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Marine Pollution Bulletin 54 (2007) 1681–1691 www.elsevier.com/locate/marpolbul
Review
A literature review on trace metals and organic compounds of anthropogenic origin in the Wider Caribbean Region Adolfo Fernandez, Asha Singh, Rudolf Jaffe´
*
Southeast Environmental Research Center, Florida International University, 11200 SW 8th St, Bldg OE 148, Miami, FL, USA
Abstract About 30 studies from the published literature were reviewed to determine the pollution status regarding heavy metals and organic compounds of the Wider Caribbean Region (WCR). The literature revealed that most studies were performed in the South and Central American Caribbean Region with sparse reports on the small island states. Collectively, the most frequently analyzed heavy metals were Pb, Cu, Zn, Fe, Cd, Ni, Mn and Cr while DDT and its metabolites were the most frequently reported organic pollutants. The samples which were analyzed vary in terms of sampling schemes, parameters and analytical techniques, as well as differences in data reporting presentation (i.e. dry weight versus wet weight, sediment fraction analyzed, or % lipids). These differences make meaningful comparisons of the available data very difficult. Furthermore, there is limited data available for most of these contaminants from the majority of nations in the WCR. Therefore, any attempt to create a regional scale assessment from contaminants data available in the open literature is limited by the scarcity of available information. 2007 Elsevier Ltd. All rights reserved. Keywords: Wider Caribbean Region; Marine; Pollution; Heavy metals; Organic pollutants
1. Introduction 1.1. General aspects of pollution in the WCR The coastal marine environment of the Wider Caribbean Region (WCR) consists of fragile ecosystems that are considered hotspots in marine biodiversity (Brooks and Smith, 2001). These ecosystems provide the region with services that are critical for economic support and development of the local population. Among the major sources of income in this region is tourism and travel thus, making it one of the most tourism dependent regions of the world (World Travel and Tourism Council, 2003). These pressures have resulted in the Caribbean Region exhibiting some signs of environmental stress (Richards and Bohnsack, 1990) and long-term ecological research and manage-
*
Corresponding author. Tel.: +1 305 348 3095; fax: +1 305 348 4096. E-mail address: jaffer@fiu.edu (R. Jaffe´).
0025-326X/$ - see front matter 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2007.08.007
ment has been advocated as an urgently needed activity to assess the potential long-term negative impact of human disturbances on the goods (e.g. fisheries) and services (e.g. ecotourism) these ecosystems provide (Rivera-Monroy et al., 2004; Singh, 2005). Within this framework, ecological effects by toxic chemicals (trace metals and organic pollutants) are a critical issue. During the past two decades, marine pollution has become an important issue in the Caribbean (GESAMP, 2001; UNEP, 1994). The Caribbean Environment Programme (CEP) of the United Nations Environment Programme (UNEP) has highlighted such problem and has reported the existing and potential environmental threats to the region (UNEP, 1999). In addition, many studies have been published which dealt with marine pollution in the Wider Caribbean Region (WCR) with some focusing on specific types of pollution. A number of these studies have focused on pollutants such as petroleum hydrocarbons (Atwood et al., 1987, 1988; Botello et al., 1997), nutrients (Siung-Chang, 1997; Rawlins et al., 1998), and sewage (Siung-Chang, 1997). However,
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there is the absence of a comprehensive assessment and few datasets are available on the occurrence and distribution of heavy metals, such as lead and mercury, and organic pollutants such as organochlorine pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) in the WCR. Therefore, the goal of this paper is to review the available literature in an effort to assess whether any conclusion or regional assessment can be drawn regarding the level of pollution by trace metal and anthropogenic organic compounds in the WCR. The WCR in this paper is the geographic region defined in Article 2 of the Convention for the Protection and Development of the Marine Environment of the Wider Caribbean Region (Cartagena Convention), excluding the United States (Fig. 1). This region includes several independent and dependent Island States in the Caribbean Sea, as well as mainland territories of South and Central America. This region covers an area of 4.3 · 106 km2, with an estimated 40% of its human population residing within 2 km of the coast (UNEP/CEP, 2001). Of particular importance in assessing the magnitude of the pollution in the marine environment is the medium or environmental matrix in which contaminants are detected. In the WCR, surface water (Mansingh and Wilson, 1995; Rajkumar and Persad, 1994; Rajkumar et al., 1995) sediments (Alonso et al., 2000; Bernard, 1995; Gonzalez and Ramirez, 1995; Gonzalez and Torres, 1990; Greenaway and Rankine-Jones, 1992; Guzman and Garcia, 2002; Guzman and Jimenez, 1992; Hall and Chang-Yen, 1986; Jaffe´ et al., 2002; Mansingh and Wilson, 1995; Rajkumar and Persad, 1994; Sbriz et al., 1998) and living organisms including mangroves, various species of fish, bivalves, echinoderms and corals (Alonso et al., 2000; Bastidas and Garcia, 1999; Gold-Bouchott, 1993; Gonzalez et al., 1999; Gonzalez and Ramirez, 1995; Guzman and Garcia, 2002; Guzman and Jimenez, 1992; Jaffe´ et al., 1992, 1995, 1998; Laboy-Nieves and Conde, 2001; Sbriz et al., 1998) were used in the analyses for various heavy metals and organic compounds. The observed low level usage of surface water (10%) as a medium for analysis of contaminants is probably due to the intrinsically low residence time and consequently low concentrations of these contaminants in water and to the high temporal and seasonal variations of aquatic pollutant concentrations. In contrast, analyses of sediments were used in the majority of the studies as pollutant archives. It is known that most organochlorine pesticides have low aqueous solubility and tend to adsorb to marine sediments and colloidal solids (Jaffe´, 1991; Rawlins et al., 1998). The use of living organisms as biomonitors of pollution which included a wide variety of organisms such as corals, sea urchins, echinoderms, fish, mussels and other bivalve species were used in many of the studies. Bivalves are the more suitable among the various types of organisms for this type of study because of their sedentary nature, ability to bioconcentrate pollutants and their widespread distribution over large geographic areas (Jaffe´ et al., 1995, 1998; NOAA, 1995; Sericano et al., 1990, 1995; Singh et al., 1992).
