U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2013–1046

Prepared in cooperation with the Bureau of Ocean Energy Management

Comparison of Aliphatic Hydrocarbons, Polycyclic Aromatic 

Hydrocarbons, Polychlorinated Biphenyls, Polybrominated 

Diphenylethers, and Organochlorine Pesticides in Pacific 

sanddab (Citharichthys sordidus) from Offshore Oil Platforms 

and Natural Reefs along the California Coast

Comparison of Aliphatic Hydrocarbons, 

Polycyclic Aromatic Hydrocarbons, 

Polychlorinated Biphenyls, Polybrominated 

Diphenylethers, and Organochlorine 

Pesticides in Pacific sanddab 

(Citharichthys sordidus) from Offshore 

Oil Platforms and Natural Reefs along the 

California Coast

By Robert W. Gale, Michael J. Tanner, Milton S. Love, Mary M. Nishimoto, and 

Donna M. Schroeder

Prepared in cooperation with the Bureau of Ocean Energy Management

Open-File Report 2013–1046

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

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Suggested citation:

Gale, R.W., Tanner, M.J., Love, M.S., Nishimoto, M.M., and Schroeder, D.M., 2013, Comparison of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polybrominated diphenylethers, and organochlorine pesticides in Pacific sanddab (Citharichthys sordidus) from offshore oil platforms and natural reefs along the 

California coast: U.S. Geological Survey Open-File Report 2013–1046, 31 p. and supplemental tables.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................2

General Petroleum Exposure..............................................................................................................2

Petroleum Exposure in the Southern California Bight....................................................................3

Nonpetroleum Exposure in the Southern California Bight.............................................................5

Methods...........................................................................................................................................................5

Study Sites and Sample Collection....................................................................................................5

Compositing and Homogenization ............................................................................................7

Materials ................................................................................................................................................7

Sample Cleanup and Analysis ............................................................................................................7

Aliphatic Hydrocarbons, Polycyclic Aromatic Hydrocarbons, and Polyaromatic 

Compounds......................................................................................................................7

Polychlorinated Biphenyls, Organochlorine Pesticides, and Polybrominated 

Diphenylethers................................................................................................................9

Principal Components Analysis...............................................................................................10

Quality Control............................................................................................................................10

Results and Discussion...............................................................................................................................10

Quality Control Results.......................................................................................................................10

This Study.............................................................................................................................................11

Aliphatic Hydrocarbons............................................................................................................12

Polycyclic Aromatic Hydrocarbons........................................................................................12

Polychlorinated Biphenyls .......................................................................................................13

Organochlorine Pesticides.......................................................................................................15

Selected Polybrominated Diphenylethers.............................................................................20

Comparison to Other Studies............................................................................................................24

References Cited..........................................................................................................................................27

Supplemental Tables ...................................................................................................................................31
iv

Figures

1. Map showing site locations in the Southern California Bight ..............................................6

2. Analytical scheme for aliphatic hydrocarbons, polycyclic aromatic

hydrocarbons, polycyclic aromatic thiophenes, and polychlorinated biphenyl

congeners, organochlorine pesticides and polybrominated diphenylethers.....................8

3. Graphs showing concentrations of polycyclic aromatic hydrocarbons in Pacific 

sanddab tissues from natural areas and platforms ..............................................................14

4. Graphs showing total-polychlorinated biphenyl concentrations in Pacific

sanddab tissues from natural areas and platforms ..............................................................16

5. Graphs showing principal components analysis of polychlorinated biphenyl

congeners in Pacific sanddab tissues from natural areas and platforms ........................17

6. Graphs showing concentrations of p,p'-dichlorodiphenyldichloroethylene in

Pacific sanddab tissues from natural areas and platforms.................................................21

7. Principal components analysis of organochlorine pesticides in Pacific sanddab

tissues from natural areas and platforms...............................................................................22

8. Graphs showing total-polybrominated diphenylether concentrations in Pacific

sanddab tissues from natural areas and platforms ..............................................................23

9. Principal components analysis of selected polybrominated diphenylether

congeners in Pacific sanddab tissues from natural areas and platforms ........................24

Tables

1. Samples for whole-fish composites of Pacific sanddab from natural areas and

platforms ........................................................................................................................................6

2. Lipid values for whole-fish composites of Pacific sanddab from natural areas and

platforms ......................................................................................................................................12

3. Total-polycyclic aromatic hydrocarbon concentrations for whole-fish composites 

of Pacific sanddab from natural areas and platforms..........................................................13

4. Total-polychlorinated biphenyl concentrations for whole-fish composites of

Pacific sanddab from natural areas and platforms ..............................................................15

5. Ranges of organochlorine pesticide concentrations in composite samples of

Pacific sanddab from natural areas and platform locations...............................................18

6. Ranges of organochlorine pesticide concentrations in composite samples of

Pacific sanddab from natural areas and platform locations...............................................19

7. Total-polybrominated diphenylether concentrations for whole-fish composites of

Pacific sanddab from natural areas and platforms ..............................................................22

8. Concentrations of contaminants determined in Pacific sanddab and reported in

Pacific sanddab and in mussels...............................................................................................25
v

Supplemental Tables

S1. Concentrations of selected polycyclic aromatic hydrocarbons and total PAHs in

tissues of Pacific sanddab at platforms and nearby natural sites .....................................31

S2. Lipid-normalized concentrations of selected polycyclic aromatic hydrocarbons

and total PAHs in tissues of Pacific sanddab at platforms and nearby natural

sites...............................................................................................................................................31

S3. Concentrations of selected congeners of polychlorinated biphenyls and total

PCBs in tissues of Pacific sanddab at platforms and nearby natural sites ......................31

S4. Lipid-normalized concentrations of selected congeners of polychlorinated

biphenyls and total PCBs in tissues of Pacific sanddab at platforms and nearby

natural sites .................................................................................................................................31

S5. Concentrations of selected organochlorine pesticides and total isodrins, chlordanes,

and dichlorodiphenyldichloroethylenes in tissues of Pacific sanddab at platforms and 

nearby natural sites....................................................................................................................31

S6. Lipid-normalized concentrations of selected organochlorine pesticides and total

isodrins, chlordanes, and dichlorodiphenyldichloroethylenes in tissues of Pacific 

sanddab at platforms and nearby natural sites.....................................................................31

S7. Concentrations of selected polybrominated diphenylethers and total PBDEs in

tissues of Pacific sanddab at platforms and nearby natural sites .....................................31

S8. Lipid-normalized concentrations of selected polybrominated diphenylethers and

total PBDEs in tissues of Pacific sanddab at platforms and nearby natural sites...........31
vi

Conversion Factors

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

micrometer (μm) 0.00003937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Volume

liter (L) 61.02 cubic inch (in3) 

milliliter (mL) 1 x 10-3 liter

microliter (μL) 1 x 10-6 liter

Flow rate

milliliter per minute (mL/min) 0.06102 cubic inches per minute (in3/min) 

Mass

metric ton (t) 1.102 ton, long (2,240 lb)

kilogram (kg) 2.205 pound avoirdupois (lb)

gram (g) 0.03527 ounce, avoirdupois (oz)

milligram (mg) 1 x 10-3 gram

microgram (μg) 1 x 10-6 gram

nanogram (ng) 1 x 10-9 gram

Concentration

microgram per milliliter (μg/mL) = part per million (ppm; 106)

nanogram per milliliter (ng/mL) = part per billion (ppb; 109)

microgram per gram (μg/g) = part per million (ppm; 106)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

 °F=(1.8×°C)+32

Concentrations of chemical constituents in liquid solutions (reagent solution, calibration 

standards, or bile) are given in nanogram per milliliter (ng/mL), or micrograms per milliliter 

(μg/mL). Concentrations of chemical constituents in solid matrices are given in microgram per 

gram (μg/g) or nanogram per gram (ng/g).
Comparison of Aliphatic Hydrocarbons, Polycyclic 

Aromatic Hydrocarbons, Polychlorinated Biphenyls, 

Polybrominated Diphenylethers, and Organochlorine 

Pesticides in Pacific sanddab (Citharichthys sordidus) 

from Offshore Oil Platforms and Natural Reefs along the 

California Coast

Robert W. Gale1, Michael J. Tanner1, Milton S. Love2, Mary M. Nishimoto2, Donna M. Schroeder3

1

U.S. Geological Survey.

2

University of California, Santa Barbara, Marine Sciences Institute, Santa Barbara, California.

3

Bureau of Ocean Energy Management (BOEM), Pacific Region, Camarillo, California.

Abstract

Recently, the relative exposure of Pacific sanddab 

(Citharichthys sordidus) to polycyclic aromatic hydrocarbons 

(PAHs) at oil-production platforms was reported, indicating 

negligible exposure to PAHs and no discernible differences 

between exposures at platforms and nearby natural areas sites. 

In this report, the potential for chronic PAH exposure in fish 

is reported, by measurement of recalcitrant, higher molecular 

weight PAHs in tissues of fish previously investigated for PAH 

metabolites in bile. A total of 34 PAHs (20 PAHs, 11 alkylated 

PAHs, and 3 polycyclic aromatic thiophenes) were targeted. 

In addition, legacy contaminants—polychlorinated biphenyls 

(PCBs) and organochlorine pesticides (OCPs),—and current 

contaminants, polybrominated diphenylethers (PBDEs) linked 

to endocrine disruption, were measured by gas chromatography with electron-capture or mass spectrometric detection, to 

form a more complete picture of the contaminant-related status 

of fishes at oil production platforms in the Southern California Bight. No hydrocarbon profiles or unresolved complex 

hydrocarbon background were found in fish from platforms 

and from natural areas, and concentrations of aliphatics were 

low less than 100 nanograms per gram (ng/g) per component]. 

Total-PAH concentrations in fish ranged from 15 to 37 ng/g at 

natural areas and from 8.7 to 22 ng/g at platforms. Profiles of 

PAHs were similar at all natural and platform sites, consisting mainly of naphthalene and methylnaphthalenes, phenanthrene, fluoranthene, and pyrene. Total-PCB concentrations 

(excluding non-ortho-chloro-substituted congeners) in fish 

were low, ranging from 7 to 22 ng/g at natural areas and from 

10 to 35 ng/g at platforms. About 50 percent of the total-PCBs 

at all sites consisted of 11 congeners: 153 > 138/163/164 > 

110 > 118 > 15 > 99 > 187 > 149 > 180. Most OCPs, except 

dichlorodiphenyltrichloroethane (DDT)-related compounds, 

were not detectable or were at concentrations of less than 

1 ng/g in fish. p,p′-dichlorodiphenyltrichloroethane (p,p′-DDE) 

ranged from 5.6 to 33 ng/g at natural areas and from 17 to 

76 ng/g at platforms, and comprised greater than 90 percent 

of the total-DDT concentrations at all sites. The only detectable PBDE congeners were PBDE-47 and PBDE-100, the 

total concentrations of which ranged from 0.4 to 1.8 ng/g at 

natural areas and from 0.5 to 3.0 ng/g at platforms. Total-PAH, 

-PCB, and -DDT concentrations were compared with other 

Southern California Bight studies involving shoreline mussel, (Mytilus Species, Kimbrough and others, 2008) and near 

shore sampling (Pacific sanddab, Schiff and Allen, 2000). At 

corresponding sites, only total-PCB concentrations agreed 

well with results from this study; total-DDT concentrations 

were generally much lower than concentrations documented 

in previous studies for samples collected nearer to shore by 

sewage treatment outfalls or 14 years earlier or closer in time 

to when DDT production was halted (1970). Natural areas and 

platforms in the Bight do not appear to be affected by harbor 

or urban pollution. Platforms were no more polluted than the 

nearby natural areas, with these locations exhibiting only low 

concentrations of PAHs, PCBs, DDTs, and other contaminants. 
2 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

Introduction

General Petroleum Exposure

Petroleum hydrocarbons exist as a naturally occurring 

highly complex mixture of aliphatic hydrocarbons, polycyclic 

aromatic hydrocarbons, and polycyclic aromatic compounds 

found in oil-containing deposits and are released into the 

environment through naturally occurring seeps. Sediment 

contamination by petroleum hydrocarbons released during 

platform operation creates a longer-term source of exposure 

for biota than intermittent oil releases into the water column. 

The relative hydrocarbon contamination after emplacement 

of an exploratory oil platform was reportedly slight, discernible only at locations close to the rig (Lytle and Lytle, 1979). 

Aliphatic hydrocarbon fractions in sediments consisted 

predominately of normal and branched C17 to C25 olefins, 

with higher concentrations of odd carbon numbered normal, 

predominately C29, alkanes; reflecting about 50 percent marine 

hydrocarbons loading into surficial sediments. A similar 

distribution of hydrocarbons has been further documented by 

Marcias-Zamora (1996) for a region south of the study area in 

the Southern California Bight . Aliphatic hydrocarbon concentrations ranged from 0.8 to 70.6 micrograms per gram (μg/g 

or parts per million) (average 15 μg/g); concentrations of the 

unresolved complex mixture ranged from less than the detection limit to 220 μg/g (average 37 μg/g); and total-polycyclic 

aromatic hydrocarbon (PAH) concentrations ranged from 

less than the detection limit to 1.9 μg/g (average 0.4 μg/g). In 

addition to the more aged hydrocarbon profiles in sediments, 

consisting of higher molecular weight compounds, some lower 

molecular weight components (odd carbon numbered alkanes: 

C15 and C17) were found, possibly resulting from plankton 

and benthic algae or from bacterial activity. Though unable to 

eliminate contributions from natural seeps, Marcias-Zamora 

reported potential sources of hydrocarbon input from sewage treatment plants and large harbor facilities, and a general 

southward transport of materials in the Southern California 

Bight (Marcias-Zamora, 1996).

