Chapter 5
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Organohalogen Contaminants in Sediment and Fish Samples from Riverine and Estuarine Waters of Savannah, Georgia, USA Dylan Benningfield,1 Joseph P. Richardson,2 Bommanna G. Loganathan,*,1 and Kenneth S. Sajwan2 1Department
of Chemistry and Watershed Studies Institute, 1201 Jesse D. Jones Hall, Murray State University, Murray, Kentucky 42071, United States 2Department of Marine and Environmental Sciences, 3219 College Street, Savannah State University, Savannah, Georgia 31404, United States *E-mail:
[email protected]
Classical and emerging persistent organic pollutants are of great concern due their negative effects on the environment, wildlife and human health. Estuaries and coastal marine environments are considered the most sensitive areas to the accumulation of these pollutants. The objective of this study was to understand the contamination status of classical and emerging pollutants in the rivers and estuarine waters of Savannah, Georgia. PCB congeners, chlorinated pesticides and PBDEs were analyzed in sediment and various fish species samples collected from the Vernon River, and other estuarine/brackish waters in the region. Standard analytical procedures were followed to determine the concentrations of these contaminants. Results revealed that detectable levels of PCBs, chlorinated pesticides and PBDEs were found in sediments and fish samples analyzed. Although several of the organochlorines were banned from production and use decades ago, residues of these compounds are still found in sediments and fish samples from Savannah, Georgia. PCBs and pesticides concentrations in fish tissues were below the Food and Drug Administration (FDA) established limits for human consumption. In addition, comparison of the geographical and historical data revealed that sediment and fish
© 2016 American Chemical Society Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
from these waters are relatively less contaminated than other freshwater and coastal/marine environments.
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Introduction Organohalogen compounds such as poychlorinated biphenyls (PCBs), polybrominated biphenyl ethers (PBDEs) and chlorinated pesticides are well known environmental pollutants (1–4). Several studies have demonstrated that environmental exposure to these compounds produces adverse health effects in aquatic and terrestrial animals including humans (4–10). Estuarine/brackish water and coastal marine environments are considered the most vulnerable areas for the accumulation of these compounds. Agricultural, industrial and other domestic activities in and around Savannah, Georgia contribute runoff and effluents to the streams, small rivers and tributaries in this region (Figure 1). The Town of Vernonburg, Chatham County, lies along the western shore of the Vernon River which, along with the Skidaway River, empties into Ossabaw Sound. The Town has long recognized the importance of good water quality in the river, and recognized that possible changes and degradations in physical, chemical, geological and biological conditions in the estuary could result from upstream environmental alterations. The Savannah River estuary is typical of estuaries of the South Atlantic Bight (Figure 1). Earlier reports have revealed that the environmental conditons in the river have improved since 1960s, however, studies have shown that here has been a significant decline (in some cases a 95% decline) in striped bass egg production in the region (11). Additionally, studies have revealed that exposure of wildlife and humans to these persistent organic pollutants is of serious concern due to chronic health effects including birth defects, endocrine disruption, intellectual disability, reproductive toxicity, immune system dysfunction and certain types of cancers (1, 13, 14). However, there exists very limited literature dealing with the status of contamination of these waters and fish with respect to organohalogen pollutants. Thus, understanding the contamination levels of these compounds is very important to help prevent human exposure via consumption of contaminated fish and harmful effects (10–14). The present study was conducted to describe the contamination levels of organohalogens in sediment and fish from rivers and estuarine/brackish waters of Savannah, Georgia, USA.
