Congener-Specific Analysis of PCB Accumulations in Chesapeake Bay Striped Congener-Specific Analysis of PCB Accumulations in Chesapeake Bay Striped Bass (Bass (Morone saxatilisMorone saxatilis))

William GardnerUniversity Maryland Eastern Shore, Princess Ann, MD

Department of Natural Science, Living Marine Cooperative Science Center

IntroductionPolychlorinated biphenyls (PCB) threaten the ecological and economic value of Chesapeake Bay striped bass (Morone saxatilis). In terms of the former, PCBs are known endocrine disruptors and have been linked to declines in wild fish populations. In terms of the latter, the state of Maryland has issued both statewide advisories for striped bass caught in the Chesapeake Bay and in Maryland’s Atlantic coastal waters. Data used to generate the statewide Chesapeake Bay advisories suggest that striped bass are exposed to sources both inside and outside the estuary. However, data is lacking for assessing the PCB levels in young striped bass maturing within their natal subestuaries. Furthermore, the state of Maryland has adopted no consumption advisories for striped bass captured in its coastal waters. This management decision is based predominantly on PCB levels in striped bass capture in New York Coastal waters, due to insufficient data elsewhere. As of result of these data gaps, the main focus of this research has been to further our understanding as to when and where striped bass are exposed to quantities of PCBs sufficient enough to cause accumulations to warrant a health advisory.

Striped Bass FisheryIt is estimated that 50 – 90 percent of the Atlantic coast striped bass migratory stock are spawned in tributaries of the Chesapeake Bay (Fig 1). In 2008 recreational and commercial landings were more than 25.6 million and 7.1 million lbs, respectively (NOAA 2009).

Striped Bass Migrations Adult striped bass migrate from the Atlantic Ocean into freshwaters of the Chesapeake Bay to spawn in the early spring. After spawning, migratory striped bass exit the Chesapeake Bay and generally move northward along the Atlantic Coast (Fig. 2). They spend most of the summer and early autumn in New England shore waters. In late autumn, striped bass return to the Chesapeake Bay region. Chesapeake Bay striped bass generally over-winter off the coast of North Carolina.

Figure 2. Striped Bass Figure 2. Striped Bass Migrations Migrations

Susquehanna River

Patuxent River

Choptank River

Potomac River

Nanticoke RiverRappahannock

River

York River

James River

Chester River

Pocomoke River

Figure 1. Chesapeake Bay Figure 1. Chesapeake Bay spawning riversspawning rivers

Maryland’s PCB AdvisoriesMaryland has issued both statewide and coastal PCB advisories for striped bass Table 1). Data used to generate these advisories suggest that striped bass are being exposed to PCB both inside and outside of the Chesapeake Bay (J. Beaman, MDE, 2005). The research proposed here has evolved from uncertainties regarding the drivers behind these advisories. The statewide advisories rely on data collected from legally harvestable fish. Thus, data is lacking for accessing PCB levels in young striped bass maturing within their natal sub estuaries. Furthermore, the USEPA has classified several of these areas as having “insufficient or inconclusive data” (Fig. 3). Secondly, Maryland’s coastal advisories is based on limited data, largely from New York coastal waters (MDE 2007 and ECASCAW 2008).

WaterbodyWaterbody Table 1. PCBs (risk driver) Table 1. PCBs (risk driver) Allowable Meal/YearAllowable Meal/YearChesapeake Chesapeake

Bay and Bay and TributariesTributaries

< 28” May 16 – < 28” May 16 – Dec 15Dec 15

> 28” April 15 > 28” April 15 – May 15– May 15

General General PopulationPopulation

8 oz meals8 oz meals

WomenWomen

6 oz meals6 oz meals

ChildrenChildren

3 oz meals3 oz meals

2525 1919 1515

99 66 AVOIDAVOID

MD Coastal MD Coastal waterswaters

1212 AVOIDAVOID AVOIDAVOID

Region of Concern- area with probable adverse effectsArea of Emphasis- area of potential adverse effectsArea of Low Probability for adverse effectsArea with insufficient or Inconclusive DataHistorically Low Levels of Chemical Contamination

Congener-Specific PCB DataPCBs are a class of chemical consisting of 209 possible congeners with varying degrees of chlorination (Fig. 3). Congener-specific PCB data can lead to the identification of likely sources through fingerprinting techniques. This involves matching the congener pattern present in biota with known sources in the environment, while accounting for environmental weathering and bioaccumulation processes. The resulting PCB signature will not be a direct reflection of the source but rather a descriptive component. Congener-specific PCB data in the Chesapeake Bay is limited (Liebert 2006).

HypothesesSpecifically, we will test several

hypotheses:1. PCB levels measured in striped bass

(1 to 3 yrs) will not be discernable between Chesapeake Bay subestuaries.

2. PCB concentrations in Chesapeake Bay striped bass collected in the aforementioned subestuaries will be similar to published values (> 313 ng/g) of fish taken from known contaminated areas.