Bioaccumulation of aliphatic and aromatic hydrocarbons 

by marine fishes has often been studied as part of injury and 

risk assessments resulting from petroleum spills. Fish collected within the slick of the Ecofisk North Sea oil platform 

blowout of 1977 contained mostly pristane, aliphatic hydrocarbons, and low concentrations of aromatics, and were not 

substantially different from background aliphatic and aromatic 

hydrocarbon concentrations in fish (Law, 1978). In highly polluted areas off the Canary Islands associated with petroleum 

industry, hydrocarbon concentrations in fish ranged from 8,800 

to 12,800 nanograms per gram (ng/g) concentrations from 

twenty to fifty-fold greater than those reported for fish from 

the Ecofisk blowout (Quintero and Diaz, 1994). Hydrocarbon 

patterns reflected biogenic components (pristane and hopanes) 

and preferential bioaccumulation of elevated concentrations of 

odd carbon numbered hydrocarbons. These patterns showed 

seasonal variations suggesting a relation with the reproductive 

cycles of the different species studied. Odd carbon numbered hydrocarbons typically result from biogenesis of algae, 

whereas even carbon numbered hydrocarbons and especially 

alkylated aromatics are signature compounds from petroleum 

related contamination. This differential accumulation of major 

odd and even carbon numbered hydrocarbons in limpets was 

used to differentiate pollution sources along the coasts of the 

Canary Islands (Pena-Mendez and others, 2001) and clearly 

indicated that sufficient amounts of aliphatic and aromatic 

hydrocarbons were bioaccumulated to discern polluted areas. 

Hydrocarbon concentrations ranged from 31 to 295,700 nanograms per gram dry-weight (ng/g dw) (average 28,400 ng/g 

dw) for the limpet Patella ulyssiponensis, and from not 

detectable to 744,000 ng/g dw (average 216,000 ng/g dw) for 

Patella crenata; concentrations of PAHs and alkyl-substituted 

PAHs ranged from not detectable to 61 ng/g dw (average 

5.4 ng/g dw) and not detectable to 2,200 ng/g dw (average 

210 ng/g dw) for P. ulyssiponensis, and from not detectable to 

24,300 ng/g dw (average 5,900 ng/g dw) and not detectable 

to 22,900 ng/g dw (average 3,400 ng/g dw) for P. crenata. 

Gonzalez and others (1992) reported that hydrocarbons in fish 

from the Campeche Bank, Mexico, oil production area consisted of predominately C10 to C14 hydrocarbons ranging from 

450 to 500 ng/g dw, and that C25 to C30 hydrocarbons predominated in shrimp and were about twenty-fold greater than those 

in fish. In the Gulf of Naples, another region of heavy petroleum industry, hydrocarbons in fish were determined to range 

from 770 to 33,200 ng/g dw (average 2,700 ng/g dw) (Amodio-Coccheri and Cirillo, 2003). Concentrations of aliphatics 

in fish collected from sewage-effected Buenos Aires coastal 

waters averaged about 70 μg/g dw and were determined to 

consist of predominately C12 to C25 hydrocarbons from bioaccumulation of fossil fuels from sewage particulates (Colombo 

and others, 2007).

Arias and others (2009) reported an average concentration of PAHs of 1,100 ng/g dw in whole fish from the Bahia 

Blanca estuary, Argentina, which was ranked as a moderate 

exposure risk in their assessment. Differences in bioavailability, diet composition and seasonal effects on diet composition, 

and biotransformation processes were proposed to explain 

large variations in PAH concentrations among biological 

species. Concentrations of higher molecular weight PAHs in 

fish muscle tissue were determined to decrease throughout a 

week-long period after uptake and to not bioconcentrate to 

any substantive extent. The half-life of benzo(a)pyrene (BaP) 

was reported longest in fat (12.4 days, d), with a wholebody half-life of 2.4 d; however, measurements after about 

20 days indicated that BaP concentrations in tissue might be 

reaching steady-state, balancing bioaccumulation and degradation (Lemaire and others, 1990). Stein and others (1993) 

determined that though BaP residence times in fish were 

short, BaP-DNA adducts in liver were moderately persistent, 

maintaining steady-state concentration from 28 to 84 days. 

In long-term feeding trials that introduced low concentrations of 16 PAHs into diets, Nácher-Mestre and others (2010) 
Introduction 3

reported that the PAH concentrations in fish decreased from 

initial concentrations of 46.6 ng/g total-PAHs and 9.1 ng/g 

BaP equivalents (BaP-eq), which were accumulated from the 

previous maintenance diets. Naphthalene (about 200 ng/g) was 

completely lost and the other PAHs (fluorene, phenanthrene, 

anthracene, fluoranthene, pyrene, benzo(a)anthracene, and 

chrysene, approximately 0.6 to 6 ng/g each) decreased about 

ten-fold throughout the first 6 months. In the second 6 months, 

these latter PAHs increased again, from 2 ng/g to about 6 ng/g 

total-PAHs, though less than 0.01 ng/g BaP-eq was reported. 

The concentration lowering was proposed to result from 

growth dilution in addition to removal through detoxification 

pathways. No accumulation was noted for trace concentrations 

of 5- or 6-ring aromatic compounds. Using cardio-respiratory 

evaluation to determine fitness, Claireaux and Davoodi (2010) 

reported the following:

"...oil exposure impaired function in fishes, with 

individuals unable to meet temperature-driven 

increases in tissue oxygen demand. Oil exposed fish 

were found to require their venous oxygen stores 

early, while non-exposed fish had no recourse to 

their stored supply [during the course of the study]."

Petroleum Exposure in the Southern California 

Bight

General colonization of natural areas near seeps and oil 

platform areas by fishes has been reported recently (Love and 

others, 2003). Some platforms were important to regional fish 

production, serving as marine refuges, and produced most or 

all of the adult fish found in the vicinity. Platforms acted as 

natural rocky outcrops, producing and attracting fishes, and 

fishes at platforms grew faster than at natural outcroppings 

and were at least as healthy. The macrofaunal benthic community condition in the Southern California Bight was assessed 

by Ranasinghe and others (2010). The overall condition was 

determined to be good and unchanging throughout the 9-year 

study; there was no evidence of disturbance near the Channel 

Islands and none on the mainland shelf. Bay and estuary communities were more frequently disturbed because of proximity 

to anthropogenic inputs (sewage treatment plant effluent and 

harbor areas).

Discharges from 23 oil platforms operating in the Southern California Bight in 1996 and 2000 were estimated from 

available data by Steinberger, and others (2004). Volumes of 

produced water (high salinity brine commingled with oil or 

gas in a well) were about 5 x 109 liters and relatively constant 

with time; amounts of associated solids decreased several-fold, 

from 12 metric tons in 1996 to 3 metric tons in 2000. These 

inputs into the Southern California Bight were considered 

minor compared to inputs from nearby coastal publicly owned 

treatment works. In contrast to platform events, releases of 

heavy crude from natural seeps offshore of Goleta, California, 

were estimated at 20 to 25 metric tons per day, and resulted in 

subsequent fallout of weathered oil to sediments with a period 

of 0.4 to 5 days (Farwell and others, 2009). Oil released from 

the seeps formed surface slicks and plumes of weathered oil 

in sediment. This weathered oil was depleted in all lower 

molecular weight components, which were dissipated by 

evaporation on the ocean surface (less than C16 components), 

and later by aerobic and anaerobic biodegradation. Dissolution 

was considered negligible, except for polar PAH components. 

Decreases in output of natural seeps of as much as 50 percent 

were reported in areas near oil-producing reservoirs with no 

net difference in total output (Quigley and others, 1999).

The effects of produced water on embryonic, larval, and 

juvenile Atlantic cod (Gadus morhua) were recently reported 

by Meier and others (2010). At 1 percent produced water, 

no effects on survival or hatching success were reported, 

but larvae had elevated concentrations of vitellogenin and 

cytochrome P450-1A biomarkers, failed to feed, and eventually starved. This was attributed to increased incidence of jaw 

deformities. Though alkylphenols (produced water additive) 

were bioconcentrated, juveniles efficiently metabolized the 

shorter chain congeners.

Triterpenoids were used to distinguish biogenic hydrocarbons (termed syngenetic biolipids) from petroleum hydrocarbons in the Southern California Bight by Simoneit and 

Kaplan (1980). The 17αH,21βH hopanes were demonstrated to 

be sensitive markers of petroleum pollution. The 17αH,21βH 

C27 to C35 hopanes comprised the major biogenic triterpenoids, whereas 17αH,18αH,21βH-28,30-bisnorhopane was the 

dominant triterpenoid in bight sediments and was proposed as 

a potential marker of Southern California petroleum. Extended 

C19 to C27 tricyclic diterpanes also were suggested as additional petroleum markers. Based on ratios of various biomarkers and PAHs, Simoneit and Kaplan concluded that sediments 

from the Southern California Bight contained petroleum from 

anthropogenic activity and seepage.

Environmental impacts of oil and gas drilling in the 

Southern California Bight were monitored from 1986 to 1990 

(Steinhauer and others, 1994). Hydrocarbon concentrations 

were sometimes elevated, but because of natural seepage 

rather than drilling. The presence of seep-related particles in 

sediments was recognized as an important factor in characterizing ambient hydrocarbon concentrations. No hydrocarbon 

concentrations sufficient to affect biota were determined in 

this study. In surface sediments collected near drilling operations, concentrations of aliphatics ranged from 23 to 180 μg/g 

dw and total-PAH concentrations ranged from not detectable 

to 1.5 μg/g dw. The greatest contributions to sediment loadings were determined to be from drilling muds (hydrocarbons 

from 137 to 988 μg/g dw, and total-PAHs from 0.87 to 51 μg/g 

dw) and tarballs (total-alkanes from 77 to 133 μg/g dw, hydrocarbons from 2 to 5 percent, aromatics from 3 to 19 percent, 

and an unresolved complex mixture comprising about 96 percent of the material). Biochemical and physiological measures 

of exposure of California halibut (Paralichthys californicus) to 

sediments from the Coal Oil Point natural oil seep (not shown) 

failed to demonstrate dose-response relations, which prevented 

estimates of sediment thresholds for biomarker responses such 
4 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

as P450 enzyme induction (Seruto and others, 2005). Seruto 

and others, also speculated that insensitivity for natural petroleum might be unique due to higher concentrations of lower 

molecular weight PAHs or other uncharacterized inhibitors as 

compared with sources of urbanized PAHs.

Peterson and others (1996) rationalized the typical failure 

to detect evidence of exposure or sublethal effects on fishes at 

drilling operations to a combination of two factors: resident 

fish populations are mobile over a much greater spatial range 

than the scale of environmental changes occurring at oil production platforms and natural seeps, and resident fish exposure 

to hydrocarbons and other contaminants is negligible. Effects 

on population sizes from exposure to hydrocarbons and PAHs 

near platforms have been observed at distances of about 

1,000 meters (m) in shallow waters with depths of only a few 

meters (Armstrong and others, 1979); however, the distances 

for effects drop off sharply as water depth increases. Osenberg and others (1992) reported that decreased populations 

extended only 100 m from oil platforms in less shallow waters 

with depths of 10 to 12 meters.

Rainbow seaperch (Hypsurus caryi) and rubberlip seaperch (Rachochilus toxodes) from a natural petroleum seep in 

the Santa Barbara Channel were investigated for a number of 

chemical markers, biomarkers, and sublethal effects by Spies 

and others (1996). PAHs and metabolites in bile, cytochrome 

450-1A, immunohistochemistry and histopathology were 

measured. Bile metabolites of naphthalene and phenanthrene 

were elevated at the seeps compared with a reference site (111 

and 137 μg/g as compared to 22 and 30 μg/g, respectively). 

Greater content of cytochrome P450-1A was documented in 

fish from the seep and total lesion scores were slightly higher 

for seep-dwelling fish, consistent with more limited movement 

and a greater degree of benthic feeding. Several biomarkers 

for xenobiotic chemicals that induce cytochrome P450-1A 

were proposed, including cartilage displaysia and abnormal 

branching of gill filaments and lamellae.

Semiquantitative measures of exposure to petroleum 

hydrocarbons in Southern California bays and harbors relative to nearby Channel Islands (not shown) using fluorescent 

aromatic compounds (FACs) in bile to estimate PAH exposure 

and a comet assay to assess DNA damage, were compared by 

Brown and Steinert (2003). From three to five-fold greater 

concentrations of FACs were measured in fish from harbors 

relative to islands. Concentrations of FACs in California halibut at harbors ranged from 1,200 to 4,100 ng BaP equivalents 

per milliliter (mL) bile (average 2,200 ng BaP-eq/mL). Pacific 

sanddab at Channel Island sites ranged from 200 to 840 ng 

BaP-eq /mL bile (average 400 ng BaP-eq/mL). A significant 

correlation between total-FAC concentrations (parent and 

substituted PACs) and DNA damage was documented at only 

two of eight harbor sites and was presumed due to contaminants other than PAHs. The FAC method integrates non-PAH 

and PAH fluorescence, producing elevated responses relative 

to PAH selective methods. In a recent study (Gale and others, 

2012), PAH metabolites in Pacific sanddab (Citharichthys 

sordidus), kelp rockfish (Sebastes atrovirens), and kelp bass 

(Paralabrax clathratus), were measured by HPLC-fluorescence; the concentrations of the PAH-glucuronides and the 

corresponding hydroxy-PAHs (OH-PAHs) were compared, 

and the resulting values were much lower than FAC estimates 

of total-PAH concentrations.

Fish collected near natural tar seeps, at nearby natural 

reefs, and at locations that were more distant from natural seeps, 

have exhibited concentration gradients of PAH metabolites in 

bile, indicating exposure (Gonzalez and others, 1992; Spies 

and others, 1996; Roy and others, 2003). However, because of 

natural regional hydrocarbon sources in the Southern California 

Bight, aliphatic and aromatic petroleum hydrocarbon concentrations in fish from platform sites must be interpreted within the 

context of the fish living in this local background. In addition, 

the variability in overall PAH exposure at platforms and near 

natural seeps results from the distribution of exposures of individual fish of differing ages to parent PAH sources from localized water concentrations and individual prey items. Additional 

variability is introduced by movement of fishes to and from 

different populations (Straughan and others, 1982; Peterson 

and others, 1996; Seruto and others, 2005). All of these factors 

contribute to the overall potential for exposure of resident fish 

populations to petroleum and other contaminants which, in turn, 

affects the health of individual species and ultimately affects 

overall ecosystem health.

The variability in concentrations of PAH metabolites 

within resident populations of platform and natural seep fishes 

from the Southern California Bight was recently determined 

(Gale and others, 2012); this previous investigation into PAH 

exposure at platforms and nearby natural areas reported only 

low concentrations of 1-hydroxypyrene in kelp rockfish from 

only the Santa Barbara Point Reef natural site. 1-Hydroxypyrene, suggested by Vuorinen for use as a bioindicator of PAH 

exposure of fish (Vuorinen and others, 2003; 2006) was not 

detected at any of the platforms (Gale and others, 2012). 

