February 6, 2023 By Katie Roundtree

Americans use about 100 billion plastic bags a year. These include plastic grocery, shopping, food storage, yard fertilizer and pet waste disposal bags.  Plastic bags are so lightweight and aerodynamic that even if we dispose of them properly, they can get misplaced.  They escape from our trash cans, garbage trucks and landfills and go where the wind takes them- into storm drains, canals, lakes, and eventually, the ocean.

Plastic bags remain toxic even after they break down. They don’t biodegrade; they photodegrade.  That means that after sunlight breaks them down, they degrade, breaking down into smaller and smaller pieces, until they can ultimately enter the food chain.  These tiny particles of plastic are called microplastics, officially defined as plastics less than five millimeters (0.2 inches) in diameter—smaller than the standard pearl used in jewelry.  There are two categories of microplastics: primary and secondary.

Primary microplastics are tiny particles designed for commercial use, such as cosmetics, or microfibers shed from clothing and other textiles, such as fishing nets.  Secondary microplastics are particles that result from the breakdown of larger plastic items, such as water bottles.  This breakdown is caused by exposure to environmental factors, mainly the sun’s radiation and ocean waves.

Single-use plastics—plastic items meant to be used just once and then discarded, such as a straw or plastic bag—are the primary source of secondary plastics in the environment.  Some of this environmental pollution is from littering.  Still, many of the plastics in waterways result from storms, water runoff, and winds that carry plastic—both intact objects and microplastics—into our waterways and oceans.

The problem with microplastics is that they do not readily break down into harmless molecules just like plastic items of any size.  Plastics can take hundreds or thousands of years to decompose—and in the meantime, wreak havoc on the environment.  On beaches, microplastics are visible as tiny multicolored plastic bits in the sand.  In the oceans, microplastic pollution is often consumed by marine animals.

Microplastics have been detected in marine organisms, from plankton to whales, commercial seafood, and drinking water.  Alarmingly, standard water treatment facilities cannot remove all traces of microplastics.  To further complicate matters, microplastics in the ocean can bind with other harmful chemicals before being ingested by marine organisms. Scientists are still unsure whether consumed microplastics are harmful to human or animal health—and, if so, what specific dangers they may pose.

Besides the environmental aspects of plastic, plastic bags in particular can cause damage to stormwater drainage systems.  Plastic bags can clog storm drains and waterways, threatening urban environments and creating severe safety hazards.  Drainage systems blocked by plastic bags have been identified as a major cause of flooding in countries like India and Bangladesh during monsoon season.

More locally, plastic bags can get caught and damage aerator motors and stormwater pumps.  Aerator maintenance costs are higher because of plastic bag debris. Recently an aerator required repair due to damage from a plastic bag.  The bag was drawn into the motor of the aerator and wrapped around the spinning shaft, causing the engine to freeze up and burn out.  It also burnt out the electrical lines and cabling attached to the motor.  After all of the repairs were completed, including replacing 250 feet of cabling, that one plastic bag caused over $4,000 in damages to the aerator.

Stormwater pumps must function optimally to provide proper drainage following rain events and storms.  They are critical to many of the stormwater systems in our area.  If debris gets caught in them, the motors can also burn out and not work properly when most needed.  The pumps used are submersed in several feet of water.  They are not easily able to be inspected from above the water.  When debris caught in the motor is discovered, the damage may already be done.

If you choose to use plastic bags, please dispose of them properly and securely.  PLEASE DO NOT THROW THEM IN THE WATERWAYS. This request not only pertains to shopping bags, but includes fertilizer bags, pet waste disposal bags and food storage bags.  Properly placing them in a secure receptacle could help keep our stormwater systems and, ultimately, our waterways clear.