Marine Pollution Bulletin 64 (2012) 169–173

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Marine Pollution Bulletin

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Metals in sediments and fish from Sea Lots and Point Lisas Harbors,Trinidad and Tobago

Azad Mohammed a,b,⇑, Thomas May b, Kathy Echols b, Mike Walther b, Anton Manoo a, Dexter Maraj a,John Agard a, Carl Orazio b

a Department of Life Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobagob US Geological Survey, Columbia Environmental Research Center, 4200 New Haven Road, Columbia, MO 65201, United States

a r t i c l e i n f o a b s t r a c t

Keywords:Sea Lots HarborPoint Lisas HarborTrinidad and TobagoHeavy metalsRare earth metals

0025-326X/$ - see front matter � 2011 Elsevier Ltd. Adoi:10.1016/j.marpolbul.2011.10.036

⇑ Corresponding author at: Department of Life SciWest Indies, St Augustine, Trinidad and Tobago. Tel.: ++1 (868) 663 5241.

E-mail address: azad.mohammed@sta.uwi.edu (A.

Concentrations of heavy metals were determined in nearshore marine sediments and fish tissue from SeaLots area on the west coast, at Caroni Lagoon National Park, and in the Point Lisas harbor, Trinidad. Themost dominant metals found in sediments were Al, Fe and Zn with mean concentrations highest at SeaLots (Al-39420 lg/g; Fe-45640 lg/g; Zn-245 lg/g), when compared to sediments from Point Lisas (Al-11936 lg/g; Fe-30171 lg/g; Zn-69 lg/g) and Caroni (Al-0400 lg/g; Fe-19000 lg/g; Zn-32 lg/g), Highconcentration of Cu, Al, Fe and Zn were also detected in fish tissue from Point Lisas and Caroni. Metal con-centrations in fish tissue showed significant correlation with sediment metals concentration, which sug-gests that tissue levels are influenced by sediment concentration. Of the metals, only Zn, Hg and Cu had abioaccumulation factor (BAF) greater than one, which suggests a high bioaccumulation potential for thesemetals.

� 2011 Elsevier Ltd. All rights reserved.

Heavy metals are common environmental pollutants gener-ated from anthropogenic activities. Metals such as lead, mercury,copper and cadmium are regarded as serious marine pollutantsbecause of their high toxicity, tendency to be incorporated intothe food chain and persistence in the environment. They canexist in the environment as dissolved species, free ions, physi-cally or chemically adsorbed onto sediments or bioaccumulatedin organisms. Sediments act as a long-term storage site formetals and serve as a potential contamination source for marineorganisms.

Over the last two decades, heavy metal pollution has become anincreasing problem in the Caribbean (GESAMP, 2001; UNEP, 1994).According to the United Nations Environmental Programme(UNEP), throughout the region there is a general lack of legislationconcerning import, export, use and disposal of heavy metals(UNEP, 2002). Regionally the most important legal framework re-lated to heavy metal pollution is the Cartagena Convention, whichentered into enforcement in 1986. This convention is a legallybinding regional multilateral environmental agreement whichdeals with reducing pollution by heavy metals through its proto-cols concerning pollution from land-based sources.

ll rights reserved.

ences, The University of the1 (868) 662 2002x82047; fax:

Mohammed).

Trinidad and Tobago (T & T), is an archipelagic state in thesouthern Caribbean, and has a total land area of approximately5125 km2 with a population of about 1.3 million people. It containsone of the oldest oil industries in the world and over the past twodecades has experienced an unprecedented increase in the rate ofgrowth of its industrial sector. This rapid industrialization has re-sulted in an increased input of contaminants into coastal regionsthrough rivers, surface run-off, and land-based point sources.Though the T & T Environmental Management Act of 2000 (EMA,2000) exists to regulate the contaminant levels in industrial efflu-ents, lack of monitoring and enforcement greatly reduces the effec-tiveness of the regulatory program.

Few studies have looked at levels and impacts of heavy metalsin the wider Caribbean (Fernandez et al., 2007) and coastal areas ofT & T (Norville, 2005; Rojas de Astudillo et al., 2002; Hall, 1985).This study investigated the levels of heavy metals, alkali, alkaliearth metals, and rare earth metals in sediments from the PointLisas and Sea Lots Harbors on the west coast of Trinidad. It hadtwo specific objectives: (1) to determine the spatial extent of metalcontamination in the two harbors; and (2) compare these values topublished thresholds for biological effects. The data obtained inthis study provides baseline information for metals contaminationin two harbors in Trinidad and Tobago that can be used to identifyhotspots which can direct future contaminants monitoring andmanagement programs.

