Microplastics and microfibers in the Guajará Bay, Amazon delta: Potential sources and variability

Area of Science:

• Environmental Science
• Marine Biology
• Oceanography

Background:

• The Amazon River's role in microplastic transport to the ocean remains unclear.
• Urbanization along the Amazon delta poses a potential source of microplastic pollution.
• Guajará Bay is identified as a critical area for assessing microplastic distribution.

Purpose of the Study:

• To assess the distribution and abundance of microplastics (MPs) and microfibers (MFs) in the Amazon delta.
• To identify potential sources and transport pathways of MPs and MFs within Guajará Bay.
• To correlate microplastic pollution with urban proximity and hydrodynamic factors.

Main Methods:

• Surface water samples collected from six stations in Guajará Bay during dry and rainy seasons (2014-2015).
• Quantification of microplastic and microfiber abundance (particles·m⁻³).
• Identification of particle types, colors, and polymer composition.

Main Results:

• Microplastic and microfiber abundance ranged from 218 to 5529.98 particles·m⁻³.
• Higher concentrations were observed near the urbanized margin of the bay.
• Anthropogenic cellulose fibers constituted the majority (68.8%), with polyethylene terephthalate (52.9%) and polyamide (34.4%) as dominant polymers.

Conclusions:

• The urban nucleus of the Amazon delta is a significant source of microplastic and microfiber pollution.
• Local hydrodynamic conditions influence the distribution of microplastics in the bay.
• Findings underscore the need for managing urban waste to mitigate marine pollution from the Amazon.