Juvenile sharks off Brazil's southeastern coast are absorbing cocaine from contaminated seawater and prey, exposing how narcotics and wastewater pollution are altering marine ecosystems.
Eric Ralls reports for Earth.com.
In short:
- Scientists at Brazil’s Oswaldo Cruz Institute found cocaine and its metabolite in every juvenile sharpnose shark they tested near the Port of Santos, a busy harbor known for high drug trafficking.
- Cocaine enters coastal waters through human waste, failing wastewater treatment, and smuggling operations, then accumulates in marine organisms, leading to biomagnification up the food chain.
- Research suggests the drug could disrupt shark development and sensory systems, similar to observed effects in zebrafish and European eels exposed to trace narcotics.
Why this matters:
Narcotics like cocaine are increasingly becoming a concerning environmental issue. Once flushed into the sea, these compounds don’t disappear. Instead, they move through water and wildlife, subtly damaging marine life and disrupting food webs. Unlike plastic or oil spills, pharmaceutical pollutants often go unnoticed, even as they impair reproduction, alter behavior, and stunt growth in fish and marine mammals. Brazil’s role as a cocaine transit hub makes its coastal waters especially vulnerable, but the problem isn’t isolated. Rivers and oceans worldwide are showing traces of human drug use, revealing how intimately connected urban life is with the natural world — and how little our infrastructure is prepared to keep those worlds separate.
Learn more: Bugs are full of our drugs—and they could be getting other critters hooked, too