Sediments were sampled from Sea Lots Harbor, Point LisasHarbor, and Caroni Lagoon National Park on the west coast of

Fig. 1. Sample locations for the Sea Lots and Point Lisas harbor and Caroni sample sites.

170 A. Mohammed et al. / Marine Pollution Bulletin 64 (2012) 169–173

Trinidad (Fig. 1). The Sea Lots Harbor, in south Port-of-Spain, re-ceives urban run-off, discharge from several light industries, anddrainage of effluents from the Beetham sewage treatment facilitiesand the Beetham municipal landfill. This 30-year-old landfill re-ceives approximately 840 tons of unsorted waste materials perday. The Point Lisas Harbor receives urban runoff and dischargesfrom the Point Lisas industrial estate, which houses about 98 com-panies comprising a mix of world class petrochemical (methanoland ammonia) industries, steel plants, medium sized manufactur-ers, and smaller service companies. The third sample site was off-shore of the Caroni Lagoon National Park (also known as the CaroniSwamp, a 32 km2 mangrove wetland) which does not receive anydirect inputs from land-based sources of contamination, but liessouth of the Caroni River which passes several small industrial es-tates along its course.

At each site, the top 5 cm of surface bed sediment was collectedusing a handheld coring device made of 50 mL polyethylene syrin-ges. The sediment samples were placed in cleaned ziplock plasticbags, and stored at 4 �C prior to analysis. Twigs and leaves werediscarded and the sediments dried at 60 �C for 24 h. Six whole fish(Cathorops spixii) within the size range 15–25 cm were collectedfrom Point Lisas and Caroni sites, however, none were found atthe Sea Lots site. The stomach and intestines were removed and

each fish was homogenized and dried at 60 �C. The dried sedimentand fish were shipped overnight on ice from University of WestIndies, Trinidad to the US Geological Survey in Columbia, MissouriUSA for analysis.

Fish and sediment samples were lyophilized and then furtherhomogenized by crushing with a glass rod to achieve a coarsedry powder consistency and analyzed using ICP-MS, according tothe method of May et al. (2009). An aliquant (0.25 g) of driedhomogenized fish tissue was heated in a microwave oven with6 mL concentrated nitric acid in a sealed Teflon vessel and then di-luted to 100 mL with deionized water. An aliquant of sediment(0.25 g) was heated similarly with a 5.5 mL nitric acid and 0.5 mLconcentrated hydrochloric acid mixture and diluted to 100 mL.To prepare samples for the determination of selenium (Se), an ali-quant (0.5 g) of dried sample was heated to dryness in a 10 mL 40%magnesium nitrate, 10 mL nitric acid, and 2 mL hydrochloric acidmixture and dry ashed at 475 �C in a muffle furnace. Hydrochloricacid (50%) (20 mL) was added to the ashed residue and concen-trated (sub-boiling) to 5–10 mL. A 50% hydrochloric acid solutionis added to bring the volume to 20 mL, which was transferredand diluted to 100 mL with deionized water.

Samples were diluted tenfold with a CETAC ASD-500 autodilut-er/autosampler and analyzed by ICP-MS (Perkin-Elmer/Sciex Elan

A. Mohammed et al. / Marine Pollution Bulletin 64 (2012) 169–173 171

6000) using the semi-quantitative scan mode (TotalQuant�). Inter-nal standards, Sc (10 ppb), Rh (10 ppb) and Th (10 ppb) were addedto all the samples. An external standard was also analyzed to im-prove calibration in the rare earth region of the mass spectral range(141Pr–193Ir). The external standard consisted of a NIST (TraceMetals in Drinking Water; High Purity Standards, Charleston, SC)traceable reference solution to which 5 (Pr, Tb, Tm, Ta and Au) ele-ments were added. Following analysis, data was transferred toMicrosoft Excel™ software where customized macros were usedto edit and compute all final data in lg/g dry weight.

Mercury was measured using a direct mercury analyzer (Mile-stone DMA-80 analyzer). An aliquant (30–40 mg) of dried samplewas combusted in a stream of oxygen to volatilize the mercury(Hg), which was then trapped by amalgamation on a gold sub-strate. The Hg was subsequently thermally desorbed and quanti-fied by atomic absorption spectrophotometry (AAS). Seleniumwas determination from dry-ashed samples using flow injectionhydride generation atomic absorption spectroscopy. Digested sam-ples were mixed with a hydrochloric acid carrier solution and re-duced by sodium tetrahydridoborate stabilized with sodiumhydroxide. The resulting volatile hydrogen selenide was trans-ferred with an argon stream into a heated quartz cell mountedon an AAS and analyzed.

