JOURNAL OF THE SCIENTIFIC AGRICULTURAL SOCIETY OF FINLAND 469 Maataloustieteellinen Aikakauskirja Voi. 47: 469—479, 1975 Content to copper, zinc, lead, cadmium and mercury in muscle, liver and kidney of Finnish cattle Ruth Stabel-Taucher, Esko Nurmi, and Eeva Karppanen Stale Veterinary Medical Institute, Helsinki Abstract. A total of 120 normal slaughter cows were analyzed with respect to Cu, Zn, Pb, Cd and Hg in muscle, liver and kidney. The cows orginated from 6 different slaughter-houses throughout the country. Imported cow livers, represented by 10 samples from Australia, 10 from Poland and 15 from Ireland, were also analyzed for comparison with the Finnish material. The Cu content in the Finnish animals turned out to be relatively low. The imported samples had even lower contents. There seemed to be no correlation between the Cu contents in muscle, liver and kidney. Statistical tests established that the mean Cu content in livers from Oulu was significantly higher than most of the others at the 5 % level. The Zn determinations revealed the highest amounts in the muscle. No correlation between the contents in muscle, liver and kidney was shown. The animals from Seinä- joki had the highest Zn contents, significantly different from most of the others. The imported livers did not differ much from the domestic ones as regards Zn content. The same was true for the Pb content. The correlation coefficients of Pb in muscle, liver and kidney were low. The animals from Kouvola contained the highest amounts of Pb, and the mean Pb content of these animals’ kidneys was significantly different from all the others. The Cd content was highest in the animals from Turku. A good correlation was observed between the Cd contents in liver and kidney. The Cd content of the imported livers was of the same order as that of the Finnish ones. No correlation was found between the Zn, Pb and Cd contents. The amounts of Hg in Finnish cattle were very low, especially so in animals from the North of Finland. The Hg content of the imported samples was of the same order as the figures recorded from the South of Finland. Introduction In the group of heavy metals we primarily find the essential metals that are needed in well balanced amounts for the optimal development of man, animal and plants. Among these elements are counted iron, cobalt, copper, chromium, manganese, molybdenum, nickel, and zinc. However, several of these essential metals may have a poisonous effect when consumed in too high amounts (Ringena 1971, Tolle et al. 1973). Some animal species are more sensitive than others. Van Ulsen (1973) describes chronical copper poisoning https://www.c-info.fi/en/info/?token=Wjsw7CuF-D1pI9I0.Vfzebr0lV7TE-hIhA3NZ9Q.TnJzLdaV185wIdRhFMCSca2DZSgT-AUt6mw98PngfAkozaZDrC2YPY2BjooQfIMiG7DSlUvloHof-yL6fGwKudgakI5vOUtI64voX1iOwfE6SEycgVr9o0QhXXrPC8rxodpG0ZMtefDhqMJiBuxvlLk_I0aF2v95LcBmhFZMd6sMFcQ8ItPSL_lvoy0bgco83A70g6POMTGyURUjoTalT2g 470 in sheep that had eaten grass from a field fertilized with liquid manure from swine fed on Cu fortified feed. However, in the last years most of the attention has been directed towards the elements lead, cadmium and mercury. These elements are not considered to be essential, and are the origin of many incidents of poisoning (Friberg et ai. 1974, Chrisholm 1971, Clarkson 1972). They have existed in our environ- ment since ancient times, but with the industrialization a shifting in the pattern of occurrence has found place. This has led to extreme accumulations in certain places and thereby to elevated concentrations of heavy metals in certain foods. Contamination with heavy metals in foods may also arise from agricultural technology, mines and food processing. In the last few years many publications from various countries have appeared giving information about the content of heavy metals in