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Preliminary Report on the Total Mercury Content of Patagonian Toothfish (Dissostichos eleginoides)
(2001) 14, 547}549 doi:10.1006/jfca.2001.1006 Available online at http://www.idealibrary.com on
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
SHORT COMMUNICATION Preliminary Report on the Total Mercury Content of Patagonian Toothfish (Dissostichos eleginoides) Eduardo MeH ndez* , Horacio Giudice-, Alfredo Pereira-, Gustavo Inocente?, Dinorah Medina*Laboratorio de Electroqun& mica, Facultad de Ciencias, Igua& 4225 casi Mataojo, 11400 Montevideo, Uruguay, -Departamento de Control de Calidad, Instituto Nacional de Pesca, Constituyente 1497, CC. 1612, Montevideo, Uruguay and ?Seccio& n Inspeccio& n Pesquera, Instituto Nacional de Pesca, Constituyente 1497, CC. 1612, Montevideo, Uruguay Received August 18, 2000, and in revised form March 7, 2001
Primary data on mercury content in Patagonian tooth"sh (Dissostichos eleginoides) revealed that low to relatively high contents of this metal are present in the #esh. Values ranging between 0.12 and 0.73 mg kg\ were found in 18 specimens analysed. These "gures are in accordance to the feeding habits and long life of this "sh. Mercury being a naturally occurring contaminant, and taking into account the values obtained for the mercury content, it is suggested that Patagonian tooth"sh be included in the Mercury Monitoring Programmes in other countries. 2001 Academic Press
Key =ords: cold vapour atomic absorption spectrometry; mercury; Patagonian Tooth"sh; Dissostichos eleginoides.
INTRODUCTION The Fish Mercury Monitoring Programme (FMMP) in Uruguay was developed in 1995, for the evaluation of the mercury content of several "sh species. These species included those recommended by international organizations (Food and Agriculture Organization of the United Nations (FAO); European Community (EC); Food and Drug Administration (FDA)), such as sword"sh, shark and tuna species. For the di!erent species, a bioaccumulation curve based on the potential model derived by Norstrom et al. (1976) is continuously updated. The Patagonian tooth"sh lives in depths between 300 and 1500 m. It can reach more than 2 m in length and more than 100 kg in weight, and may live up to 35 and 50 years of age. It is an active predator with a powerful set of jaws and sharp teeth, feeding on squid and smaller "sh (de la Marc and Williams, 1996). The Patagonian tooth"sh "sheries is relatively new, and there has been a rapid increase in the catch over the last few years. Most of the research focused on this "sh is related to the assessment of its stock, due to both legal and illegal catch. Since 1997, the Patagonian tooth"sh (Dissostichos eleginoides) was considered for inclusion in the FMMP, due to the size achieved by this "sh, and its carnivorous habits. To whom correspondence and reprint requests should be addressed. E-mail: [email protected] 0889}1575/01/050547#03 $35.00/0
2001 Academic Press
548
MENDEZ E¹ A¸.
FIGURE 1. Total mercury content}"sh weight relationship for the Patagonian tooth"sh.
The preliminary results presented in this work show that moderately high levels for total mercury content can be found in the edible parts of the Patagonian tooth"sh. The sampling procedure and the analytical methodology have been fully detailed elsewhere (MeH ndez et al., 2001). Eighteen samples of Patagonian tooth"sh were analysed over a period of 3 years (1997}1999), yielding total mercury content values ranging from 0.12 to 0.73 mg kg\ (wet basis), with a mean value of 0.4$0.2 mg kg\ (wet basis). For a limited number of samples, the total "sh weight was known. For them, a strong linear relationship (n"6, r"0.9932, P(0.0001) was obtained between the total mercury content and the total "sh weight (Fig. 1). These samples were in the weight range 3.2}18 kg, that is, signi"cantly lower than the higher weight achieved by this species. Thus, the model proposed by Norstrom et al. (1976) should not be discarded, as the data analysed would lie in the beginning of the bioaccumulation curve, which can be approximated to a straight line. The average market weight for the Patagonian tooth"sh is 10 kg, which, according to the linear regression obtained in Figure 1, would correspond to a total mercury content of 0.40 mg kg\, below the tolerance limit of 0.5 mg kg\ considered by international organizations for low mercury content "sh. However, considering the total weight range used in Figure 1, higher mercury values should be expected for older "sh, probably exceeding the value of 0.5 mg kg\. The accumulation of high levels of mercury in "sh #esh is directly related to the life span and size achieved by the "sh species (e.g. Monteiro and Lopes, 1990). Mercury being a natural contaminant, its accumulation and biomagni"cation is produced through the food chain web. Considering the feeding habits of the Patagonian tooth"sh, relatively high values for mercury content is expected. Based on these preliminary results, it is suggested that the Patagonian tooth"sh be included in the Mercury Monitoring Programmes in other countries, in order to assess whether this specie should be included within the low or high mercury accumulating "sh.