The quality control (QC) for this study included proceduralblanks, sediment matrix blanks, sediment reference materials,and spiked sediment samples. Recoveries for elements in QC sedi-ment samples ranged from 66% to 118% for V, Cu, Zn, Ni, Co, Cd, Pb,As, Li, Mn and Ag from three sediment/soil reference materials(NRCC PACS-1 and MESS-3; NIST 2709). Recoveries of Hg and Sefrom these materials ranged from 100% to 110%. With the excep-tion of Fe, recoveries of elements from tissue reference materials(NIST 1566b; NRCC DORM-2) ranged from 71% to 135%. Recoveriesof elements from NIST 1577 bovine liver ranged from 76% to 133%with the exception of Cr and As, both of which were certified at lev-els approaching the reporting limit (<0.04 lg/g dry weight) for thesemi-quantitative ICP-MS determination. Recoveries of Hg and Sefrom tissue reference materials ranged from 92% to 118%. Differ-ences in metal concentrations between sites were assessed usingpaired t-tests.

The concentrations of metals in the surface sediments from thethree sample sites are presented in Table 1. Heavy metals in Sea Lotssediments were significantly (P < 0.05) higher than those at PointLisas, with the exception of As (18 lg/g). Both Point Lisas and SeaLots Harbor sediments had metal concentrations which weresignificantly higher (P < 0.05) than sediments from Caroni. The mostdominant metals found at all three sites were Al (6300–45300 lg/g),Fe (19000–48800 lg/g) and Zn (32–268 lg/g). The mean concentra-tions of these metals were highest at Sea Lots (Al-39420 lg/g;Fe-45640 lg/g; Zn-246 lg/g), when compared to sediments from

Table 1Concentration of metals in sediments (lg/g dw) from Sea Lots Harbor in Port-of-Spain, theCaroni reference site).

Metals Point Lisas Sea Lots

Conc. range Mean conc. (n = 3) Conc. range Mean c

Al 6300–21000 11936 34900–45300 39420As 13–26.0 18.0 6.2–11.7 10Cd bdl–0.12 0.08 0.23–0.62 0.Cr 10.9–24.6 16 40.1–48.0 44Cu 3–17 8 45.0–85.8 57Fe 26200–34900 30171 42000–48800 45640Hg bdl–0.06 0.05 0.16–0.3 0.Ni 9.5–17.4 12 26.9–31.3 29Pb 7.5–15.5 11 44.6–55.3 49Zn 59.8–92.7 69.0 212–268 246

⁄Canadian Interim Sediment Quality Guidelines for total metals in surficial marine sedim

Point Lisas (Al-11936 lg/g; Fe-30171 lg/g; Zn-69 lg/g) and Caroni(Al-10400 lg/g; Fe-19000 lg/g; Zn-32 lg/g) (Table 1). Higherconcentrations of Cr (44 lg/g), Cu (57 lg/g), Ni (29 lg/g) and Pb(49 lg/g) were also found in sediments from Sea Lots whencompared to Point Lisas (Cr-16 lg/g, Cu-8 lg/g, Ni-12 lg/g,Pb-11 lg/g) and Caroni (Cr-14 lg/g, Cu-9 lg/g, Ni-9 lg/g,Pb-10 lg/g) (Table 1).

Metal levels in sediments from the Caroni and Point Lisas siteswere below the Canadian Interim Sediment Quality Guidelines(CaISQG) for marine sediments with the exception of As (18 lg/g; exceeded the guideline 2-fold) at the Point Lisas site (Table 1)(CCME, 2001). Metal concentrations were also lower than the IAEA(International Atomic Energy Agency) tolerable level for metals insediments (Wyse et al., 2003) which suggests that the sedimentmetals are unlikely to pose a significant risk to human health. Fiveof the metals (As, Cu, Hg, Pb and Zn) detected in the Sea Lots sed-iment exceeded the CaISQG levels (Table 1), however these werestill below the CaPEL (probable effect limit) (CCME, 2001). Levelsof Cd, Cu, Hg, Pb and Zn from the sealots sediments were all abovethe recommended IAEA tolerable limits, and could therefore beconsidered hazardous to human health (Table 1).

