You've probably heard about plastic in the ocean. Images of sea turtles tangled in six-pack rings have become environmental shorthand for waste gone wrong. But here's something more unsettling: plastic isn't just out there anymore—it's inside you. Studies now detect microplastics in human blood, breast milk, and even unborn babies.

This isn't just a health story. It's an economics story about costs we're only beginning to count. When pollution becomes part of our bodies, who pays? How do markets respond when the damage is invisible and the cleanup nearly impossible? The answers reveal a case study in environmental economics—and a warning about what happens when we ignore the price of convenience.

Microplastics are tiny plastic fragments smaller than five millimetres. They shed from synthetic clothing, break down from packaging, and flake off car tyres. We inhale them, drink them, and eat them daily. Recent research estimates the average person consumes about a credit card's worth of plastic every week.

Here's where economics enters the picture. Early studies link microplastic exposure to inflammation, hormone disruption, and potentially cardiovascular problems. If even a fraction of these health effects prove significant, we're looking at billions in healthcare costs that nobody budgeted for. Economists call this an externality—a cost created by one activity but paid by someone else entirely. Plastic manufacturers profit from production while healthcare systems absorb the consequences.

The challenge is attribution. Unlike smoking or lead exposure, we can't easily trace a heart condition to a specific plastic source. This makes liability murky and policy responses sluggish. But uncertainty about exact costs doesn't mean those costs are zero—it means we're accumulating debt we haven't yet measured.

Takeaway

When the costs of production fall on healthcare systems rather than producers, markets have no incentive to change. Externalities don't disappear because they're hard to measure—they just get paid by different people.

Commercial fisheries face a problem that's increasingly difficult to ignore. Fish and shellfish absorb microplastics from contaminated water, and those plastics concentrate as they move up the food chain. Studies have found plastic particles in species from sardines to tuna, from oysters to shrimp.

This creates real economic consequences. Seafood loses value when consumers worry about contamination. Some markets already see price premiums for fish from cleaner waters, while products from heavily polluted regions face growing consumer resistance. For fishing communities dependent on healthy ocean ecosystems, plastic pollution threatens both their product quality and their livelihoods.

Food security enters the equation too. Roughly three billion people depend on seafood as their primary protein source. When plastic contamination reduces the safety or perceived safety of fish, it doesn't just affect prices—it affects nutrition. The poorest communities, often most dependent on affordable seafood, bear disproportionate costs from pollution they didn't create.

Takeaway

Pollution doesn't respect market boundaries. When plastic enters marine ecosystems, it degrades a shared resource that billions depend on—turning everyone's problem into a tragedy of the commons with real nutritional and economic stakes.

Here's the brutal arithmetic of microplastic economics: stopping plastic before it spreads costs a tiny fraction of removing it afterward. Better waste management, improved product design, and filtration systems at key points can prevent microplastics from entering waterways. Once dispersed into oceans, soil, and air, collection becomes practically impossible.

This is the economic principle of marginal cost applied to pollution. The first dollar spent on prevention buys enormous results—catching plastic at a factory outflow or sewage treatment plant. The last dollar spent on cleanup buys almost nothing—trying to filter microscopic particles from open ocean water is prohibitively expensive and largely futile.

Yet our current economic system often inverts this logic. Producers face no requirement to prevent microplastic release, while society eventually bears cleanup and health costs. Some economists advocate for extended producer responsibility—policies that make manufacturers accountable for their products' full lifecycle. When companies pay for the pollution their products create, they suddenly find prevention very affordable indeed.

Takeaway

Prevention and remediation aren't equally viable options separated by time—they're fundamentally different economics. Once pollution disperses, affordable solutions vanish. Policy that waits for damage before acting isn't cautious; it's expensive.

Microplastics represent a textbook case of what happens when prices lie. Plastic products appear cheap because their true costs—healthcare burdens, fishery degradation, impossible cleanup—don't show up on receipts. We've been running a tab for decades without realising it.

The economics here aren't complicated, just inconvenient. We can pay a little now through prevention, or pay enormously later through consequences. The plastic in your blood is already evidence of which path we've chosen so far. The question is whether we're ready to recalculate.