Eating clams is like eating broken glass? How did the material that makes ships immortal end up on human dinner tables?

The story begins in the mid-20th century with the emergence of a material called fiberglass reinforced plastic (GRP). It consists of two parts: fine glass fibers as a skeleton and resin (usually polyester or epoxy) as filler.

 

This combination was lightweight, strong, and corrosion-resistant, quickly replacing wood and becoming the darling of the shipbuilding industry. In Brazil, with the rise of recreational sailing and fishing, thousands of fiberglass boats were launched. At the time, people only saw its advantages: it didn't rot like wood, nor did it rust like steel. However, the material's "durability" turned into a disaster decades later.

By the 21st century, the first fiberglass boats launched were reaching their retirement age. However, dealing with these behemoths was extremely expensive and technically difficult. Mixing glass and resin together is as difficult as reverting a perfectly made cake back to flour and eggs.

 

In Brazil, due to the lack of a proper recycling system and the high cost of formal scrapping, many boat owners have opted for a primitive method: drilling a hole in the hull and letting it disappear silently in a remote mangrove forest or bay. Statistics show that in Guanabara Bay alone, dozens, even hundreds, of these "zombie boats" have been sitting idle for extended periods, their hulls beginning to disintegrate under the combined effects of ultraviolet radiation and waves.

 

But this is only part of the pollution problem. Even vessels still in service create problems during maintenance. To prevent barnacles from attaching, the hulls are typically coated with antifouling paint containing heavy metals and bactericides.

 

When workers sand the hulls in preparation for repainting, or when the hulls naturally wear down in the water, dust containing fiberglass debris and alkyd resins falls like snowflakes onto the surface.

 

Bivalve mollusks are the "vacuum cleaners" of the ocean; they must constantly filter seawater to obtain nutrients. A single adult oyster can filter nearly 200 liters of water per day. They capture particulate matter in the water using cilia on their gills. These organisms cannot distinguish between phytoplankton and tiny glass fiber fragments, ingesting them all.

 

Dr. Corina Ciocan of the University of Brighton in the UK conducted a study in which she discovered an astonishing number of glass fibers in oysters from Chichester Harbour (an area with high yacht activity). During the winter, the peak season for ship maintenance, up to 11,220 glass fiber particles were found per kilogram of oyster meat.

 

While this groundbreaking study directly targeting glass fiber counts was conducted in the UK, the situation in Brazil may be even more serious. Researchers at the Federal University of São Paulo (UNIFESP) in Brazil discovered large amounts of alkyd polymers, a major component of ship paint, in bivalves in a coastal protected area. Since the surface paint has been ingested by the clams, the glass fibers that form the substrate are naturally not spared either.

 

Studies have shown that these sharp fibers can pierce the lining of the clam's digestive tract, triggering a severe inflammatory response. This leads to decreased clam health and stunted growth. Ironically, these clams often experience a "false sense of fullness" due to ingesting indigestible plastic and glass, ultimately suffering from malnutrition despite their "garbage" stores.

 

What does this mean for Brazilians?

 

It means that when someone orders a plate of delicious steamed clams with garlic, they might also be ordering a "miniature fiberglass meal." While it won't kill them, imagining tiny glass needles and paint chips filled with heavy metals traveling through your digestive system is certainly not a pleasant experience.

 

Research has found that these particles carry heavy metals such as lead, copper, and zinc, as well as chemicals like phthalates. Phthalates are widely believed to disrupt the human endocrine system. While most particles may be excreted after entering the body, residual particles may release these toxic additives, or the particles themselves may migrate, posing a long-term risk of chemical exposure to tissues.

 

Currently, this problem is becoming increasingly urgent. From the bustling industrial port of Paranagua to the theoretically pristine Rocas Atoll, researchers have detected anthropogenic particles originating from ships. Ocean currents and winds, like tireless deliverymen, transport these tiny pollutants to every corner.

 

As long as the dust from polishing the ship's hull continues to fall into the sea unchecked, the clams underwater will continue to devour it.