A cost-effective algae-based biosensor for water quality analysis: development and testing in collaboration with peasant communities

PRUDKIN SILVA, C*; LANZAROTTI, E *; ÁLVAREZ, L *; VALLERGA, MB; FACTOROVICH, M; MORZAN, U; GÓMEZ, M; GONZÁLEZ, N; ACOSTA, Y.; CARRIZO, F; CARRIZO, E; GALEANO, S; LAGORIO, MG; JUÁREZ, AB; ITHURALDE, RAÚL ESTEBAN*; ROMERO, JM*; URDAMPILLETA, C* (*EQUAL CONTRIBUTION)

Environmental Technology & Innovation

Elsevier

Año: 2021 vol. 22

2352-1864

New anthropic potentially harmful compounds are released into the environmenteveryday. In this context, broad range bioassays have emerged providing economicallyviable and widely applicable alternatives due to their ability to detect the cumulativetoxicity of mixtures of both known and unknown chemicals in a sample, thus allowingdirect information about water quality.Here we present a low-cost, wide-range algae-based biosensor that is easy toassemble and operate by untrained users and provides direct readings. It wasdeveloped as a request of a peasant social movement organization to assess thetoxicity of drinking water in rural communities affected by pesticide spraying.Two fresh water algae strains, Scenedesmus acutus and Pseudokirchneriellasubcapitata , were immobilized in alginate beads and tested as bioindicators. Afterincubation with different pollutants for five days, naked eye analysis by severalobservers proved to be a successful method to survey algae ́s growth and establishthe detection limits. Best detection limits were 10 ppm for technical-grade acidglyphosate, 15 ppm for glyphosate-based formulation, 50 ppb for atrazine formulation,7.5 ppm for copper and 250 ppb for chromium. Absorbance measurements upon algaeresuspension validated these results.Finally, tThe developed device was successfullytested in participatory workshops conducted at rural communities. Children, adults andelders with no scientific training were able to build the sensor and interpret the results,evaluating the quality of rain and well water used in their communities.