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Total Hydrocarbons in Waters, Superficial Sediments and Bioindicator Bivalves in the Pacific Colombian Coast
PII: S0025-326X(99)00050-8
Marine Pollution Bulletin Vol. 38, No. 9, pp. 819±823, 1999 Ó 1999 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0025-326X/99 $ - see front matter
Total Hydrocarbons in Waters, Super®cial Sediments and Bioindicator Bivalves in the Paci®c Colombian Coast A. J. MARRUGO GONZALEZ*, R. FERNANDEZ MAESTRE and R. GAITAN IBARRA Universidad de Cartagena, Departamento de Quõmica, Campus de Zaragocilla, Cartagena de Indias, Colombia Contamination of hydrocarbons was determined from 1987 to 1993 in the Colombian Paci®c. Water, super®cial sediments and bioindicating organisms (bivalves) were collected at eight coastal stations of the Colombian Paci®c. In general, contamination decreased with time along the Colombian Paci®c Coast, though in some areas like the bays of Malaga and Solano levels are rising. The concentration of dispersed/dissolved hydrocarbons in water increased only in the Juanchaco and Solano stations in Malaga Bay. The highest concentrations of the three studied parameters were obtained in the ®rst two years of monitoring, with a decrease in the following two years, followed by an increase. Ó 1999 Elsevier Science Ltd. All rights reserved. Keywords: total hydrocarbons; waters; super®cial sediments; bivalves; Colombian Paci®c Coast.
Areas vulnerable to high and low hydrocarbon contamination on the Colombian Paci®c Coast were chosen. 24 samples were taken every year from 1987 to 1993 at eight stations in the Tumaco inlet, Gorgona Island and the bays of Guapi, Buenaventura, M alaga and Solano (Fig. 1). Three samples at each station were taken at dierent times of the year to take into account the in¯uence of the dry and rainy seasons. Water samples were taken at a depth of one meter, extracted with n-hexane, and then concentrated and analyzed by ¯uorometry (UNESCO, 1982a). Sediment samples were digested in an alkaline solution, extracted with n-hexane, separated in alumina columns and analyzed by ¯uorometry and gas chromatography (UNESCO, 1982b). Sample organisms were digested in an alkaline solution, extracted with ethylic ether, concentrated until dry and restituted with n-hexane, separated in columns of alumina/silica gel and analyzed by polar and non polar
*Corresponding author. E-mail: [email protected]
¯uorometry and gas chromatography (Bruhn et al., 1987). For analysis of bivalves, samples of Striostrea prismatica, Anadara sp., Crassostrea columbience and Sacostrea palmula were taken. Monitoring stations with the same characteristics but at various distances from contamination sources were used in order to determine the natural reference levels for hydrocarbons on the Paci®c Coast. With this purpose in mind, stations including Gallo Island, El Muelle and Solano (Fig. 1) were monitored.
Results and Discussion The following Ônatural reference levelsÕ were obtained from Gallo Island, El Muelle and Solano: 1.34 lg/l for dispersed/dissolved hydrocarbons in water, 5.85 lg/g for total hydrocarbons in sediments and 77.76 lg/g for total hydrocarbons in bivalves. At the Puente del Pindo station (Fig. 3), the concentration of dispersed/dissolved hydrocarbons showed a decrease over time (r ÿ0.80) during the monitoring years. Total hydrocarbons in sediments had a similar though smaller trend (r ÿ0.49) while total hydrocarbons in bivalves showed a slight increase (r 0). The concentration of dispersed/dissolved hydrocarbon was found to be below the Ônatural reference levelsÕ in the last four years of monitoring. Total hydrocarbons in sediments registered concentrations higher than the natural reference levels and according to projections based on calculated declines, it would take six years to reach the natural reference levels. In the Gallo Island station, hydrocarbon concentration showed a decrease in all three materials. The concentration there was low compared with zones of high contamination risk (Fig. 2). At the Bocana Guapi station (Fig. 4), the concentration of dispersed/dissolved hydrocarbons and total hydrocarbons in sediments was found to be below the natural reference levels, and is falling. Total hydrocarbons in bivalves tended to increase, with a projected 13 years to reach the natural reference levels. 819
Fig. 1 Geographical location of the sampling stations (d), (h) Water, (n) sediments, (*) Organisms.
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Fig. 2 Hydrocarbons in Gallo Island station.
Fig. 3 Hydrocarbons in Puente del Pindo station.
Fig. 4 Hydrocarbons in Bocana Guapi station.
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Fig. 5 Muelle station.
Fig. 6 Hydrocarbons in Anchicay a station.
Fig. 7 Hydrocarbons in Muelle petrolero station.
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Fig. 8 Hydrocarbons in Juanchaco station.
