One TMDL for Zinc in Tissue in Nueces Bay

Faith Hambleton, Program Manager Total Maximum Daily Load Program Commission on Environmental Quality TMDL Components

¾ Background Project Information ¾ Problem Definition ¾ Endpoint Identification ¾ Source Analysis ¾ Link Between Sources and Receiving Water ¾ Pollutant Load Allocation ¾ Reasonable Assurance of Implementation ¾ Public Participation Watershed Area Goals and Authority

¾Clean Water Act requires states to: ¾ establish water quality standards (WQS) ¾ identify waters not meeting WQS (303d List) ¾ develop TMDLs ¾Coastal Bend Bays & Program ¾WSQ-1 Implement plans to improve water and sediment quality in identified segments. ¾Bays Plan- identified community concerns Problem Definition

Zinc in Oyster Tissue in Texas Bays 1969-2002

3000 2500 2000 1500 1000 500 0 y y re a a y ay a d

Zinc in Oyster Tissue (mg/kg) Tissue Oyster in Zinc e re y a B B Bay B Bay B ake A a e s Bay s Ba Ma L te Bay p rt Lak it a e risti a e o o os Bay a nio u s c n n tr p i u q n e u i s e to s opano u Ch g b tagord n ra N s a a Trinity Bay Ba e a A C A u S Fr ncah Me L Chocola M n GalvestonGalveston Bay Bay t ra a s S Corp Ea Tres PalacCa PowderhornEspiritu Lake Santo Bay East West Zinc in Nueces Bay Oyster Tissue (1980-2005)

3000

2500

2000

1500

1000

500

0 1980 1982 1983 1984 1994 2002 2005 Annual Avg Zinc (mg/kg) Avg Zinc Annual

n=4 n=2 n=2 n=2 n=2 n=12 n=25 Endpoint Identification

¾ TSHS’s health assessment comparison value: 700 mg zinc/kg oyster tissue

¾ HAC value assumes: ¾Body weight = 70 kg (154 lbs) ¾Consumption rate = 30 g/day (or 8 oz/wk) ¾30-year exposure rate Water QualityTarget

¾Bioconcentration factor (BCF) = tissue:water

¾Zinc BCF = 23,820 L/kg (USEPA, 1987)

¾23,820 L/kg = 700 mg/kg/ [Zn water] target zinc concentration in Water = 29 ug/L Historical Water Data (from Mrini, et al., 2003)

160.0 Total zinc in Nueces Bay 140.0

120.0

100.0

80.0

60.0 Mean = 46.8µg/l Conc (µg/L) Conc 40.0

20.0

0.0 1/1/80 5/15/81 9/27/82 2/9/84 6/23/85 11/5/86 3/19/88 8/1/89 Date

13422 13421 13420 13423 Historical Water Data (from Mrini, et al., 2003)

70.0 Total zinc in CC Inner Harbor 60.0

50.0

40.0 Mean = 37µg/L 30.0

20.0 Conc (µg/L)

10.0

0.0 12/1/80 8/28/83 5/24/86 2/17/89 11/14/9 8/10/94 5/6/97 1/31/00 1 Date 13430 13429 13432 13439 Historical Sediment Data (from Mrini, et al., 2003) 400 Zinc in sediments of Nueces Bay 350 (1980- 2002) 300

250 Mean = 92.8 mg/kg 200

150

100

Conc (mg/kg dry weight)(mg/kg Conc 50

0 1/1/80 9/27/82 6/23/85 3/19/88 12/14/90 9/9/93 6/5/96 3/2/99 11/26/01 8/22/04

Date Data source TCEQ CCBNEP Carr et al Historical Sediment Data (from Mrini, et al., 2003)

Zinc in se dime nts of the Inne r H arbor (1980-2002)

TCEQ stations 6000 13430 13432 5000 13439 Mean = 497 mg/kg 13433 4000 13434 Mean = 497 13435 3000 mg/kg 13436 13437

Conc. (mg/kg) 2000 13438 13429 1000 13428 13427 0 1/1/80 6/23/85 12/14/90 6/5/96 11/26/01 Date Source Analysis

¾ Total zinc loadings Model (Mrini, et al., 2003)

¾ CSTR model ¾ Nonpoint sources (GIS-based watershed model) ¾Upstream watershed ¾Adjacent watershed ¾ Atmospheric deposition (dry) ¾ Point sources ¾Municipal ¾Industrial Non-point Sources into Nueces Bay (frm Upstream Watershed)

LOADINGS

Background zinc concentration for freshwater. Load = 4.27 Kg/day

Flow from USGS gauge on Q = 2.47 m3/s Non-point Sources (frm NB Adjacent Watershed)

Precipitation Runoff LOADINGS Land Use/ Load = 3.69 Kg/day Land Cover

Q = 1.83 m3/s EMC Concentration Atmospheric Source

LOADINGS (Atmospheric deposition1) (bay area) Load = 18.67 Kg/day

1Wade, et al., 2000 Permitted Point Sources

Name Permit No. Permit type Max permitted flow (MGD) Nueces Bay WQ0001244-000 Industrial 500 Power Station City of Portland WQ0010478-001 Municipal 2.5

Sublight WQ0011096-001 Municipal 0.009 Enterprises Inc. City of Odem WQ0010297-002 Municipal <1 (pending) Point Sources (Municipal)

LOADINGS (Typical Pollutant Concentration1 0.165 mg/l) (Permitted Flow) Load = 1.57 Kg/day

1Armstrong and Ward, 1998 Point Sources (Industrial)

(Avg. zinc concentration in CCIH LOADINGS 37ug/l) (Permitted Flow from Nueces Bay Power Station 500 MGD) Load = 70.01 Kg/day Total Zinc Loads Source Load (kg/d) % NPS Upstream 4.27 4.35 Adjacent 3.69 3.76 Atm. Dep. 18.67 19.01 Subtotal 26.63 27.1 PS Municipal 1.57 1.6 Industrial 70.01 71.3 Subtotal 71.58 72.9 Total 98.2 100 Modeled vs. Observed

Total Zinc in Nueces Bay (1980-1988)

160.0 140.0 120.0 100.0 80.0 Observed/TCEQ Data 60.0 Mean = 46.8µg/L 40.0 Modelled results Concentration (µg/L) 20.0 = 44.5 ug/L 0.0 1/1/80 5/15/81 9/27/82 2/9/84 6/23/85 11/5/86 3/19/88 8/1/89 Date Pollutant Load Allocation

Scenario Load Conc. Flow (m3/s) (kg/d) (ug/l) Current 98.2 61.4 26.31

Target 65.9 29 26.31

Load Reduction 32.3 ------needed Pollutant Load Allocation

TMDL = ∑LA + ∑ WLA+ AFG

TMDL = 26.6 kg/d + 32.6 kg/d + 6.7 kg/d TMDL = 65.9 kg/d

Where ∑LA = subtotal for NPS (26.6 kg/d), ∑WLA = subtotal for PS (71.58 kg/d) – load reduction (32.3 kg/d), and AFG = 10% of TMDL (65.9 kg/d) New Data (June 2004 to May 2005)

¾ Parameters: ¾ Zinc in water and sediment ¾ Field (temp., DO, salinity, pH, cond., etc.) ¾ Other (TOC, total solids, TSS, sediment grain size) ¾ Frequency: ¾ Quarterly for water ¾ Biannually for sediment ¾ Stations: ¾ 8 in Nueces Bay, 2 in Nueces River ¾ 4 in Corpus Christi Inner Harbor Nueces ZINC TMDL ProjectNew Data ¯

12961

13423 13425 13424 13420 Nueces River 12960 13439 Nueces Bay 13422 13421

18365 AEP-CPL Power Plant 14833 13436 13432 13430

City of Corpus Christi

051234 Kilometers Power Stn Flows

Nueces Bay Power Station Permit no. WQ0001244000

600 500 400 300 200 100 0 3 4 9 0 01 02 03 l-04 Average Monthly Flow (MGD) 98 99 -00 ul- n-0 ul Jul- an-0 J Ja Ju Jan-05 Jul- an-0 J Jan-01Jul- Jan-02 J Jan-98Jul- Jan-9 J

9

43

3

1

3436

1

2

3

34

1

0

1343

8365

1

3

83

4

1

13425

4

2 Station

34

1

3

Nueces Bay Inner Harbor

1342

2

2

34

1

1

42

3 1

(June 2004-May 2005) 13420

1

6

29

1

0

96

2 1 Dissolved Zinc in Water Nueces River

8.00 0.00 6.00 2.00 4.00

12.00 10.00 Dissolved Zinc (ppb) Zinc Dissolved Average Dissolved Zinc (2004-05)

Waterbody Avg. Diss. Zinc (ug/l) Nueces River tidal 0.21

Nueces Bay 1.11

Corpus Christi Inner Harbor 5.12 Nueces Bay TMDL Mean Dissolved Zinc (ppb)

< 0.268 0.268 - 0.886 ¯ 0.887 - 1.323

1.324 - 6.085

12961

13423 13425 13424 Nueces River 13420 12960 13439 Nueces Bay 13422 13421

18365 AEP-CPL Power Plant 14833 13436 13432 13430

City of Corpus Christi

051234 Kilometers Nueces Bay Average Dissolved Zinc 1999-2004

10

8

6

4

2 Dissolved Zinc(ug/l) 0 1999 2000 2001 2002 2003 2004 2005

39

4

3

1

36

4

3

1

13432

30

4

3

1

18365

3

3

8

4

1

3425

1

4

2 Station

134

3

2

4

3 Nueces Bay Inner Harbor 1

3422

1

1

2

134

3420

1

1

6

129

60

9

2 1 Total Zinc in Water Nueces River

0.00

10.00 50.00 30.00 20.00 40.00 Total Zinc (ppb) Zinc Total Average Total Zinc

Segment Avg. Tot. Zn (ug/l) Nueces River tidal 4.63

Nueces Bay 10.15

Corpus Christi Inner Harbor 7.93 Nueces Bay TMDL Mean Total Zinc (ppb)

< 3.60 3.60 - 7.18 ¯ 7.19 - 11.03

11.04 - 13.85

12961

13423 13425 13424 Nueces River 13420 12960 13439 Nueces Bay 13422 13421

18365 AEP-CPL Power Plant 14833 13436 13432 13430

City of Corpus Christi

051234 Kilometers Nueces Zinc TMDL Total Suspended Solids Mean Concentrations (mg/L) < 25.00 ¯ 25.01 - 50.00

50.01 - 75.00

> 75.00

12961

13423 13425 13424 Nueces River 13420 12960 13439 Nueces Bay 13422 13421

18365 AEP-CPL Power Plant 14833 13436 13432 13430

City of Corpus Christi

051234 Kilometers Sediment (Upper): Mean Zinc (mg/kg)

< 31.00 31.00 - 62.00 ¯ 62.01 - 124.00 124.01 - 197.50 (TEL) 197.51 - 271.00 > 271.00 (PEL)

12961

13423 13425 13424 Nueces River 13420 12960 13439 Nueces Bay 13422 13421

18365 AEP-CPL Power Plant 14833 13436 13432 13430

City of Corpus Christi

051234 Kilometers Public Comment 303(d) List TCEQ Approval

Initiate TMDL EPA Approval Projects for Impaired Waters Public Comment

TMDL TCEQ Approval Allocation Report

Develop Implementation Plan

Stakeholders Implement The Plan Implementation Plan Strategy

¾ Phased Implementation: ¾ I. Reduce NBPS zinc load ¾ II. Investigate source of atmospheric deposition ¾ III. CCIH dredging options ¾ Continue monitoring water, sediment and tissue ¾ Evaluate progress toward achieving TMDL on a continuing basis ¾ Hold regular stakeholder meetings Load Reduction Scenarios L = Q * C , where L = load (kd/d), Q = flow (m3/s), and C = concentration (ug/l) then:

% flow reduction Reduced flow (m3/s) Avg. Total zinc in Zinc load from CPL Load reduction Q CCIH (kg/d) (kg/d) C L 100 0 37 0 70.01 90 2.19 37 7.0 63.01 80 4.38 37 14.0 56.01 70 6.57 37 21.0 49.01 60 8.76 37 28.0 42.01 50 10.95 37 35.0 35.01 40 13.14 37 42.0 28.01 30 15.3 37 48.91 21.10 20 17.5 37 55.94 14.07 10 19.7 37 62.98 7.03 www.tnrcc.state.tx.us/water/quality/tmdl/

Faith Hambleton, Program Manager [email protected]

Sandra Alvarado, Project Manager [email protected] 512/239-6643