foods. (Hecht 1973, Kirkpatrick and Coffin 1973, Schelenz and Diehl 1973, Beckman et al. 1974, and Bramsö et ai. 1974). Material and Methods The purpose of the present work was to gather information concerning the content of heavy metals in Finnish cattle. Samples from 20 cows were collected from 6 slaughterhouses in different geographical locations in order to establish whether the contamination was heavier in the Southern than in the Northern parts of the country. Another aim was to find out whether regions with closely adjacent industry, mines or heavy traffic were more strongly contaminated than other regions presenting no such pollution risk factors. In order to establish whether there was any marked difference between Finnish and imported cow livers, 10 Australian, 10 Polish, and 15 Irish liver samples were analyzed for comparison. The six slaughterhouses were instructed to take approximetely 100 g of the pectoral muscle, liver and kidney of 20 normal slaughter cows from different producers. The samples were enclosed in polyethylene bags, cooled down and transported by the fastest possible route to our laboratories. Flere they were kept at —2o° C up to the day of analysis. The samples were then thawed and the fat, if any, was removed. From the kidneys the cortex was used. For the determination of Pb, Cd, Zn and Cu, 10 g of the homogenized material was weighed into quartz dishes and dried on a water bath for about 3 hours. The samples were then placed on an asbestos screen and pre-ashed over a low flame until no more smoke emerged. Finally, they were ashed at 450° C over night. After cooling, 0.5 ml of cone. HN03 was added together with a small quantity of water. This was followed by drying on the water bath and renewed ashing at 450° C, for 3 hours. The ash was dissolved in 0.5 ml of cone. HN03 , diluted with deionized water, filtered into a 50 ml volumetric flask and filled up to the mark. After suitable dilutions had been made, the content of Pb, Cd, Cu and Zn was determined with the aid of atomic absorption spectrometry (Perkin-Elmer 303, fitted with a graphite furnace and a deuterium background corrector). The instrument was operated according to the manufacturer’s manual. Cu and Zn were determined in the flame, and Pb and Cd in the furnace. 471 For the determination of Hg, 10 g of the material was freeze-dried over night. About 0.5 g of this material was then subjected to combustion in an oxygen flask containing sulphuric acid (Helminen at al 1966), and Hg was determined from the absorption solution with the aid of a Coleman Mercury Analyzer MAS-50, following the operating directions of Coleman Instruments. The statistical treatment of the data obtained consisted of calculation, with a Compucorp 445 Statistician, of the mean value (x), standard deviation (SDn l ) and correlation coefficients (r) between the metal contents of muscle and liver, liver and kidney, kidney and muscle. The correlation coefficients between Zn and Pb, Pb and Cd, and Cd and Zn were also calculated. The results were tested for significant differences between the metal contents in cattle originating from different regions of the country by Duncan’s New Multiple Range Test (Steel and Torrie 1960). Results The results of the Cu, Zn, Pb and Cd determinations in Finnish cattle are seen in Table 1. The results of the Hg determinations are given in Table 2. The sensitivity of the Coleman Mercury Analyzer MAS-50 is equal to or better than 0.01 /ug of Hg. As it soon became evident that our samples contained only small amounts of mercury, we contented ourselves with analyzing only the samples of about 10 cows from each slaughterhouse, and merely those of their muscles and livers. The result of Duncan’s New Multiple Range Test is shown in Table 3, while Table 4 shows the results of the metal determinations with the imported