Rio turns discarded salon hair into barriers that protect mangroves from oil

In a unique and promising project in Rio de Janeiro's Guanabara Bay, leftover human hair that would otherwise be discarded is being repurposed to form a barrier designed to protect mangroves from oil and other pollutants. The initiative, spearheaded by the Brazilian non-governmental organization Fiotrar, is making waves due to its innovative use of an abundant waste material.

The concept behind the solution is based on the hair's unique ability to attract oil while repelling water. Oleophilic in nature, human hair has a natural affinity for oily substances, which allows it to absorb up to five grams of oil per gram of hair. This property makes it an ideal material for creating containment materials that can effectively absorb pollutants from oil spills.

Scientists have demonstrated the effectiveness of this method in a laboratory setting. By pouring oil onto a container filled with water and hair, the oil adheres to the surface of the hair, while the water remains clean. This principle is what enables the hair to serve as an effective barrier against pollutants, keeping them contained for up to four months.

The project began testing in Bom Jesus Cove, which is impacted by Guanabara Bay. The site was selected because of the existing waste containment barrier, allowing for the integration of the new hair barrier structure. Measuring about 350 meters in length, the barrier uses approximately 250 kilograms of hair and is the first of its kind in Brazil to exceed the 300-meter mark.

The hair used for this project is sourced from beauty salons, with around a dozen establishments contributing their surplus hair. The criteria for usability are more flexible than those for wig-making, as hair as short as 2.5 centimeters can be used for the containment mats. Essentially, all hair that falls on the salon floor can be used, making the raw material nearly inexhaustible in a country with the number of salons Brazil has.

The hair is not simply tossed into the water as one might expect. Instead, it is packaged into rolls made from cotton mesh, forming cylinders that resemble blankets or sausages. These cylinders are then secured to the floating orange barrier, which already collects waste on the surface. Environmental engineer Ana Beatriz Gonçalves explains that the existing structure supports Fiotrar's barrier, with the hair being responsible for trapping the oil while the floating barrier keeps everything afloat.

The barriers themselves are composed of styrofoam, fabric, layers of geosynthetic blankets, and a tarpaulin cover. When deployed from small vessels into the bay, they form a continuous line on the water's surface. The deployment process involves small vessels, which transport the cylinders to their designated locations.

The duration of the barriers' effectiveness is a key factor in their operation. They can remain in the water for up to four months, capturing pollution from various sources, including vessels, illegal discharges, and chronic contamination. After this period, the material must be collected and replaced. Weekly maintenance is conducted by a technical team that monitors the condition of the mats and the volume of oil retained.

The community of fishermen in the area has been directly affected by pollution, with oil spills disrupting their fishing activities. Fishermen often encounter oil on the water's surface, which can extend to depths of about one and a half meters, causing fish to disappear. The community has taken an active role in trash removal and now participates in addressing oil pollution through the hair barrier project.

This project is not the first of its kind. In 2013, Mariana Robrahn and Mylene Duarte founded Cabelegria, an NGO that provides free wigs to cancer patients using donated hair. Robrahn's previous work in creating wigs laid the foundation for this innovative environmental solution.

The Guanabara Bay has long suffered from pollution due to heavy maritime traffic, with ships constantly entering and leaving the region. This makes it an ideal location to test the effectiveness of the hair barrier project. The fishing community, in particular, is hopeful that the barriers will aid in the recovery of the bay's ecosystems, addressing both the chronic and everyday leaks that often go unnoticed.