The temporal and spatial coverage of sample collection are also critical in evaluating the potential magnitude of marine pollution. Single sampling events conducted in localized regions provide only a snapshot view of pollution in that area. In contrast, long-term monitoring studies that consist of multiple sampling events collected from a wide geographic area are a more effective means of assessing marine pollution. Furthermore, sampling over a wide geographic area can allow for distinguishing between localized ‘hotspots’ situated near point sources and more widespread anthropogenic contamination as well as providing important information on the transport and dispersal of pollutants from both point and non-point sources. Long-term studies that are conducted over several years are also helpful in determining rates of input of contaminants versus their transport and degradation and may better indicate which areas are susceptible to significant environmental stressors. The probable effects of trace metal contamination in sediments, which were conducted in some studies, were evaluated against guideline values developed by NOAA to interpret the effects of contaminants on biological endpoints. The guidelines values are the threshold effects level (TEL) and a probable effects level (PEL). The TEL represents the upper range limit of contamination for which no effects have been observed in the majority of toxicity studies performed on that contaminant. Below this level, pollutants are not considered a significant hazard to aquatic organisms. The PEL represents the lower limit of a pollutant concentration, which is usually associated with adverse biological effects to aquatic organisms. Above this level, pollutants concentrations can potentially be associated with adverse biological effects (NOAA, 1999). 1.2. Sources of heavy metals and organic pollutants in the WCR The main pollution sources which were identified for the WCR include sewage inputs, mineral extraction, pesticide usage in the agricultural sector, hydrocarbon extraction and transportation and waste from the industrial sector. Mineral extraction is primarily in the form of bauxite mining but other small scale metallurgical activities also exist. In 1999, it was estimated that bauxite producing countries (Jamaica, Dominican Republic, Haiti, Guyana and Suriname) in the WCR account for over 29.3% of the world’s bauxite production (UNEP, 1999). There are also significant exports of nickel from Dominican Republic and Mexico and copper from Cuba and Dominican Republic. The extraction of mineral deposits in the WCR has resulted in pollutants such as lead, copper and zinc reaching the marine environment. In Cuba, for example, nickel mining and metallurgical activities have resulted in elevated concentrations of nickel, iron, cobalt, and manganese in sediment deposits (Gonzalez and Ramirez, 1995). Agricultural activities are another source of pollution in the WCR. Many countries have relatively vibrant agricultural sectors and in 1999 it was estimated that over 25%
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Fig. 1. Map of the Wider Caribbean Region.
