Determining the Probable Cause of an Impaired Benthic Community in the Naugatuck River Chris Bellucci and Lee Dunbar Connecticut Department of Environmental Protection Bureau of Water Management Planning & Standards Division 79 Elm Street Hartford, CT

TMDL Program Chris Bellucci Kelly Streich Monitoring & Assessment Ernie Pizzuto Guy Hoffman Mike Beauchene Watershed Coordinator Susan Peterson Water Toxics Laboratory Tracy Lizotte Al Iacobucci Aquatic Toxicity Thom Haze Rose Gatter-Evarts Municipal Facilities Rowland Denny Inspection Ed Finger Watershed Permitting Melissa Blais Steve Edwards Kevin Barrett EPA Mike Marsh – Region 1 Susan Cormier – ORD NAUGATUCK TMDL TEAM

Monitor and Assess Conditions List and Prioritize Impaired Waters for TMDLs Identify Cause(s) of Impairment Stressor ID Analysis Develop TMDL for pollutant causing impairment Point and non-point load allocations, margin of safety. Adopt TMDL Public Participation State establishes TMDL with revisions as warranted EPA reviews and approves TMDL Implement TMDL Re-issue NPDES permits TMDL PROGRAM OVERVIEW

TMDL Study Area Listed on CT 2002 Impaired Waters List for not meeting aquatic life use goals – Cause Unknown Part of a larger effort to restore the Naugatuck River Watershed. Other projects include TMDLs on tributaries, dam removal projects, POTW upgrades NPDES permit re-issuance – 3 industrial expire 9/04 1 municipal expired 3/03 Why Focus on the Upper Naugatuck?

What is the Goal ? E P T

Study Area: Naugatuck River near Thomaston ~ 5-mile stretch of Naugatuck River 3 Metals Finishing Discharges, 1 POTW Two large dredge holes excavated in early 1970’s changed the river from wadable to 1-mile long lacustrine segment with maximum depths of 30 ft Dam Metal Finishing Discharge POTW Nibbling Bk Jericho Bk Northfield Bk Branch Bk Rock Bk Leadmine BkNaugatuck R Route 6 Reynolds Bridge Frost Bridge Q W S USGS Discharge USGS Monitoring

Cause Unknown Investigation Review of Existing Data Additional Samples from River and Effluents Stressor ID Analysis Conceptual Model Diagram

Review of Existing Data DMRs and ATMRs ArcView coverages Biological monitoring Physical/chemical monitoring (CTDEP and USGS) Hydrology (USGS Gage)

Additional Sampling 10 Rounds of Ambient Sampling at 4 sites during 2002 Sampling Season 7 Acute Toxicity Tests in 2002 on each point source discharge Jan 2003 Chronic Toxicity Test w/ EPA 2002 and 2003 Macroinvertebrate Sampling

What Did the Data Tell Us? Hydrology is Important The abundance of sensitive invertebrates declines downstream of each point discharge Low D.O. may be an issue Effluents toxic and extremely variable (job shops)

Allocated ZOI Exceeds 7Q10 Zone Of Influence Allocations QRD = 11.4 cfs Whyco = 18 cfs Summit = 18 cfs Thomaston POTW = 6.8 cfs Total = 54.2 cfs Route 6 7Q10 = 12.6 cfs Frost Bridge 7Q cfs QRD THOMASTON POTW WHYCO SUMMIT ?

Streamflows less than 7Q10 are Common

The abundance of sensitive macroinvertebrates declines downstream of each point discharge

SI Procedure DEP’s analysis was performed consistent with EPA Guidance and has been reviewed by the principal authors of the Guidance

Transport of water from hypolimnion Death or reproductive failure Increased nutrients Increased algal growth Decomposition leading to oxygen depletion Surface run-off Dredge Holes Low DO in hypolimnion Loss of Sensitive invertebrate taxa Conceptual Model of Low DO Sources Impairment Causal Pathway Nutrient data from USGS Station at Frost Bridge and CTDEP standard site at Frost Bridge are at background levels X X DO exceeded criteria at USGS Station and CTDEP station at Frost Bridge

3. Complex Mixture 2. Ammonia1. Metals Chronic toxicity Death or reproductive failure Acute toxicity Loss of Sensitive invertebrate taxa Point Source Discharges Non-Point Sources 4. Episodic Events Conceptual Model of Toxic Contamination Sources Impairment Causal Pathway

3. Complex Mixture 2. Ammonia1. Metals Chronic toxicity Death or reproductive failure Acute toxicity Loss of Sensitive invertebrate taxa Point Source Discharges Non-Point Sources 4. Episodic Events Pathway 1: Metals No individual metal correlated with measured effluent toxicity Metals data from USGS Station at Frost Bridge and CTDEP standard site at Frost Bridge did not exceed criteria X Conceptual Model of Toxic Contamination Sources Impairment Causal Pathway Monte Carlo analysis shows low probability of individual metal parameters to cause toxic conditions instream

