The citizen scientists' laboratory – Quantifying copper in drinking water

Jan E. Kath^1*Christian G. Strippel¹Vanessa van den Bogaert²Joachim Wirth³Katrin Sommer¹

• ¹Chair for Chemistry Education, Ruhr-University Bochum, Bochum, Germany
• ²Institute of Education, Leibniz University Hannover, Hannover, Germany
• ³Department of Research on Learning and Instruction, Ruhr-University Bochum, Bochum, Germany

Safely managed drinking water is of utmost importance. Citizen scientists have been successful in collecting water monitoring data worldwide. However, in these projects, usually test strips or colorimetric assays have been used. The implementation of laboratory methods within a citizen science project could confer both benefits and risks with regard to the data that is collected. This study, therefore, compared citizen scientists' data collected using either a colorimetric method or a spectrophotometric method. The citizen scientists' data (n = 456) were evaluated by comparing these data with reference data obtained in external laboratory analyses. Citizen scientists' colorimetric data were highly correlated and showed a moderate percentage agreement with the reference data (percentage agreement: 60 %, Spearman r = .671). The percentage agreement was, however, poor for drinking water samples that contained a larger amount of copper when the citizen scientists used a colorimetric method. Data of the same samples obtained by the citizen scientists with a spectrophotometric laboratory method were also compared with the reference data and showed a slightly higher percentage agreement and stronger correlation to the reference data (percentage agreement: 69 %, Spearman r = .727). The percentage agreement was consistent for samples that contained different amounts of copper when the citizen scientists used a spectrophotometric method. The data indicated that citizen science projects could improve data quality by involving citizen scientists in laboratory work.