1-hydroxyfluorene was the most prevalent OH-PAH measured 

by Gale and others (2012); 1-hydroxfluorene was detected 

at only 2 of 7 platforms, and at low concentrations, less than 

50 ng per mg protein. The highest concentrations of another 

isomer, 2-hydroxyfluorene were documented in fish from Platform Holly and were only about 3-fold above the concentrations documented in fish from Horseshoe Reef, East Anacapa 

Island, and Coche Point natural sites; the concentrations at 

these sites were low and the concentration differences among 

these sites were not substantial (Gale and others, 2012). The 

PAH metabolite concentration ranges reported were among 

the lowest reported in the recently reviewed literature (refer to 

the Section: Comparison to Other Studies) and are approaching those concentrations reported in fish from pristine ocean 

sampling (Goksøyr and others, 2009).
Methods 5

Nonpetroleum Exposure in the Southern 

California Bight

The fate and dynamics of nonpetroleum related organic 

contaminants in sediments along the Palos Verdes shelf has 

been studied in detail; for overviews see Schiff (2000) and 

Schiff and others (2000) and Venkatesan and others (2010). 

The predominant nonpetroleum related contaminants in 

sediments are 1,1,1-trichloro-2,2-di(4-chlorophenyl)ethane (p,p’-DDT) and its degradation products resulting from 

historic discharges of DDT manufacturing waste; a second 

major contaminant class, polychlorinated biphenyls (PCBs) 

again resulted from historic discharges of manufacturing waste 

(Zeng and Venkatesan, 1999; Schiff, 2000; Schiff and others, 

2000; Eganhouse and others, 2000; Eganhouse and Pontillo, 

2000). Total-DDT related chemicals (DDT and its degradation 

products, or DDTs), originally from sediment stores close to 

outfalls, provided sources for widespread contamination of 

sediments in the Southern California Bight by resuspension, 

transport, and redeposition. The degradation of p,p′-DDT to 

1,1- dichloro-2,2-di(4-chlorophenyl)ethene (p,p′-DDE) indicates hydrolytic dehydrochlorination at the sediment surface, 

whereas formation of 1,1-dichloro-2-di(4-chlorophenyl)

ethylene (p,p′-DDMU) represents reductive dechlorination in 

subsediments. Most of the changes in concentrations of DDTs 

and degradates result from mobilization of sediments and subsequent resettling over greater areas of less contaminated sediment farther from the source. Long-term predictions suggest 

that the existing inventory of DDTs will remain buried and 

that surface concentrations will gradually decrease throughout 

the next several decades. In addition, erosion processes south 

of the outfalls will introduce some DDEs into the surface 

sediments and release some DDEs into the overlying water 

column by prevailing ocean currents (Sherwood and others, 

2002). The percent of DDE degradates in DDTs is uniformly 

about 90 percent in sediments far from sources, but is much 

lower, about 10 percent, in sediments near sources (Eganhouse 

and others, 2000; Eganhouse and Pontillo, 2000). Compared 

with the profiles of DDTs, the profiles of PCB congeners were 

highly conserved over much greater distances down-plume 

from waste treatment plant outfalls, due to the lack of substantial metabolic activity.

The termination of the dominant source of DDT to the 

Los Angeles County Sanitation District’s Joint Water Pollution 

Control Plant (JWPCP) submarine outfalls in 1970 decreased 

DDT input by thirty-fold. In 1973, the total-DDT concentration in outfall sediments was about 440 μg/g. In the several 

years that followed, total-DDT in some impacted marine fishes 

decreased from four to eight-fold from peak concentrations, 

though, no decrease was noted in the bottom-feeding Dover 

sole (Microstomus pacificus) (Smokler and others, 1979). 

Resident top-level carnivores such as the California sea lion 

(Zalophus californianus) and the harbor seal (Phoca vitulina) 

were reported to continue to exhibit elevated concentrations 

of contaminants, mainly DDTs and PCBs, compared with 

transient species such as the northern elephant seal (Mirounga 

angustirostris) (Blasius and Goodmanlowe, 2008). Farther 

south, below San Diego Harbor (not shown), monitoring 

has shown some areas of the shelf contaminated with PCBs 

(Parnell and others, 2008). Parnell and others (2008) have 

attributed most of the current PCB loading in fish to the ongoing practice of dumping contaminated sediments dredged from 

San Diego Bay.

To extend our previous work, which investigated potential acute exposure to PAHs by determining metabolites in bile 

of fishes at platform and nearby natural areas, in this study, we 

measure recalcitrant, higher molecular weight PAHs in fish tissues of Pacific sanddab to provide a measure of any potential 

chronic exposure to PAHs of fish resident at platforms and 

nearby natural areas, which was not readily detectable by PAH 

metabolite measurements. In addition, legacy contaminants, 

PCBs and organochlorine pesticides (OCPs), and the more 

recent contaminants, polybrominated diphenylethers (PBDEs), 

were measured to provide critical information about exposure 

in fish populations at platforms compared to natural seeps, and 

insight into the movement or recruitment of fish from nearby 

locations. Measurements of aliphatic hydrocarbons, PAHs, 

PCBs, PBDEs, and OCPs in fish populations from natural 

areas also were determined, providing a measure of the background exposure concentrations of petroleum hydrocarbons 

from natural petroleum seepage, and PAHs and other contaminants from waste treatment plant outfalls and harbor activities 

that are transported into the vicinities of platforms and natural 

areas.

Methods

Study Sites and Sample Collection

In earlier phases of this research, heavy metal burdens in 

fishes and PAH-metabolites in bile from fishes were characterized at platforms and nearby natural areas in the Southern California Bight (Love and others, 2009; Gale and others, 2012). 

Sites previously selected for the metals and bile metabolite 

studies were used during the present study to provide continuity. Pacific sanddab was selected as a model species, being a 

widespread, opportunistic-feeding bottom dweller that does 

not make widespread movements (Love and Goldeberg, 2009). 

The whole fish samples (less gall bladders), corresponding 

to the fish previously investigated for bile metabolites, were 

used in this study. The sampling effort was done by the Marine 

Science Institute at the University of California at Santa 

Barbara. Sampling corresponded to the previously selected 

13 sites (7 platform sites and 6 adjacent, natural area reference sites) outlined in earlier work (fig. 1) (Gale and others, 

2012). Pacific sanddab that were platform resident and others 

that were part of the regional background (the areas off Point 

Conception, within the Santa Barbara Channel, and within the 

San Pedro Basin, not shown) were collected (table 1).
6 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

6D

6C

5C

5B

4B 4C

3B

3C

2C

2B

1B

1C 1A

2A 3A

4A

5A

6A

6B

Figure 1. Site locations in the Southern California Bight. Platforms (red) and natural areas (green).

Table 1. Samples for whole-fish composites of Pacific sanddab from natural areas and platforms.

[g, grams; ±, plus or minus; cv, coefficient of variation (percent relative standard deviation)]

Sample Latitude

(degrees, minutes)

Longitude

(degrees, minutes)

Composite

Range (g) Number Average (g) ± cv 

(percent)

Natural areas 10–242 32 54.9 ± 125

CAND (Campus Point) 34.22.365 -119.50.168 20–42 5 34.4 ± 25

RIND (Rincon) 34.15.300 -119.33.120 11–242 5 77.4 ± 123

HUEN (Hueneme) 34.07.097 -119.12.685 12–40 6 22.7 ± 50

NESC (NE Santa Cruz) 34.01.870 -119.30.380 86–231 5 171.6 ± 36

EDND (Platform Edith Natural Area) 33.35.050 -118.12.770 17–27 5 19.8 ± 21

SBPN (Santa Barbara Natural Area) 34.22.800 -119.41.670 10–29 6 17.3 ± 39

Platforms 11–82 36 32.1 ± 61

HOLL (Holly) 34.23.339 -119.54.436 24–33 5 28.8 ± 15

PLATC (Platform C) 34.19.987 -119.38.029 11–27 9 17.4 ± 30

HOGA (Hogan) 34.20.275 -119.32.539 13–56 5 31.2 ± 55

GINA (Gina) 34.07.050 -119.16.684 13–22 6 17.2 ± 24

GILD (Gilda) 34.10.896 -119.25.236 41–74 5 54.2 ± 25

EDIT (Edith) 33.35.670 -118.08.050 24* 1 24*

ELLE (Ellen) 33.35.000 -118.07.770 43–82 5 60.4 ± 27

*

Platform EDIT—only one sample was available.
Methods 7

Adult Pacific sanddab of the same size class, were collected from the decommissioned oilrig platforms and the 

platform shell mounds, and from natural areas away from 

platforms. The fish were collected by spearfishing with 

SCUBA gear or other standard collection methods such as 

hook-and-line, traps, or trawls. Five fish were collected at each 

site; additional collection trips were necessary to collect some 

species at sparsely populated sites, and were completed within 

a few days of the initial collection trips. The fish samples were 

immediately placed on ice and were returned to the laboratory 

for gall bladder excision for measurement of PAH metabolites in bile (Gale and others, 2012). Following gall bladder 

removal, the whole fish (less gall bladders) were placed in 

an appropriately labeled storage container and transferred 

to either a -20 degrees Celsius (oC) or a -80 oC freezer. The 

frozen samples were labeled with the collection site identifier, 

wrapped in aluminum foil, placed in a ziplock bag, and packaged on dry ice for overnight transport to the U.S. Geological 

Survey (USGS), along with chain of custody forms and any 

additional, pertinent sample collection documentation. Following arrival, the samples were inventoried and stored in a 

-20 oC freezer when not in use.

Compositing and Homogenization

Only Pacific sanddab, collected from near seven offshore oil-platforms and from six nearby natural sites, were 

targeted for contaminants analysis (table 1). The fish ranged in 

size from 10 to 242 g (n=68), with 76 percent of the samples 

being less than 50 g; though sample size differences confound detailed data interpretation, the small sizes of some 

individual fish and the cost of analyzing individual fish was 

prohibitive. The gallbladders (with a small part of the liver) 

were excised for PAH metabolite analyses, and the remaining fish (less gallbladder) used for PAH and organochlorine 

contaminant analyses. Individual whole fish (less gallbladder) 

were removed from the -20 oC freezer and homogenized by 

a combination of band-sawing, slicing, and, finally, grinding. 

Composites were made by homogenizing 3-g portions of each 

previously homogenized individual fish sampled at each site; 

sufficient tissue was retained to allow analysis of individual 

fish should sufficient concentrations of any analyte be found 

in any composite sample. This method of compositing did not 

allow statistical testing for the effects of variable fish size; 

moreover, had size-related differences been present, small 

individuals were given the same weight as large individuals in 

the composited sample.

Materials

Dichloromethane, hexanes, acetone, methanol, methylt-butylether, and 2,2,4-trimethylpentane (all Optima Grade) 

were obtained from Fisher Scientific (Fair Lawn, New Jersey). 

All open-column fractionations were performed in 1-centimeter (cm) inner-diameter glass columns. The octadecyl silica/

Silica Gel (C18/SG) columns for PCB/PBDE/OCP fractionation were prepared by layering 1.00 g of octadecyl silica [C18

40 micrometers (μm), 60 angstroms (Å) pore size, Varian, 

Palo Alto, California] on top of 5.00 g of silica gel 60 (70–

230 mesh, activated at 130 °C, Merck, Darmstadt, Germany). 

The potassium-hydroxide impregnated silica gel (KS) was 

prepared by reacting a methanolic solution of 168 g of KOH 

(Fisher Scientific, Fair Lawn, New Jersey) with 300 g of silica 

gel 60, followed by rotary evaporation to remove methanol 

and activation of the KS at 130 °C; 5.00 g columns were used 

for cleanup of aliphatic hydrocarbon/PAH fractions after 

low-performance size-exclusion chromatography (LP-SEC). 

The deactivated SG was prepared by adding 3.00 mL of water 

(Millipore Synergy UV 18 megaohm per centimeter (mΩ/cm) 

water-purification system, Millipore, Billerica, Massachusetts) 

to 100 g of silica gel 60, previously activated at 130 °C; 5.00 g 

of the deactivated SG were used for aliphatic hydrocarbon/

PAH fractionation.

LP-SEC used a primary 60 x 2.5 cm glass column 

containing 70 g of Biobeads S-X3 and a 30 x 2.5 cm glass 

guard column containing 10 g of S-X3 (Bio-Rad Laboratories, Richmond, California) with a dichloromethane mobile 

phase [flow rate 4.00 milliliters per minute (mL/min)]. 

High-performance size-exclusion chromatography (HP-SEC) 

used a Phenogel® guard column and a 30 x 2.12 cm Phenogel® (10 μm, 100 Å pore) analytical column (Phenomenex, 

Torrance, California) with a dichloromethane mobile phase 

(flow rate also 4.00 mL/min).

All analytical standards for aliphatic hydrocarbons, 

PAHs, OCPs, PCBs, and PBDEs were purchased from 

AccuStandard, New Haven, Connecticut. Deuterated and perdeuterated procedural and instrumental internal standards were 

purchased from Cambridge Isotope Laboratories, Andover, 

Massachusetts.

Sample Cleanup and Analysis

Two parallel analytical schemes were used to analyze the 

fish: the first, targeting aliphatic hydrocarbons and selected 

PAHs (consisting of a set of 20 parent PAHs, 11 alkyl-substituted PAHs, and 3 polycyclic aromatic thiophenes), and the 

second, targeting PCBs, OCPs, and PBDEs, as outlined in 

figure 2. The schemes allowed independent optimization of 

extraction and fractionation procedures for aliphatic hydrocarbons/PAHs and PCB/OCP/PBDEs, respectively.

