Successful mitigation of stormwater-driven nutrient, fecal bacteria and suspended solids loading in a recreational beach community.

Marine and estuarine waterways adjacent to urban areas are often the final recipient of polluted stormwater runoff. Microbial degradation of coastal water quality is a direct threat to human health through fecal contamination of bathing waters and shellfish, as well as distressing local economies through the loss of waterways to commercial (shellfishing) and recreational use. In coastal waters reduction of nitrogen loading is a key strategy for prevention of noxious and toxic algal blooms. Best management practices (BMPs) can be successful tools for mitigating such pollutants in runoff, but BMPs must be tailored to individual situations for maximum effectiveness. This study examines the efficacy of a set of BMPs installed in the coastal resort Town of Wrightsville Beach, North Carolina, USA. The BMPs targeted the highly-impervious (90%+) drainage area of two stormwater outfall pipes emptying into recreationally used Banks Channel. Mitigation measures included replacement of impervious pavement with pervious concrete and construction of an infiltration chamber in the parking lot of a local recreational seaside club. Significant reductions were achieved in total stormwater discharge (62%), as well as loading of the fecal indicator bacteria Enterococcus (76%) and total nitrogen (TN - 87% decrease). Additionally, there were reductions in loading of total phosphorous (TP) and total suspended solids (TSS) to estuarine waters following BMP installment. The set of BMPs applied here have wide management applicability to coastal ecosystems, as well as freshwater riparian areas characterized by sandy, porous soils.

Investigation of polyethylene terephthalate (PET) drinking bottles as marine reservoirs for fecal bacteria and phytoplankton.

Polyethylene terephthalate (PET) is frequently used in the food and beverage industry and therefore contributes greatly to plastic marine debris. The fecal pollution indicator bacteria Enterococcus is used for marine water contamination assessments and is regularly found in storm water discharge. In order to examine if PET drinking bottles act as refuges for Enterococcus, a study was conducted within euhaline tidal waters of Wrightsville Beach, NC, USA via the deployment of bottle floats positioned nearby two stormwater outfall pipes. Bottles were retrieved weekly to assess the accumulation of fecal bacteria and phytoplankton. Each bottle was analyzed for the presence of Enterococcus on plastic surfaces and within water inside the bottle. Abundance of Enterococcus and planktonic chlorophyll α was found to be significantly greater in association with PET bottles versus the surrounding waters. Bottles were observed to act as reservoirs for both Enterococcus and phytoplankton with concentrations well above the state, federal, and WHO standards.