At the El Muelle station (Gorgona Island), taken as a reference to calculate the natural reference levels, all trends are downwards (Fig. 5). At Muelle Petrolero (Fig. 7) and Anchicay a (Fig. 6) stations, located in Buenaventura, levels tended to decline, with the exception of total hydrocarbons in bivalves in the former. Total hydrocarbons in sediments have values beyond those of the natural reference levels, and according to projections, they would take two years to reach them. In total hydrocarbons in bivalves a strong decrease was evident in the ®rst two years, although there was an accelerated increase between 1990 and 1992, and ®nally a slight diminution during 1993. The total average was of 188 lg/g, a value that is found to be 2.4 times the natural reference levels. At the Anchicay a station, in Buenaventura Bay, the concentration of dispersed/dissolved hydrocarbons was below the natural reference levels with the exception of the year 1987; total hydrocarbons in sediments remained close to the natural reference levels with a descending trend. Total hydrocarbons in bivalves showed values over the natural reference levels in the ®rst two monitoring years, then decreased strongly during the next two years, and later increased until exceeding them. At the Juanchaco station the tendencies increased (Fig. 8) in the three environments; each average was
found to be below the natural reference levels. Making the respective projections, it would take 11 years for the concentration of dispersed/dissolved hydrocarbons to overtake the natural reference levels, and four years in the case of the total hydrocarbons in sediments. At the Solano station, taken as a reference, the tendencies increased for three years in all the environments, mostly in sediments and organisms. It was calculated by projections that if the same tendencies continue, within a short period the values of total hydrocarbons in sediments and total hydrocarbons in bivalves would exceed the natural reference levels. The concentration of dispersed/dissolved hydrocarbons was below the international regulation of 10 lg/L, established by UNESCO for super®cial waters free from hydrocarbon contamination. Bruhn, C., Duke, V., Lecaros, O., Marrugo, A.J. and Sonnerholzner, S. (1987) Tecnicas Analõticas para la Determinaci on de Hidrocarburos del Petr oleo en Organismos y Sedimentos Marinos en el Pacõ®co Sudeste. In Informe del Curso Regional CPPS (Comisi on Permanente del Pacõ®co Sur) UNEP/IOC (Intergovernmental Oceanographic Commission), p. 23. UNESCO (1982a) No. 13. IOC Manuals and Guides (Manuals for surveillance of Dissolved/Disperses oil and petroleum hydrocarbons in Sea Water and Beaches). UNESCO (1982b) No. 11. IOC Manuals and Guides (Petrogenic Hydrocarbon Determination in Sediments).
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Marine Pollution Bulletin Vol. 38, No. 9, pp. 819±823, 1999 Ó 1999 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0025-326X/99 $ - see front matter
Total Hydrocarbons in Waters, Super®cial Sediments and Bioindicator Bivalves in the Paci®c Colombian Coast A. J. MARRUGO GONZALEZ*, R. FERNANDEZ MAESTRE and R. GAITAN IBARRA Universidad de Cartagena, Departamento de Quõmica, Campus de Zaragocilla, Cartagena de Indias, Colombia Contamination of hydrocarbons was determined from 1987 to 1993 in the Colombian Paci®c. Water, super®cial sediments and bioindicating organisms (bivalves) were collected at eight coastal stations of the Colombian Paci®c. In general, contamination decreased with time along the Colombian Paci®c Coast, though in some areas like the bays of Malaga and Solano levels are rising. The concentration of dispersed/dissolved hydrocarbons in water increased only in the Juanchaco and Solano stations in Malaga Bay. The highest concentrations of the three studied parameters were obtained in the ®rst two years of monitoring, with a decrease in the following two years, followed by an increase. Ó 1999 Elsevier Science Ltd. All rights reserved. Keywords: total hydrocarbons; waters; super®cial sediments; bivalves; Colombian Paci®c Coast.
Areas vulnerable to high and low hydrocarbon contamination on the Colombian Paci®c Coast were chosen. 24 samples were taken every year from 1987 to 1993 at eight stations in the Tumaco inlet, Gorgona Island and the bays of Guapi, Buenaventura, M alaga and Solano (Fig. 1). Three samples at each station were taken at dierent times of the year to take into account the in¯uence of the dry and rainy seasons. Water samples were taken at a depth of one meter, extracted with n-hexane, and then concentrated and analyzed by ¯uorometry (UNESCO, 1982a). Sediment samples were digested in an alkaline solution, extracted with n-hexane, separated in alumina columns and analyzed by ¯uorometry and gas chromatography (UNESCO, 1982b). Sample organisms were digested in an alkaline solution, extracted with ethylic ether, concentrated until dry and restituted with n-hexane, separated in columns of alumina/silica gel and analyzed by polar and non polar
*Corresponding author. E-mail: [email protected]
¯uorometry and gas chromatography (Bruhn et al., 1987). For analysis of bivalves, samples of Striostrea prismatica, Anadara sp., Crassostrea columbience and Sacostrea palmula were taken. Monitoring stations with the same characteristics but at various distances from contamination sources were used in order to determine the natural reference levels for hydrocarbons on the Paci®c Coast. With this purpose in mind, stations including Gallo Island, El Muelle and Solano (Fig. 1) were monitored.