3. Complex Mixture 2. Ammonia1. Metals Chronic toxicity Death or reproductive failure Acute toxicity Loss of Sensitive invertebrate taxa Point Source Discharges Non-Point Sources 4. Episodic Events Pathway 2: Ammonia X Ammonia data from USGS Station at Frost Bridge and CTDEP standard site are at background levels High ammonia concentrations in effluent not observed concurrent with measured toxicity Conceptual Model of Toxic Contamination Sources Impairment Causal Pathway

3. Complex Mixture 2. Ammonia1. Metals Chronic toxicity Death or reproductive failure Acute toxicity Loss of Sensitive invertebrate taxa Point Source Discharges Non-Point Sources 4. Episodic Events Pathway 3: Complex Mixture Effluents show acute and chronic toxicity in laboratory tests Biological monitoring links impact with outfall locations Inconsistent, complex array of chemicals in effluent samples measured with toxicity Monte Carlo analysis identified WET as the pollutant with highest probability to cause toxic impact Conceptual Model of Toxic Contamination Sources Impairment Causal Pathway

DS conc = ((US flow x US conc ) + (EF flow x EF conc )) / (US flow + EF flow ) Flow Data USGS Gauge Industrial Toxicity Database LIS Nutrient Database Concentration Data USGS Monitoring Station Industrial Toxicity Database DEP Ambient Monitoring database Monte Carlo Analysis

Relative Probability (%) of Toxic Impact LocationToxicityCopperLeadNickelZinc Rte. 6 < 0.01 downstream QRD < 0.01 downstream POTW < 0.01 downstream Branch Bk. < < 0.01 downstream Whyco < 0.01 downstream Summit < 0.01 Monte Carlo Analysis

3. Complex Mixture 2. Ammonia1. Metals Chronic toxicity Death or reproductive failure Acute toxicity Loss of Sensitive invertebrate taxa Point Source Discharges Non-Point Sources 4. Episodic Events Pathway 4: Episodic Events Unknown episodic event (e.g. treatment upset, illicit discharge) could contribute to impairment Non point contributions not well characterized but not likely to cause observed impacts. X Conceptual Model of Toxic Contamination Sources Impairment Causal Pathway

Recommendations Develop TMDL for Whole Effluent Toxicity Implement TMDL through NPDES Permits to Industries Reassess metals limits for each facility Monitor to measure compliance with TMDL Reassess the need to iterate the SI Process

1. All 3 Metal Finishing Discharges Exhibit Acute Toxicity 2. Biological Monitoring Links Impact with Outfall Locations 3. No Excursions Above Numeric WQ Criteria Measured In-Stream 4. Current Allocations to ZOI Exceed 7Q10 Flow 5. No Individual Chemical Parameter Correlated with Toxicity in Discharge Monitoring 5 Reasons to Target Toxicity for TMDL

TMDL – How Big is the Pie? Acute TMDL = 93 gps * 0.33 ATU Acute Toxic Units Chronic TMDL = 93 gps * 1 CTU Chronic Toxic Units 7Q10 = 12.6 cfs = 93 gps ATU = 100/LC 50 Acute TMDL = 30.7 gATU/sec Acute ProtectionChronic Protection Chronic TMDL = 93 gCTU/sec 0.33 ATU is the maximum allowable amount of toxicity 1 CTU is the maximum allowable amount of toxicity

Acute TMDL QRD WHY SUM Chronic TMDL QRD WHY SUM 14.9 gCTU/sec 49.4 gCTU/sec 28.9 gCTU/sec Flow Proportions QRD WHY SUM 100,000 gpd 195,000 gpd 330,000 gpd 4.9 gATU/sec 9.5 gATU/sec 16.3 gATU/sec FacilityADF (gpd) Flow Proportion Acute TMDL (gATU/sec) Chronic TMDL (gCTU/sec) QRD100, WHY195, SUM330, Total625, TMDL – How to Split Up the Pie

@ Rte LocationStreamflowTMDL WLALA QRD NF Bk POTW Branch Bk Whyco Nibb. Bk Summit Frost Br Streamflow in cfs, TMDL in gCTU/sec. Naugatuck River Toxicity TMDL

Initiate Public Participation and formal comment period – Public Notice Review comments from dischargers, other stakeholders and EPA, revise TMDL as warranted. Establish TMDL and submit to EPA for review and approval. Upon EPA approval, implement TMDL through revisions to NPDES permits. Establishing The TMDL

NPDES permits expire for QRD, Whyco, and Summit in September 2004 NPDES permit expired for Thomaston POTW in March 2003 Significant reductions in Whole Effluent Toxicity will be required to achieve compliance with permit limits Redirecting industrial discharges to the POTW is not a viable option Implementation