Aliphatic Hydrocarbons, Polycyclic Aromatic 

Hydrocarbons, and Polyaromatic Compounds

Previous investigation of these samples for PAH-related 

bile metabolites indicated that acute exposure to PAHs was 

low; therefore, sample preparation for 34 PAHs (consisting of 

20 parent PAHs, 11 alkyl-substituted PAHs, and 3 polycyclic 

aromatic thiophenes) was planned; and sensitivity increased 

by concentrating the final extracts to 200 microliters (μL). 
8 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

Lipid 

Determination

Sample homogenization 

and Surrogate Amendment

(5 gram-eq)

Low Performance - Size Exclusion Chromatography

(higher loading)

High Performance - Size Exclusion Chromatography

(lower loading)

KOH-SG

5% MTBE/hexanes

(HC/PAH fraction only)

Soxhlet Extraction

1:1 acetone/DCM

Column Extraction

DCM

Aliphatics/PAHs c-PCBs, OCPs, PBDEs

Data Interpretation

C18 / Silica Gel 

OCP/PBDE Fractionation

OCPs/PBDEs

Analysis: GC/ECD (dual column)

c-PCBs/ OCPs

Analysis: GC/ECD (dual column)

Silica Gel (3% deactivated) 

Fractionation

SG(3%)-1

hexanes

PAHs

Analysis: GC/MS

Aliphatic Hydrocarbons

Analysis: GC/FID

SG(3%)-2

25% MTBE-hexanes

C18 / SG-2

40% MTBE-hexanes

C18 / SG-1

hexanes

Aliphatics/PAHs c-PCBs, OCPs, PBDEs

Figure 2. Analytical scheme for aliphatic hydrocarbons (HCs), polycyclic aromatic hydrocarbons

(PAHs), polycyclic aromatic thiophenes (PACs) (left), and polychlorinated biphenyl congeners

(c-PCBs), organochlorine pesticides (OCPs) and polybrominated diphenylethers (PBDEs) (right). Eq, 

equivalents; DCM, dichloromethane; SG, silica-gel; KOH-SG, potassium hydroxide impregnated SG; 

%, percent; MTBE, methyl-t-butyl ether; C18, octadecylsilane; GC/FID, gas chromatography-flame 

ionization detection; GC/ECD, GC-electron capture detection; GC/MS, GC-mass spectrometry.
Methods 9

Accordingly, approximately 5-g portions of fish composite 

samples were removed for analysis, dehydrated by addition of 

anhydrous sodium sulfate (Na2SO4), and spiked with 250 ng 

of each of 16 perdeuterated PAHs (d-PAHs) as procedural 

internal standards (surrogates). Soxhlet extraction was used to 

recover potentially recalcitrant PAHs from fish tissues. Samples were soxhlet-extracted with 1:1 acetone:dichloromethane 

(volume:volume, v:v) for 18 hours, solvent-exchanged to 

dichloromethane and extractable lipids determined on a 2-percent aliquant.

The analytes were separated from residual higher molecular weight compounds in the extracts by sequential LP-SEC 

and HP-SEC. The LP-SEC step was capable of higher lipid 

loadings (750 milligrams, mg) but with a lower resolution 

separation of the analytes from higher molecular weight 

biogenic interferences. Therefore, a KS cleanup, eluting with 

5 percent methyl-t-butylether in hexanes, was introduced after 

the LP-SEC fractionation step to remove additional biogenic 

compounds, before clean-up by the HP-SEC fractionation step. 

After removal of biogenic interferences, the aliphatic hydrocarbons and the PAHs were separated using 3 percent water-deactivated silica gel. Activated silica gel sorbents may strongly 

retain or degrade some aromatic sulfur heterocycles (dibenzothiophene, benzonaphthothiophene, and benzo[b]naphtho[2,1-

d]thiophene); therefore, slight water-deactivation of silica gel 

was used to minimize degradation while fractionating most 

aliphatic hydrocarbons from the aromatics. The aliphatic 

hydrocarbons were eluted with hexanes, followed by elution of 

the PAHs with 25 percent methyl-t-butylether in hexanes.

The fractions for alkane analysis were concentrated to 

approximately 1.0 mL and 100 ng of p-terphenyl-d14 added 

as the instrumental internal standard. Aliphatic hydrocarbons 

were quantified by gas chromatography with flame-ionization 

detection (GC-FID) using cool on-column injection onto 

a retention gap (3 m x 530 μm inner diameter, methyldeactivated) connected by a press-tight fitting to a 5-percent 

phenyl-methylsiloxane capillary column (60 m x 250 μm inner 

diameter, 0.25 μm film thickness). The hydrogen carrier gas 

was pressure-regulated at 25 pounds per square inch gauge 

(psig) and the FID was held at 330 °C. The GC temperature 

was held at 40 °C for 5 min, then ramped at 10 °C/min to 

310 °C and held for 15 min. Aliphatic hydrocarbon standards 

(C9–C40 n-alkanes, pristine, and phytane) at six concentrations 

ranging from 0.20 to 100 μg/mL were used for component 

identification and calibration.

For PAH screening, the final extracts were concentrated 

to approximately 1.0 mL and 100 ng of 2-methylnaphthalene-d10 and benzo[e]pyrene-d12 were added as instrumental 

internal standards. The PAH analytes were quantified by gas 

chromatography with quadrupole mass spectrometric detection, using cool on-column injection onto a retention gap (3 m 

x 530 μm inner diameter, methyl-deactivated), connected 

by a press-tight fitting to a 5-percent phenyl-methylsiloxane 

capillary column (30 m x 250 μm inner diameter, 0.25 μm 

film thickness). The helium carrier gas was pressure-regulated 

at 13 psig. The GC temperature was held at 50 °C for 2 min, 

ramped at 25 °C/min to 130 °C, held for 1 min, then increased 

at 6 °C/min to 310 °C and held for 5 min. The transfer-line, 

source, and quadrupole were held at 310, 230, and 120 °C, 

respectively. Standards of 34 PAHs at 6 concentrations ranging from 10 to 2,000 ng/mL were used for component identification and isotopic-dilution calibration. After screening 

for PAHs and other potential contaminants or interferences 

at 5 gram-equivalents/milliliter (g-eq/mL) in full-scan mode 

(35-600 atomic mass units (amu)) to avoid degraded chromatography from overloading the GC column with high amounts 

of matrix, the extracts were concentrated to 25 g-eq/mL 

(200 μL final volume) and PAHs were quantified by GC-MS 

using selected-ion monitoring.

Polychlorinated Biphenyls, Organochlorine 

Pesticides, and Polybrominated Diphenylethers

As was done for the aliphatic hydrocarbon and PAH 

analyses above, 5-g portions of fish composite samples 

were removed for analysis, dehydrated by addition of 

anhydrous Na2SO4, and spiked with 40 ng each of the 

procedural internal standards: 2,4,5-trichlorobiphenyl 

(PCB 029); 2,2′,4,4′,6,6′-hexachlorobiphenyl (PCB 155); 

2,2′,3,4,4′,5,6,6′-octachlorobiphenyl (PCB 204); and octadeuterated 1,1- dichloro-2,2-di(4-chlorophenyl)ethane (p,p′-

DDD-d8). PCBs, OCPs, and PBDEs were column-extracted 

from tissues with dichloromethane. Activated silica gel fractionation was used to separate most PCB congeners and a few 

pesticides from most of the pesticides and PBDEs. Dichloromethane extractable lipids were determined on 2 percent 

aliquants of the extracts.

The analytes were separated from residual higher molecular weight compounds in the lipophilic extracts by sequential 

LP-SEC and HP-SEC. The KS cleanup between the LP-SEC 

and the HP-SEC steps was omitted, as KS removes some 

pesticides. After removal of biogenic interferences, the PCBs, 

OCPs, and PBDEs were fractionated using C18 layered SG. 

The first silica gel fraction (SG-1) was eluted with hexanes and 

comprised greater than 90 percent of the total-PCB concentration, along with six pesticides: aldrin, pentachlorobenzene, 

hexachlorobenzene, heptachlor, p,p′-DDE (partial recovery), 

and mirex. The second silica gel fraction (SG-2) was eluted 

with 40 percent methyl-t-butylether/hexanes and comprised 

less than 10 percent of the total-PCB concentrations (greater 

than 50 percent of 22 of the less-chlorinated congeners and 

greater than 10 percent of 18 additional less-chlorinated congeners), along with the remaining pesticides and PBDEs.

Final extracts from SG-1 and SG-2 were concentrated 

to 1.0 mL (5 g-eq/mL) and 40 ng of 2,4,6-trichlorobiphenyl 

(PCB 30) and 2,2′,3,3′,4,4′,5,6,6′-nonachlorobiphenyl (PCB 

207) were added as instrumental internal standards. Individual congeners of PCBs and PBDEs, and organochlorine 

pesticides were quantified by dual-column gas chromatography with electron-capture detection (GC-ECD), using cool 

on-column injection onto retention gaps (3 m x 530 μm inner 
10 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

diameter, methyl-deactivated), connected by press-tight fittings to a 100-percent methylsiloxane capillary column and 

to a 5-percent phenyl-methylsiloxane capillary column (each 

60 m x 250 μm inner diameter, 0.25 μm film thickness) from 

Agilent, Inc., Santa Clara, California. The hydrogen carrier 

gas was pressure-regulated at 25 psig and the ECDs were 

held at 330 °C. The initial GC temperature was 60 °C and 

immediately ramped at 15 °C/min to 150 °C, then ramped 

at 1 °C/min to 240 °C, and finally ramped at 10 °C/min to 

330 °C and held for 15 min. As many as nine concentrations 

of standards, ranging from 0.03–30 ng/mL (PCB congeners), 

0.1–80 ng/mL (OCPs), and 2–200 ng/mL (PBDE congeners), 

were used for component identification and internal standard 

calibration. Potential analyte peaks were identified on one 

column and confirmed on the second column wherever possible (Schwartz and Stalling, 1991).

Principal Components Analysis

The PCA applications used in this study were part of 

the Soft Independent Modeling by Class Analogy software 

SIMCA-P 8.0 (UMetrics AB, Umeå, Sweden). Principal Components are bilinear projection models constructed by decomposing a class data matrix into score, loading, and residuals 

matrices (Schwartz and Stalling, 1991). The objective was 

to build models for each class of contaminant, projecting the 

n-dimensional pattern or profile of the contaminant dataset 

onto two or three dimensions for interpretation of the relations 

between samples. Concentration data were normalized before 

PCA, removing the strong correlation of the first PC with total 

concentration.

Quality Control

Exposure to light was avoided or minimized during all 

sample and standard handling steps to reduce losses from 

photodegradation of PAHs, and to a lesser extent, of PBDEs. 

Method performance was monitored using several quality 

control measures. The inclusion of procedural blanks was 

used to assess the laboratory background of analytes and the 

recoveries of procedural internal standards. Procedural spikes 

were used to assess the recoveries of all analytes through the 

procedure. Bluegill (Lepomis macrochirus) fish tissue (negative control) matrix blanks were used to assess the potential 

background interferences from tissue subjected to the cleanup 

and fractionation schemes, and negative control fish tissue 

samples spiked with low concentrations of analytes were used 

to determine method recoveries of the analytes. An “in-house” 

positive control material prepared from common carp (Cyprinus carpio) from Saginaw Bay, Michigan, with environmentally incorporated residues of many analytes, was used to monitor the long-term performance of the analytical methods for 

several years (Hinck and others, 2007). Replicated (actually 

pseudoreplicate) analyses of randomly selected field samples 

in triplicate were used to demonstrate the reproducibility of 

the methods for the study samples. The procedural internal 

standards were added to all samples at the beginning of the 

preparatory scheme, before the extraction step, to monitor and 

adjust recoveries for each sample (sample handling losses).

Method reporting limits (MRLs) for total-aliphatic 

hydrocarbon and –PCB concentrations were set at 3 times the 

average total amounts measured in the procedural blanks run 

with each set, or based on the lowest calibration standard run 

in the calibration curve (200 ng/mL per alkane and 0.1 ng/

mL per PCB congener). The MRLs were set to 10 ng/mL for 

PAHs, 0.1 ng/mL for OCPs, and 2 ng/mL for PBDEs, based 

on procedural background amounts and the analysis of lowconcentration calibration standards.

Aliphatic hydrocarbons were only screened, using external standards and quality control samples, and no procedural 

internal standards were used to monitor recoveries throughout 

the aliphatic hydrocarbon cleanup procedures. Recoveries 

of aliphatic hydrocarbons were estimated from recoveries of 

spiked negative control fish material (matrix spikes), and were 

within quality control guidelines of 50 to 125 percent, indicating acceptable performance of the screening method.

Results and Discussion

Quality Control Results

A brief summary of quality control related information 

associated with the various analytical measurements is presented below.

Recoveries of the deuterated PAH procedural internal 

standards (deactivated silica-gel, fraction 2) were within quality control guidelines of 50 to 125 percent. All sample recoveries were between 51 and 119 percent; recoveries of volatile 

components (naphthalene-d8, acenaphthylene-d10, acenaphthene-d10) were lower, ranging from 51 to 78 percent. Recoveries of less volatile PAHs (fluorene-d10 through benzo[g,h,i]

perylene-d12) averaged 79 to 92 percent. Isotope-dilution quantification inherently corrects each target PAH analyte for the 

recovery of the corresponding labeled surrogate. The precision 

of replicate analyses (n=3) of Pacific sanddab from Platform C 

for those PAHs greater than the reporting limits of the method 

ranged from 5 to 19 percent.

Recoveries of the procedural internal standards indicative 

of OCP and PCB analytes (PCB 029, 155 and 204) in the first 

silica-gel fraction, SG-1, were within quality control guidelines of 50 to 125 percent and ranged from 62 to 105 percent 

in all samples, with the lowest recoveries (62 to 93 percent) 

occurring for the most volatile procedural internal standard 

(PCB 029). Recoveries of total-PCB concentrations from the 

fortified negative control material were 103 percent, with individual congeners ranging from 60 to 117 percent. Again, lower 

recoveries were limited to only the three volatile monochlorosubstituted PCB congeners (PCBs 1, 2, and 3). The recovery 

of total-PCB concentrations from the positive control material 
Results and Discussion 11

was 120 percent of the historical average. The precision of 

replicate analyses (n=3) of Pacific sanddab from Platform C 

ranged from 2 to 74 percent for those PCB congeners greater 

than the reporting limits of the method. Most of the variability 

was introduced as a result of most congeners being near the 

method reporting limits; precision for those PCB congeners at 

concentrations greater than 10 times the reporting limits generally ranged from 2 to 20 percent. The precision for total-PCB 

concentrations (sum of PCB congener concentrations above 

the reporting limit) was artificially much improved by the 

weightings introduced from congeners with greater concentrations: sanddab from Platform C averaged 10 ng/g total PCBs, 

coefficient of variation 1.8 percent. The procedural blank 

analysis indicated a mass-based method background of about 

12 ng of total-PCB amounts; this is equivalent to about 2.6 

ng/g total-PCB concentrations in the 5-g field samples and is 

less than 20 percent of the lowest PCB concentrations measured in any field samples.

The recoveries of the procedural internal standard p,p’-

DDD-d8, indicative of the OCP analytes second silica-gel 

fraction (SG-2), were within quality-control guidelines (50 to 

125 percent) with recoveries in most samples between 99 to 

117 percent.

