TITLE:
Combined Sewer Overflows (CSOs) Impact on Water Quality and Environmental Ecosystem in the Harlem River
AUTHORS:
Jingyu Wang
KEYWORDS:
CSOs, Ammonia, Phosphate, Fecal Coliform, E.Coli, Enterococcus, PCBs, Fish Consumption Safety
JOURNAL NAME:
Journal of Environmental Protection,
Vol.5 No.13,
October
30,
2014
ABSTRACT: The Harlem River, a 9.3-mile channel that flows from the Hudson River to
the East River, has experienced decades of industrial abuse and remains gritty
and industrial. During heavy rains, the pipes discharge raw sewage into the
river through combined sewer overflows (CSOs) that can contain bacteria and
cause illness. Water samples were collected from CSO discharge point and
several adjacent sites along the river in the Bronx side close to River Park
Towers at Richman Plaza and Manhattan side at Wards Island. Nutrients, bacteria,
polychlorinated biphenyls (PCBs), and fish consumption safety have been
analyzed. Results showed that phosphorus, ammonia concentration as well as
fecal coliform, E.Coli, enterococcus levels increased significantly during
heavy rainstorms. Ammonia concentration was up to 2.725 mg/L during tropical
storm Arthur on July 2, 2014 and rainstorm in May 2013, and soluble reactive
phosphorus (SRP) or orthophosphate was up to 0.197 mg/L during heavy
thunderstorm in April 2011; both nutrients were exceeded EPA regulation for
ammonia (0.23 mg/L) and phosphate (0.033 mg/L) for New York City (NYC) waters.
The colonies of fecal coliform were more than 5 million MPN/100ml (most
probable number per 100 ml) during tropical storm Arthur in July 2014 and heavy
rainstorm in April 2014, and fecal coliform was more than 10,000 MPN/100ml
during storm in July and November 2013; E.Coli reached more than 5000 MPN/100ml
during tropical storm Arthur and storm in May 2013; enterococcus reached more
than 10,000 MPN/100ml during tropical storm Arthur and heavy rainstorm in April
2014. These bacteria (pathogen) levels in the Harlem River were significantly
higher than EPA standards (fecal coliform: 200 MPN/100ml, E.Coli: 126
MPN/100ml, enterococcus: 104 MPN/100ml), especially during rainstorm/tropical
storm. Of particular significance, nutrients and bacteria were analyzed before
and after Hurricane Sandy devastated NYC in late October 2012; results
determined that bacteria and ammonia concentrations increased after this
monumental storm, elucidating the environmental impact of large storm events.
PCB 11 (3,3’-dichlorobiphenyl, C12H8Cl2), the
high molecular weight (MW), an indicator of raw sewer and storm water runoff in
the NYC harbor waters, is the major polychlorinated biphenyls (PCBs) in the
Harlem River. PCBs are carcinogenic, which could bioaccumulate via food chain
from fish and seafood, endangering public health. Oyster farming has been used
to purify water and improve water quality in the river. CSOs and storm water
runoff have degraded water quality and been threatening environmental ecosystem
and public health. This research will help local communities understand CSO
impact on nutrients, bacteria, PCBs contamination and fish consumption safety, and
make contributions on CSOs reduction as well as improve water quality and
environmental ecosystem in the Harlem River.