Bay Bacteria Sampling – Page 2

July 2-8, 2023

On July 5, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 1.25 inches as recorded at TF Green, most of which occurred on July 4.

The geometric mean of fecal coliform results for all sites was 3472 MPN/100 mL compared to 31 MPN/100 mL on June 21. Overall, bacteria counts were higher in both the Seekonk and Providence Rivers this week than during the previous sampling event on June 21. Fecal coliform counts were geomeans of 3160 MPN/ 100 mL in the Seekonk River and 3629 MPN/ 100 mL in the Providence River. The maximum count (46,000 MPN/100 mL) was measured at Off FP Outfall in the Providence River.

Enterococci results had an overall geometric mean of 1250 MPN/100 mL. Enterococci counts ranged from 246 MPN/100mL at a Conimicut Point duplicate to 5475 MPN/100 mL at Point St. Bridge.

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.

June 18-24, 2023

On June 21, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 1.30 inches as recorded at TF Green.

The geometric mean of fecal coliform results for all sites was 31 MPN/100 mL compared to 17 MPN/100 mL on June 7. Overall, bacteria counts were higher in the Seekonk River this week than during the previous sampling event on June 7. Fecal coliform counts were geomeans of 256 MPN/ 100 mL in the Seekonk River and 12 MPN/ 100 mL in the Providence River. The maximum count (4300 MPN/100 mL) was measured at Bishop Point in the Seekonk River.

Enterococci results had an overall geometric mean of 12 MPN/100 mL. Enterococci counts ranged from non-detect at Conimicut Point, Phillipsdale Landing, South FP East, and Gaspee Point to 41 MPN/100 mL at Point St. Bridge.

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.

June 4-10, 2023

On June 7, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 0.14 inches as recorded at TF Green.

The geometric mean of fecal coliform results for all sites was 17 MPN/100 mL compared to 73 MPN/100 mL on May 24. Overall, bacteria counts were lower in the Seekonk River and Providence River this week than during the previous sampling event on May 24. Fecal coliform counts were geomeans of 41 MPN/ 100 mL in the Seekonk River and 12 MPN/ 100 mL in the Providence River. The maximum count (210 MPN/100 mL) was measured at Point St. Bridge in the Providence River.

Enterococci results had an overall geometric mean of 15 MPN/100 mL. Enterococci counts ranged from non-detect at South FP East and Gaspee Point to 52 MPN/100 mL at Point St. Bridge.

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 21-27, 2023

On May 24, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 3.04 inches as recorded at TF Green, most of which occurred on May 20.

The geometric mean of fecal coliform results for all sites was 73 MPN/100 mL compared to 23 MPN/100 mL on May 10. Overall, bacteria counts were higher in the Seekonk River and Providence River this week than during the previous sampling event on May 10. Fecal coliform counts were geomeans of 132 MPN/ 100 mL in the Seekonk River and 56 MPN/ 100 mL in the Providence River. The maximum count (430 MPN/100 mL) was measured at Narragansett Boating Center (Seekonk River) and Point St. Bridge (Providence River).

Enterococci results had an overall geometric mean of 13 MPN/100 mL. Enterococci counts ranged from non-detect at Phillipsdale Landing, South FP East, and Conimicut Point to 74 MPN/100 mL at Point St. Bridge.

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 7-13, 2023

On May 10, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 0.26 inches as recorded at TF Green.

The geometric mean of fecal coliform results for all sites was 23 MPN/100 mL compared to 29 MPN/100 mL on April 26, 2023. Overall, bacteria counts were lower in the Seekonk River and Providence River this week than during the previous sampling event on April 26. Fecal coliform counts were 40 MPN/ 100 mL in the Seekonk River and 18 MPN/ 100 mL in the Providence River. The maximum count (430 MPN/100 mL) was measured at Point St. Bridge in the Providence River.

Enterococci results had an overall geometric mean of 14 MPN/100 mL. Enterococci results were non-detect at all sites except the Point St. Bridge site with a measurement of 134 MPN/100 mL.