Recoveries of OCPs from the fortified negative control 

material (whole bluegill) ranged from 78 to 113 percent, 

though for most analytes recoveries were more precise, 

averaging about 92 percent. The exception was methoxychlor, recovered at 132 percent, the result of only partial 

chromatographic resolution from background interference. 

The recovery of OCPs from the positive control Saginaw Bay 

carp material ranged from 50 to 125 percent of the historical 

average for those pesticides with concentrations substantially 

above the reporting limits, with an average OCP recovery 

of 110 percent. The slightly higher values for coefficients 

of variation were related to slight on-column degradation of 

active contaminants (endrin, p,p’-DDT, and methoxychlor) 

and the precision of methoxychlor was less than most other 

OCPs because of PBDE and PCB interferences. Only 16 of the 

29 targeted OCPs were quantified at concentrations above the 

MRL (0.1 ng/g) in the replicates, and 15 of these OCPs were 

less than 0.5 ng/g and had larger coefficients of variation (5 to 

16 percent); the concentration of the remaining OCP (p,p’-

DDE) averaged 11 ng/g and had a smaller coefficient of variation (1.2 percent). The procedural blank analyses indicated 

negligible background concentrations of OCPs. The long-term 

MRLs for OCPs are less than 0.1 ng/g.

The procedural blank analyses indicated normal laboratory 

background concentrations of individual PBDEs ranging from 

less than 0.01 to 0.03 ng/g (PBDE-099 and -100), which were 

considered when evaluating the lower PBDE concentration samples (Supporting Information, tables S5 and S6). The precision 

of replicate analyses (n=3) of Pacific sanddab from Platform C 

for PBDE-047 was 1.6 percent at a concentrations of 0.50 ng/g; 

the precision was undetermined for all PBDEs because concentrations of selected PBDE congeners were less than the method 

reporting limits of 0.4 ng/g for replicates of this sample.

This Study

The masses of the 68 Pacific sanddab from natural 

and platform locations ranged from 10 to 242 g, with fish 

from the natural areas averaging 55 g and fish from platform locations averaging 32 g, from table 1. This size range 

included immature and mature life stages of sanddab. On 

average, fish from natural areas were larger than fish from 

platforms. The effects on contaminant concentrations for 

each class of contaminant in fish are discussed later in this 

section. The fish masses from the natural areas were biased 

by all fish from northeast Santa Cruz, which were larger 

(86–231 g, average 172 g, n=5) than the averages of any 

other natural or platform location (averages 17–77 g). Only 

one of the five fish collected from the Rincon natural area 

was similar in size to those from the northeast Santa Cruz 

natural area (242 g). All other fish from natural and platform 

locations were smaller, and similar in size, ranging from 10 

to 42 g and averaging 29 g (n=58). Only one Pacific sanddab 

sample (24 g) could be collected from Platform Edith. This 

sample was low in extractable lipid, about three-fold lower 

than most other platform samples, and the sample was 

relatively high in contaminants; this combination caused 

lipid-normalized values to be elevated relative to all other 

samples, as will be discussed.

Extractable lipid content of Pacific sanddab from natural 

and platform locations ranged from 0.57 to 2.27 percent 

and averaged 1.43 percent (n=13 composites of 5 fish each, 

table 2). Recoveries of procedural internal standards were 

within quality-control specifications, and generally ranged 

from 80 to 100 percent, which indicated complete extraction 

and recovery of the analytes. This indicated that extraction 

efficiencies for lipids (as total dichloromethane-extractable 

residues) were also excellent.

The percentage of extractable lipids averaged 1.63 percent (n=6 composites) for fish from the natural areas and was 

slightly less (1.35 percent, n=7 composites) for fish from the 

platform locations. Comparisons were made among composites that contained predominantly larger fish and those that 

contained mostly smaller fish; this grouped fish composites 

into platforms and natural areas (because of size differences). 

Note that fish composites from platforms Ellen and Edith had 

much lower percentages of extractable lipids. Overall, lipid 

normalization made only slight differences, again, mostly for 

those composites of small fish.

Thirteen composite samples of Pacific sanddab were 

prepared and analyzed for aliphatic hydrocarbons, PAHs, 

PCBs, OCPs, and PBDEs by USGS, and the results are 

presented below. All contaminant values in field samples 

were adjusted for recoveries of procedural internal standards 

(surrogates) and corrected for procedural blank background 

values (Detailed individual sample information may be found 

in the Supporting Information, tables S1–S8). Procedural 

blank values were adjusted for surrogate recoveries before 

being used to correct field results for background contaminant values.
12 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

Table 2. Lipid values for whole-fish composites of Pacific 

sanddab from natural areas and platforms.

[Lipids are expressed as a percent based on wet tissue weight, of dichloromethane column-extractable material; ±, plus or minus; cv, coefficient 

of variation (percent relative standard deviation); range, average, and 

coeffificent of variation summarize the composites from the natural areas 

and from the platforms]

Sample Extractable lipids

(percent)

Natural areas Range: 1.30–2.27

Average ± cv: 1.63 ± 24

CAND (Campus Point) 2.08

RIND (Rincon) 2.27

HUEN (Hueneme) 1.31

NESC (NE Santa Cruz) 1.32

EDND (Platform Edith Natural Area) 1.52

SBPN (Santa Barbara Natural Area) 1.30

Platforms Range: 0.57–1.72

Average ± cv: 1.35 ± 32

HOLL (Holly) 1.57

PLATC (Platform C) 1.68

HOGA (Hogan) 1.44

GINA (Gina) 1.72

GILD (Gilda) 1.54

EDIT (Edith) 0.57

ELLE (Ellen) 0.92

Aliphatic Hydrocarbons

As a supplemental part of the analysis of fish for polycyclic aromatic hydrocarbons, the first deactivated silica 

gel fractions, containing aliphatic hydrocarbons that were 

separated from PAHs, were retained and screened to assess 

the patterns and concentrations of nonaromatic hydrocarbons 

in fish collected from platforms and nearby natural areas. 

As stated for the extraction of lipids, recoveries of procedural internal standards ranged from 80 to 100 percent, thus, 

recoveries of about 90 percent were estimated for aliphatic 

hydrocarbons from C9

 to C40. This indicated complete extraction and recovery of the analytes, including aliphatic hydrocarbons. Aliphatic hydrocarbons comprise a major fraction 

of petroleum and may be used to assess contamination by oil, 

from platforms and natural seeps, in the marine environment 

(Law, 1978; Lytle and Lytle, 1979; Simoneit and Kaplan, 

1980; Gonzalez and others, 1992; Steinhauer and others, 

1994; Quintero and Diaz, 1994; Marcias-Zamora, 1996; 

Peterson and others, 1996; Spies and others, 1996; Quigley 

and others, 1999; Pena-Mendez and others, 2001; Farwell and 

others, 2009.

Aliphatic hydrocarbon concentrations were uniformly 

low in all samples from the platforms and the natural locations 

and below the limits of detection of the screening method 

used. Method limits of detection were estimated at 20 ng/g 

based on tissue wet-weight (ww) per component or 200 ng/g 

ww for total-aliphatic hydrocarbons. Reporting limits were 

200 ng/g ww for total-aliphatic hydrocarbons. Because of 

the lack of detectable components, calculated metrics such as 

total hydrocarbons, even-numbered carbon and odd-numbered 

carbon alkane concentrations, the carbon predominance index, 

and ratios between C17/pristane, C18/phytane, and pristane/

phytane ratios could not be determined. Application of these 

metrics in situations of sufficient detectable concentrations 

may have been otherwise used to evaluate the petrogenic and 

pyrogenic contamination contributions at platform sites and 

the nearby natural areas.

Polycyclic Aromatic Hydrocarbons

Total-PAH concentrations (expressed are the sum of 

20 parent PAHs, 11 alkyl-substituted PAHs, and three polycyclic aromatic thiophenes) in composite Pacific sanddab ranged 

from 15 to 37 ng/g ww in samples collected at natural areas 

and from 8.7 to 22 ng/g ww in samples collected at platforms 

(tables 3, S1, S2). Average total-PAH concentrations were 

low in fish from all locations, but concentrations in fish from 

natural areas were nearly twice concentrations in fish from 

platforms (p=0.0045); however, because of the small numbers of samples and the use of composite whole-fish samples 

(including gut-contents), any interpretation of this difference 

would require further investigation.

Seven of the 34 target PAHs (naphthalene, 2-methyl 

and 1-methylnaphthalenes, biphenyl, phenanthrenes, fluoranthene, and pyrene) were reported in Pacific sanddab 

from natural areas and platforms; additionally, 2-methylphenanthrene was reported in sanddab from four of the six 

natural areas, and chrysene and benzo(k)fluoranthene were 

reported only in sanddab from the Campus Point natural 

area. (fig. 3A). The numbers of positive samples are few for 

the parent PAHs (this study) and for the OH-PAH metabolites (Gale and others, 2012). The positive OH-PAH detections included only 2 Pacific sanddab individuals, all other 

OH-PAH positives were for other species, for which parent 

PAHs were not determined in this study. This paucity of data 

necessitated prudence in reaching conclusions or associations 

between positive PAH concentrations and positive OH-PAH 

concentrations.

Normalization of contaminant concentrations for extractable lipids in the composite samples was performed for PAHs 

and for the other targeted contaminants. Lipid normalization decreased the differences in contaminant concentrations 

between composites from platforms and natural areas but 

did not improve the comparability of samples within natural 

areas and within platforms, or between samples from natural 

areas and platforms (table 3 and fig. 3). Lipid-normalization 

was anticipated to decrease the variance of the sample set, 

if the fish were exposed to a relatively constant long-term 

background of contaminants, though no quantitative statistical 

comparisons were made. However, the low-lipid samples from 

Platforms Edith and Ellen had concentrations of contaminants 
Results and Discussion 13

Table 3. Total-PAH concentrations for whole-fish composites of Pacific sanddab from 

natural areas and platforms.

[ng/g, nanograms per gram; lipid, dichloromethane extractable material; ±, plus or minus; cv, coefficient 

of variation (percent relative standard deviation)]

Sample Total PAHs

(ng/g wet weight)

Total PAHs

(ng/g lipid)

Natural areas Range: 15–37

Average ± cv: 27 ± 29

Range: 1,200–2,200

Average ± cv: 1,700 ± 24

CAND (Campus Point) 37 1,800

RIND (Rincon) 29 1,300

HUEN (Hueneme) 21 1,600

NESC (NE Santa Cruz) 29 2,200

EDND (Platform Edith Natural Area) 30 2,000

SBPN (Santa Barbara Natural Area) 15 1,200

Platforms Range: 8.7–22

Average ± cv: 15 ± 30

Range: 950–2,300

Average ± cv: 1,200 ± 44

HOLL (Holly) 16 1,000

PLATC (Platform C) 22 1,300

HOGA (Hogan) 18 1,300

GINA (Gina) 14 1,300

GILD (Gilda) 11 700

EDIT (Edith) 13 2,300

ELLE (Ellen) 8.7 950

that were similar to samples with higher lipid content on a 

wet-weight basis; therefore, lipid normalization served to 

increase the difference between these two samples and the rest 

of the sample set.

Polychlorinated Biphenyls

Total-PCB concentrations were quantified in samples by 

summing concentrations of 90 individual congeners, 22 unresolved pairs of congeners, and 2 unresolved multiplets of 

congeners. Procedural blank concentrations of PCBs were low 

(13 ng total PCBs per sample), corresponding to 2.6 ng/g ww 

total-PCBs in a typical 5 g-eq/mL extract. These background 

concentrations were approximately five- to ten-fold less than 

the lowest concentration determined for a field sample. Congener concentrations were adjusted for recoveries of surrogates 

and corrected for procedural background concentrations of 

PCBs.

Tissue wet-weight concentrations and lipid-normalized 

total-PCB concentrations in composite Pacific sanddab 

samples are presented in tables 4, S3, and S4. Total-PCB concentrations were low in all composite samples from platforms 

and natural areas. It was estimated that about 50 percent of 

the total-PCB concentration in all samples comprised nine 

congeners: PCBs 153, 138/163/164, 110, 118, 15, 99, 187, 

149, 180, ranked in decreasing order of overall contribution to the total-PCB concentration in most samples. About 

one-half of these congeners (PCBs 118, 

138, 153, 180, 187) were reported as 

among the 12 congeners (of 27 target 

PCBs) comprising most of the total-PCB 

concentration in Pacific sanddab from 

the Southern California Bight by Schiff 

and Allen, 2000, collected in areas 

overlapping some sampling locations in 

this study. Using all 12 PCB congeners 

suggested by Schiff and Allen accounted 

for 41 to 50 percent of the total-PCB 

concentrations, whereas using just the 

six congeners in common with Schiff 

and Allen and this study accounted for 

29 to 40 percent of the total-PCB concentrations. Some of the apparent difference results from the smaller subset of 

27 congeners selected for analysis, 7 of 

which were not detected in any sample, 

by Schiff and Allen (2000). The broader 

target list used here allowed a greater 

number of potentially bioaccumulated 

congeners to be investigated, several of 

which (PCBs 110, 15, 99, and 149) were 

determined to be major components 

of the total PCB loading of the Pacific 

sanddab at these locations.

Tissue-weight based total-PCB 

concentrations ranged from 7 to 22 ng/g ww in samples collected at natural areas and from 10 to 35 ng/g ww in samples 

collected at platforms. Samples in table 4 and in figure 4 

are grouped by natural or platform location for comparison. 

