Removal of Nutrients and Pesticides from Agricultural Runoff Using Microalgae and Cyanobacteria

Miguel Castellanos-Estupiñan,Samantha Bryan,Astrid Carrillo-Botello,Néstor Urbina-Suarez,Janet García-Martínez,Andrés Barajas-Solano,Dorance Becerra-Moreno,Antonio Zuorro,Germán López-Barrera,Linell Rozo-Granados

doi:10.3390/w14040558

Abstract

The use of pesticides in agriculture has ensured the production of different crops. However, pesticides have become an emerging public health problem for Latin American countries due to their excessive use, inadequate application, toxic characteristics, and minimal residue control. The current project evaluates the ability of two strains of algae (Chlorella and Scenedesmus sp.) and one cyanobacteria (Hapalosyphon sp.) to remove excess pesticides and other nutrients present in runoff water from rice production. Different concentrations of wastewater and carbon sources (Na2CO3 and NaHCO3) were evaluated. According to the results, all three strains can be grown in wastewater without dilution (100%), with a biomass concentration comparable to a synthetic medium. All three strains significantly reduced the concentration of NO3 and PO4 (95 and 85%, respectively), with no difference between Na2CO3 or NaHCO3. Finally, Chlorella sp. obtained the highest removal efficiency of the pesticide (Chlorpyrifos), followed by Scenedesmus and Hapalosyphon sp. (100, 75, and 50%, respectively). This work shows that it is possible to use this type of waste as an alternative source of nutrients to obtain biomass and metabolites of interest, such as lipids and carbohydrates, to produce biofuels.

Highlights

Introduction published maps and institutional affilEnsuring water availability and quality, sustainable agriculture, and food security are critical issues that require sustainable alternatives that positively impact the growth of societies [1]
The physicochemical analysis shows the initial characteristics present in the agricultural wastewater (Table 1); considering the study, it can be observed that the wastewater from the discharge of the irrigation canal presents a high concentration of pesticides
Due to its concentration of excess fertilizers, agricultural runoff is an exciting source of nutrients for algal biomass production; different pesticides can reduce the growth capacity of algal strains

Summary

Introduction

Introduction published maps and institutional affilEnsuring water availability and quality, sustainable agriculture, and food security are critical issues that require sustainable alternatives that positively impact the growth of societies [1]. Pesticides are one of the most important agricultural inputs that guarantee quality and efficiency in crop production Due to their excessive use, inadequate application, toxic characteristics, and minimal residue control, pesticides have become an emerging problem of public health, water pollution, and environmental contamination in general [2]. Agricultural sectors such as the rice industry use large amounts of water and agrochemicals for their crops that can be transported through surface runoff, leaching into the soil and evaporating into the atmosphere, contaminating bodies of surface or groundwater, food, and the air we breathe [3].

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