Release of Microplastics from Urban Wastewater Treatment Plants to Aquatic Ecosystems in Acapulco, Mexico

Abstract

Contamination by microplastics (MP) in aquatic ecosystems is largely due to the release of millions of these particles from treated effluents from Wastewater Treatment Plants (WWTP). Due to the lack of policies and regulations that establish criteria for the control and elimination of MP from WWTP effluents, this research evaluated the presence of MP for particle sizes of 38 and 150 µm in influents and effluents from three WWTP in the port of Acapulco, Mexico. Using optical microscopy and Fourier transform infrared spectroscopy (FTIR) techniques, the MP detected were polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) and polyvinyl chloride (PVC). MP removal efficiencies of 82.5 to 98.7% (38 µm) and 86.8 to 97.5% (150µm) were obtained; the MP average daily emissions to the receiving bodies of these three WWTPs were in the ranges of 9.5 x 106 - 4.70 x 108 particles and the annual emissions in the range of 3.05 x 109 - 1.72 x 1011 particles. This work reveals the urgency of implementing regulatory policies to avoid the continuous emission of MP to aquatic ecosystems from WWTPs in Acapulco, Mexico.