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of the total GDP is derived from agriculture for all the countries in this region. However, poor land management practices and the increased lost of agricultural lands to other economic activities have led to increased pesticide usage (Singh, 2005). Pesticides are also used to control vector borne diseases on livestock and in some household applications (UNEP, 2002). It is estimated that as much as 90% of pesticide applications in the WCR do not meet their intended target and a high proportion is believed to be entering the marine environment via surface and drainage runoff, erosion, misapplication and atmospheric transport (UNEP, 1994). Many banned chlorinated pesticides such as DDT, chlordane, aldrin, dieldrin, heptachlor, and toxaphene were found to still been used in the late 1990s (Alegria et al., 2000). This is evident from some studies such as Gold-Bouchott (1993), Jaffe´ et al. (1995, 1998), Mansingh and Wilson (1995), Sbriz et al. (1998) and Jaffe´ et al. (2002) which have all reported the presence of these pollutants in the marine environment of the WCR. Another type of common organic pollutant are the polychlorinated biphenyls (PCBs) which have been used extensively in the WCR since the 1930s. PCBs reach the marine environment via dry and wet deposition, sewage sludge used as fertilizer, and leaching from landfills (UNEP, 2002). PCBs are extremely persistent in the environment especially those with half-lives of more than six years and are found in aerobic soils and sediments. They are also known to be carcinogenic and have shown evidence of endocrine disruption in laboratory tests (UNEP, 2002). Jaffe´ et al. (1995), Mansingh and Wilson (1995), Sbriz et al. (1998) and Jaffe´ et al. (2002) in their studies have reported the presence of PCB in the WCR. Hydrocarbon presence in the WCR is one of the most significant threats to marine life according to UNEP (1999). Among those causing pollution are land based and maritime activities as well as petroleum and gas extractions. The WCR, especially the Caribbean Sea, is one of the principal waterways in the world harbouring in excess of 50,000 ship calls per year (ACS, 2002), and is classified as having one of the most intensive maritime traffic in the world (UNEP, 2005). It is estimated that over 5 million barrels of oil and its by products are transported everyday in this region (Botello et al., 1997). This high transportation rate coupled with refining and extraction make the marine environment extremely susceptible to hydrocarbon pollution. In terms of direct pollution, it is estimated that approximately seven million barrels of oil are discharged annually in the WCR from tank washing (Botello et al., 1997). The UNEP estimated that in excess of 50% of the pollution in the WCR is caused by ballasting and emptying of bilges (UNEP, 1994). As a result of these activities, oil slicks in coastal waters and along beaches in the Caribbean were reported, as a frequent occurrence for example, in Jamaica (Wade et al., 1987) and Curac¸ao (Buth and Ras, 1992). High levels of dispersed/dissolved petroleum hydrocarbons (DDPH) were recorded at various cruise stations in the South Eastern part of the Caribbean Sea (Persad
and Rajkumar, 1995), and in other areas of the sea (Harvey, 1987). In addition, elevated levels of DDPH including polycyclic aromatic hydrocarbons (PAHs) were observed throughout the WCR (Atwood et al., 1987; Botello et al., 1997). PAHs such as napthalenes, phenanthrenes, and crysenes are toxic compounds which bioconcentrate in invertebrates in the aquatic environment. These compounds are known to cause adverse effects on tropical ecosystems such as mangrove forests and coral reefs (Botello et al., 1997; Gold-Bouchott et al., 1995). Other sources of PAHs in the environment result primarily from fossil fuel combustion and emissions associated with the burning of charcoal, wood, oil and other biomass as well as motor vehicle emissions and urban runoff (UNEP, 2002). The use of petroleum products and paints in the shipping industries have also contributed to pollution in the marine environment (Laboy-Nieves and Conde, 2001). A variety of studies conducted by Botello et al. (1991), Singh et al. (1992), Corbin (1993) and Jaffe´ et al. (1995, 1998, 2002) have reported the presence of PAHs in the WCR marine environment. 2. Results and discussion To facilitate comparison of the data obtained from various studies, the WCR was divided into four subregions. (a) South America: Colombia, Suriname, Venezuela, Trinidad and Tobago, Aruba, Bonaire and Curac¸ao. (b) Central America: Belize, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua and Panama. (c) North Caribbean: Bahamas, Cayman Islands, Cuba, Dominican Republic, Haiti, Jamaica, Puerto Rico, Anguilla, Turks and Caicos, US Virgin Islands and British Virgin Islands. (d) Eastern Caribbean: St. Kitts and Nevis, Antigua and Barbuda, Barbados, Dominica, Grenada, Guadeloupe, Martinique, Montserrat, St. Barthelemy, St. Lucia, St. Martin/St. Marteen, Barbados and St. Vincent and the Grenadines. A total of 29 studies are cited for this paper, three of these conducted analysis of water samples, 15 conducted Table 1 Number of studies reported in the open literature for selected contaminants by country Country
Metals
Organochlorine pesticides
PCBs
PAHs
Aruba Belize Colombia Costa Rica Cuba Dominican Republic Guadeloupe Honduras Jamaica Mexico Panama Trinidad and Tobago Venezuela
NA NA 1 2 3 1 1 NA 2 2 2 3
* * * * * 1 NA * 2,* 1,* * *
* * * * * 1 NA * 1,* * * *
NA NA NA NA NA NA NA NA 1 NA NA NA
5
2,*
2,*
2
* Indicates at least 1 MWI sampling station located in that country.
