Validating smartphone-based water quality monitoring for rapid environmental assessment

ABSTRACT The use of smartphones in assisting with water quality measurement enables us not only to collect quantitative environmental information but also to use smartphones as an environmental education and management tool. In this study, we evaluated the performance of a smartphone-based water quality monitoring method, known as the SMART PACKTEST, for environmental assessments. Specifically, we measured nitrogen parameters (ammonium-nitrogen (NH4-N), nitrite-nitrogen (NO2-N), and nitrate-nitrogen (NO3-N)) using the SMART PACKTEST with an iPhone 12 Pro Max and compared the results to those obtained using the DIGITAL PACKTEST, which uses a simplified portable absorption spectrophotometer. The water samples analyzed were collected from the Komaba-ike Pond at the University of Tokyo. The SMART PACKTEST tended to overestimate NH4-N and NO3-N concentrations by 1.5 to 2.6 times, respectively. However, the results obtained by the two methods showed good agreement, with the pseudo coefficients of determination being 0.96–0.98. This suggests that the SMART PACKTEST could be used for preliminary investigations to determine overall spatial/temporal water quality trends in the target area rather than for collecting accurate data. Further research is needed to confirm the applicability of this smartphone-based water quality monitoring method, particularly in developing regions with diverse water conditions.