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Presence of microplastics in two common dried marine fish species from Bangladesh

Microplastics pollution of aquatic environments is a global concern: in 2010, about 275 million tons of plastic products were manufactured throughout the world and significant portions of them ended up in marine environments. New research undertaken by DFM researchers and colleagues at Bangladesh Agricultural University confirms the presence of microplastics in two popular species of dried fish sold in Bangladesh: Bombay duck and ribbon fish.

Microplastics are carried into the Bay of Bengal by three major riverine systems, which carry contaminants from hundreds of rivers originating in Bangladesh and neighbouring countries. These plastics are also introduced through the breakdown of fishing lines and nets that have been lost at sea, which are driven to shallow coastal waters through ocean currents. Improper disposal of plastic waste along the popular tourist beaches of Cox’s Bazar and Kuakata also contributes to pollution in the Bay of Bengal.

The identification of microplastics in dried Bombay duck and ribbon fish is highly troubling. These fish products are typically consumed whole, causing potentially toxic microplastics to enter the bodies of human consumers and to accumulate in their organs.

Millions of people in Bangladesh regularly consume dried fish, and the country is producing increasing quantities of plastics. Yet the effects on many millions of consumers of regularly ingesting microplastics with dried fish are unknown. Consumers in Bangladesh are largely unaware of the possible dangers, and the government has not established a system for monitoring microplastics in food products.

In light of the high levels of microplastics contamination identified in the present study, the authors recommend that the relevant ministries and government departments work together to identify long-term solutions to the potentially grave risks posed by the increasing presence of microplastics in dried fish and other food products.

Microscopic images of selected microplastics: a, b & c – fibers; d, e & f – fragments; g, h & i – films; j – microbeads; k – pellets; and l – foams.

Highlights

  • Microplastics (MP) were identified in the two most common marine dried fish products in Bangladesh.
  • High levels of MP were found in all samples of both fish species from two locations.
  • Fibers were the most common type of MP identified.
  • ATR-FTIR analysis of dried fish samples revealed polymer types of polyethylene, polystyrene and polyamide.
  • MP in dried fish may be transferred to the human body through consumption, with unknown health effects.

Abstract

We examined microplastics (MP) in two commercially important dried fish, Bombay duck (Harpadon nehereus) and ribbon fish (Trichiurus lepturus), collected from two sites on the Bay of Bengal (Cox’s Bazar and Kuakata). The number of MP found in dried Bombay duck and ribbon fish from Kuakata was significantly higher (41.33 g−1 and 46.00 g−1, respectively) than the MP present in samples collected from Cox’s Bazar (28.54 g−1 and 34.17 g−1, respectively). Fibers were the most common type of MP identified in all samples (41–64%), followed by fragments (22–34%), microbeads (9–16%), films (3–4%), foams (1–4%), and pellets (0–2%). ATR-FTIR analysis revealed three different types of MP polymer – polyethylene (35–45%), polystyrene (20–30%) and polyamide (30–45%) in the dried fish samples. The study confirms the presence of high MP loads in dried fish from the Bay of Bengal, with high potential of trophic transfer of MP to the human body.

Citation

Hasan, Jabed, SM Majharul Islam, Md Samsul Alam, Derek Johnson, Ben Belton, Mostafa Ali Reza Hossain, and Md Shahjahan. 2022. “Presence of Microplastics in Two Common Dried Marine Fish Species from Bangladesh.” Marine Pollution Bulletin 176: 113430. https://doi.org/10.1016/j.marpolbul.2022.113430