A. Fernandez et al. / Marine Pollution Bulletin 54 (2007) 1681–1691
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Table 2 Concentrations of trace elements and heavy metals detected in the WCR Country
Media
South American Region Colombia Fish: Mugil incilis Fish: Eugerres plumier Sediment
Concentrations reported
Source
Hg DL-166 (lg/kg dw) Hg DL-852 (lg/kg dw) Hg 20–10,293 (lg/kg dw)
Alonso et al. (2000)
Venezuela
Coral: Porites astreoides
Al 1.44–846.49, Fe nd–369.31, Cu 3.33–89.57, Zn 0.83–42.45, Cr 0.16–23.9, Pb 0.029–4.74 (lg/g dw)
Bastidas and Garcia (1999)
Venezuela
Echinoderm: Holothuria mexicana Echinoderm: Isostichopus badionotus
Al 0.0–711.7, Cu 47.5–3043.2, Mn 0.0–40.5, Ni 0.0–224.5, Pb 49.4–1334.7, Zn 17.5–2165 (ppm dw) Al 20.8–543.1, Cu 59.0–3854.0, Mn 0.0–46.8, Ni 0.0–219.8, Pb 73.7–2018.6, Zn 14.6–4472.5 (ppm dw)
Laboy-Nieves and Conde (2001)
Venezuela
Bivalve: Isognomon alatus
Cd 0.33–0.91, Cr 0.46–1.2, Cu 14–49, Ni 11–18, Pb 0.4–0.71, Zn 0.25–2.1 (lg/g dw)
Jaffe´ et al. (1998)
Venezuela
Bivalve: Tivela mactroidea
Cd 2.2–3.3, Cr 1.6–4.6, Cu 58.9–152, Ni 12.0–30.7, Pb 2.0–3.1, Zn 226–266 (lg/g dw) Ba
Jaffe´ et al. (1995) and Alfonso et al. (2005)
Trinidad and Tobago
Sediments
Fe 12.39–15,716, Cu 0.06–15.95, Cd 0.04–2.12, Pb 0.30–20.91, Zn 0.10–39.29 (lg/g dw) Fe 0.96–1703, Cu 0.50–14.27, Cd 0.06–1.13, Pb 0.50–6.94, Zn 0.50–92.23 (lg/L)
Rajkumar and Persad (1994)
Seawater Trinidad and Tobago
Seawater
Fe 16.01–114.27, Cu 1.5, Ni 2.33–2.88, Zn 5.9–29.66, Mn 4.6–57.8 (ppb)
Rajkumar et al. (1995)
Trinidad and Tobago
Sediments
Fe 1.08–29.45, Cu 120–421, Cr 3.08–42.82, Mn 5.70–32.28, Ni 2.35–30.49, Pb nd–4.90, Cd 1.88–67.90 (ppm dw)
Hall and Chang-Yen (1986)
Al 313.0, V 44.7, Cr 7.3, Mn 7.3, Fe 113.2, Ni 91.6, Cu 2.0, Zn 10.2, Cd 7.5, Pb 31.0 (mean, ppm dw) Al 9261.1, V 153.7, Cr 19.1, Mn 303.8, Fe 4868.6, Ni 100.5, Cu 8.7, Zn 19.6, Cd 5.9, Pb 28.6 (mean, ppm dw)
Guzman and Jimenez (1992)
Hg 15.2 (mean, ppm dw)
Guzman and Garcia (2002)
Central American Region Costa Rica Coral: Siderastrea siderea Sediments Costa Rica
Coral: Siderastrea siderea Sediments
Hg 85.9 (mean, ppm dw)
Mexico
Oyster: Crasostrea virginica
Cd 3.8–4.4, Cu 284–380, Fe 725–1128, Mn 36–44, Pb 7.5–12.4, Zn 426–759 (mean, mg/kg dw)
Vasquez et al. (1993)
Mexico
Coral: Montastraea annularis
Pb 12–85 (nmol Pb/mol Ca)
Medina-Elizalde et al. (2002)
Panama
Coral: Siderastrea siderea Sediments
Al 250.7, V 41.8, Cr 9.9, Mn 6.9, Fe 70.8, Ni 93.7, Cu 3.8,Zn 8.9, Cd 7.6, Pb 32.3 (mean, ppm dw) Al 4094.6, V 66.0, Cr 9.2, Mn 171.0, Fe 1705.6, Ni 93.1, Cu 4.1, Zn 15.8, Cd 7.0, Pb 33.2 (mean, ppm dw)
Guzman and Jimenez (1992)
Panama
Coral: Siderastrea siderea Sediments
Hg 21.4 (mean, ppm dw)
Guzman and Garcia (2002)
Northern Caribbean Region Cuba Sediment (<63 lm) Cuba Cuba
Dominican Republic
Sea urchin: Echinometra lucunter Rhizophora mangle leaves Sediments Bivalves Sediments
Hg 62.0 (mean, ppm dw)
Cr 22–339, Cu 18–716, Hg 0.64–76, Mn 79–251, Ni 11–112, Pb 44–903, Zn 72–3736 (lg/g dw) Al 1.2–39, Cr 3.6–8.3, Cu 0.58–2.9, Fe 49–129, Mn BDL–0.90, Ni BDL–3.0, Zn 163–412 (lg/g dw) Fe 24–342, Ni BDL–23.6, Mn 82–297, Zn 2.2–4.7 (lg/g dw)
Gonzalez and Torres (1990) Gonzalez et al. (1999) Gonzalez and Ramirez (1995)
Pb 4.6–9.6, Cu 4.1–28, Zn 7.9–129, Co 7.7–327, Fe 0.64–22.66%, Mn 125–2957, Ni 69–4764 (lg/g) Al 3.80–2240, Cd 0.04–2.57, Cr 1.66–10.7, Cu 3.08–866, Fe 50.9–3400, Hg 0.29–7.02, Ni 1.25–7.92, Pb 0.09–1.49, Zn 22.9–4380 (lg/g dw) Al 276–33,000, Cd 0.028–0.435, Cr 8.88–186, Cu 1.01–111, Fe 230–48,700, Hg 0.096–0.565, Ni 1.71–124, Pb 0.42–81.8, Zn 2.34–244 (lg/g dw)
Sbriz et al. (1998)
(continued on next page)
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Table 2 (continued) Country
Media
Concentrations reported
Source
Jamaica
Sediments (<63 lm)
Al 0.10–6.49%, Fe 0.12–3.67%, As 0.84–10.3, Sb 0.15–1.20, V 7.8–105, Cr 16.6– 53.1, Mn 33–649, Co 0.75–13.0 (ppm)
Greenaway and RankineJones (1992)
Jamaica
Sediments
V 6.6–112, Cr 5.0–48.0, Co 0.68–16.1, Ni 3.7–23.9, Cu 3.5–73.8, Zn 7.9–70.0, As 1.4–7.03, Cd nd–10.0, Pb 6.4–31.1, Hg 0.05–0.30 (mg/kg dw)
Jaffe´ et al. (2002)
Pb 1.7–235.7, Zn 19–664.3, Cu 9.3–187.2, Cd <0.3 to 0.6 (lg/g dw)
Bernard (1995)
Eastern Caribbean Region Guadelupe Sediments
