WMA water withdrawal and NPDES wastewater discharge summary

Use Assessment

Aquatic Life

Toxicity

The Scituate WWTP staff collects water from the North River near fourth cliff beach (Rowland 2004). These samples are used as dilution water in the facility’s whole effluent toxicity tests. Survival of Mysidopsis bahia (exposed 48 hours) ranged from 85 to 100% in the 16 tests conducted between February 2000 and August 2004. Survival of Menidia beryllina exposed (7-day) to the river water ranged from 88 to 100% with the exception of one test (survival = 63% in February 2001 test event) in the 16 tests conducted between February 2000 and August 2004.

Chemistry-water

The Scituate WWTP staff collects water from the North River near fourth cliff beach (Rowland 2004).
Data from the facility’s whole effluent toxicity test reports were entered into the DWM’s TOXTD database and the results between March 2001 and August 2004 are summarized below.
pH

The pH measurements ranged from 7.4 to 7.8 SU (n=5)(TOXTD database).

Suspended solids

The suspended solids concentrations ranged from 48 to 66 mg/l (n=3)(TOXTD database).

Ammonia-nitrogen

The ammonia-nitrogen concentrations ranged from <0.1 to 0.6 mg/L (n=3)(TOXTD database).

Total residual chlorine (TRC)

The total residual chlorine measurements were all <0.05 mg/L (n=5)(TOXTD database).

The Aquatic Life Use is assessed as support based primarily on the good survival of test organisms exposed to water collected from this segment of the North River.

Shellfish Harvesting

The DMF Shellfish Status Report of July 2000 indicates that Areas MB5.2 and MB5.4 (which contain 0.09 mi² of this segment) are prohibited and Area MB5.1, which contains 0.47 mi² of this segment, is conditionally approved (MA DFG 2000 and Appendix G, Table G3). It should be noted, however, that opening for Area MB5.1 has recently been extended for an additional month (Churchill 2005b).
Based on the DMF shellfish growing area status, the Shellfish Harvesting Use is assessed as impaired presumably due to elevated fecal coliform bacteria. Although the sources of bacteria are currently unknown, discharges from municipal separate storm sewers and boats are suspected.

Primary and Secondary Contact RECREATION and Aesthetics

Although no quality-assured data are available, it should be noted that since 1994 NSRWA volunteers have conducted bacteria sampling as part of their River Watch Monitoring Program on a weekly basis during the summer months. They sample at two locations in this segment of the North River - off Damon’s Point and near the mouth of the North River near Circle End Terrace (NSRWA 2005b).
No objectionable conditions have been observed by DWM biologists in this segment of the North River (DeCesare 2005).
The Primary and Secondary Contact Recreational are not assessed for this segment of the North River, but the Aesthetics Use is assessed as support based on the lack of aesthetically objectionable conditions.
North River (MA94-06) Use Summary Table

Designated Uses		Status
Aquatic Life		SUPPORT
Fish Consumption		NOT ASSESSED
Shellfish Harvesting		IMPAIRED Cause: Elevated fecal coliform bacteria Source: Unknown (Suspected sources: Marina/boating sanitary on-vessel discharges, discharges from municipal separate storm sewer systems)
Primary Contact		NOT ASSESSED
Secondary Contact		NOT ASSESSED
Aesthetics		SUPPORT

Directory: eea -> docs -> dep -> water -> resources -> 71wqar09
dep -> Charles D. Baker Governor
dep -> Charles D. Baker Governor
dep -> Charles D. Baker Governor
dep -> Index of Photographs
dep -> Department of environmental protection one winter street, boston, ma 02108 617-292-5500
water -> Water Resource Management Planning
71wqar09 -> 2004 water quality assessment report

Download 3.32 Mb.

Share with your friends: