Total Maximum Daily Load for PCBs 

in the Houston Ship Channel

University of Houston

Parsons

July 14, 2009

Outline

• FY 2008 PCB results

• 2009 PCB sampling status

• PCB concentration over time
FY 2008 PCB Results

FY 2008 PCB Sampling

– 37 sites sampled for water (dissolved & 

suspended)

– 25 sites sampled for sediment 

– 26 sites sampled for catfish and 19 sites sampled 

for seatrout or atlantic croaker

– Additional sediment samples collected as part of 

intensive sediment sampling

– Total PCB calculated as sum of 43 congeners 

(McFarland and Clarke, 1989); non-detects 

assumed as 1⁄2 MDL
PCB Concentrations by Segment (2008)

Water Sediment

Catfish Seatrout/Atlantic croaker

PCB Homologue Distribution in Water, Sediment, and Fish

* Fish results include average of catfish and seatrout/atlantic croaker results
Suspended vs Dissolved Dioxin/PCB in Water

• Dioxin concentrations = ∑17 congeners; 

• PCB concentrations = ∑ 43 congeners (McFarland and Clarke, 1989)

Dioxin

PCB

Location Reference

Coastal locations in Hong 

Kong, China Wurl et al., 2006

Yangtse river, China Jiang et al., 2000

Singapore Wurl et al., 2006a

Delaware River Rowe et al., 2007

Barcelona, Spain Garcıa-Flor et al., 

2005

Banyuls-sur-Mer, France Garcıa-Flor et al., 

2005

Lake Michigan Swackhamer et 

al., 1987

Green Bay Swackhamer et 

al., 1987

Ebro River, Spain Dachs et al., 1997

Danube Estuary, 

Romania

Maldonado

and Bayona, 2002

Water bodies reported to have 

PCB higher in dissolved phase

Summary 2008 PCB results Summary 2008 PCB results

• Water quality criteria exceeded in 41% of the samples

• More than 70% of the fish samples exceeded DSHS 

Health Assessment Comparison Value.

• Dissolved PCB concentration higher than suspended 

PCB concentration, contrary to what was observed 

during dioxin study.
2009 PCB Sampling Status

PCB Ambient Sampling - 2009 

• 45 sites sampled for water (dissolved & suspended); 3 sites remain.

• 33 sites sampled for sediment ; 2 sites remain.

• Catfish and Seatrout/Atlantic croaker caught at 28 and 15 sites respectively, out of 36 

sampled; 2 sites remain.
Runoff Sampling - 2009 

• 4 sites sampled (dissolved & suspended); 8 sites remain

• 2 sites to be determined for small ditch to obtain a direct runoff concentration

Effluent Facility Selection Criteria

• Presence of chlorinated organic compounds 

on the NPDES permit

• Flow magnitude

• Flow frequency: regular monthly flows 

required

• Diversity of industry types

• Location of outfalls to known PCB hot spots

• Good spatial coverage of the entire HSC
• Sampling planned once permissions received

• 1 power plant facility under selection and not included in the figure

Effluent Sampling - 2009 

Industry Types to be Sampled for Effluent

• 20 Main Sampling Facilities (one still to be determined)

• 5 Alternate Facilities

SIC SIC Expansion Primary Alternate

2812 Alkalies and Chlorine 1 0

2821 Plstc Mat./Syn Resins/NV Elast 3 1

2869 Indust. Organic Chemicals NEC 5 0

2879 Pesticides & Ag Chemicals 1 0

2911 Petroleum Refining 1 0

4226 Special warehousing and storage 1 0

4911 Electrical Services 1 0

4952 Sewerage Systems 6 3

4953 Refuse Systems 1 0

2865 Cyclic Crude Intermediate Dyes 0 1
Summary FY 2009 PCB Sampling Summary FY 2009 PCB Sampling

• Second round of ambient sampling almost 

complete for water, sediment and tissue

• Runoff sampling on-going

• Effluent sampling planned for near future

PCB Conc. Comparison: 2002-2003 & 2008 by Segment

Water Sediment

Catfish
PCB Homologue Distribution Comparison

Dissolved 

water

Sediment Fish

Suspended 

water

Comparison of Water/tissue Quality 

Standard Exceedance

Media

2008 Sampling 2002-2003 Sampling

Stations 

sampled 

Stations 

that exceed 

standard 

Station

exceedance

(%)

Stations 

sampled 

Stations that 

exceed 

standard

Station

exceedance

(%)

Watera 37 15 41% 32 12 38%

Catfishb 26 19 73% 45 36 80%

Seatrout/Atlantic

Croakerb 19 16 84% Not sampled

* Concentrations based on 1/2 detection limit and ∑43 congeners a WQS (0.885 ng/L)

b DSHS Health Assessment Comparison Value (47 ng/g)