TOTAL MERCURY CONTENT OF TOOTHFISH
549
Note Added During the revision of this paper, 10 new samples of Patagonian tooth"sh were analysed for total mercury content. Nine out of ten were in the range 0.12}0.49 ppm, and one sample had 1.16 ppm of total mercury. Thus, the expectations formulated in this paper were con"rmed.
REFERENCES de la Marc, W. K. and Williams, R. (1996). Abundance of Patagonian tooth"sh at Macquire Island estimated from tagging studies during the 1995}96 "shing season. CCAM¸R Document =G-FSA-96/39. Mendez, E., Giudice, H., Pereira, A., Inocente, G., and Medina, D. (2001). Total mercury content-"sh weight relationship in sword"sh (Xiphias gladius) caught in the Southwest Atlantic Ocean. J. Food Comp. Anal. 14, 453}460. doi:10.1006/jfca.2001.1005. Monteiro, L. R. and Lopes, H. D. (1990). Mercury content of sword"sh, Xiphias gladius, in relation to length, weight, age, and sex. Mar. Pollut. Bull. 21, 293}296. Norstrom, R. J., McKinnon, A. E., and De Freitas, A. S. (1976). A bioenergetics-based model for pollutant accumulation by "sh. Simulation of PCB and methylmercury residue levels in Ottawa river yellow perch (Perca -avescens). J. Fish. Res. Board Can. 33, 248}267.
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
SHORT COMMUNICATION Preliminary Report on the Total Mercury Content of Patagonian Toothfish (Dissostichos eleginoides) Eduardo MeH ndez* , Horacio Giudice-, Alfredo Pereira-, Gustavo Inocente?, Dinorah Medina*Laboratorio de Electroqun& mica, Facultad de Ciencias, Igua& 4225 casi Mataojo, 11400 Montevideo, Uruguay, -Departamento de Control de Calidad, Instituto Nacional de Pesca, Constituyente 1497, CC. 1612, Montevideo, Uruguay and ?Seccio& n Inspeccio& n Pesquera, Instituto Nacional de Pesca, Constituyente 1497, CC. 1612, Montevideo, Uruguay Received August 18, 2000, and in revised form March 7, 2001
Primary data on mercury content in Patagonian tooth"sh (Dissostichos eleginoides) revealed that low to relatively high contents of this metal are present in the #esh. Values ranging between 0.12 and 0.73 mg kg\ were found in 18 specimens analysed. These "gures are in accordance to the feeding habits and long life of this "sh. Mercury being a naturally occurring contaminant, and taking into account the values obtained for the mercury content, it is suggested that Patagonian tooth"sh be included in the Mercury Monitoring Programmes in other countries. 2001 Academic Press
Key =ords: cold vapour atomic absorption spectrometry; mercury; Patagonian Tooth"sh; Dissostichos eleginoides.
