BOGOTA – Dozens of Colombian waste pickers inundated Bogota’s iconic Bolivar Square with about 15 tons of recyclable goods Tuesday to protest decreasing income and tougher conditions for scavengers. They collect trash from homes, factories and office buildings and sell it to local recycling plants.

The demonstration was organized by 14 waste picker associations in Bogota, a city where approximately 20,000 scavengers work long hours gathering items like plastic bottles, scrap metal and cardboard boxes. About 100 waste pickers gathered and some pretended to swim in between the mounds of trash.

“We want factories to pay us a fair price for the materials we collect” said Nohra Padilla, the president of Colombia’s National Association of Waste Pickers. “Colombians and their government need to realize that without our work landfills would be saturated.”

Most waste pickers in Colombia work independently, pulling heavy carts and gathering recyclable items that are not collected by local garbage trucks. The trucks, which are run by contractors or municipal governments, focus on gathering organic and nonrecyclable trash.

The income of these waste pickers depends largely on how many kilos of plastic, cardboard or scrap metal they can sell every day to warehouses or local associations, which then sell the material to recycling plants.

Jorge Ospina, the president of the ARAUS waste pickers association, said that over the past two months the price his association gets paid by recycling plants for every kilogram of plastic fell from about 75 U.S. cents to 50 cents. He said he can only afford to pay waste pickers about 25 cents per kilo of plastic they drop off at the ARAUS warehouse in Bogota.

Ospina said imports of fresh plastic from countries including China could be behind the sharp drop in prices.

“We need more government regulation,” he said, warning that if prices fall further waste pickers might no longer be motivated to collect recyclable goods, and landfills in Colombia would “overflow.”

Colombia’s constitution protects waste pickers, who often come from impoverished backgrounds

These trash collectors are prioritized over large contractors when it comes to gathering recyclable goods and in large cities municipal governments are obliged to pay a monthly fee to waste pickers associations that varies in accordance with how many tons of trash each association collects.

But prices for recyclable trash are unstable and Colombian waste pickers also face increasing competition from Venezuelan migrants who are doing the same kind of work in cities like Bogota and Medellin.

Waste pickers in Colombia tend to make less than the national minimum wage of $350 a month.