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 23-29, 2023

On April 26, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 0.91 inches as recorded at TF Green.

The geometric mean of fecal coliform results for all sites was 29 MPN/100 mL compared to 10 MPN/100 mL on April 13, 2023. Overall, bacteria counts were higher in the Seekonk River and Providence River this week than during the previous sampling event on April 13. Fecal coliform counts were 68 MPN/ 100 mL in the Seekonk River and 19 MPN/ 100 mL in the Providence River. The maximum count (430 MPN/100 mL) was measured at Point St. Bridge in the Providence River.

Enterococci results had an overall geometric mean of 14 MPN/100 mL. Enterococci results ranged from non-detect at Phillipsdale Landing, South FP East, and one of the Conimicut Point duplicates to 52 MPN/100 mL at the Point St. Bridge site.

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 9-15, 2023

On April 13, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. No precipitation was recorded at TF Green in the five days prior to sampling.

The geometric mean of fecal coliform results for all sites was 10 MPN/100 mL compared to 32 MPN/100 mL on March 29, 2023. Overall, bacteria counts were lower in both the Seekonk River and Providence River this week than during the previous sampling event on March 29. Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 29 MPN/100 mL and 7 MPN/100 mL, respectively). The maximum count (430 MPN/100 mL) was measured at Point St. Bridge in the Providence River.

Enterococci results had an overall geometric mean of 11 MPN/100 mL. Enterococci results ranged from non-detect at Phillipsdale Landing, South FP East, Gaspee Point, and Conimicut Point to 20 MPN/100 mL at the Point St. Bridge site.

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.

March 26-April 1, 2023

On March 29, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 0.67 inches as recorded at TF Green.

The geometric mean of fecal coliform results for all sites was 32 MPN/100 mL compared to 60 MPN/100 mL on March 16, 2023. Overall, bacteria counts were lower in the Seekonk River and Providence River this week than during the previous sampling event on March 16. Fecal coliform counts were similar in the Seekonk River and Providence River sites (geometric means of 32 MPN/100 mL and 33 MPN/100 mL, respectively). The maximum count (750 MPN/100 mL) was measured at Point St. Bridge in the Providence River.

Enterococci results had an overall geometric mean of 12 MPN/100 mL. Enterococci results ranged from non-detect at Point St. Bridge, South FP East, and one of the Conimicut Point duplicates to 20 MPN/100 mL at the Phillipsdale Landing site.

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

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

March 12-18, 2023

On March 16, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Five of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 3.2 inches as recorded at TF Green.

The geometric mean of fecal coliform results for all sites was 60 MPN/100 mL compared to 11 MPN/100 mL on March 1, 2023. Overall, bacteria counts were higher in the Seekonk River and Providence River this week than during the previous sampling event on March 1. Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 79 MPN/100 mL and 52 MPN/100 mL, respectively). The maximum count (430 MPN/100 mL) was measured at Collier Point Park in the Providence River.

Enterococci results had an overall geometric mean of 32 MPN/100 mL. Enterococci results ranged from 10 MPN/100 mL at one of the Conimicut Point duplicates to 74 MPN/100 mL at the South FP East site.

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

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

February 26-March 1, 2023

On March 1, fifteen stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers. Four of these stations were also sampled for enterococci bacteria. Precipitation in the five days prior to sampling totaled 0.67 inches as recorded at TF Green.

The geometric mean of fecal coliform results for all sites was 11 MPN/100 mL compared to 25 MPN/100 mL on January 18, 2023. Overall, bacteria counts were lower in the Providence River this week than during the previous sampling event on January 18. The Providence River geomean this week was 10 MPN/ 100 mL. Only one site was sampled this week in the Seekonk River (43 MPN/100 mL at Crook Point). The maximum count (390 MPN/100 mL) was measured at Point St. Bridge in the Providence River.

Enterococci results had an overall geometric mean of 10 MPN/100 mL. Enterococci results ranged from non-detect at South FP East, Gaspee Point, and Conimicut Point to 52 MPN/100 mL at the Point St. Bridge site.

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

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