Smartphone microscopic method for imaging and quantification of microplastics in drinking water

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Microplastic analysis in drinking water is difficult due to small particle sizes and low concentrations.
• Existing methods can be expensive and complex, limiting widespread application.
• Developing accessible tools for microplastic detection is crucial for water quality monitoring.

Purpose of the Study:

• To develop and validate a low-cost smartphone microscopic system for imaging and quantifying microplastics in drinking water.
• To assess the presence and characteristics of microplastics in commercial bottled and jar water samples.
• To provide an accessible alternative for preliminary microplastic screening.

Main Methods:

• Utilized a smartphone camera with a 4mm diameter sapphire ball lens for imaging.
• Employed zinc chloride (ZnCl2) solution for sample pre-concentration.
• Validated the method's performance using filtered distilled and deionized water, with spike recovery and limit of detection assessments.
• Analyzed commercial bottled and jar water samples.
• Confirmed particle composition using Fourier-transform infrared (FTIR) spectroscopy.

Main Results:

• The smartphone microscopic system effectively imaged microplastics down to 20 μm, comparable to commercial systems.
• Spike recovery was 55.6% ± 9.7% with a limit of detection of 34 particles/L in controlled water samples.
• Microplastics were detected in commercial bottled water (0-91 particles/L) and jar water (0-130 particles/L).
• Particles of diverse shapes and sizes were observed in both bottled and jar water.
• FTIR analysis confirmed that 97% of the collected particles were plastic.

Conclusions:

• The developed smartphone microscopic system is a cost-effective and user-friendly tool for preliminary microplastic analysis in drinking water.
• The presence of diverse microplastics in bottled and jar water highlights the need for continued monitoring and potential mitigation strategies.
• This technology can empower broader accessibility to microplastic detection, contributing to public health and environmental awareness.