Materials and Methods Sampling Locations and Samples Figure 1 shows various streams, rivers, estuarine/brackish waters, and the sampling locations in and around Savannah, Georgia. Along with the Ogeechee and Forest Rivers, the Vernon River Estuary is one of three primary branches of the upper reach of Ossabaw Sound. Unlike the other branches, the main uppermost reaches of the Vernon River Estuary is a major storm water drainage system serving urban and suburban Savannah. These major storm water systems include the Wilshire Canal, the Harmon Canal, and the Casey Canal that includes 108 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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a pumping station where the canal becomes the Hayners Creek salt marsh ecosystem. These major storm water drainage systems forming the upper reaches of the estuary. Vernon River water quality is influenced by rain events, surface run off, non-point urban and suburban pollution, and altered flow velocities and frequencies. Throughout its length, from the upper reaches of Hayners Creek to Ossabaw Sound, the estuary functions as fish and shellfish habitat and supports recreational activities, sport and commercial (mostly crab) fishing. A number of communities, including the towns of Vernonburg, Montgomery, Beaulieu, Vernon View, Burnside Island, and southern Skidaway Island lie along the banks of the Vernon River Estuary. The “Harmon Canal” location is near the southern end of the Harmon Canal where it empties into the Hayners Creek (upper end of the estuary); this site represents one of the three main tributaries into the estuary.
Figure 1. Map showing sediment (sampling site numbers 1 – 10) and fish sampling (F1 and F2) locations in and around Savannah, Georgia, USA. Figure 1 and Table 1 show the sampling locations and sample details. Sediment sampling was done during October 2011. Surface sediment (Grab sampling: 0-5 cm) samples were collected using a Ponar Grab. The samples were transferred to pre-cleaned (acetone and hexane rinsed) I-Chem bottles and 109 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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stored at -20 ° C until further analysis. Fish samples were obtained using castnet and trawl operations (Table 1). The fish were identified, measured, and their wet weight was determined. About same size specimens of each species were packed in pre-cleaned aluminum foil and stored at -20 °C until their analysis. The species were selected for analysis based on their general acceptance as table food and their common occurrence in the region (Table 1). Standard analytical procedures were followed for analysis of organohalogens (PCB congeners, chlorinated pesticides and PBDEs) using GC-ECD (15). Ten sediment samples were collected at selected locations (Figure 1). Details of fish samples collected and analyzed were as follows: Carnivores: Silver Perch: Bairdiella chrysoura; Southern Flounder: Paralichthys lethostigma Omnivore: Pinfish: Lagondon rhomboides Plankton feeder (filter feeder): Mullet: Mugil cephalus Detritus/bottom deposit feeder: White Shrimp: Penaeus setiferus Sediment and fish samples were freeze dried for about 60 hours using the Labconco Free Zone Freeze Dry System 77535. About 15 g of dry sediment was Soxhlet extracted using 3:1 mixture of methylene chloride and hexane. The sample extract volume reduction was performed using a Kuderna-Danish apparatus. Silica gel column chromatography was used for clean-up and separation of PCB congeners, PBDEs, from some chlorinated pesticides. Activated copper and sulfuric acid treatments were performed to remove elemental sulfur and other interfering materials in the extracts. PCB congeners and chlorinated pesticides were analyzed using an Agilent Technologies Gas Chromatograph equipped with a DB-5 capillary column and a 63Ni electron capture detector. The column oven temperature program was 90 °C for 1 min., increasing at 5 °C per min to 180 °C; and increasing at 2 °C per min. to 280 °C and held for 6 min. The injector and detector temperatures were set at 270 °C and 330 °C, respectively. Helium at 1.0 ml/min and nitrogen at 29 ml/min were used as the carrier and makeup gases, respectively. About 5.0g (dry weight) of the edible portion of the fish