analysis of sediment samples, and 13 conducted analysis of both living organisms and nearby sediment samples. The review shows that less than 50% of the countries in the WCR feature easily accessible, open literature and other published reports which contain data on the presence of heavy metals and organic pollutants. The number of studies reported in this review in these countries and territories are presented in Table 1. 2.1. Trace metals A total of 14 trace elements from environmental samples were reported for each subregion. These include aluminum (Al), antimony (Sb), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni), vanadium (V), and zinc (Zn). The most frequently analyzed trace metals were Pb, Cu, Zn, Fe, Cd, Ni, Mn, and Cr all of which were surveyed in 10 (32%) of the studies reviewed. Table 2 provides a summary of concentration ranges of trace elements detected in a variety of environmental samples collected from the WCR. Several of the studies reviewed conducted analyses of samples collected from areas which are known to be impacted by direct inputs of contaminants (point sources) such as industrial areas, harbours and river outflows. However, other studies investigated areas of non-point source inputs of contaminants for potential impacts. The results of these studies suggest that although concentrations detected are generally higher in those areas closest to anthropogenic activities, remote areas are also being impacted by these activities. This was suggested in a study conducted along the Caribbean coasts of Costa Rica and Panama (Guzman and Jimenez, 1992). In this study 23 coral reef sites were surveyed and high concentrations of Al, Fe and Mn were detected in both coral skeletons and reef sediments thus indicating that long distance transport of metal pollutants was occurring. Another survey that suggests evidence of long-range transport of heavy metals was conducted along the Venezuelan coast near the outfall of the Tuy River using bivalves (Jaffe´ et al., 1995). This study revealed elevated concentrations of Cd, Ni and Cu in the sampled organisms at stations near the river outfall as well as those stations several miles from the outfall. The evidence of long-range transport of metals further demonstrate the potential impacts of these contaminant
on large geographic area both in terms of water quality and ecological effects. The same locations were re-investigated about 10 years later (Alfonso et al., 2005) and trace metal concentrations in Tivela mactroidea namely Ba, Cd, Co, Cr, Cu, Ni, Sr, Ti, V and Zn were reported. In this study it was found that Cd, Co, Cr, Cu, Ni, Ti, Sr were high and it was concluded that the Tuy River plume continues to be an influencing factor in pollution over a wide coastal area. In addition, the occurrence of Cr in the sampled organisms was higher that the legal limit stipulated by the FAO (5 lg/g dry wt.). Overall, concentrations of many trace metals were reported at similar levels in the earlier study (Jaffe´ et al., 1995), thus suggesting that the state of the Tuy River as a major point source of pollutants to the Central Venezuelan coast had shown no significant improvement over the last decade. Another study conducted in Morrocoy National Park (MNP), in Venezuela compared metal concentrations in coral specimens (Bastidas et al., 1999). This study revealed higher concentrations of Al, Fe, Cu, and Zn in samples closer to river discharge points, although, Fe and Cr concentrations were lower at the sites in closer proximity to the river outfall. A comparison of the data presented by Bastidas et al. (1999) on metal content of coral specimens in MNP in Venezuela and the data provided by Guzman and Jimenez (1992) and by Guzman and Garcia (2002) on metal content in the coral reefs of Costa Rica and Panama revealed higher average concentrations of Al and Fe in samples from Costa Rica than those from Panama. However, concentrations of Fe, Cu and Hg were higher in Panama with an insignificant difference in Fe concentrations between both countries. The average concentrations of Al, Fe, Cu, Zn, Pb, and Hg were lower in the MNP than those reported for Costa Rica and Panama. Jaffe´ et