Within the natural areas and platform groups, samples have 

concentrations that range no more than two-fold that of the 

average concentrations reported for each group. Average 

total-PCB concentrations were low at all locations, but were 

nearly twice as great at platforms compared to natural areas, 

The PCB concentrations do not indicate clear separation 

between these two groups of locations, suggesting that PCBs 

were not associated with the platforms, but may be associated 

with other, more widely ranging sources. Normalization of 

PCB concentrations for the percentages of extractable lipids in the composite samples does not affect the variation in 

concentrations for natural areas, but approximately doubles 

the variation in concentrations for platforms. Most of the 

increase after lipid-normalization for platform sample concentrations resulted from the two low-lipid composites from 

Platform Edith (only one fish collected) and, to a lesser extent, 

from Platform Ellen. Lipid-normalization provided a marked 

difference in contaminant concentrations for these samples 

compared with the remaining samples in either the platform or 

natural area groups. As noted for PAHs, lipid-normalization of 

PCB concentrations did not increase the comparability within 

natural areas, within platforms, or between natural areas and 

platforms.
14 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast PAH Concentration (ng/g lipid)

Natural Areas Platforms

0

200

400

600

800

1000

1200

CAMP RINCON HUEN NESC EDND SBPN HOLLY PLAT C HOGA GINA GILD EDITH ELLEN

0

2

4

6

8

10

12

14

16

18

20

CAMP RINCON HUEN NESC EDND SBPN HOLLY PLAT C HOGA GINA GILD EDITH ELLEN

Naphthalene

2-methylnaphthalene

1-methylnaphthalene

Biphenyl

Phenanthrene

2-methylphenanthrene

Fluoranthene

Pyrene

Chrysene

Benzo[k]fluoranthene

PAH Concentration (ng/g ww)

Natural Areas Platforms

A

B

Figure 3. Concentrations of polycyclic aromatic hydrocarbons in Pacific sanddab tissues from natural 

areas and platforms. A, Tissue concentration in nanograms per gram (ng/g ww) based on wet weight; 

B, Tissue concentrations normalized to extractable lipid weight.
Results and Discussion 15

The principal components analysis (PCA) of the PCB 

congener concentrations in fish from natural area and platform 

locations indicated separation of Platforms Edith and Holly 

from the other locations and from each other (refer to fig. 5). 

Compared in Aroclor®1242/1248/1254/1260-space, the 

cluster containing most of the natural area and platform locations compared more closely with Aroclor® 1254, whereas 

Platforms Edith and Holly, though still more closely associated with Aroclor® 1254, tended to exhibit some Aroclor® 

1260-like character (fig. 5A); this difference may be the result 

of source composition, weathering, biomagnification (foodweb 

differences), and metabolism. Examination of the loadings 

for the dataset (not shown) indicated that the separations were 

based on the few major congeners summarized above. The 

dataset was normalized to total-PCB concentrations before 

principal components analysis; however, the separation 

between samples continued to follow the relative proportion 

of these few major congeners. Other natural area and platform locations were grouped more closely together, which 

is emphasized in figure 5A, in which the four Aroclors® are 

included in the score-plot. Removing the four Aroclors® from 

the score-plot emphasized the distribution of samples, which 

followed a trajectory away from projections for Platforms 

Edith and Holly, with the Santa Barbara natural area being 

furthest-removed from the major cluster of natural areas and 

platforms. Trajectories, such as this, which follow a smooth 

path in PCA scores plot, were determined to be typical of a 

series of samples with similar concentration profiles and that have proportionally 

decreasing component concentrations, 

which produce sequential losses of 

those components decreasing below the 

detection limits (R.W. Gale, unpub. data, 

2012).

Closer inspection of the PCB 

profiles confirmed the inference made 

above—that as the concentrations of 

the several major congeners tended to 

decrease, their relative concentrations 

among sites remained similar, and that 

the minor contributing congeners tended 

to increase, relatively, forming a general 

low-concentration PCB background 

profile common to all samples.

Organochlorine Pesticides

Thirty-one pesticides were targeted 

in the samples; including 4 benzene 

hexachloride (BHC) (or hexachlorocyclohexane, HCH) isomers (α-HCH, 

β-HCH, γ-HCH, δ-HCH), 7 chlordane 

components (cis-chlordane, trans-chlordane, cis-nonachlor, trans-nonachlor, 

oxychlordane, heptachlor, heptachlor 

epoxide), 6 DDT series components 

(p,p’-DDT, o,p’-DDT, p,p’-DDD, o,p’-DDD, p,p’-DDE, o,p’-

DDE), 3 endosulfan components (endosulfan I, endosulfan 

II, endosulfan sulfate), and 5 chlorinated isodrin components 

(aldrin, dieldrin, endrin, endrin aldehyde, endrin ketone). 

Concentrations were adjusted for recoveries of surrogates and 

corrected for procedural background concentrations of OCPs.

Procedural blank concentrations of most pesticides were 

below the reporting limit (less than 0.1 ng absolute, less than 

0.02 ng/g ww), though background concentrations of pesticides, or interferences, were slightly above the detection 

limit for six pesticides: hexachlorobenzene, pentachloroanisole, dacthal, and trans-chlordane (0.05 ng), methoxychlor 

(0.15 ng), and p,p’-DDE (0.6 ng). Some pesticides were not 

detectable in any sample (pentachlorobenzene, δ-BHC, heptachlor, endosulfan sulfate, aldrin, and dacthal), and additional 

pesticides (pentachloroanisole, γ-BHC, endosulfan I and II, 

total endrin, and mirex) were not detectable in most samples. 

Recoveries of OCPs from fortified negative control fish matrix 

ranged from 78–113 percent (average cv 90 ± 11 percent). The 

exception was methoxychlor, with a slightly biased recovery 

of 132 percent, resulting from incomplete resolution from an 

interference.

Tissue weight-based concentrations of OCPs detected in 

Pacific sanddab composites from natural areas and from platforms are presented in tables 5 and S5 and lipid-normalized 

concentrations in tables 6 and S6. Samples are grouped into 

natural areas and platforms for comparison. As previously 

Table 4. Total-polychlorinated biphenyl concentrations for whole-fish composites of 

Pacific sanddab from natural areas and platforms.

[ng/g, nanograms per gram; lipid, dichloromethane extractable material; ±, plus or minus; cv, coefficient 

of variation (percent relative standard deviation)]

Sample Total PCBs

(ng/g wet weight)

Total PCBs

(ng/g lipid)

Natural areas Range: 7.5–22

Average ± cv: 13 ± 37

Range: 570–1,400

Average ± cv: 820 ± 38

CAND (Campus Point) 12 590

RIND (Rincon) 16 690

HUEN (Hueneme)` 11 860

NESC (NE Santa Cruz) 11 800

EDND (Platform Edith Natural Area) 22 1,400

SBPN (Santa Barbara Natural Area) 7.5 570

Platforms Range: 10–35

Average ± cv: 23 ± 41

Range: 600–5,900

Average ± cv: 2,100 ± 85

HOLL (Holly) 35 2,200

PLATC (Platform C) 10 600

HOGA (Hogan) 21 610

GINA (Gina) 17 1,500

GILD (Gilda) 24 1,000

EDIT (Edith) 34 5,900

ELLE (Ellen) 16 1,700
16 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

0

1000

2000

3000

4000

5000

6000

7000

CAND RINCONHUEN NESC EDND SBPN HOLLY PLATC HOGA GINA GILD EDITH ELLEN

PCB Concentration (ng/g lipid)

Natural Areas Platforms

0

5

10

15

20

25

30

35

40

CAND RINCONHUEN NESC EDND SBPN HOLLY PLATC HOGA GINA GILD EDITH ELLEN

Natural Areas Platforms

PCB Concentration (ng/g ww)

A

B

Figure 4. Total-polychlorinated biphenyl concentrations in Pacific sanddab tissues from 

natural areas and platforms. A, Tissue concentration in nanograms per gram (ng/g ww) 

based on wet weight; B, Tissue concentrations normalized to extractable lipid weight.
Results and Discussion 17

-10

0

10

-10 0 10

t[2] (28% of the variance)

t[1] (31% of the variance)

CAMP

RINCON

HUEN

NESC

EDND

SBPN

HOLLY

PLATC

HOGA

GINA

GILD

EDITH

ELLEN

-20 -10 0 10 20

t[1] (41% of the variance)

Scores: t[1]/t[2]

CAMP

RINCON

HUEN

NESC

EDND

SBPN

HOLLY

PLATC

HOGA GINA

GILD

EDITH

ELLEN

1242

1248

1254

1260

-10

0

10

t[2] (18% of the variance)

Scores: t[1]/t[2]

A)

B)

Figure 5. Principal components analysis of polychlorinated biphenyl congeners in Pacific sanddab tissues from 

natural areas (green) and platforms (red). A, Score-Plot with Aroclors® included; B, Score-Plot with Aroclors® 

omitted. The percent of the total variance that is explained by each plotted principal component (x and y axes) is 

reported in the axis label.
18 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

Table 5. Ranges of organochlorine pesticide concentrations in composite samples of Pacific sanddab from natural areas 

and platform locations (wet-weight basis).

[ng/g, nanograms per gram based on wet-weight; cv, coefficient of variation (percent relative standard deviation); n, number of samples in which the 

analyte was detected (Natural Areas n=7; Platform Locations n=6); ±, plus or minus; <, less than; total endrin, the sum of endrin, endrin aldehyde, 

and endrin ketone]

Pesticide

Natural areas Platform locations

Range

ng/g wet-weight

Average

ng/g

wet-weight

cv (n)

Range

ng/g wet-weight

Average

ng/g 

wet-weight 

cv (n)

Pentachlorobenzene < 0.03 0 < 0.03 0

Hexachlorobenzene 0.06 – 0.2 0.1 ± 34 6 0.05 – 0.2 0.1 ± 39 6

Pentachloroanisole < 0.03 – 0.04 0.03 ± 34 1 < 0.03 0

alpha-BHC (α-HCH) < 0.03 – 0.05 0.03 ± 23 4 0.05 0.05 ± 1.0 3

beta-BHC (β-HCH) 0.04 – 0.08 0.06 ± 22 6 < 0.03 – 0.09 0.06 ± 41 6

Lindane (γ-HCH) < 0.03 – 0.04 0.03 ± 26 1 0.04 0.04 1

delta-BHC (δ-HCH) < 0.03 0 < 0.03 0

Heptachlor < 0.03 0 < 0.03 0

Heptachlor epoxide < 0.03 – 0.04 0.03 ± 12 2 0.04 – 0.08 0.06 ± 59 4

Methoxychlor 0.09 – 0.6 0.3 ± 57 5 0.04 – 0.5 0.3 ± 64 6

cis-Chlordane 0.05 – 0.2 0.1 ± 53 6 0.04 – 0.2 0.1 ± 62 6

trans-Chlordane < 0.03 – 0.07 0.05 ± 37 4 0.05 – 0.08 0.06 ± 26 4

Oxychlordane < 0.03 – 0.07 0.04 ± 23 6 0.06 – 0.1 0.1 ± 63 5

cis-Nonachlor 0.1 – 0.3 0.2 ± 32 6 0.1 – 0.4 0.2 ± 50 6

trans-Nonachlor 0.1 – 0.7 0.3 ± 49 6 0.2 – 1.0 0.5 ± 84 6

o,p’-DDE 0.04 – 0.05 0.05 ± 11 4 0.06 0.06 ± 6.9 2

o,p’-DDD < 0.03 – 0.1 0.07 ± 60 4 0.04 – 0.1 0.07 ± 65 5

o,p’-DDT 0.04 – 0.2 0.08 ± 59 6 < 0.03 – 0.09 0.06 ± 38 5

p,p’-DDE 5.6 – 33 17 ± 48 6 17 – 76 34 ± 110 6

p,p’-DDD 0.3 – 0.6 0.5 ± 27 6 0.3 – 0.7 0.5 ± 37 6

p,p’-DDT 0.4 0.2 ± 56 6 0.1 – 0.5 0.3 ± 78 6

Endosulfan I 0.03 0.03 1 < 0.03 0

Endosulfan II 0.03 0.03 1 < 0.03 0

Endosulfan sulfate < 0.03 0 < 0.03 0

Aldrin < 0.03 0 < 0.03 0

Total endrin < 0.03 – 0.04 0.03 ± 19 2 0.04 0.04 1

Dieldrin 0.04 – 0.10 0.07 ± 24 6 0.03 – 0.2 0.09 ± 74 6

Mirex 0.03 – 0.05 0.04 ± 42 1 0.03 – 0.04 0.03 ± 11 4

Dacthal < 0.03 0 < 0.03 0
Results and Discussion 19

Table 6. Ranges of organochlorine pesticide concentrations in composite samples of Pacific sanddab from natural areas 

and platform locations (lipid-weight basis).

[ng/g, nanograms per gram based on extractable lipid amount; lipid, dichloromethane extractable material; cv, coefficient of variation (percent relative standard deviation); n, number of samples in which the analyte was detected (Natural Areas n=7; Platform Locations n=6); ±, plus or minus; ; 

<, less than; total endrin, the sum of endrin, endrin aldehyde, and endrin ketone; the reporting limit for lipid-normalized concentrations is given as 

the maximum wet-weight limit adjusted for the minimum percent extractable lipid].

Pesticide

Natural areas Platform locations

Range

ng/g wet-weight

Average

ng/g wetweightcv (n) Range

ng/g wet-weight

Average

ng/g wetweight cv (n)

Pentachlorobenzene < 2 0 < 5 0

Hexachlorobenzene 4.7 – 9.5 7.1 ± 22 6 6.6 – 10 8.4 ± 18 6

Pentachloroanisole 1.7 – 2.6 2.1 ± 31 1 < 5 0

alpha-BHC (α-HCH) 1.4 – 2.4 2.0 ± 14 4 3.1 – 3.4 3.3 ± 9.9 3

beta-BHC (β-HCH) 3.1 – 4.5 3.9 ± 13 6 3.5 – 5.6 4.4 ± 18 6

Lindane (γ-HCH) 2.0 – 2.5 2.3 ± 14 1 2.6 2.6 1

delta-BHC (δ-HCH) < 2 0 < 5 0

Heptachlor < 2 0 < 5 0

Heptachlor epoxide 1.5 – 1.8 1.6 ± 4.0 2 2.1 – 5.4 3.9 ± 70 4

Methoxychlor 6.6 – 33 19 ± 46 5 3.9 – 30 19 ± 55 6

cis-Chlordane 4.0 – 13 7.4 ± 37 6 5.7 – 15 9.1 ± 42 6

trans-Chlordane 1.7 – 4.4 2.9 ± 30 4 3.2 – 5.1 4.0 ± 30 4

Oxychlordane 1.8 – 3.3 2.5 ± 12 6 5.0 – 9.3 7.4 ± 52 5

cis-Nonachlor 8.4 – 19 11 ± 25 6 11 – 28 20 ± 47 6

trans-Nonachlor 9.7 – 44 18 ± 42 6 23 – 64 42 ± 60 6

o,p’-DDE 2.3 – 3.7 3.1 ± 16 4 3.5 3.8 3.7 ± 7.2 2

o,p’-DDD 2.0 – 5.9 3.8 ± 34 4 2.3 – 24 8.5 ± 200 5

o,p’-DDT 2.9 – 11 4.8 ± 51 6 2.8 – 13 6.3 ± 93 5

p,p’-DDE 430 – 2,200 1,000 ± 33 6 1,000 – 13,000 4,100 ± 260 6

p,p’-DDD 22 – 38 28 ± 16 6 35 – 58 43 ± 29 6

p,p’-DDT 3.3 18 10 ± 30 6 11 – 82 30 ± 180 6

Endosulfan I 1.8 1.8 1 < 5 0

Endosulfan II 1.3 1.3 1 < 5 0

Endosulfan sulfate < 2 0 < 5 0

Aldrin < 2 0 < 5 0

Total endrin 1.4 – 1.7 1.6 ± 11 2 2.6 2.6 1

Dieldrin 3.3 – 5.5 4.3 ± 16 6 4.1 – 11 6.6 ± 54 6

Mirex 1.4 – 3.3 2.3 ± 44 1 2.2 – 6.2 3.6 ± 58 4

Dacthal < 2 0 < 5 0
20 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

mentioned, six pesticides (pentachlorobenzene, δ-BHC, 

heptachlor, endosulfan sulfate, aldrin, and dacthal) were not 

detected in any sample (< 0.02 ng/g ww). Most other pesticides were detected at concentrations of < 1 ng/g ww in all 

composite samples from natural areas and platforms.

