Total Gill Overload: Unintended Consequences of Urbanization
Microparticles produced by tire wear are emerging as a significant source of land-based pollution for estuarine habitats. Scaling up the estimated tire wear production of 133 mg/mile/vehicle to the ~9.75 million daily miles traveled (VMT) in Charleston County infers that 1297 kg/day of microparticles are generated daily on the rougly 1,600 miles of County roads (Transportation Plan, 2018). Furthermore, since polyaromatic hydrocarbons (PAHs) adsorb onto these particles, they may transport additional pollutants into estuaries via stormwater runoff. We examined particle density in the gills of fiddler crabs (Uca pugnax) living in local estuarine marshes close to roadway bridges with daily traffic counts between 2 and 50,500 (SCDOT VMT). Particle counts in the gills ranged from 3 to 41 particles/gill, and were positively correlated with VMT (p=0.0049, R2=0.0893). Since fiddler crabs are an important food source for many marsh predators, these results infer that the burgeoning traffic associated with Charleston’s rapid urbanization may be an increasingly important vector for the introduction of pollutants into Lowcountry marsh ecosystems.
Fiddler Crabs, Tire Particles, Microplastics, Pollution, Urbanization