al. (1992) used various species of ocotocorals in Venezuela and also found a high level of Zn. However, it should be noted that different species were analyzed and this may contribute to some of the observed differences in anomalies. In terms of PEL and TEL comparisons (Fig. 2), trace metals reported for Cuba exceeded the PEL values in 6 of the 7 reported elements and 4 elements for Guadeloupe. This was followed by Panama and Dominican Republic with three elements above the PEL values, while this value was exceeded for one element for Jamaica and Colombia. Among the countries where heavy metal studies were available, Cuba reported the highest levels of Pb, Cu, Cr
A. Fernandez et al. / Marine Pollution Bulletin 54 (2007) 1681–1691
Fig. 2. The PEL and TEL comparison for (a) Hg, (b) Cd, (c) Cr, (d) Zn, (e) Ni, (f) Cu, (g) Pb.
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and Zn in sediments. These high levels were recorded in Havana, a populated/industrial area (Gonzalez and Torres, 1990) and Ni in Levisa Bay, a nickel mining area (Gonzalez and Ramirez, 1995), while Guadeloupe reported the highest levels of Cd in a populated, agricultural and industrial area (Bernard, 1995). For the Dominican Republic, the reported second highest values of Cr and Ni in sediments were from a broad study of its coastal areas (Sbriz et al., 1998). In contrast, Costa Rica reported low values for all the elements investigated except Hg where it was ranked highest (Guzman and Garcia, 2002; Guzman and Jimenez, 1992; Fig. 2). The presence of these metals in above guideline values is likely to have negative consequences on the surrounding habitats, thus highlighting the threat these pollutants pose on near-shore marine resources if sources are not identified or properly managed. 2.2. Organochlorine pesticides and PCBs Six studies report on the presence of organic pollutants in the WCR. Table 3 provides a summary of the concentrations detected in the WCR for such pollutants. Of importance is the International Mussel Watch (IMW) program
which was initiated to establish a regional database of concentrations of organic pollutants distributed along the coasts of some countries in the WCR using bivalves (Sericano et al., 1995). This study is one of the most extensive in terms of geographic coverage for this region. Concentrations of selected organic contaminants detected IMW stations are provided in Table 4. Over 90% of the available data on organic pollutants in the WCR (including those from the MWI program sites), are from surveys conducted in the Central and South American Subregions with the exception of two studies conducted in Jamaica (Jaffe´ et al., 2002; Mansingh and Wilson, 1995), and from MWI stations in Jamaica, Trinidad and Tobago, and Aruba (Sericano et al., 1990). The most frequently reported organic pollutants in the WCR was DDT and its metabolites, DDE and DDD, a and cchlordanes, aldrin, dieldrin, and PCBs. The ubiquitous presence of these compounds suggests the existence of long-range transport for these compounds within the WCR. A study of chlorinated pesticides in air samples from two locations in Belize detected concentrations of total DDTs, dieldrin, and total chlordanes, which were consistently higher than those detected in air samples from
Table 3 Concentrations of organochlorine pesticides and PCBs detected in the WCR Country
Media
South American Region Venezuela Tree oyster: Isognomon alatus
Venezuela
Bivalve: Tivela mactroidea
Central American Subregion Mexico Bivalve: Crassostrea virginica Bivalve: Rangia cuneata Bivalve: Brachidontes recurvus Sediments
Northern Caribbean Region Dominican Bivalves Republic Sediments Jamaica
Sediments
Seawater
Jamaica
Sediments
Concentrations reported
Source
c-Chlordane <0.22 to <0.74, a-chlordane: <0.13 to <0.45, trans-nonachlor <0.12 – <0.40, cis-nonachlor <0.21 to <0.72, oxychlordane <0.25 to <0.83, o-p 0 DDE <0.12 – <0.40, p-p 0 DDE <0.44 to <1.5, o-p 0 DDD <0.13 to <0.43, p-p 0 DDD <0.32 to <1.1, o-p 0 DDT <0.18 to <0.61, p-p 0 DDT 0.52–2.2, total PCBs 0.60–12 (ng/g dw)
Jaffe´ et al. (1998)
Total hexachlorocyclohexanes ND–0.5, a- and c-chlordanes ND–0.2, cis- and transnonachlor ND–0.4, dieldrin ND–0.7, heptachlor ND–0.6, endrin ND–trace, total DDTs 0.9–2.3, total PCBs 4.8–63 (ng/g dw)