muscle was homogenized using about 15 g of anhydrous sodium sulfate salt. Homogenized sample was Soxhlet extracted using 3:1 mixture of methylene chloride and hexane. K-D concentration was used for volume reduction solvent exchange as done for sediments. Fat content (% lipid) determination was performed by a gravimetric method in an aliquot of extracts from selected samples. Lipid removal from the extracts were performed using a Florisil dry column chromoagraphic technique. Silica gel column chromatography was carried out to remove impurities and separation of PCBs, PBDEs, and chlorinated pesticides. Additional steps in the analysis were similar to those described above for sediments, except that the extracts were not treated with activated copper to remove sulfur. Quality control measures included the use of reagent blanks, and surrogate (4,4′-dibromooctafluorobiphenyl-DBOFB) recoveries (100+/- 30%). Calibration and calibration verification were routinely checked at the beginning and end of each batch of 10 samples. Detection limits were calculated following the methods of the Federal Register (16). 110 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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Table 1. Details of fish samples collected from riverine and estuarine waters of Savannah, Georgia, USA Sample ID
Date of Sampling
Location
Common Name
Species
Standard Length (mm)
Total wt. (g)
Fish-1a
10/19/2011
Sav. Riv. Est. (SRE)
Anchovy(30)
Anchoa mitchilli
40.06-54.26
0.79-1.92
Fish-2b
10/26/2011
Chimney Creek, SRE
Silver Perch(8)
Bairdiella chrysoura
52.36-72.63
5.35-9.82
Fish-3c
10/06/2011
Vernon Riv., BD
Silver Perch(1)
Bairdiella chrysoura
82.15
13.04
Fish-4c
10/06/2011
Vernon Riv., BD
White Shrimp(6)
Penaeus setiferus
94.98-110.4
7.81-15.58
Fish-5d
10/19/2011
SRE-Trawl 2&3
Blue Crab(2)
Callinectes sapidus
128.8-135.6
149-156
Fish-6c
10/06/2011
Vernon Riv., BD
Pinfish(2)
Lagodon rhomoides
92.03-105.8
21.14-38.31
Fish-7b
10/26/2011
Chimney Creek, SRE
Pinfish(6)
Lagodon rhomoides
82.45-115.5
16.4-58.1
Fish-8c
10/06/2011
Vernon Riv., BD
Mullet(5)
Mugil cephalus
109.7-148.9
31.2-62.8
Fish-9b
10/26/2011
Chimney Creek, SRE
Mullet(6)
Mugil cephalus
112.6-130.6
28.6-47.96
Fish-10c
10/06/2011
Vernon Riv., BD
Southern Flounder(1)
Paralichthys lethostigma
205.0
172.0 Continued on next page.
Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
Sample ID
Date of Sampling
Location
Common Name
Species
Standard Length (mm)
Total wt. (g)
Fish-11
11/02/2011
Savannah River
Red Drum(1)
Sciaenops ocellatus
335.0
635.0
Fish-12
11/02/2011
Savannah River
Spotted Sea Trout(2)
Cynoscion nebulous
300-355
383-826
a
Numbers in parenthesis indicate the number of specimens pooled for analysis. small tributary, 10ft depth, temperature: 23.3 °C, Salinity: 20.6 ppm, Trawl 4 start: 32 03.964N, 81 00.255 End: 32 03.884N, 81 00.570W. b Castnet to 3ft depth, temperature: 20.0 °C, Salinity: 32.0 ppm, 32 01.176N, 80 51.065W. c Vernon River, Benson Dock sampling depth: 6ft., 31 57.82N, 81 07.20W. d Trawl 2: South Channel start at Fields Cut, 6-8 ft depth, Temperature: 23.1 °C, Salinity: 20.3 ppm, Trawl start: 32 03.990N, 80 58.647W; End: 32 03.649N, 80 57.978W. Trawl 3: Start: 32 05.433N, 81 00.911W, End: 32 05.129N, 81 00.285W.
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Table 1. (Continued). Details of fish samples collected from riverine and estuarine waters of Savannah, Georgia, USA
Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries I ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
Results and Discussion
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Organohalogen Contaminants in Sediments Figure 1 and Table 1 show the details of sampling for sediments and fish. PCB congeners and chlorinated pesticides concentrations in sediment samples are presented in Tables 2 and 3. Total PCB concentrations in sediments ranged from 9.0 to 23.5 ng/g dry wt. Lower chlorinated congeners (monopentachlorobiphenyls) contributed significantly (>50%) to the total PCB concentrations. Higher chlorinated PCBs (hexa- to decachlorobiphenyls) were barely detectable or below the detection limits. Among chlorinated pesticides analyzed, hexachlorobenzene (HCB) and cis-chlordane (cis-CHL) were detected in most sediments. However, concentrations were very low (
