detecting them. In an effort to overcome these hurdles, the researchers conducted an experiment employing a specialized hyperspectral stimulated Raman scattering (SRS) imaging platform.
- This setup enabled the acquisition of multiple images of molecular structures at various wavelengths, providing the scientists with a comprehensive view to decipher the object's composition.
- SRS microscopy, utilizing the Raman effect or Raman scattering, involves directing light of a specific frequency at a group of atoms or molecules.
- These entities absorb and scatter some of the energy in different directions, constituting inelastic scattering.
- The research team utilized the SRS imaging platform in conjunction with a custom algorithm designed to identify plastics.
- This algorithm extracted intricate details, specifically at the single-particle level, regarding the chemical composition from the data generated by the SRS platform.
- Upon validating that this integrated apparatus could rapidly and accurately detect plastic particles, the researchers applied it to investigate micro- and nano-plastics using bottled water as a model system
3.Findings of the report
- The investigation disclosed the existence of approximately 240,000 micro- and nano-plastic particles per liter of bottled water, with a margin of error of 130,000. Drawing from the substantial scale of these findings, significantly surpassing previous reports focused solely on larger microplastics, the researchers suggested that experts might have been underestimating the concentration of microplastics in bottled water.
- In terms of assessing human exposure, these values are considerably higher than those currently documented in the literature, primarily due to the newly identified nanoplastic fraction of plastic particulate.
- These minute particles, previously unseen through conventional imaging, constitute approximately 90% of the total population of detected plastic particles. The remaining 10%, identified as microplastics, exhibit a concentration of around 30,000 particles per liter, predominantly below 2 micrometers in size.
- Larger particles (2 micrometers), more easily discernible under regular optical microscopy, align with reported microplastic analyses, depending on detection limits determined by distinct technologies
- Traditional single-particle chemical imaging methods like Fourier transform infrared spectroscopy and Raman microscopy face limitations in instrumental resolution and detection sensitivity, restricting their capacity to explore the chemical composition of materials beyond the microscopic scale.
- Meanwhile, advanced techniques capable of tracking individual particles such as atoms and molecules, like electron microscopy and atomic force microscopy, lack the ability to distinguish between different compositions, preventing unique material identification
4.Which plastics are in the water?
- The algorithm employed by the research team to detect the presence of plastics in bottled water could identify various types, including polyamide 66, polypropylene (PP), polyethylene, polymethyl methacrylate, polyvinyl chloride (PVC), polystyrene, and polyethylene terephthalate (PET).
- The study confirmed the breakdown of plastic content in real-world water samples beyond the micrometer scale. Notably, the research team utilized the SRS platform, revealing a 'hidden world' of even smaller plastic particles that conventional imaging techniques had overlooked.
- The researchers also noted a complex relationship among the compositions, shapes, and sizes of plastic particles when counting them in the model system. For instance, polystyrene particles were found to be approximately 100-200 nanometers in size, while PET particles measured around 1-2 micrometers.
- According to the researchers, this discrepancy "explains why PET is a more significant component when measuring [the particles] in mass, while polystyrene clearly dominates when counting the number of particles."
- The publication of this study coincides with a critical time when plastic pollution has become a defining concern, with microplastics discovered in diverse ecosystems, ranging from ocean trenches to the summits of Himalayan mountains.
- Additionally, studies have indicated that plastic items can degrade into sub-micrometer pieces, enabling them to breach biological barriers and enter various parts of living beings' bodies
5. Nano Particles
- Nano particles refer to extremely small particles with dimensions typically in the nanometer range, which is on the scale of 1 to 100 nanometers. These particles can be composed of various materials, including metals, metal oxides, polymers, or carbon-based substances.
- Due to their minuscule size, nano particles often exhibit unique physical, chemical, and biological properties that differ from their bulk counterparts.
- Nano particles have gained significant attention in various scientific and technological fields due to their potential applications in areas such as medicine, electronics, materials science, and environmental science.
- In medicine, for example, nano particles can be designed for targeted drug delivery to specific cells or tissues. In electronics, they may be used to enhance the performance of electronic devices. In materials science, nano particles can be incorporated into materials to impart specific properties.
- However, the use of nano particles has also raised concerns, particularly in terms of environmental and health impacts.
- The small size of these particles allows them to interact with biological systems in ways that larger particles might not, and there is ongoing research to understand the potential risks associated with their use and exposure.
- It's important to note that the term "nano particles" is quite broad, encompassing a wide range of materials and applications across different scientific disciplines
6. Way Forward
A study has confirmed the fragmentation of the plastic content of real-world water samples beyond the micrometre scale. Its findings are distinguished by the research team’s use of a technique that could reveal a ‘hidden world’ of even smaller plastic particles that have eluded conventional imaging methods
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Previous Year Questions
1.Consider the following statements: (UPSC CSE 2022)
1. Other than those made by humans, nanoparticles do not exist in nature.
2. Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.
3. Nanoparticles of same commercial products which enter the environment are unsafe for humans.
Which of the statements given above is/are correct?
A. 1 Only
B. 3 Only
C. 1 and 2
D. 2 and 3
Answer (D)
2.There is some concern regarding the nanoparticles of some chemical elements that are used by the industry in the manufacture of various products. Why? (UPSC CSE 2014)
1. They can accumulate in the environment, and contaminate water and soil.
2. They can enter the food chains.
3. They can trigger the production of free radicals.
Select the correct answer using the code given below.
A.1 and 2 only
B.3 only
C.1 and 3 only
D.1, 2 and 3
Answer (D)
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Source: The Hindu
