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Analysis of the Dissolved Oxygen, pH, and Temperature of the Water in the Passaic River

Updated: Oct 6, 2022

--By Justin Santiago, Stephlyn Buchanan, Aksarapuk Mullane


The purpose of this study was to raise awareness of how climate change affects the dissolved oxygen, pH (potential hydrogen) and temperature levels of the river. This study revealed that the dissolved oxygen, pH levels, and temperature were normal at each of the sites we tested. In comparison to historical data, the dissolved oxygen improved, pH stood consistent, and the temperature has gotten cooler. The sites were located west of the Passaic – Bergen County border. This project was done from May 2022 – July 2022.


The Passaic River runs through the city of Paterson and into the Great Falls. The lower portion of the river is this project’s focus. The lower portion runs for about seventeen miles, between Dundee Dam and Newark Bay. This part of the river transverses several urban areas and is subject to pollution. The Passaic River is considered one of the most polluted rivers in the nation according to Yusuf Yildiz, who described the Passaic River in his research paper “Ion Selective Electrode Determination of Ammonia Nitrogen in Passaic River Waste Water in New Jersey Essex County Area”. This is due to the mass industrialization of Paterson during the 19th and 20th centuries. Yildiz stated that industrial plants had dumped their toxic waste into the river polluting the river. There were attempts to clean the river, in 1972 with the clean water act and in the early 2000s the Environmental Protection Agency took several actions to clean the river. The most notable of which was in 2014 in which the EPA enacted a $1.7 billion plan to remove 4.3 billion tons of toxic mud from the river. This was the biggest cleanup projects done.

This Passaic County Community project will test the dissolved oxygen, pH, and temperature of the river. The reason for these parameters is these are important requirements for marine life. Marine life requires dissolved oxygen concentrations of 3 mg/L to survive but need at least 5 mg/L to live comfortably. Moreover, marine life needs pH levels of 7, and temperatures of about 25℃ to live. Furthermore, the data will be compared with historical data from 2010 to gauge whether the river has improved or deteriorated since then. The dissolved oxygen historical data was taken from a 2010 report from the New Jersey Harbor Discharges group, while pH and temperature were taken from the United States Geological Survey website. The overall goal of this project is to raise awareness for climate change using the data obtained from this research.

Materials and Methods

For accurate data this project used a Vernier Go Direct dissolved oxygen probe, Vernier Go Direct pH probe, and a Science First 1.5L Water Sampler. The probes give dissolved oxygen and pH readings per second. To obtain water samples, the water sampler is attached to rope and thrown into the river. In addition to the dissolved oxygen and pH measurements, temperature is also recorded with a thermometer. Water samples are poured into a measuring cup.

Samples are taken from the shallow and deep areas of the river. This is because dissolved oxygen and pH readings may be different in those two areas of the river. If the shallow area of the river is easily accessible, then the probes may be dipped directly into the river by hand for a more accurate reading, else the water sampler is dropped by rope into it. For deep area measurements, the water sampler is thrown further into the river and forced to sink to the bottom. At the bottom the sampler is closed and drawn back in. Once the water samples are procured, the tube that is attached to the water sampler is placed at the bottom of a measurement cup and lifted as the water level rises. The probes and thermometer are then immediately placed into the measuring cup and the readings are recorded. The probes are left in the sample for about 120 seconds, as that will give the most accurate readings and account for any rise in dissolved oxygen and pH. The thermometer is left in for about 30 seconds.

These samples were taken from June 2022 to July 2022. Since dissolved oxygen, pH, and temperature can differ every season, this project was done only during the summer months, so that environmental conditions stood consistent. Each site was also tested twice on different days that were at least a week apart. Figure 1 below is a map that shows where the sites are located.

Figure 1: Map showing the location of the sites that were tested. Results from Passaic County Community College Urban Scholars for Climate Change

Research Project in 2022 (Compared to historical water data below)

Table 1: Dissolved oxygen concentrations per site and per region. “1st” and “2nd” refer to the 1st and 2nd days in which the data was recorded. The lowest concentration was 6.59 mg/L, and the highest was 9.09 mg/L. The data was taken at 0 seconds, then at 120 seconds.

Table 2: pH values per site and per region. The lowest was 6.68 and the highest was 8.23.

Table 3: Temperature per site and per region. The lowest was 23℃ and the highest was 27℃.

Table 4: Dissolved Concentration per site and region. Marine life needs dissolved oxygen saturation levels from 80% to 120% according to the government of northwest territories.

Historical Data (as compared to current water data above as tested by PCCC Urban Scholars for Climate Change research project)

Figure 2: Dissolved oxygen trend taken from the 2010 New Jersey Harbor Discharges Group report. The dissolved Oxygen has stood at about 5.5 mg/L – 5.8 mg/L from 2004 to 2010. At 2010 their reading was at about 5 mg/L at the deep or bottom end, while at the shallow or surface, it was about 6.3 mg/L.

Figure 3: Dissolved oxygen per site taken from the 2010 New Jersey Harbor Discharges group report. Theunnumbered small dark blue ovals are this project’s site locations.

Figure 4: pH trends taken from the United States Geological Survey website. The graph generated is the pH readings per hour since 2010. The location of this data is further west from this project’s most western site (Morris Canal Park) at Two Bridges NJ.

Figure 5: Temperature trends taken from the United States Geological Survey website. The graph generated provides a temperature reading per hour from July 1 2010 to July 31 2010. This data was taken further west from this project’s most western site (Morris Canal Park) at Two Bridges NJ


In comparison to historical data the dissolved oxygen concentrations have improved around historical site 2 in figure 3. The dissolved oxygen concentrations in that area has risen, which allows more marine life to live in that area. The pH levels stood consistent since 2010. For the temperature, it has gotten a little bit colder. This project’s average temperature was 25℃, and figure 5 shows that in 2010, the average stood above 25℃. This is interesting because many people expect with global warming for temperatures to rise, however temperatures have fallen slightly. The temperature is significant because temperature has a direct correlation with dissolved oxygen, as temperature and dissolved oxygen affect the dissolved oxygen saturation. Marine life needs saturation of at least 80% and no more than 120%. Table 4 shows that every location has suitable saturation percentages. However, these percentage are almost approaching the minimum, which does not allow for negative changes to occur. Thus, there should be a focus to increase the dissolved concentrations further.


The overall condition of the river has improved since 2010, but there is room for more improvement. Unfortunately, while the dissolved oxygen improved in some sites, the dissolved oxygen saturation is too close to the lower threshold where marine life will flourish. Meaning that if the saturation percentage will go below 80%, marine life will suffer. The pH has remained consistent. The temperature has gotten colder.


Government of Northwest Territories. Accessed 23 August 2022.

The New Jersey Harbor Dischargers Group. The New Jersey Harbor Dischargers Group 2010 Water Quality Report. Accessed 23 8 2022.

United States Geological Survey. “Home.” Accessed 23 August 2022.

Yusuf Yildiz, et al. “on Selective Electrode Determination of Ammonia Nitrogen in Passaic River Waste Water in New Jersey Essex County Area.” American Journal of Analytical Chemistry, vol. 13, 2022, Accessed 23 8 2022.

Student researchers Stephlyn and Justin discuss their findings in a wrap up interview

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