IBPS RRB PO Mains 10 Sep 2023 Paper

Question Numbers: 144-148
Directions: Read the given passage carefully to answer the following questions. Each question will have five alternatives as its answer. Choose the correct option as your answer.
A recent study conducted by scientists at Columbia University in New York has uncovered alarming levels of micro- and nano-plastics in bottled water. Published on January 8, 2024, in Proceedings of the National Academy of Sciences, the research indicates that a litre of bottled water may contain over one lakh particles of these tiny plastic fragments, with 90% classified as nanoplastics. The findings, challenging previous estimates, suggest a significantly higher concentration of these minuscule plastic particles than initially believed. The scientists aimed to bridge the knowledge gap in nanoplastic analysis, utilizing a custom hyperspectral stimulated Raman scattering (SRS) imaging platform to profile individual plastic particles.
Analyzing nanoplastics poses challenges due to their size and the limitations of available diagnostic techniques. In response, the researchers employed a custom hyperspectral SRS imaging platform in their experiment. This platform captured multiple images of molecules at different wavelengths, enabling a comprehensive understanding of the object's composition. SRS microscopy, utilizing the Raman effect, involved beaming light at specific frequencies to induce inelastic scattering, providing detailed information about the chemical makeup of plastic particles. An automated algorithm, developed by the research team, processed data from the SRS platform to identify plastics. The scientists validated the setup's efficiency using bottled water as a model system to detect micro- and nano-plastics.
The investigation unveiled approximately 2.4 lakh micro- and nano-plastic particles per litre of bottled water, challenging previous estimations focusing on larger microplastics. The study's magnitude suggests that experts may have underestimated microplastic concentrations in bottled water. Notably, the newly detected nanoplastic fraction constitutes around 90% of the total population of plastic particles, which were previously invisible under conventional imaging. The study's implications extend beyond concentration levels; it also revealed the presence of particles not conforming to existing standards, suggesting a broader range of particulate inhabitants in bottled water. The research highlights the pressing issue of plastic pollution at the nanometer level and the urgent need for more accurate analysis methods.