The concentration of metals in sediments from the Gulf of Paria,on the west coast of Trinidad has been previously reported by var-ious authors (Norville, 2005; Rojas de Astudillo et al., 2005; Halland Chang-Yen, 1984). Norville (2005) reported metal concentra-tions (dry weight) for 37 stations in Gulf of Paria and reportedthe mean concentrations across two seasons for Fe (11 mg/g), Mn(501.5 lg/g), Al (2.2 mg/g), Cr (19.2 lg/g), Cd (0.15 lg/g), Pb(11.3 lg/g), Zn (57.2 lg/g), Cu (7.5 lg/g), Hg (0.025 lg/g) and Ni(10.4 lg/g). However few stations were within the Sea Lots orPoint Lisas Harbors. Metal concentrations for Sea Lots harbor sed-iments were 2–6 times higher than those reported by Norville(2005) for some of the metals. Metal concentrations from Point Li-sas harbor sediments were about 2–3 times higher for some metalswhile Caroni sediments were of a similar order of magnitude whencompared to levels reported by Norville (2005). The sediment lev-els reported in this study also exceed those reported by Persad andRajkumar (1994), Hall and Chang-Yen (1984) and Rojas de Astudil-lo et al. (2005) for Gulf of Paria sediments. The high levels of metalsdetected at Sea Lots may be as a result of effluent runoff from thenearby Beetham landfill and other land-based sources, as well asderelict ships within the bay. Sea Lots is also more enclosed thanthe Point Lisas harbor so sediment drift is less influenced by tidalstreams and ocean currents. The main factor that may contributeto movement of sediment metals in Sea Lots would be dredgingactivities, which occurs periodically to maintain navigation chan-nels. The Point Lisas harbor also receives runoff from the nearbyindustrial estate and drainage from the Couva River, which mayserve as significant sources of contaminant inputs.

Point Lisas Harbor and Caroni sample sites (there was only one sample station at the

Conc. at Caroni CaISQG⁄ IAEA-407 Tolerable levels

onc. (n = 3)

104005.4 7.24 18.9

4 0.07 0.7 0.1514 52.3 1369 18.7 30.819000

22 0.03 0.13 0.179 39.410 30.2 2632 124 101

ents. bdl – below detection limits ISQG (CCME, 2001).

Table 2Concentration and Bioaccummulation factor (BAF) of heavy metals in fish Cathorops spixii (lg/g dw) from Caroni and the Point Lisas Harbor; (bdl) below detection limit.

Metals Cathorops spixii (Point Lisas) BAF Cathorops spixii (Caroni) BAF IAEA-407 Tolerable levels

Conc. range Mean conc. Conc. range Mean conc.

Al 471–656 589 0 2200–2400 2300 0.2 13.8As 4.5–5.0 4.7 0.3 4.0–5.3 4.7 0.9 12.6Cd bdl–0.06 0.05 0.2 bdl – 0 0.19Cr 2.2–2.8 2.5 0.2 3.4–4.8 4.1 0.3 0.73Cu 16.6–20.4 18.7 2.2 7.5–35.5 20.1 3.1 3.28Fe 839–1040 931 0 523–2810 1860 0.1 146Hg 0.12–0.13 0.13 2.5 0.33–0.60 0.50 15 0.22Ni 1.0–1.5 1.2 0.1 0.48–2.1 1.4 0.1 0.60Pb 0.39–0.47 0.44 0 0.18–1.3 0.89 0.1 0.12Zn 221–289 265 3.7 351–494 439 13.1 67.1

172 A. Mohammed et al. / Marine Pollution Bulletin 64 (2012) 169–173

Levels of metals in fish tissue (C. spixii) from Point Lisas andCaroni are shown in Table 2. Of the metals analysed, only Zn(2300 lg/g) and Al (439 lg/g) were significantly (P < 0.05) higher

Table 3Concentration of trace elements in sediments and fish tissue (lg/g dw) from Sea Lots Hdetection limit.

Elements Sediments Conc. at Ca

Point Lisas Sea Lots

Conc. range Mean Conc. Conc. range Mean Conc.

Ag bdl–0.11 0.08 2.0–5.2 3.3 1.8Au bdl – bdl–0.06 0.05 bdlBa 13.5–48.9 28.3 119.0–169.0 159.0 27.5Be 0.60–1.1 0.7 0.81–1.6 1.28 0.42Bi 0.09–0.17 0.12 0.29–0.75 0.52 0.09Ca 1470–6400 2797 3780–5650 4690 1250Ce 16.5–26.1 19.4 24.5–37.8 29.2 bdlCo 6.4–9.2 7.7 9.6–11.6 10.7 4.8Cs 0.51–1.6 1.3 3.7–4.2 3.9 1.0Dy 1.9–3.8 2.2 2.6–3.1 2.8 1.2Er 0.78–1.2 0.91 1.0–1.2 1.1 0.43Eu 0.50–0.79 0.58 0.79–1.1 0.86 0.41Ga 4.0–8.9 7.7 18.0–22.7 20.2 5.3Gd 2.4–3.6 2.7 3.5–4.3 3.8 1.9Ge 0.06–0.09 0.07 0.12–0.17 0.12 0.07Hf 0.10–0.15 0.12 0.11–0.23 0.16 0.06Ho 0.30–0.46 0.35 0.39–0.51 0.43 0.18In bdl – 0.06–0.08 0.06 bdlK 1460–5270 2993 9510–11900 10682 1830La 7.3–11.2 8.0 10.8–13.0 12.6 8.0Li 8.6–17.6 16.2 47.0–53.6 50.3 13.5Lu 0.09–0.14 0.11 0.14–0.18 0.15 0.06Mg 2350–4990 3376 6330–8820 7532 1850Mn 207–751 440.0 229–449 341 159Mo 0.37–0.72 0.57 1.4–5.8 3.3 0.40Na 2730–9580 5189 23300–56700 35740 5740Nb bdl–0.07 0.06 0.03–0.12 0.09 bdlNd 9.4–14.2 10.8 13.6–18.7 15.3 8.9Pd bdl – bdl–0.14 0.09 bdlPr 2.6–4.0 3.0 3.8–5.3 4.2 2.7Rb 8.3–38.0 19.7 43.0–55.3 49.1 12.5Sb bdl–0.56 0.05 0.10–0.79 0.28 0.09Se 0.07–0.53 0.17 0.52–1.3 0.73 0.17Sm 2.1–3.1 2.4 2.8–4.0 3.2 1.7Sn 0.47–1.48 0.72 0.65–4.7 2.1 bdlSr 14.6–69.4 27.8 56.5–77.9 63.8 17.3Ta bdl 7.7 bdl–0.07 0.07 0.05Tb 0.34–0.51 0.38 0.46–0.63 0.52 0.25Ti 72.1–117 88.0 144–214 176 69.4Tl 0.05–0.14 0.12 0.42–0.84 0.60 0.14Tm 0.10–0.15 0.12 0.14–0.20 0.17 0.06U 0.39–0.92 0.61 1.0–1.5 1.3 0.49V 29.4–49.2 37.3 55.2–67.6 60.5 20.9W bdl–0.03 0.02 bdl – bdlY 5.8–8.9 6.6 7.6–9.0 8.2 3.5Yb 0.74–1.1 0.88 0.89–1.3 1.1 0.39Zr 2.4–4.0 3.0 2.9–5.6 3.8 1.3

in fish tissue from Caroni compared to fish from Point Lisas (Al-589 lg/g; Zn-265 lg/g). The metals in tissue were also dominatedby Al (589–2300 lg/g), Fe (931–1861 lg/g) and Zn (265–439 lg/g)

arbor in Port-of-Spain, the Point Lisas Harbor and Caroni sample sites. (bdl) below

roni Fish tissue

Cathorops spixii (Point Lisas) Cathorops spixii (Caroni) IAEA-407

Conc. range Mean Conc. Conc range Mean Conc.

bdl–0.05 0.05 bdl–0.05 0.05bdl – bdl –6.0–7.1 6.7 9.3–10.4 9.8bdl–0.04 0.04 bdl–0.12 0.09bdl – bdl –18800–42500 30233 3290–13000 7943 270.41–0.53 0.47 1.5–1.6 1.60.39–0.52 0.47 0.39–0.85 0.69 0.10.06–0.09 0.08 0.05–0.23 0.17bdl–0.05 0.05 bdl–0.14 0.13bdl – bdl–0.06 0.06bdl – bdl –0.49–0.56 0.54 0.18–1.4 1.00.04–0.06 0.05 bdl–0.19 0.19bdl – bdl–0.06 0.06bdl – bdl –bdl – bdl –bdl – bdl –19200–21400 20300 18300–21100 19633 13.10.19–0.24 0.22 0.09–0.78 0.530.84–0.93 0.89 0.32–2.48 1.7 0.69bdl – bdl –1860–1920 1880 1210–1420 1333 2.723.8–28.5 26.2 58.6–184 121.1 3.50.14–0.21 0.17 bdl–0.19 0.115460–5770 5663 4450–5470 4883 13.1bdl – bdl–0.07 0.060.20–0.27 0.24 0.81–0.85 0.83bdl – bdl –0.06–0.08 0.07 bdl–0.25 0.246.5–7.7 7.1 6.4–9.7 8.5 2.90.04–0.18 0.10 bdl – 0.011.35–1.58 1.4 1.5–2.9 2.1 2.30.04–0.06 0.05 bdl–0.16 0.151.5–1.9 1.7 0.44–4.9 2.4146–452 292 25.4–80.9 52.1 130bdl – bdl –bdl – bdl –32–48.6 41.1 18.7–45.9 36.5bdl–0.07 0.06 bdl –bdl – bdl –bdl – bdl–0.25 0.211.3–1.6 1.5 4.0–4.3 4.2 1.43bdl – bdl –0.13–0.16 0.14 0.39–0.43 0.41bdl–0.02 0.02 bdl–0.05 0.050.17–0.18 0.17 0.34–0.40 0.39

A. Mohammed et al. / Marine Pollution Bulletin 64 (2012) 169–173 173

for both sample sites. When compared to the IAEA tolerable valuesfor metals in fish, levels of Al, Cr, Cu, Fe, Ni and Pb, from both sitesand Hg from the Caroni site were all above the tolerable values andthus potentially hazardous to human health (Table 2). Fish fromboth sites also had Cu and Zn levels that exceeded the local maxi-mum permissible levels (Food and Drugs Act, 2007) of 20 lg/g wetweight and 50 lg/g wet weight, respectively, for both metals.

Few studies have reported metal levels in marine organisms inTrinidad. Singh et al. (1991) reported levels of Zn (4.4–6.7 lg/g), Fe(3.7–14.3 lg/g) and Cu (0.2–0.8 lg/g) for five species of fish fromTrinidad, however, the levels of these metals were higher in C. spixiifrom both the Caroni and Point Lisas sites. The concentrations of Cr(4.1 lg/g), Cu (20.1 lg/g), Hg (0.5 lg/g), Ni (1.4 lg/g) and Zn(439 lg/g) for tissue from the Caroni site were higher than that re-ported by Rojas de Astudillo et al., 2005 for Crassostrea rhizophoraefrom Caroni (Cr-0.23 lg/g, Cu-14.6 lg/g, Hg-0.05 lg/g, Ni-0.43 lg/g, Zn-171 lg/g). Metal concentrations in fish tissue from Point Lisasshowed a 95% correlation with sediment metals, while at Caroni itwas 90%. This strong positive correlation would suggest that metallevels in fish tissues are greatly influenced by sediment concentra-tion. Of the metals, only Zn, Hg and Cu had a bioaccumulation fac-tor (BAF) greater than one, which suggests a high bioaccumulationpotential for these metals (Table 2).

The concentrations of other elements from all three sites areshown in Table 3, none of which have been previously reported forTrinidad and Tobago or the Caribbean. Measureable concentrationsof Ba (13.5–169 lg/g), Ca (1250–5650 lg/g), Ce (below detectionlimit (bdl) – 37.8 lg/g), K (1830–11900 lg/g), Li (13.5–53.6 lg/g),Mg (1850–8820 lg/g), Mn (159–449 lg/g), Nd (8.9–18.7 lg/g), Rb(8.3–55.3 lg/g), Sr (14.6–77.9 lg/g), Ti (69.4–214 lg/g) and V(20.9–67.6 lg/g) were indicated in sediments from all three sites.However, only Mn exceeded the IAEA tolerance limits for metalsin sediments. Fish tissue from Point Lisas and Caroni had measurablelevels of Ba (7.1–10.4 lg/g), Ca (3290–42500 lg/g), K (18300–21400 lg/g), Mg (1210–1920 lg/g), Mn (23.8–184 lg/g), Rb(6.4–9.7 lg/g), Sr (25.4–452 lg/g) and Ti (18.7–48.6 lg/g). Theseelements may also contribute to the overall contamination withinthe area. Fish samples from both Point Lisas and Caroni had concen-trations of Co, K, Li, Mg, Mn, Na, Rb, Sb, Sr and V above the IAEA rec-ommended levels, indicative of being hazardous for human healthconsumption. Some elements (Ca, K, Se, Sn and Sr) showed a

bioaccumulation factor greater than one, suggesting significant up-take from the environment.

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