livers. The correlation between the metals Zn, Pb, and Cd are seen in Table 5. Discussion I—2 mg of Cu per day is considered the necessary daily intake (Tolle et al. 1973), and this also agrees with the average value (2.1 mg daily intake/ person) obtained from diet surveys in Canada (Somers 1974). Chronic Cu poisoning of humans has not been described in the literature, but chronic poisoning of animals may occur in the neighbourhood of copper mines and of industry where contamination of the water and fields may occur. The content of Cu in the feed usually differs widely. A content of less than 10—12 ppm Cu in the feed may result in Cu deficiency in cows (Tolle et al. 1973) Our Cu anlyses showed high variances, especially in the livers, where Cu accumula- tes. By comparing our results with those reported in the literature, we found that ours were lower. Hecht (1973) reports the mean value of Cu in muscle to be 3.25 ppm (SD = 3.74, N = 30). Our corresponding value was 0.88 ppm (SD = 0.38, N = 120). Our liver samples also showed a lower content of Cu (x = 56.65, SD = 40.05, N = 120) than is considered normal for milkcows in West Germany, viz. 100—200 ppm (Rosenberger, 1970). Biochemisches Taschenbuch, 1964, reports a value of 85 ppm in liver of cattle. The imported livers (Australia 22.21 ppm, Poland 22.10 ppm, and Ireland 8.81 ppm Cu) contained even less Cu than the Finnish ones. 472 Table 1. Metal content, mg/kg wet weight, in cattle from six different Finnish slaughter-houses. vr ~ ~ N=2oN=2oN=2oN= 20 N = 20 N = 20 Whole material Metal Tissue Oulu Joensuu Seinäjoki Kouvola Kerava Turku 120 cows Muscle (0.70-1. 35) 1 ) (0.50-1.75) (0.55-1.15) (0.35-095) (0.45-1.30) (0.50-1.98) (0.35-1.98) 1.010.37 2 ) 1.090.54 0.74 0.18 0.720.16 0.800.23 0 92 0.510.88 0.38 Cu Liver (49.5-199.0) (9.0-113.0) (3.5-150.0) (6.0-57.5) (6.0-147.5) (7.0-102.5) (3.5-199,0) 87.940.8 60.127.2 56.037.6 28.6 11.1 82.551.8 42.9 26.7 59.740.1 Kidney (2.2-6.0) (2.2-5. 2) (3.6-5. 2) (3.0-6.3) (2.8-6.0) (2.65-4.8) (2,2-6.0) 3.96 0.95 4.07 0.83 4.16 0.41 4.18 0.83 4.42 1.03 3.88 0.54 4.11 0.80 Muscle (25.1-51.0) (24.4-55.9) (37.5-95.3) (42.5-70.0) (14.7-91.2) (24.7-49.0) (14.7-95.3) 38.4 11.0 39.2 12.0 72.7 14.5 55.1 7.06 60.4 22.2 36.4 7.21 50.4 18.8 Zn Liver (28.5-67.0) (29.0-43.8) (26.3-70.0) (23.0-47.5) (27.0-80.0) (14.5-43.8) (14.5-80.0) 41.2 10.3 36.5 4.69 45.0 12.2 36.8 7,22) 40.4 14.5 33.5 6.98 38.9 10.4 Kidney (14.5-23.0) (15.5-21.3) (16.5-27.0) (12.5-23.5) (13.0-20.9) (15.0-24.4) (12.5-27.0) 18.7 2.30 18.3 1.59 19.6 2.56 17.0 2,95 17.2 2.42 18.1 2.32 18.1 2.51 Muscle (0.08-0.50) (0.04-0.12) 0.032-0.146) (0.13-0.12) (0.044-0.39) (0.045-0.40) (0.032-0.50) 0.12 0.10 0.08 0.02 0.07 0.04 0.09 0.06 0.11 0.09 0.10 0.09 0.10 0.07 Pb Liver (0.13-0.36) (0.13-0.36) (0.11-0.41) (0.14-0.75) (0.15-0.55) (0.06-0.38) (0.06-0.75) 0.28 0.08 0.23 0.06 0.24 0.10 0.32 0.16 0.29 0.10 0.24 0.09 0.27 0.11 Kidney (0.09-0.72) (0.10-0.44) (0.11-0.74) (0.05-0,85) (0.12-0.49) (0.08-0.44) (0.05-0.85 0.26 0.11 0.25 0.10 0.29 0.14 0.41 0.22 0.27 0.11 0.21 0.11 0.28 0.15 Muscle (0.009-0.05) (0.004-0.01) (0.003-0.054) (0.001-0.059) (0.02-0.037) (0.006-0.095) (0.001-0.095) 0 01 0 01 0.01 0.005 0.01 0.01 0.01 0.01 0.02 0.01 0.04 0.03 0.02 0.02 Cd Liver (0.05-0.47) (0.07-0.50) (0.03-0.27) (0.018-0.258) (0.04-0.54) (0.05-0.54) (0.018-0.54) 0.13 0.09 0.16 0.10 0.11 0.06 0.07 0.06 0.15 0.11 0.22 0.16 0.14 0.11 Kidney (0.10-2.25) (0.63-2.53) (0.33-2.53) (0.05-2.08) (0.02-2.5) (0.15-3.98) (0.05-3.98) 1.06 0.69 1.28 0.57 0.97 0.63 0.43 0.46 0.93 0.72 1.47 1.11 1.02 0.78 *) Range. 2 ) Mean and Standard deviation. N = number of cows. 473 Table 2. Hg content in Finnish cattle, mg/kg wet weight. Oulu Joensuu Seinäjoki Kouvola Kerava Turku No Muscle Liver No Muscle Liver No Muscle Liver No Muscle Liver No Muscle Liver No Muscle Liver 1 n.d. 1 ) n.d. 1 n.d. n.d. 1