Daria DiBiasio – Narrabay

July 2, 2025

On July 2nd, 2025, 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, 0.02 inches of precipitation was recorded at TF Green. Overall bacteria counts were higher than during the previous sampling event.

Fecal coliform counts were higher in the Seekonk River, compared to the Providence River (geometric mean of 4916 MPN/100 mL for the Seekonk River compared to 49 MPN/100mL for the Providence River) for sampling conducted on July 2nd. The maximum count (240,000 MPN/100 mL) was measured at the Point St. Bridge sampling location.

Fecal coliform counts were higher in the Providence River, compared to the previous sampling on June 4th (geometric mean of 49 MPN/100 mL compared to 30 MPN/100 mL on 6/4). Fecal coliform counts were higher in the Seekonk River, compared to the previous sampling on June 4th (geometric mean of 4916 MPN/100 mL compared to 93 MPN/100 mL on 6/4).

Enterococci results had an overall geometric mean of 333 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at Conimicut Point and Gaspee Point to 6488 MPN/100 mL at Point St Bridge.

The next scheduled sampling date is July 16th.

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.

Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.

July 8, 2025

Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on July 8, 2025. In the five days prior to the survey, 0.55 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.3 meters. The lowest clarity this week (1.3 meters) was measured at Phillipsdale Landing, while the greatest clarity (3.7 meters) was measured at Conimicut Point. There was a general north-to-south trend of increasing water clarity among the sites this week. Overall, water clarity remained approximately the same from the previous measurements (data collected July 2, 2025).

July 2, 2025

Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on July 2, 2025. In the five days prior to the survey, 0.02 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.2 meters. The lowest clarity this week (1.4 meters) was measured at Phillipsdale Landing, while the greatest clarity (2.9 meters) was measured at Conimicut Point. There was a general north-to-south trend of increasing water clarity among the sites this week. Overall, water clarity remained approximately the same from the previous measurements (data collected June 25, 2025).

June 25, 2025

Phytoplankton samples were collected on June 25, 2025 at Bullock’s Reach and analyzed in the laboratory shortly after collection.

The water temperature was 24.98 °C, the salinity was 24.10 psu, and the chlorophyll a was 8.14 ug/L.

The qualitative tow net sample had a long filtration time. The filtrate contained jellyfish and had a golden brown coloration.

The analysis of the quantitative whole water sample revealed a total of 1,501,000 cells/L. The microflagellates were found at 330,000 cells/L. The most predominant phytoplankton genera were Cerataulina spp. at 437,000 cells/L, Skeletonema spp. at 287,000 cells/L, and Heterocapsa spp. at 147,000 cells/L.

200x phase contrast micrograph of *Akashiwo sanguinea*

Akashiwo sanguinea is a planktonic dinoflagellate which lives as a single cell and uses one flagellum for locomotion. These dinoflagellates are mixotrophic, which means they can use different sources for energy and carbon uptake. They are photosynthetic, containing a large number of chloroplasts radiating from the center of the cell, and also prey on various types of smaller organisms.

June 11, 2025

Phytoplankton samples were collected on June 11, 2025 at Bullock’s Reach and analyzed in the laboratory shortly after collection.

The water temperature was 18.0 °C, the salinity was 21.28 psu, and the chlorophyll a was 4.24 ug/L.

The qualitative tow net sample had a moderate filtration time. The filtrate had a medium brown/green coloration.

The analysis of the quantitative whole water sample revealed a total of 5,517,000 cells/L. The microflagellates were found at 112,000 cells/L. The most predominant phytoplankton genera were Guinardia spp. at 1,652,000 cells/L, Chaetoceros spp. at 1,448,000 cells/L, and Leptocylindrus spp. at 1,044,000 cells/L.

200x phase contrast micrograph of phytoplankton

June 25, 2025

Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on June 25, 2025. In the five days prior to the survey, 0.01 inches of precipitation were recorded at TF Green. Secchi depth averaged 2.3 meters. The lowest clarity this week (1.3 meters) was measured at Phillipsdale Landing, while the greatest clarity (2.7 meters) was measured at India Point Park and Pomham Rocks. There was no clear north-to-south gradient in water clarity among the sites this week. Overall, water clarity at most locations remained relatively consistent compared to previous measurements (data collected June 11, 2025).