Jaffe´ et al. (1995)
Lindane 0.45–0.066, DDD 1.28–1.85, endrin ND–56.7, aldrin 5.26–6.56, Aroclor 1254 1.65–2.0 (ng/g dw)
Gold-Bouchot (1993)
Lindane 1.21, DDD 16.8, endrin ND, aldrin ND, Aroclor 1254 3.96 (ng/g dw) Lindane 1.25, DDD 4.09, endrin ND, aldrin ND, Aroclor 1254 3.96 (ng/g dw)
Lindane ND–0.57, DDD ND–0.55, DDE ND–17.67, aldrin ND–9.02, HCB ND–0.32, Aroclor 1260 ND–12.99, Aroclor 1254 ND–258.6 (ng/g dw)
Total chlordanes 0.51–7.47, total DDTs BDL–30.9, total PCBs 11.3–82.3 (ng/g dw) Total chlordanes BDL–7.47, Total DDTs 0.21–12.5, Total PCBs 0.46–41.9 (ng/g dw)
Sbriz et al. (1998)
a-Endosulfan 0.003–1.0, b-endosulfan 0.006–0.76, endosulfan sulfate BDL, p-p 0 DDT 0.03–0.04, dieldrin 0.001, aldrin 0.002–36.7, endrin 0.006, lindane 0.003–0.77, HCB 1.01, diazinon 0.002–0.007 (ng/g) a-Endosulfan 0.118–5.56, b-endosulfan 0.01–15.7, endosulfan sulfate 0.0003, p-p-DDT 7.02, dieldrin 0.014–3.75, aldrin BDL, endrin 0.012–0.9, lindane BDL, HCB BDL, diazanon 0.0003–0.1 (ng/L)
Mansingh and Wilson (1995)
Total chlordanes 0.4–0.92, Total DDTs 1.45–23, dieldrin 0.24–6.13, total PCBs 0.76–73 (lg/kg dw)
Jaffe´ et al. (2002)
A. Fernandez et al. / Marine Pollution Bulletin 54 (2007) 1681–1691
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Table 4 Concentrations of organochlorine pesticides and PCBs detected at MWI sites in the WCR (ng/g dw) Country
# of stations
Belize 1 Costa Rica 1 Honduras 1 Mexico 4 Panama 2 Colombia 2 Venezuela 3 Cuba 1 Jamaica 2 Aruba 1 Trinidad and Tobago 2 From NOAA Technical Memorandum NOS ORCA 95
Total BHCs
Total chlordane
Total DDTs
Total PCBs
ND 0.36 0.43 ND–13.43 0.43–1.22 ND–0.86 ND–0.46 ND–1.08 ND–3.43 0.53 ND–0.95
ND 1.26 0.46 ND–14.08 2.28–6.21 ND–2.78 ND–1.25 ND–4.08 ND–7.87 6.54 ND–2.39
59.87 14.63 7.08 14.47–166.3 4.59–24.73 2.21–7.48 0.84–3.9 2.01–2.46 5.45–24.02 12.83 0.47–6.73
ND 6.5 3.2 ND–103.7 7.3–12.5 ND–8.3 ND–76.4 ND–11.5 ND–36.1 441.6 ND–13.8
sites in the Great Lakes Region of North America (Alegria et al., 2000). The presence of these compounds at both an inland station near major agricultural developments as well as a coastal station, which is relatively isolated from agriculture, indicate that aerial transport may contribute significantly to the widespread distribution of these compounds and suggest the continued use in this region of pesticides that have been banned in the United States decades ago. Hydrophobic organic pollutants such as pesticides and PAHs have the tendency to accumulate in organic rich, fine particles of sediments (Jaffe´, 1991), particularly in areas of high anthropogenic impact, such as urban environments. As such, sediments of Montego Bay, Jamaica, were found to contain a variety of organics derived from sewage, fossil fuels, industry as well as agriculture (Jaffe´ et al., 2002). It was suggested that these compounds released into the coastal zone by direct inputs from harbour operations, discharge by gullies, water treatment plants and through riverine transport. As such, they have the potential to be transported further to more remote locations by ocean currents, thus exerting a potentially negative impact on the ecological resources. In studies where tissue samples were collected together with sediment samples, the data indicated as expected, that most organisms tend to bio-accumulate these contaminants (Jaffe´, 1991). For example, in the Dominican Republic, the average ratios of total DDT, PCB and chlordane concentrations in bivalve tissues to sediment samples from the same location were 20 (2–20), 7 (1–10) and 15 (2–45), respectively (Sbriz et al., 1998). This is in accordance with the finding of NOAA’s Status and Trends Mussel Watch Program (Sericano et al., 1990), which reported higher concentrations of chlorinated hydrocarbons in bivalve samples with respect to the concentrations detected in sediments for the same location. In those cases where IMW samples were collected from areas where other studies were conducted on bivalve tissues, such as in Venezuela (Jaffe´ et al., 1995, 1998) the values reported for total DDTs, total chlordanes, and total PCBs are similar with the values reported from IMW stations.