Results and Discussion The following Ônatural reference levelsÕ were obtained from Gallo Island, El Muelle and Solano: 1.34 lg/l for dispersed/dissolved hydrocarbons in water, 5.85 lg/g for total hydrocarbons in sediments and 77.76 lg/g for total hydrocarbons in bivalves. At the Puente del Pindo station (Fig. 3), the concentration of dispersed/dissolved hydrocarbons showed a decrease over time (r ÿ0.80) during the monitoring years. Total hydrocarbons in sediments had a similar though smaller trend (r ÿ0.49) while total hydrocarbons in bivalves showed a slight increase (r 0). The concentration of dispersed/dissolved hydrocarbon was found to be below the Ônatural reference levelsÕ in the last four years of monitoring. Total hydrocarbons in sediments registered concentrations higher than the natural reference levels and according to projections based on calculated declines, it would take six years to reach the natural reference levels. In the Gallo Island station, hydrocarbon concentration showed a decrease in all three materials. The concentration there was low compared with zones of high contamination risk (Fig. 2). At the Bocana Guapi station (Fig. 4), the concentration of dispersed/dissolved hydrocarbons and total hydrocarbons in sediments was found to be below the natural reference levels, and is falling. Total hydrocarbons in bivalves tended to increase, with a projected 13 years to reach the natural reference levels. 819
Fig. 1 Geographical location of the sampling stations (d), (h) Water, (n) sediments, (*) Organisms.
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Fig. 2 Hydrocarbons in Gallo Island station.
Fig. 3 Hydrocarbons in Puente del Pindo station.
Fig. 4 Hydrocarbons in Bocana Guapi station.
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Fig. 5 Muelle station.
Fig. 6 Hydrocarbons in Anchicay a station.
Fig. 7 Hydrocarbons in Muelle petrolero station.
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Fig. 8 Hydrocarbons in Juanchaco station.
At the El Muelle station (Gorgona Island), taken as a reference to calculate the natural reference levels, all trends are downwards (Fig. 5). At Muelle Petrolero (Fig. 7) and Anchicay a (Fig. 6) stations, located in Buenaventura, levels tended to decline, with the exception of total hydrocarbons in bivalves in the former. Total hydrocarbons in sediments have values beyond those of the natural reference levels, and according to projections, they would take two years to reach them. In total hydrocarbons in bivalves a strong decrease was evident in the ®rst two years, although there was an accelerated increase between 1990 and 1992, and ®nally a slight diminution during 1993. The total average was of 188 lg/g, a value that is found to be 2.4 times the natural reference levels. At the Anchicay a station, in Buenaventura Bay, the concentration of dispersed/dissolved hydrocarbons was below the natural reference levels with the exception of the year 1987; total hydrocarbons in sediments remained close to the natural reference levels with a descending trend. Total hydrocarbons in bivalves showed values over the natural reference levels in the ®rst two monitoring years, then decreased strongly during the next two years, and later increased until exceeding them. At the Juanchaco station the tendencies increased (Fig. 8) in the three environments; each average was
found to be below the natural reference levels. Making the respective projections, it would take 11 years for the concentration of dispersed/dissolved hydrocarbons to overtake the natural reference levels, and four years in the case of the total hydrocarbons in sediments. At the Solano station, taken as a reference, the tendencies increased for three years in all the environments, mostly in sediments and organisms. It was calculated by projections that if the same tendencies continue, within a short period the values of total hydrocarbons in sediments and total hydrocarbons in bivalves would exceed the natural reference levels. The concentration of dispersed/dissolved hydrocarbons was below the international regulation of 10 lg/L, established by UNESCO for super®cial waters free from hydrocarbon contamination. Bruhn, C., Duke, V., Lecaros, O., Marrugo, A.J. and Sonnerholzner, S. (1987) Tecnicas Analõticas para la Determinaci on de Hidrocarburos del Petr oleo en Organismos y Sedimentos Marinos en el Pacõ®co Sudeste. In Informe del Curso Regional CPPS (Comisi on Permanente del Pacõ®co Sur) UNEP/IOC (Intergovernmental Oceanographic Commission), p. 23. UNESCO (1982a) No. 13. IOC Manuals and Guides (Manuals for surveillance of Dissolved/Disperses oil and petroleum hydrocarbons in Sea Water and Beaches). UNESCO (1982b) No. 11. IOC Manuals and Guides (Petrogenic Hydrocarbon Determination in Sediments).
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