Week of August 6 - 12, 2023
Nutrients Sampling
Nutrient samples were collected from seven river stations and seven bay stations on August 9th, 2023. All bay stations were sampled at the surface and bottom. In the five days prior to sampling, there were 0.48 inches of rainfall recorded at T.F. Green.
Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN) and dissolved inorganic nitrogen (DIN) concentrations were observed at Pawtuxet River @ Broad St. (TN = 1,390 ppb, TDN = 1,520 ppb, and DIN = 1244.2 ppb). The lowest TN and TDN were observed at Moshassuck River @ Footbridge at Mill Street (TN = 741.5 ppb, TDN= 680.5 ppb, average of duplicates), while the lowest DIN was at Blackstone River @ Bikepath Bridge (DIN = 484.7 ppb).
Among the bay stations sampled, the highest surface TN, TDN, and DIN concentrations were observed at Phillipsdale Landing (TN = 1,050 ppb, TDN = 919 ppb, DIN = 561 ppb). The lowest surface TN, TDN, and DIN concentrations were observed at Conimicut Point (TN = 738 ppb, TDN = 360 ppb, DIN = 143.2 ppb). Chlorophyll a concentrations at the surface bay stations averaged 4.16 μg/L overall with a maximum at the Bullock Reach Buoy (6.94 μg/L, average of duplicates).
June 17, 2024
Bacteria Sampling
On June 17th, seventeen stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers; five of these stations were also sampled for enterococci bacteria. In the five days prior to sampling, precipitation totaled 0.06 inches as recorded at TF Green.
Overall, bacteria counts were lower in both the Seekonk and Providence Rivers than during the previous sampling event.
Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 135 MPN/100 mL and 52 MPN/100 mL, respectively). The maximum count (430 MPN/100 mL) was measured at Collier Point Park.
Enterococci results had an overall geometric mean of 18 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at Gaspee Point and Conimicut Point to 98 MPN/100 mL at Point St Bridge.
The next scheduled sampling date is July 3.
The table below lists the Rhode Island bacteria standards for primary contact and shellfishing established by the Rhode Island Department of Environmental Management (RIDEM). RIDEM defines primary contact as any recreational activities in which there is prolonged and intimate contact with water, involving considerable risk of ingesting water (e.g., swimming, diving, water skiing and surfing). Please note that the RIDEM bacteria standards are provided here for informational purposes only and are not intended to indicate official state compliance with primary contact or shellfishing standards.
Summary of Rhode Island Bacteria Standards for Saltwater Primary Contact and Shellfishing
| Fecal Coliform | Enterococci |
| Primary Contact1 | Geometric mean ≤50 MPN/100 mL
<10% of samples >400 MPN/100 mL
| Geometric mean ≤35 colonies/100 mL
All samples ≤104 colonies/100 mL2 |
| Shellfishing | Geometric mean ≤14 MPN/100 mL
<10% of samples >49 MPN/100 mL3 | NO ENTEROCOCCI CRITERIA
|
1Fecal coliform primary contact criteria applied only when adequate enterococci data are not available;
2Single sample maximum criterion for determining beach swimming advisories at designated beaches as evaluated by the Rhode Island Department of Health;
3For a three-tube decimal dilution
June 5, 2024
Bacteria Sampling
On June 5th, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers; five of these stations were also sampled for enterococci bacteria. In the five days prior to sampling, there was no precipitation recorded at TF Green. Overall, bacteria counts were higher in both the Seekonk and Providence Rivers than during the previous sampling event.
Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 204 MPN/100 mL and 13 MPN/100 mL, respectively). The maximum counts (930 MPN/100 mL) were measured at Bishop Point and Off BP Outfall.
Enterococci results had an overall geometric mean of 28 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at Gaspee Point and Conimicut Point to 158 MPN/100 mL at Point St Bridge.
The next scheduled sampling date is June 17.
The table below lists the Rhode Island bacteria standards for primary contact and shellfishing established by the Rhode Island Department of Environmental Management (RIDEM). RIDEM defines primary contact as any recreational activities in which there is prolonged and intimate contact with water, involving considerable risk of ingesting water (e.g., swimming, diving, water skiing and surfing). Please note that the RIDEM bacteria standards are provided here for informational purposes only and are not intended to indicate official state compliance with primary contact or shellfishing standards.
Summary of Rhode Island Bacteria Standards for Saltwater Primary Contact and Shellfishing
| Fecal Coliform | Enterococci |
| Primary Contact1 | Geometric mean ≤50 MPN/100 mL
<10% of samples >400 MPN/100 mL
| Geometric mean ≤35 colonies/100 mL
All samples ≤104 colonies/100 mL2 |
| Shellfishing | Geometric mean ≤14 MPN/100 mL
<10% of samples >49 MPN/100 mL3 | NO ENTEROCOCCI CRITERIA
|
1Fecal coliform primary contact criteria applied only when adequate enterococci data are not available;
2Single sample maximum criterion for determining beach swimming advisories at designated beaches as evaluated by the Rhode Island Department of Health;
3For a three-tube decimal dilution
June 17, 2024
Surface Mapping
Surface chlorophyll data were collected on June 17, 2024 while the R/V Monitor was underway collecting bacteria samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as poor in the Seekonk River and as fair in all other areas. Overall, chlorophyll ranged from 0.0 to 72.05 µg/L with an average of 13.74 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
June 12, 2024
Surface Mapping
Surface chlorophyll data were collected on June 12, 2024 while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as good in the Pawtuxet River, poor in the Northern Providence River Channel, and as fair in all other areas. Overall, chlorophyll ranged from 1.48 to 44.81 µg/L with an average of 14.44 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