INTRODUCTION The Fish Mercury Monitoring Programme (FMMP) in Uruguay was developed in 1995, for the evaluation of the mercury content of several "sh species. These species included those recommended by international organizations (Food and Agriculture Organization of the United Nations (FAO); European Community (EC); Food and Drug Administration (FDA)), such as sword"sh, shark and tuna species. For the di!erent species, a bioaccumulation curve based on the potential model derived by Norstrom et al. (1976) is continuously updated. The Patagonian tooth"sh lives in depths between 300 and 1500 m. It can reach more than 2 m in length and more than 100 kg in weight, and may live up to 35 and 50 years of age. It is an active predator with a powerful set of jaws and sharp teeth, feeding on squid and smaller "sh (de la Marc and Williams, 1996). The Patagonian tooth"sh "sheries is relatively new, and there has been a rapid increase in the catch over the last few years. Most of the research focused on this "sh is related to the assessment of its stock, due to both legal and illegal catch. Since 1997, the Patagonian tooth"sh (Dissostichos eleginoides) was considered for inclusion in the FMMP, due to the size achieved by this "sh, and its carnivorous habits. To whom correspondence and reprint requests should be addressed. E-mail: [email protected] 0889}1575/01/050547#03 $35.00/0
2001 Academic Press
548
MENDEZ E¹ A¸.
FIGURE 1. Total mercury content}"sh weight relationship for the Patagonian tooth"sh.
The preliminary results presented in this work show that moderately high levels for total mercury content can be found in the edible parts of the Patagonian tooth"sh. The sampling procedure and the analytical methodology have been fully detailed elsewhere (MeH ndez et al., 2001). Eighteen samples of Patagonian tooth"sh were analysed over a period of 3 years (1997}1999), yielding total mercury content values ranging from 0.12 to 0.73 mg kg\ (wet basis), with a mean value of 0.4$0.2 mg kg\ (wet basis). For a limited number of samples, the total "sh weight was known. For them, a strong linear relationship (n"6, r"0.9932, P(0.0001) was obtained between the total mercury content and the total "sh weight (Fig. 1). These samples were in the weight range 3.2}18 kg, that is, signi"cantly lower than the higher weight achieved by this species. Thus, the model proposed by Norstrom et al. (1976) should not be discarded, as the data analysed would lie in the beginning of the bioaccumulation curve, which can be approximated to a straight line. The average market weight for the Patagonian tooth"sh is 10 kg, which, according to the linear regression obtained in Figure 1, would correspond to a total mercury content of 0.40 mg kg\, below the tolerance limit of 0.5 mg kg\ considered by international organizations for low mercury content "sh. However, considering the total weight range used in Figure 1, higher mercury values should be expected for older "sh, probably exceeding the value of 0.5 mg kg\. The accumulation of high levels of mercury in "sh #esh is directly related to the life span and size achieved by the "sh species (e.g. Monteiro and Lopes, 1990). Mercury being a natural contaminant, its accumulation and biomagni"cation is produced through the food chain web. Considering the feeding habits of the Patagonian tooth"sh, relatively high values for mercury content is expected. Based on these preliminary results, it is suggested that the Patagonian tooth"sh be included in the Mercury Monitoring Programmes in other countries, in order to assess whether this specie should be included within the low or high mercury accumulating "sh.
TOTAL MERCURY CONTENT OF TOOTHFISH
549
Note Added During the revision of this paper, 10 new samples of Patagonian tooth"sh were analysed for total mercury content. Nine out of ten were in the range 0.12}0.49 ppm, and one sample had 1.16 ppm of total mercury. Thus, the expectations formulated in this paper were con"rmed.
REFERENCES de la Marc, W. K. and Williams, R. (1996). Abundance of Patagonian tooth"sh at Macquire Island estimated from tagging studies during the 1995}96 "shing season. CCAM¸R Document =G-FSA-96/39. Mendez, E., Giudice, H., Pereira, A., Inocente, G., and Medina, D. (2001). Total mercury content-"sh weight relationship in sword"sh (Xiphias gladius) caught in the Southwest Atlantic Ocean. J. Food Comp. Anal. 14, 453}460. doi:10.1006/jfca.2001.1005. Monteiro, L. R. and Lopes, H. D. (1990). Mercury content of sword"sh, Xiphias gladius, in relation to length, weight, age, and sex. Mar. Pollut. Bull. 21, 293}296. Norstrom, R. J., McKinnon, A. E., and De Freitas, A. S. (1976). A bioenergetics-based model for pollutant accumulation by "sh. Simulation of PCB and methylmercury residue levels in Ottawa river yellow perch (Perca -avescens). J. Fish. Res. Board Can. 33, 248}267.