June 4, 2025

On June 4th, 2025, 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, 0.39 inches of precipitation was recorded at TF Green. Overall bacteria counts remained approximately the same as the previous sampling event.

Fecal coliform counts were higher in the Seekonk River, compared to the Providence River (geometric mean of 93 MPN/100 mL for the Seekonk River compared to 30 MPN/100mL for the Providence River) for sampling conducted on June 4th. The maximum count (430 MPN/100 mL) was measured at the Point Street Bridge sampling location.

Fecal coliform counts were lower in the Providence River, compared to the previous sampling on May 21st (geometric mean of 30 MPN/100 mL compared to 45 MPN/100 mL on 5/21). Fecal coliform counts were higher in the Seekonk River, compared to the previous sampling on May 21st (geometric mean of 93 MPN/100 mL compared to 37 MPN/100 mL on 5/21).

Enterococci results had an overall geometric mean of 18 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 183 MPN/100 mL at Point St Bridge.

The next scheduled sampling date is June 18th.

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

Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.

May 21, 2025

On May 21st, 2025, 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, 0.04 inches of precipitation was recorded at TF Green. Overall bacteria counts were lower than during the previous sampling event.

Fecal coliform counts were lower in the Seekonk River, compared to the Providence River (geometric mean of 37 MPN/100 mL for the Seekonk River compared to 45 MPN/100mL for the Providence River) for sampling conducted on May 21st. The maximum count (2,300 MPN/100 mL) was measured at the Point Street Bridge sampling location.

Fecal coliform counts were lower in the Providence River, compared to the previous sampling on May 7th (geometric mean of 45 MPN/100 mL compared to 369 MPN/100 mL on 5/7). Fecal coliform counts were lower in the Seekonk River, compared to the previous sampling on May 7th (geometric mean of 37 MPN/100 mL compared to 1121 MPN/100 mL on 5/7).

Enterococci results had an overall geometric mean of 16 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 74 MPN/100 mL at Point St Bridge.

The next scheduled sampling date is June 4^th.

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

Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.

May 7, 2025

On May 7th, 2025, 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, 2.10 inches of precipitation was recorded at TF Green. Overall bacteria counts were higher than during the previous sampling event.

Fecal coliform counts were higher in the Seekonk River, compared to the Providence River (geometric mean of 1121 MPN/100 mL for the Seekonk River compared to 369 MPN/100mL for the Providence River) for sampling conducted on May 7th. The maximum count (9,300 MPN/100 mL) was measured at the Collier Point Park sampling location.

Fecal coliform counts were higher in the Providence River, compared to the previous sampling on April 23rd (geometric mean of 369 MPN/100 mL compared to 12 MPN/100 mL on 4/23). Fecal coliform counts were higher in the Seekonk River, compared to the previous sampling on April 23rd (geometric mean of 1121 MPN/100 mL compared to 72 MPN/100 mL on 4/23).

Enterococci results had an overall geometric mean of 128 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at Conimicut Point to 2046 MPN/100 mL at Point St Bridge.

The next scheduled sampling date is May 21^st.

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

Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.

April 23, 2025

On April 23rd, 2025, 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, 0.05 inches of precipitation was recorded at TF Green. Overall bacteria counts were lower than during the previous sampling event.

Fecal coliform counts were higher in the Seekonk River, compared to the Providence River (geometric mean of 72 MPN/100 mL for the Seekonk River compared to 12 MPN/100mL for the Providence River) for sampling conducted on April 23rd. The maximum count (430 MPN/100 mL) was measured at the Point Street Bridge sampling location.

Fecal coliform counts were lower in the Providence River, compared to the previous sampling on March 26th (geometric mean of 12 MPN/100 mL compared to 38 MPN/100 mL on 3/26). Fecal coliform counts were higher in the Seekonk River, compared to the previous sampling on March 26th (geometric mean of 72 MPN/100 mL compared to 67 MPN/100 mL on 3/26).

Enterococci results had an overall geometric mean of 12 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 20 MPN/100 mL at Point St Bridge.

The next scheduled sampling date is May 7th.

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

Table adapted from Rhode Island Water Quality Regulations (250-RICR-150-05-1); see regulations for complete details.