2.3. Petroleum hydrocarbons and PAHs Data published showed that DDPH levels exceeded 1.0 lg/L, and in many samples near Yucatan and in the Gulf of Mexico values exceeded 10 lg/L (Atwood et al., 1988). These values exceed by more than an order of magnitude of the concentration considered to be significant (0.1 lg/L) based on data collected in the 1970s from the Marine Pollution Monitoring Program for Petroleum (MAPMOPP) as stated by Atwood et al. (1988). Subsequent studies conducted in the WCR for DDPHs revealed similar findings: Rajkumar and Persad (1994) reported concentrations ranging from 0.11 to 1.55 lg/L in seawater and 0.46 to 21.33 lg/g (dry wt.) in sediments in near-shore areas of Tobago. Rajkumar et al. (1995) reported DDPH concentrations ranging from 0.11 to 0.78 lg/L in seawater samples collected from the South-Eastern Caribbean in the area between Barbados, Trinidad and Tobago, and Martinique. Corbin (1993) reported average DDPH concentrations of 1.7 lg/L in coastal bay stations and 17.7 lg/L in open ocean stations around St. Lucia. The concentrations of total PAHs in bivalve samples collected for the IMW program (NOAA, 1995) ranged from 28 to 13,800 ng/g (dry wt.), and were suggested to be derived from both petroleum and combustion sources. In other studies on PAHs in bivalves from the WCR, Jaffe´ et al. (1995) reported total PAH concentrations ranging from 1.9 to 29 lg/g in Tivela mactroida, collected near the Tuy River outfall in Venezuela, with molecular distributions indicating both fossil fuel and combustion derived sources. In contrast, total PAH concentrations in the flat tree oyster (Isognomon alatus) from MNP in Venezuela, were found to have lower values than those sampled near the Tuy River. The PAH distribution indicated the presence of fossil fuel products such as fuels and oils used by local boat owners (Jaffe´ et al., 1998). PAH concentrations in sediments from Montego Bay, Jamaica, ranged from 0.76 to 73 lg/kg, suggesting significant anthropogenic impact on the sediment quality. In addition to using bivalves, sediments, and seawater for analysis of these pollutants, other species of animal were used as shown in Table 5.
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Table 5 Surveys conducted on the presence of polyaromatic hydrocarbons (PAHs) in the WCR Country
Media
Source
South American Region Venezuela Bivalve: Isognomon alatus Venezuela Bivalve: Tivela mactroidea
Jaffe´ et al. (1998) Jaffe´ et al. (1995)
Central American Region Mexico Sediment
Botello et al. (1991)
Northern Caribbean Region Jamaica Sediment
Jaffe´ et al. (2002)
Eastern Caribbean Region St. Lucia Water
Corbin (1993)
Southern Caribbean Region Trinidad and Tobago Fish, crabs, mussels
Singh et al. (1992)
3. Conclusions From this review it is evident that there is a urgent need of generating standard environmental quality data regarding trace metals and organic pollutants in most of the WCR. As presently existing data on environmental samples vary in terms of sampling schemes, determined parameters, environmental matrices analyzed and analytical techniques utilized, as well as differences in the formats of data reporting, the existing dataset makes meaningful comparisons of the available data very difficult. Furthermore, there is limited or no data available for many of these contaminants from the majority of nations in the WCR. Although the existing data provides clear evidence of coastal pollution in many areas of the WCR, any attempt to create a regional scale assessment of these contaminants is not possible given the scarcity of available data. However, the available data do indicate that low concentrations of both trace metals and organic pollutants can be found in most parts of this region including locations that are significantly remote from obvious pollution sources, thus indicating long-range transport of these contaminants and that the potential for environmental effects exists. Elevated concentrations of most pollutants are observed in the vicinity of harbours, ports, industrial areas, semi-enclosed bays, and outfalls of major rivers, especially those which are sourced from agricultural lands. In some instances pollutant levels were above TEL and/or PEL standards, suggesting the existence of environmentally damaging ecotoxicological scenarios. The scarcity of data, especially for the small island states reiterates the imminent need for such studies throughout this region. There is a noted lack of data available on the occurrence of organochlorine pesticides throughout the WCR. Such studies are important considering the continued application of these compounds and their potential persistence and negative impacts on the environment. Data on the concentrations of PAHs are also lacking despite the presence of a variety of petroleum extraction operations, processing facilities and an established shipping network.
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