Toxic Hitchhikers, Gym Pollution, and the World's Greatest Migrants

The Point by Modern Sciences - September 3, 2025

Author

Don Smith
September 03, 2025

By The Modern Sciences Team

September 3, 2025

Happy Wednesday, Cultivators of Curiosity!


Welcome to the 35th volume of The Point by Modern Sciences. For this milestone edition, we are exploring the unseen forces and hidden connections that shape our health and our planet. From risks that emerge at the microscopic level to ecological marvels that fly right past our eyes, this issue reveals the complex science hiding in plain sight.


First, we take a closer look at a growing environmental threat. A new study reveals that nanoplastics act as "toxic taxis," absorbing and transporting heavy metals like lead. This finding has profound implications, suggesting that the plastic pollution in our bodies and ecosystems may be far more dangerous than we realized. Next, we step inside to uncover a surprising source of air pollution. Researchers have found that climbing gyms can contain airborne toxic chemicals from shoe rubber at levels comparable to those found on busy roads, challenging our assumptions about indoor "healthy" spaces. Finally, we invite you to reframe your perspective on a typical insect. It’s time to give flies their due as the most numerous and ecologically vital migratory animals on Earth, whose quiet work is essential for pollination, nutrient cycling, and the very health of our world.

Picture taken at Mirissa Harbour on May 30th. In addition to the usual plastic trash on that beach now there a millions of litte plastic pellets that come from the ship X-Press Pearl. On 20 May 2021, the ship caught fire off the Sri Lankan coast of Colombo. On 27 May 2021, the vessel was engulfed in flames and lost containers, some of them including the plastic pellets spreading all over the west coast of Sri Lanka.

EARTH

Study Finds Nanoplastics Can Absorb Toxic Metals, Increasing Health Risks

A new study reveals that nanoplastics, tiny particles from plastic waste, can absorb harmful heavy metals like lead, cadmium, and zinc, increasing health risks. The research shows that nanoplastics, particularly those made from polypropylene, can attract and hold onto toxic metals, potentially leading to bioaccumulation in the human body. This discovery highlights the need for further investigation into the health and environmental impact of nanoplastics.



The Point:

  • Tiny plastics, bigger risk: Nanoplastics from common waste can bind to toxic heavy metals like lead and cadmium, potentially harming the environment and human health.

  • Rapid metal adsorption: In experiments, polypropylene nanoplastics absorbed over 99% of lead ions within five minutes, showing strong potential for pollutant transport.

  • Health implications are rising: Nanoplastics are found in human bodies, and their ability to carry heavy metals raises serious concerns about bioaccumulation and long-term toxicity.


HEALTH AND THE BODY

Study Links Toxic Chemicals in Climbing Shoes to Air Pollution in Gyms

A new study has raised concerns about indoor air quality in climbing gyms, linking the chemicals in climbing shoe soles to potential health risks. Researchers found that rubber-derived compounds (RDCs) are released into the air as shoes wear down, with concentrations similar to pollution levels found on busy city streets. The study highlights the need for better ventilation and safer materials in climbing gear to protect gym-goers' health.



The Point:

  • Researchers found that climbing gyms contain high levels of harmful rubber-derived compounds released from climbing shoes: These compounds, similar to those in car tires, raise concerns about indoor air quality and potential health effects.

  • Air samples from gyms in multiple countries revealed pollution levels comparable to busy roads, especially in high-traffic facilities: The study showed that more climbers in a gym correlated with more airborne contaminants.

  • The presence of toxic chemicals like 6PPD underscores the need for improved ventilation, safer materials, and further research into health impacts: Experts call for action to protect climbers, particularly vulnerable groups like children.


NATURE

Flies are masters of migration – it’s about time they got some credit

Flies are the most numerous and ecologically vital insect migrants, outnumbering butterflies and dragonflies. They pollinate crops, decompose waste, and transport nutrients across continents—yet their importance remains underappreciated. Understanding and protecting these tireless travelers is essential for food security, soil health, and ecological balance in a rapidly changing world.



The Point:

  • Flies: The Most Numerous Migrants: Flies are the most abundant migratory insects, making up nearly 90% of all terrestrial insect migrants. Their migration, often overlooked, plays a crucial ecological role, including pollination, decomposition, and nutrient transport, vital for ecosystem health.
    Ecological Impact of Migratory Flies: Migrating flies contribute to pollination, decomposition, and nutrient cycling, with some species helping to maintain genetic diversity in plants, while others support healthy soil by transporting nutrients. However, some species also pose challenges, such as crop pests and disease carriers.

  • Threats and Conservation of Migratory Flies: Declines in migratory fly populations, such as the 97% decrease in aphid-eating hoverflies in Germany, highlight the risks to agriculture and ecosystem balance. Protecting these vital insects through improved landscape connectivity, reduced pesticide use, and suitable habitats could help restore their populations and safeguard their ecological functions.