Determining the Probable Cause of an Impaired Benthic Community in

the Naugatuck River

Chris Bellucci and Lee DunbarConnecticut Department of Environmental Protection

Bureau of Water ManagementPlanning & Standards Division

79 Elm StreetHartford, CT 06106-5127

TMDL ProgramChris BellucciKelly Streich

Monitoring & AssessmentErnie PizzutoGuy HoffmanMike Beauchene

Watershed CoordinatorSusan Peterson

Water Toxics LaboratoryTracy LizotteAl Iacobucci

Aquatic ToxicityThom HazeRose Gatter-Evarts

Municipal FacilitiesRowland Denny

InspectionEd Finger

Watershed PermittingMelissa BlaisSteve EdwardsKevin Barrett

EPAMike Marsh – Region 1Susan Cormier – ORD

NAUGATUCK TMDL TEAM

Monitor and Assess ConditionsList and Prioritize Impaired Waters for TMDLs

Identify Cause(s) of ImpairmentStressor ID Analysis

Develop TMDL for pollutant causing impairment Point and non-point load allocations, margin of safety.

Adopt TMDLPublic ParticipationState establishes TMDL with revisions as warrantedEPA reviews and approves TMDL

Implement TMDLRe-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 withmaximum 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

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

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 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 eachpoint 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 Bridge7Q10 - 17.2 cfs

QRD

THOMASTON POTW

WHYCO

SUMMIT

?

Streamflows less than 7Q10 are Common

Duration of Low Flow (<=13 cfs)Naugatuck River at Thomaston

0 5 10 15 20 25 30 35 40 45

1990

1991

1992

19931994

1995

1996

19971998

1999

2000

2001

Yea

r

Number of Days

Longest Span (days)

The abundance of sensitive macroinvertebrates declines downstream of each point discharge

Fall 1991

0102030405060708090

100

Reynolds Br Railroad Br Frost Br

% o

f R

efe

ren

ce

Sit

e

Meets Water Quality Criteria

QR

D

SU

M

TH

MW

HY

Fall 2001

0102030405060708090

100

Reynolds Br Railroad Br Frost Br

% o

f R

efe

ren

ce

Sit

e

Meets Water Quality Criteria

QR

D

SU

M

TH

MW

HY

Fall 2002

0102030405060708090

100

Reynolds Br Railroad Br Frost Br

% o

f R

efe

ren

ce

Sit

e

Meets Water Quality Criteria

QR

D

SU

M

TH

MW

HY

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

Route 6

Background

US Flow US Concentration

QRD

EF Flow

Model Output 1EF Concentration

US Flow US Concentration

ThomastonPOTW

EF Flow

Model Output 2EF Concentration

US Flow US Concentration

Branch Bk

EF Flow

Model Output 3EF Concentration

US Flow US Concentration

Whyco

EF Flow

Model Output 4EF Concentration

US Flow US Concentration

Summit

EF Flow

Model Output 5EF Concentration

Frost Bridge

DSconc = ((USflow x USconc) + (EFflow

x EFconc)) / (USflow + EFflow)

  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

0

0.2

0.4

0.6

0.8

1

1.2

0.00 1.00 2.00 3.00 4.00 5.00 6.00

Chronic Toxic Units

Cum

ulat

ive

Fre

quen

cyZinc

Nickel

Lead

Copper

Toxicity

% of Values Exceeding 1.0 CTUZinc = < 0.01%Nickel = < 0.01%Lead = 0.7%Copper = 4.5 %Toxicity = 13.3 %

Relative Probability (%) of Toxic Impact

Location Toxicity Copper Lead Nickel Zinc

Rte. 6 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01downstream QRD 1.80 0.20 < 0.01 < 0.01 < 0.01downstream POTW 1.80 0.50 0.03 0.04 < 0.01downstream Branch Bk. < 0.01 0.50 < 0.01 < 0.01 < 0.01

downstream Whyco 3.80 1.30 0.30 0.10 < 0.01downstream Summit 13.30 4.50 0.70 < 0.01 < 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 gpsATU = 100/LC 50

Acute TMDL = 30.7 gATU/sec

Acute Protection Chronic 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

330,000gpd

4.9 gATU/sec

9.5gATU/sec

16.3gATU/sec

Facility ADF

(gpd)

Flow

Proportion

Acute

TMDL

(gATU/sec)

Chronic

TMDL

(gCTU/sec)

QRD 100,800 0.16 4.9 14.9

WHY 195,000 0.31 9.5 28.9

SUM 330,000 0.53 16.3 49.4

Total 625,800 1.00 30.7 93.2

TMDL – How to Split Up the Pie

@ Rte 6 12.60 93.24 0.00 0 93.24

Location Streamflow TMDL WLA LA MOS

@ QRD 12.76 94.42 15.02 0 79.40@ NF Bk. 12.87 95.24 15.02 0 80.22@ POTW 14.97 110.78 15.02 0 95.76@ Branch Bk. 15.75 116.55 15.02 0 101.53@ Whyco 16.05 118.77 44.07 0 74.70@ Nibb. Bk. 16.12 120.00 44.07 0 75.93@ Summit 16.63 123.06 93.24 0 29.82@ Frost Br. 17.17 127.06 93.24 0 33.82

Streamflow in cfs, TMDL in gCTU/sec.

Naugatuck River Toxicity TMDL

Chronic TMDL

0102030405060708090

100110120130

Ro

ute

6

QR

D

N.F

. Bk

PO

TW

Bra

nch

Bk

Wh

yco

Nib

b. B

k

Su

mm

it

Fro

st B

r

gC

TU

/ s

MOS

WLA

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