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Water quality is an important indicator of a river's health. Poor water quality not only affects the ecosystem as a whole, but also can negatively impact human health. Partnering with Interstate Environmental Commission (IEC), Hackensack Riverkeeper has begun testing physical, biological, and chemical parameters at five non-swimming public access sites along the Hackensack River to get a glimpse into the water quality and health of our watershed. 

So, what exactly are we testing?


pH it is a figure between 1 and 14 defining how acidic or basic a body of water is. Marine organisms are incredibly sensitive to pH; fish can't live in lemonade... or Draino. 

Dissolved Oxygen

Dissolved oxygen refers to the level of oxygen present in water. It is an important parameter in assessing water quality because without it many organisms would not be able to breathe.


Conductivity is a measure of water’s capability to pass electrical flow. The more conductive a solution is the more saline it is. 


Salinity is the total concentration of all dissolved salts in water. Since the Hackensack River and Newark Bay is brackish water, meaning that water is a mixture of salt and fresh water, the salinity can vary with the tides. 

Fecal Coliform

Fecal coliform is an indicator of human waste. We use this to measure the duration of sewage pollution. 


Enterococcus is also an indicator of human waste, but which gives a screenshot of pollution at the moment.  The presence (or not) of Enterococcus bacteria is the best indicator for safe contact. 


Temperature is the measure of heat in a river. It is important because many of the living creatures are cold blooded, meaning that they depend upon their environment to regulate their temperature.  

Presence of Activity

Human and/or animal activity can affect many of the parameters including the bacteria numbers. For example, geese can elevate bacterial levels.  

Hack Bacteria Data at a Glance...

The New Jersey State Sanitary Code requires that the concentration of bacteria not exceed 104 colonies of Enterococci bacteria per 100 milliliters of a sample. Enterococcus levels are used as indicators of the presence of disease-causing bacteria in water bodies. An exceedance of this concentration may be harmful to human health to the people interacting with this water. The graph above shows our sites’ progress so far, for each sampling event. The red line indicates the 104 CFU (colony forming unit) NJ criteria, so anything above the red line is over NJ State Sanitary Code concentration designation. You can clearly see the elevated levels that occur after a rain event indicated by the big spike at the beginning of August. This was likely due to a large rain event - that is, the tropical storm that occurred 8/4.

A Short History of Pollution on the Hackensack

For two centuries, the river suffered from extremely severe pollution. The construction of the Oradell Reservoir dam in 1921 essentially changed the lower river from a free-flowing stream into a brackish estuary, allowing the encroachment of marine species. Urbanization in the region intensified after World War II, with the expansion of roads and highways, including the New Jersey Turnpike (1952), as well as the Meadowlands Sports Complex (1970s). By the 1960s, much of the lower river was essentially a turbid hypoxic dead zone, with only the hardiest of species, such as the mummichog, able to survive in its waters. Chemical companies dumped large volumes of waste into Berry's Creek - a major tributary - during the 20th Century, resulting in the highest concentrations of methyl mercury of any fresh-water sediment in the world, as well as extensive residues of PCBs and other chemicals. Three sites along the creek are federally-designated Superfund sites and require major cleanup operations, which are ongoing as of 2019.

The river recovered somewhat by the late 2000s following the decline in manufacturing in the area, as well as from enforcement of Clean Water Act regulations and from the efforts of local conservancy groups. Recreational fishing has staged a modest comeback, although catch and release may be advisable, as there are continuing health advisories against the consumption of fish caught in the river. Urban runoff pollution, municipal sewage discharges from sanitary sewer overflows and combined sewer overflows, and runoff from hazardous waste sites continue to impair the river's water quality.


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