3. Whether PCB accumulations are occurring mainly within the Bay or in marine habitats will be accomplished by comparing PCB concentrations in out-migrating sub-adults with adults over-wintering in NC’s coastal waters.

4. Will PCB concentrations measured in striped bass overwintering (NC) be similar to published values for fish taken from NY’s Coastal water (400 ng/g)?

5. We will also test the hypotheses that fish size, age and lipid content will influence PCB levels, and we will asses their relative importance.

Figure 4Figure 4

Fig 3.Fig 3.

MethodsFifthteen striped bass ages 1 to 3

yrs will be collect from natal Chesapeake Bay subestuaries and twenty-five 3 to 5 yrs will be collect in the Bay’s lower mainstem. Thirty striped bass > 3 yrs will be collected in the winter off the coast of North Carolina deep water trawl nets during NOAA-funded LMRCSC winter survey (Fig. 5)

PCB analysis will be carried out at the NOAA/NMFS) James J. Howard Marine Sciences Laboratory (Fig. 5) according to previously described methods (Dockum 2009, Williams 2006).

The statistical approach undertaken will follow U.S. EPA recommendation for testing fish tissue data (U.S. EPA 2000).

ObjectiveThe objective of this study will be to characterize the effects of spatial variation and life history traits on PCB accumulations in Chesapeake Bay striped bass.

Figure 5. Sample collection and analysis utilizing NOAA resources

8 18

170

187195

206

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

PCB Congener BZ#

Figure 6. PCB congener accumulations in Figure 6. PCB congener accumulations in Upper Bay mainstem striped bass Upper Bay mainstem striped bass

ng/g

818

99101

110

118

128

170

0

0.2

0.4

0.6

0.8

1

1.2

PCB Congener BZ#

ng/g

Figure7. PCB congener accumulations in Figure7. PCB congener accumulations in Choptank striped bass Choptank striped bass

206

1951809544

0

1

2

3

4

5

6

7

PCB Congeners BZ#

Figure 8. PCB congener accumulations Figure 8. PCB congener accumulations in Pocomoke River striped bass in Pocomoke River striped bass

ng/g

Location Location nn Weight Weight (g)(g)

Length Length (cm)(cm)

Lipid Lipid content content

(%)(%)

PCBs PCBs (ng/g)(ng/g)

*Upper *Upper Chesapeake Chesapeake Bay, Rock Bay, Rock

HallHall

99 146 146 ++ 99 99 24 24 ++ 6 6 0.5 0.5 ++ 0.3 0.3 7 7 ++ 6.7 6.7

**Pocomoke **Pocomoke River,River,

BullbeggerBullbegger

1010 260 260 ++ 172 172 24 24 ++ 9 9 0.7 0.7 ++ 0.4 0.4 8.3 8.3 ++ 2.9 2.9

**Choptank **Choptank River,River,

Tred AvonTred Avon

99 292 292 ++ 203 203 29 29 ++ 4 4 0.5 0.5 ++ 0.3 0.3 3.7 3.7 ++ 3.5 3.5

Preliminary Results Table 2. Preliminary PCB Data for striped bass Table 2. Preliminary PCB Data for striped bass

collected in Maryland waterscollected in Maryland waters

* Area Not Characterized due to historically low levels* Area Not Characterized due to historically low levels** Area of Insufficient or Inconclusive Data** Area of Insufficient or Inconclusive Data

Location Location AgeAge(yrs)(yrs)

Length Length (cm)(cm)

Weight Weight (g)(g)

Lipid Lipid content content

(%)(%)

PCBs PCBs (ng/g)(ng/g)

Atlantic Atlantic Coast, NC Coast, NC

Cape Cape Hatteras, Hatteras,

(n=40)(n=40)

7 7 ++ 2 2 73.4 73.4 ++ 10.5 10.5

4224 4224 ++ 1857 1857

5 5 ++ 3 3 145.99 145.99 ++ 55.10 55.10

Table 3. Preliminary PCB Data for striped bass Table 3. Preliminary PCB Data for striped bass collected in North Carolina’s coastal waterscollected in North Carolina’s coastal waters

ConclusionsPreliminary results showed average

PCB concentrations were 7.0, 8.3, and 3.7 (ng/g) for young striped bass collected in the Upper Bay mainstem, Pocomoke River and Choptank River, respectively (Table 2). These levels are below levels observed in “regions of concern”. Although PCB levels were similar in magnitude from all three natal subestuaries, spatial differences in PCB congener accumulation patterns were visually apparent (Fig. 6, 7, & 8) (suggestive of localized sources). Striped bass collected from NC’s coastal waters ranged in age from 3 to 10 (yrs) with a mean PCB concentration of 145.99 + 55.10 (ng/g) (Table 3), which is well below level observed in NY’s coastal water. This may argue for less-restrictive coastal advisories in MD’s water.