The exceptions were the DDTs: p,p′-DDE ranged from 

5.6 to 33 ng/g ww at natural areas and from 17 to 76 ng/g ww 

at platforms. In addition to p,p′-DDE, there were detectable concentrations of the DDT-series of chemicals in most 

samples, ranging from not detectable to about 1 ng/g ww; 

typically, the p,p′-isomers predominated, with the DDT-series 

decreasing in the order: p,p′-DDE >> p,p′-DDD > p,p′-DDT 

>> o,p′-DDT ≈ o,p′-DDD > o,p′-DDE. The concentrations 

of p,p′-DDE were similar in Pacific sanddab from platforms 

and from natural areas when compared on a wet weight or 

a lipid normalized basis (fig. 6). The exception is the single 

Pacific sanddab sampled from Platform Edith. This is the only 

sanddab that could be sampled at this site and had an extractable lipid content about three-fold less than all other samples; 

this suggests that this species—and particularly this sample—

may not be resident at this platform or representative of contaminant loadings at this site, or that the health and nutrition of 

this individual may have been compromised.

Concentrations of chlordane-related compounds were low 

with concentrations ranging from 0.1 to 1.0 ng/g ww and displayed similar profiles at natural areas and platforms (tables 5 

and 6, and Supporting Information tables S5 and S6). Generally, chlordane-related compounds followed the order: transnonachlor > methoxychlor > cis-nonachlor ≈ trans-chlordane 

≈ cis-chlordane ≈ oxychlordane ≈ heptachlor epoxide; heptachlor was not detected in any composite sample.

Overall, the coefficients of variation for pesticide 

concentrations were not reduced by lipid-normalization; the 

decreases were inconsistent and increases were seen for some 

chlordane components as for other analytes. This generally 

did not provide better comparisons among the natural areas 

or among the platforms. The low concentrations of extractable lipids in Pacific sanddab from Platforms Edith and Ellen 

tended to weight more greatly the lipid-normalized concentrations from these two sites and did not produce any insight into 

the distributions of contaminants between natural areas and 

platform locations.

The principal components analysis of the normalized 

Pacific sanddab OCP concentrations did not indicate clear or 

partial groups by natural areas or platform locations (fig. 7). 

OCP concentrations in Pacific sanddab composites were grouped 

closely for the replicated samples (PLATC), indicating the 

adequate reproducibility of the analytical method. The loadings 

plot for the separation of the first two principal components of 

the OCPs indicates that the DDT-series components most greatly 

structured the data, followed by analytes detected only occasionally and at low concentrations in some composite samples.

Lipid-normalization of OCP concentrations did not 

increase the principal components analysis class separation of 

the samples into better-defined groups (data not shown). The 

low lipid content samples from Platforms Ellen, and especially 

Edith, were separated from the rest of the natural areas and 

platform locations, again, suggesting that these samples were 

more different from the rest of the samples because of lipid 

concentrations rather than because of contaminant concentrations. The major components separating the samples were 

DDT-related, though concentration differences were small 

and variable. Generally, lipid-normalization demonstrated that 

differences in extractable lipid content between fish from the 

natural areas and the platform locations provided the major 

determinant for separating the samples, and that differences in 

lipid content were much more important that the much smaller 

differences in pesticide concentrations between samples. 

Many of the values for lipid-normalized concentrations of 

OCPs are low, and only appear to be substantial because of the 

magnification caused by the lipid-normalization process. The 

lipid-normalized values less than about 1 ng/g lipid are suspect 

and should be discounted or carefully reviewed before forming 

conclusions about the relations between contaminant concentration and differences between Pacific sanddab from natural 

areas and platform locations.

Selected Polybrominated Diphenylethers

Total-PBDE concentrations were quantified in samples as 

the sum of nine congeners representing major PBDE components in commercial formulations. Congener concentrations 

were adjusted for recoveries of surrogates and corrected for 

procedural background concentrations of PBDEs.

The amount of total-PBDEs in the procedural blank was 

low, approximately 0.2 ng. This background was contributed 

by PBDE-100 (0.05 ng absolute) and PBDE-99 (0.15 ng 

absolute). Total-PBDE concentrations in these samples were 

comprised of only two congeners: PBDE-47, the predominant 

congener in composite samples at all locations, comprising 

from 70 to 100 percent of the total; the remaining 30 percent 

(or less) was comprised of PBDE-100. PBDE-99 was not 

quantified in any composite sample at concentrations above 

the reporting limit of 0.4 ng/g ww (2–5 ng/g lipid). TotalPBDE concentrations were documented at less than 3 ng/g ww 

(or less than ten-fold above the reporting limit for quantification). Recoveries of PBDEs fortified in negative control fish 

tissue ranged from 90 to 94 percent.

Tissue weight-based concentrations and lipid-normalized 

total-PBDE concentrations in Pacific sanddab composite 

samples are presented in tables 7, S7, and S8. All composite 

sample concentrations were low with respect to the reporting limits of this study, ranging from 0.4 to 3.0 ng/g ww. 

The tissue- weight-based and lipid-normalized total-PBDE 

concentrations are shown in figure 8, with the results grouped 

by natural area and platform location. The PBDE concentrations do not indicate clear separation between natural areas 

and platforms. There were no samples with substantial PBDE 

concentrations and the relative concentrations between natural 

areas and platforms are not consistent. Lipid-normalization 

did not enhance the comparability between the two groups of 

samples.
Results and Discussion 21

Natural Areas Platforms

p,p’-DDE Concentration (ng/g lipid)

0

2000

4000

6000

8000

10000

12000

14000

16000

CAMP RINCON HUEN NESC EDND SBPN HOLLY PLATC HOGA GINA GILD EDITH ELLEN

0

10

20

30

40

50

60

70

80

CAMP RINCON HUEN NESC EDND SBPN HOLLY PLATC HOGA GINA GILD EDITH ELLEN

Natural Areas Platforms

p,p’-DDE Concentration (ng/g ww)

A

B

Figure 6. Concentrations of p,pʹ-dichlorodiphenyldichloroethylene (p,pʹ-DDE) in Pacific sanddab 

tissues from natural areas and platforms. A, Tissue concentration in nanograms per gram (ng/g ww) 

based on wet weight; B, Tissue concentrations normalized to extractable lipid weight.
22 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

-5

0

5

-10 0 10

t[2] (11% of the variance)

t[1] (78% of the variance)

CAMP

RINCON

HUEN

NESC EDND

SBPN

HOLLY

PLATC

HOGA

GINA

GILD

ELLEN EDITH

Figure 7. Principal components analysis (Score-Plot) of organochlorine pesticides in Pacific sanddab tissues 

from natural areas (green) and platforms (red). The percent of the total variance that is explained by each plotted 

principal component (x and y axes) is reported in the axis label.

Table 7. Total-polybrominated diphenylether concentrations for whole-fish composites 

of Pacific sanddab from natural areas and platforms.

[ng/g, nanograms per gram; lipid, dichloromethane extractable material; cv, coefficient of variation (percent relative standard deviation); ±, plus or minus; <, less than; The reporting limit for lipid-normalized 

concentrations is given as the maximum wet-weight limit adjusted for the minimum percent extractable 

lipid]

Sample Total PBDE

(ng/g wet weight)

Total PBDEs

(ng/g lipid)

Natural areas Range: < 0.4–1.8

Average ± cv: 0.8 ± 80

Range: < 30–120

Average ± cv: 47 ± 84

CAND (Campus Point) 0.5 25

RIND (Rincon) 1.0 46

HUEN (Hueneme) 0.6 43

NESC (NE Santa Cruz) 0.6 49

EDND (Platform Edith Natural Area) 1.8 120

SBPN (Santa Barbara Natural Area) < 0.4 < 30

Platforms Range: 0.5–3.0

Average ± cv: 1.4 ± 65

Range: 30–190

Average ± cv: 120 ± 49

HOLL (Holly) 3.0 190

PLATC (Platform C) 0.5 30

HOGA (Hogan) 2.1 150

GINA (Gina) 1.1 67

GILD (Gilda) 2.6 170

EDIT (Edith) 0.8 140

ELLE (Ellen) 1.5 170
Results and Discussion 23

0

50

100

150

200

250

CAMP RINCON HUEN NESC EDND SBPN HOLLY PLATC HOGA GINA GILD EDITH ELLEN

Natural Areas Platforms

total PBDE Concentration (ng/g lipid)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

CAMP RINCON HUEN NESC EDND SBPN HOLLY PLATC HOGA GINA GILD EDITH ELLEN

Natural Areas Platforms

total PBDE Concentration (ng/g ww)

A

B

Figure 8. Total-polybrominated diphenylether concentrations in Pacific sanddab tissues from 

natural areas and platforms. A, Tissue concentration in nanograms per gram (ng/g ww) based on 

wet weight; B, Tissue concentrations normalized to extractable lipid weight.
24 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

The principal components analysis of the PBDE congener 

concentrations in Pacific sanddab composites (fig. 9) did not 

indicate any partial groupings for natural areas and platform 

locations. Because only two PBDE congeners (PBDE-47 and 

100) were quantifiable in these samples, the only separation 

possible is that based on the percentage of PBDE-100 in the 

samples. This is indicated by the linear separation of those 

samples with increasing percentages of PBDE-100 from most 

of the samples comprised of only PBDE-47 (cluster of sites in 

the left center of figure 9); for reference, the Pacific sanddab 

composite sample from Platform Edith natural area was comprised of 36 percent PBDE-100. The Santa Barbara natural 

area sample (SBPN) is separated from the rest of the samples 

because it had no quantifiable PBDEs.

Comparison to Other Studies

The concentrations of PAHs, PCBs, OCPs, and PBDEs 

were low and similar in composites of Pacific sanddab from 

natural areas and platform locations. No large differences in 

the concentrations or profiles of contaminants were observed 

between samples from natural areas and platforms.

Previous measurements of the bile of these Pacific 

sanddab for hydroxylated PAHs, and PAH-glucuronides or 

-sulfates did not indicate acute PAH exposure. The purpose of 

this report was to investigate the potential chronic exposure of 

Pacific sanddab to PAHs by determining tissue concentrations 

of the more persistent and bioaccumulative higher molecular 

weight PAHs. No evidence was found to indicate elevated 

PAH exposure of sanddab from any of the natural areas or 

platform locations and no greater exposure of sanddab at platform locations as compared with natural areas was observed.

The concentrations of PAHs, PCBs, DDTs, and isodrins 

in fish from platforms and nearby natural areas measured 

here were compared with previously reported concentrations 

(refer to table 8). Most reports of DDTs and PCBs in fish in 

the Southern California Bight were from studies done near 

shore to investigate contamination from industrial, harbor, 

and wastewater treatment outfalls. Few historic data exist for 

contaminant burdens in fishes at any of the platform locations 

or the natural areas near seeps studied in this report.

From 1980–1982, the total PCB input near the JWPCP 

outfall at Palos Verdes (not shown), was estimated at 281 kilograms per year (kg/year), and was similar to the estimated 

total PCB input from the Hyperion outfall at Santa Monica 

Bay (not shown); however, the input of total DDTs was estimated to be ten-fold greater (396 kg/year) from the JWPCP 

than from Hyperion (Brown and others, 1986). Concentrations 

of DDTs and PCBs in Pacific sanddab collected from sites 

near the Palos Verdes and Hyperion outfalls were reported by 

Brown and others (1986). Total-DDT concentrations ranged 

from 42 to 610 μg/g ww in liver and 0.33 to 15 μg/g ww in 

gonad, total-PCB concentrations from 4.8 to 16 μg/g ww in 

liver and 0.018 to 0.88 μg/g ww in gonad. The concentrations of total-PCBs at study sites reportedly remained constant 

from 1977 to 1987; however, concentrations of total-DDTs 

-2

0

2

-3 0 3

t[2] (34% of the variance)

t[1] (66% of the variance)

HUEN

SBPN

HOLLY

PLATC

HOGA GILD

ELLEN

CAMP

RINCON

NESC

EDND

GINA

EDITH

Figure 9. Principal components analysis (Score-Plot) of selected polybrominated diphenylether congeners in 

Pacific sanddab tissues from natural areas (green) and platforms (red). Only two congeners (major component, 

PBDE-47, minor component, PBDE-100) were detected in any sample; Santa Barbara natural area (SBPN) is isolated 

in this plot because there were no detectable polybrominated diphenylethers in the sample. The percent of the total 

variance that is explained by each plotted principal component (x and y axes) is reported in the axis label.
 and in m

, oxych

 (Schiff and Allen, 2000)

, trans-nonachlor

and reported in Pacific sanddab

Agency; PAHs, total concentration of polycyclic aromatic h

trans-chlordane, cis-nonachlor 

Concentrations of contaminants determined in Pacific sanddab (this study) [ng/g, nanograms per gram wet-weight; USGS, U.S. Geological Survey; NOAA, National Oceanic and Atmospheric cis-chlordane, 

-DDE; PCBs, total concentration of polychlorinated biphenyls; --, not r

concentration of aldrin, dieldrin, endrin, endrin aldehyde, endrin ketone; chlordanes, total concentration of 

s, total concentrations of p,p’-DDT, o,p’-DDT, p,p’-DDD, o,p’-DDD, p,p’-DDE, o,p’

able 8.T

others, 2008).

chlor epoxide; DDT

This study Selected 

from points 

closest to 

USGS 

locations

Schiff and Allen, 2000 Distance 

from 

closest 

USGS 

locations

Kimbrough and others, 

Pacific sanddab (ng/g whole fish) Pacific sanddab (ng/g liver) Mussels (ng/g tissu

USGS 

locations PAHs Isodrins Chlordanes DDTs PCBs DDTs PCBs NOAA locations PAHs Isodrins Chlorda

-- -- -- -- -- -- -- 50 mi NW SLSL 348 6.8 7.-- -- -- -- -- 100 – 1,000 10 – 50 30 mi N PCPC 247 1.5 3.

