Microplastic ingestion in Otariids

Transportation of microplastics along the food chain is no surprise. Trophic transfer from prey to predators is a fairly common source of microplastics, especially in top predators. A recently published research by Perez-Venegas et al. (2020) evidenced the ingestion of microplastics in Otariids from the coast of Chile and Peru by analyzing their scats.

Fig. 1. Arctocephalus sp. 

As reported in the study, the occurrence of micro-fibres (ranging from 63 to 100%) was much bigger than fragments (1 to 14%). Higher concentrations in samples from the Juan Fernández Archipielago may be due to the influence of the South Pacific subtropical gyre, an area of high plastic debris concentration. The presence of these particles can potentially be harmful to these animals, although this requires further research.

Reference
Perez-Venegas, D.J., Toro-Valdivieso, C., Ayala, F., Brito, B., Iturra, L., Arriagada, M., Seguel, M., Barrios, C., Sepúlveda, M., Oliva, D., Cárdenas-Alayza, S., Urbina, M.A., Jorquera, A., Castro-Nallar, E., Galbán-Malagón, C., 2020. Monitoring the occurrence of microplastic ingestion in Otariids along the Peruvian and Chilean coasts. Mar. Pollut. Bull. 153, 110966. https://doi.org/10.1016/j.marpolbul.2020.110966

How much micro- and mesoplastics can seaweed retain?

During a microplastic sampling campaign in Lima, Perú, we noticed in an extremely polluted beach, seaweed inhabiting intertidal rock formations were retaining high amounts of micro- and mesoplastics (Fig. 1, 2).

Fig. 1. First photo of microplastics retained in seaweed in a sandy beach of Lima, Perú

Fig. 2. Second photo of microplastics retained in seaweed in a sandy beach of Lima, Perú

It is noticeable that MPs are trapped in seaweed formations, rather than rock surface. A question comes: How much MP and mesoplastic can seaweed retain under extreme pollution conditions? 

We are looking forward to do some research regarding these observations. 

Commercial bivalves contaminated with microplastics in Peru

The mussel Aulacomya atra, also known as "choro", is one highly consumed bivalve species of commercial importance. The second most consumed after the Peruvian scallop Argopecten purpuratus. A. atra is commonly served fresh and eaten as a whole, thus presenting a higher chance of microplastic ingestion. 

We investigated the abundance and characteristics of microplastics in A. atra from fishery markets in three Peruvian provinces: Huarmey, Lima and Pisco (Fig. 1). 

Fig.1 Map of the three Peruvian provinces. S1: Huarmey, S2: Lima and S3: Pisco

Results indicated that microplastics were ubiquitous in A. atra from fishery markets. Microplastics of different sizes, shapes and colors were found and recorded (Fig. 2).

Fig. 2 Microplastics found in A. atra. A: Red microbead, B: Blue fiber, C: White fragment, D: Green line, and E: White film. Scale bar indicated 1 mm.

This is the first evidence of microplastic contamination in A. atra. The presence of microplastics in the last step of the supply chain confirms that the Peruvian population are subject to microplastic intake through contaminated seafood. Further research must continue surveying markets and fishery markets aiming to contribute to the microplastic human intake estimation. 

This manuscript is currently under review by the Journal of Food Science and Technology, once it gets published, I will make sure to share the research entirely. Questions regarding this research, feel free to send me an email: gabriel.e.dltp@gmail.com 

Microplastic distribution in sandy beaches of Lima, Peru

In a research we conducted two years ago (and have been recently accepted in the Marine Pollution Bulletin), assessing larger microplastic (1-5 mm) abundance in the intertidal (ITZ) and supralittoral zone (SLZ) in four sandy beaches (Yuyos, Sombrillas, Agua Dulce and Pescadores) of Lima (Fig. 1), we found very strange results.

Fig. 1. Map showing the region and the sites selected in the coast of Lima. S1: Yuyos, S2: Sombrillas, S3: Agua Dulce, and S4: Pescadores. Black squares above the high tide line indicate the orientation of the transects from the supralittoral zone and below the transect from the intertidal zone.

The microplastic (MP) concentrations varied considerably but, in general terms, our main issue was finding larger amounts of MPs in the ITZ in the two most polluted beaches (See Fig. 2 for a reference of the magnitude). Trying to explain why was hard. Superficial current did not make much influence as we assessed a very small area (the four beaches were very close to each other. 

Fig. 2 Boxplot of the microplastic abundance (particles m-2) per beach and beach zone. SLZ: Supralitoral zone, and ITZ: Intertidal zone

Reduced tidal action was observed in Yuyos and Pescadores, as they were highly influenced by artificial structures, like intertidal breakwaters. Aguilera et al. (2016) revealed that these structures promote retention and accumulation of human derived litter, including the entrapment of floating debris. This is one factor to understand the lack of washed up microplastics in this two beaches.
However, the extremely high abundance in Sombrillas and Agua Dulce may be do to something else. Something we should highlight is that the vast majority of the overall microplastics found in the four beaches were foams (78.3%), which is another very unusual result, as literature report fibers or fragments as the most common microplastics in sandy beaches. Also, the majority of the foams did not show weathering conditions, like coloring and degrade. We concluded that the high abundance of foams (determined PS after FTIR analysis) was due to the disposal of styrofoam materials (cups, plates, and other stuff) around the beach by beachgoers, provided by many local food businesses within Sombrillas and Agua Dulce. During the summer season, recreational beaches, like Sombrillas and Agua Dulce are overcrowded with people who make an inappropriate disposable of these materials or just bury them in the sand. 

Our article is currently accepted but not yet published. Once it goes online, I will share it with whoever requests it on ResearchGate. 

References

Aguilera MA, Broitman BR, Thiel M (2016) Artificial breakwaters as garbage bins: Structural complexity enhances anthropogenic litter accumulation in marine intertidal habitats. Environ Pollut 214:737-747. doi:10.1016/j.envpol.2016.04.058