HOLL 16 0.09 1.5 33 35 0.05 – 1,000 0.05 – 10

CAND 37 0.10 1 15 12 0.05 – 1,000 < 0.05

SBPN 15 0.05 0.66 6.1 7.5 100 – 1,000 < 0.05 SBSB NW 112 2.7 7.

PLATC 22 0.08 1.4 12 10 100 – 1,000 10 – 50

HOGA 18 0.13 1.7 25 21 100 – 1,000 50 – 500

RIND 29 0.13 1.7 21 16 100 – 1,000 10 – 50

-- -- -- -- -- -- -- 20 mi SW 

(Offshore)

SCFP 121 3.4 6.

NESC 29 0.06 0.43 12 11 100 – 1,000 10 – 50

GILD 11 0.18 2.4 36 24 100 – 1,000 50 – 500

GINA 14 0.10 1.4 18 17 100 – 1,000 50 – 500

HUEN 21 0.04 0.35 9.0 11 100 – 1,000 50 – 500

-- -- -- -- -- -- -- Between 

HUEN (north) 

and EDIT 

(south)

PDPD 69 1.9 4.

-- -- -- -- -- 1,000 – 10,000 50 – 500 TBSM 347 5.6 15 -- -- -- -- -- 1,000 – 10,000 500 – 2,000 MDSJ 2,093 12 37 -- -- -- -- -- 1,000 – 10,000 50 – 500 RBMJ 278 6.6 15 -- -- -- -- -- 10,000 – 43,300 500 – 2,000 10 mi NW PVRP 90 1.9 5.

EDND 30 0.06 0.95 34 22 100 – 1,000 10 – 50

Palos 

Verdes

SPBP 4,434 1.8 5.

EDIT 13 0.03 0.46 77 34 100 – 1,000 10 – 50 LBBW 222 14 25 

ELLE 8.7 0.04 0.62 19 16 100 – 1,000 10 – 50 ABWJ 522 2.5 17 

-- -- -- -- -- -- --

25 mi SW 

(Offshore) SCBR 63 0.23 0.

-- -- -- -- -- 100 – 1,000 10 – 50 15 mi SE NBWJ 96 3.6 8.

-- -- -- -- -- 100 – 1,000 10 – 50 60 mi SE OSBJ 195 22 25 
26 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

increased. Schiff (2000) suggested that historical sediments 

deposited near outfalls with high concentrations of DDTs 

might have resurfaced and been transported into the bight.

Elevated total-DDT concentrations and total-PCB concentrations in sediments were reported by Schiff (2000) for 

near shore locations in the general area of the northern USGS 

study sites (HOLL, CAMP, SBPN, PLATC, HOGA, RINC, 

GILD, and GINA). Concentrations of DDTs reported by Schiff 

(2000) were greater near some platform sites, ranging from 10 

to 50 ng/g dw at Platforms Hogan, Rincon, Gilda, and Gina; 

and lower at other platform sites and natural areas, less than 

20 ng/g dw at Platform Holly and Platform C and at Campus 

Point and Santa Barbara natural areas. Inputs were identified 

as mainly from the waste treatment plant outfall points and 

river and creek entries. Southern USGS study sites (Platforms 

Edith and Ellen, and Platform Edith natural area) were offshore too far for comparison.

Schiff and others (2000) reported that 89 percent of 

near-shore sediments in the Southern California Bight were 

contaminated with total-DDT concentrations and that almost 

100 percent of Pacific sanddab collected at these near-shore 

locations in that study also were contaminated with totalDDTs and total-PCBs, having detectable liver concentrations 

of typically greater than 1 ng/g. Schiff and Allen (2000) 

reported that Pacific sanddab livers analyzed averaged about 

15.9 percent lipid and total-DDT and -PCB concentrations 

averaged 654 ng/g and 74 ng/g, respectively.

Total-DDTs and total-PCBs in livers of Pacific sanddab 

were greatest in samples collected on the Palos Verdes Shelf 

at the sewage treatment outfall, near White Point, 42,000 ng/g 

and 1,100 ng/g, respectively (Schiff and Allen, 2000). This 

site was 20 kilometers north of three of the four most southern 

USGS sites in this study (Platforms Edith and Ellen, and the 

Platform Edith natural area). Schiff and Allen (2000) reported 

that total-DDT concentrations remained uniformly lower in 

areas much to the south of the outfall near White Point; however, total-PCB concentrations were higher at Orange County 

and the City of San Diego wastewater outfalls to the south of 

White Point (locations not shown). Though large reservoirs 

of contaminants existed at these outfalls, the current release 

concentrations were extremely low or undetectable. Yet, these 

reservoirs were considered an ongoing route of exposure for 

bottom-feeding species. Total-PCB concentrations were about 

ten-fold higher in livers of Pacific sanddab at these outfalls 

than in sanddab distant from the outfalls (2,000 ng/g as 

compared to 200 ng/g). Schiff and Allen (2000) also reported 

that the previous trend in increasing tissue concentrations 

with northward progress (following prevailing currents) has 

decreased and that substantial decreases have occurred during 

the past 10 to 20 years, with contaminant concentrations in 

Pacific sanddab collected at the same locations decreasing by 

one to two orders of magnitude (Tran and Zeng, 1998).

The concentration of p,p′-DDE in fish livers was determined to co-vary with the sediment concentration and normalizing concentrations to percent lipid and percent organic 

carbon increased these correlations. For PCBs, the covariance 

of tissue and sediment concentrations was determined to 

differ by PCB congener. Contamination was reported to be 

widespread but limited to DDE and PCBs by Schiff and Allen 

(2000). Pacific sanddab were contaminated throughout most of 

their range in the Southern California Bight. Although DDTs 

and PCBs often were measurable, PAHs were rarely detected, 

largely due to metabolism of PAHs (Schiff and Allen, 2000; 

Mearns and others, 1991).

Concentrations of DDTs near outfalls have not declined 

rapidly or continuously since the termination of DDT into the 

Palos Verdes outfall in 1970. From 2 to 5 years after termination, total-DDT concentrations in muscle ranged from 100 to 

87,000 ng/g in the discharge zone, from 100 to 43,000 ng/g at 

the boundary of the discharge zone, and from 10 to 670 ng/g 

in the farther removed, control zone, with more DDT in the 

southern areas studied (Smokler and others, 1979). Twentyfour years after termination, total-DDTs in liver remained 

high in the discharge zone, ranging from 1,000 to 43,000 ng/g 

(Schiff and Allen, 2000). This study did not investigate fish 

close to the discharge or boundary zones, where exposure 

to DDT- and PCB-affected sediments remains high. This 

comparison of platform locations with nearby natural areas 

has indicated that exposure to urban pollution sources is 

negligible, and that any additional exposure to pollutants from 

platform discharges is indistinguishable, at this level of discrimination, from the background exposure defined by nearby 

natural areas.

The National Oceanic and Atmospheric Administration 

(NOAA) has reported monitoring data as part of the Mussel 

Watch Program in the Southern California Bight that overlap some of the USGS study areas (Kimbrough and others, 

2008). PAHs, which bioaccumulate in mussels (Mylitus species), were found at all NOAA shoreline locations along the 

Southern California Bight, ranging from 63 to 4,400 ng/g. 

Conversely, PAHs are typically at much lower concentrations 

in water and sediments (and presumably in the food web) 

at locations further offshore, and are not substantially accumulated by fish. Bile metabolites of PAHs were not found in 

fishes collected at platform locations or at nearby natural areas 

in this study, nor were parent PAHs or aliphatic hydrocarbons 

found in tissues of Pacific sanddab at these locations.

Generally, lower concentrations of persistent organochlorine compounds were reported in the northern part of USGS 

study area (above Palos Verdes), at offshore locations (Kimbrough and others, 2008); higher concentrations were reported 

for Palos Verdes, and sites immediately south of Palos Verdes, 

and at other treatment plant outfalls. Within the USGS study 

area, concentrations of organochlorine contaminants in mussel 

tissue reported by Kimbrough and others (2008) ranged from 

0.23 to 22 ng/g for total isodrins, from 0.85 to 37 ng/g for 

total-chlordanes, from 15 to 129 ng/g for total-PCBs, and from 

8.9 to 462 ng/g for total-DDTs.

Comparisons of total isodrins in Pacific sanddab (this 

study) and mussel (Kimbrough and others, 2008) did not indicate any similarity in trends with locations. Total isodrins in 

Pacific sanddab were consistently low at all locations in each 
References Cited 27

of these studies, however, concentrations were about thirty- to 

fifty-fold lower in this study than reported by NOAA for mussels from the most closely corresponding near shore sites. Bioaccumulation of contaminant classes is highly dependent upon 

species-specific metabolism and comparisons between fish and 

bivalves are only suitable for investigating general trends. No 

correlations were observed for total-chlordanes among USGS 

Pacific sanddab samples and NOAA mussel samples from 

nearby sites. Again, total-chlordane concentrations in Pacific 

sanddab were from 10 to 50-fold lower in this study than 

concentrations in mussels reported by NOAA (Kimbrough 

and others, 2008). Total-PCB concentrations agreed somewhat among this study, and those of Kimbrough and others, 

(Kimbrough 2008), and Schiff and Allen (2000). The totalPAH, -DDT, -PCB, and isodrin concentrations are presented in 

table 8. At those sites most nearly corresponding sites reported 

by Kimbrough and others (2008), total-PCBs ranged from 

7.5 to 34 ng/g (USGS), from 15 to 107 ng/g (Kimbrough and 

others, 2008), and from 10 to 50 ng/g (same range for all sites 

(Schiff and Allen, 2000). Total-DDT concentrations did not 

compare as well as total-PCB concentrations among studies, total-DDTs ranged from 6.1 to 77 ng/g (USGS), from 12 

to 452 ng/g (Kimbrough and others, 2008), and from 100 to 

1,000 ng/g (same range for all sites, Schiff and Allen, 2000). 

Unfortunately, several circumstances limit the comparability of the Kimbrough and Schiff datasets to this study. The 

data from Kimbrough and others (2008) though closer in time 

(2004–2005), report contaminant concentrations for a different target organism (mussel) with collection being limited to 

sites close to the coastline. The Schiff and Allen (2000), report 

contaminant concentrations in Pacific sanddab livers at collection sites much closer to the USGS study sites, but separated 

by about 14 years (July–August 1994).

The distribution and sources of PBDEs in sediments from 

the Southern California Bight has recently been reported by 

Dodder and others (2012). Using a probabilistic approach, 

sediments from coastal embayments and to the lower slope of 

the outer continental shelf were investigated. Thirteen PBDEs 

were detected in 92 of 121 sites sampled, with a reported geometric mean total-PBDE concentration of 4.7 ng/g dry weight 

and a maximum concentration of 560 ng/g. The highest concentrations of PBDEs were determined to be predominately 

composed of PBDE-209, which is enriched in sediments and 

is mainly related to the production levels of the commercial 

PBDE technical mixtures. Highest total PBDE concentrations 

were determined to be associated with mouths of urban rivers 

along coastal embayments and were reportedly the result of 

urban runoff rather than wastewater treatment plants. Offshore 

sediments, near sites associated with this study had a reported 

geometric mean total-PBDE concentration of 2 ng/g dry 

weight, and ranged from 1.6 to 2.5 ng/g. Pacific sanddab from 

this study ranged in total-PBDE concentrations from <0.3 to 

about 3 ng/g ww, with only one congener, PBDE-047, being 

detected.

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Supplemental Tables 31

Supplemental Tables

The Excel file containing all tables of supporting information may be downloaded from 

http://pubs.usgs.gov/of/2013/1046/downloads/supplemental_tables.xlsx

Table S1. Concentrations of selected polycyclic aromatic hydrocarbons (PAHs) and total PAHs in 

tissues (ng/g) of Pacific sanddab (Citharichthys sordidus) at platforms and nearby natural sites.

Table S2. Lipid-normalized concentrations of selected polycyclic aromatic hydrocarbons (PAHs)

and total PAHs in tissues (ng/g lipid) of Pacific sanddab (Citharichthys sordidus) at platforms and 

nearby natural sites.

Table S3. Concentrations of selected congeners of polychlorinated biphenyls (PCBs) and total 

PCBs in tissues (ng/g) of Pacific sanddab (Citharichthys sordidus) at platforms and nearby natural 

sites.

Table S4. Lipid-normalized concentrations of selected congeners of polychlorinated biphenyls 

(PCBs) and total PCBs in tissues (ng/g lipid) of Pacific sanddab (Citharichthys sordidus) at platforms 

and nearby natural sites.

Table S5. Concentrations of selected organochlorine pesticides and total isodrins, chlordanes, and 

dichlorodiphenyldichloroethylenes in tissues (ng/g) of Pacific sanddab (Citharichthys sordidus) at 

platforms and nearby natural sites.

Table S6. Lipid-normalized concentrations of selected organochlorine pesticides and total isodrins, 

chlordanes, and dichlorodiphenyldichloroethylenes in tissues (ng/g lipid) of Pacific sanddab 

(Citharichthys sordidus) at platforms and nearby natural sites.

Table S7. Concentrations of selected polybrominated diphenylethers (PBDEs) and total PBDEs in 

tissues (ng/g) of Pacific sanddab (Citharichthys sordidus) at platforms and nearby natural sites.

Table S8. Lipid-normalized concentrations of selected polybrominated diphenylethers (PBDEs) and 

total PBDEs in tissues (ng/g lipid) of Pacific sanddab (Citharichthys sordidus) at platforms and nearby 

natural sites.
32 Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast

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Gale and others— Comparison of PAHs and POPs in sanddab from Platforms and Natural Reefs along the California Coast—OFR 2013–1046