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Heavy metal concentration in sediments from Pasajes Harbour, Spain
Volume 22/Number 4/April 1991
the maximum permissible limits prescribed for seafoods for human consumption (10 ppm, 50 ppm respectively) in India (FAO, 1983). No seaweed investigated in the present study is used as food in the study areas. The authors thank Prof. A. Subramanian, Director, Centre of Advanced Study in Marine Biology and authorities of the Annamalai University for facilities and encouragement. They also thank Dr. A. N. Subramanian for his helpful suggestions. They are grateful to the Department of Ocean Development, Government of India, New Delhi for financial support with which the present investigation was carried OUt.
M. GANESAN R. K A N N A N K. RAJENDRAN C. GOVINDASAMY P. SAMPATHK UMAR L. KANNAN Centre of Advanced Study in Marine Biology, Annamalai University, Parangipettai, 608 502, Tamil Nadu, India Agadi, V. V., Bhosle, N. B. & Untawale, A. G. (1978). Metal concentration in some seaweeds of Goa (India) Bot. Mar. 21,247-250. Bryan, G. W. (1969). The absorption of Zinc and other metals by the brown seaweed Laminaria digitata. J. mar. biol. Ass. U.K. 49, 225243. Eisler, R. (1981). Trace Metal Concentration in Marine Organisms. Pergamon Press, New York. FAO (1983). Compilation of legal limits for hazardous substances in fish and fishery products. Goldberg, E. D. (1952). Iron assimilation by marine diatoms. Biol. Bull. 102,243-248. Ho, Y. B. (1988). Metal levels in three intertidal macroalgae in Hong Kong waters. Aquat. Bot. 29, 367-372. Lobban, C. S., Harrison, P. J. & Duncan, M. J. (1985). The Physiological Ecology of Seaweeds. Cambridge University Press, New York. Luoma, S. N., Bryan, G. W. & Longston, W. J. (1982). Scavenging of heavy metals from particulate by brown seaweed. Mar. Pollut. Bull. 13,392-396. Kesava Rao, C. H. & Indusekar, V. K. (1986). Manganese, Zinc, Copper, Nickel and Cobalt content in seawater and seaweeds from Saurashtra coast. Mahasagar. Bull-Natn. Inst. Oceanogr. 19(2), 129-136. Patel, B., Pawar, S., Balani, M. C. & Patel, S. (1980). Maeroalgae as sentinel of trace and heavy metals in the management of coastal environment. In Management of Environment (B. Patel, ed.), pp. 371-388. Wiley Eastern Ltd, New Delhi. Say, P. J., Burrows, I. G,, Whitton, B. A. & Harding, J. P. L. (1986). A method for the sampling, treatment and analysis of the seaweed Enteromorpha to monitor heavy metals in estuarine and coastal waters. In Enteromorpha as monitor of heavy metals in estuarine and coastal waters, pp. 1-20. Northern Environmental Consultants Ltd, Durham, England. Sivalingam, E M. (1978). Biodeposited trace metals and mineral content studies of some tropical marine algae. Bot. Mar. 21,327-330. Tewari, A., Thampan, S. & Joshi, H. V. (1990). Effect of chlor-alkali industry effluent on growth and biochemical composition of two marine macro algae. Mar. Pollut. Bull. 21, 33-88. Zingde, M. D., Singbal, S. Y. S., Moroses, C. E & Reddy, C. V. G. (1976). Arsenic, Copper, Zinc and Manganese in marine flora and fauna of coastal estuarine waters around Goa. Indian J. mar. Sci. 5,212-217.
MarinePollutionBulletin. Volume22, No. 4. pp. 207-209. 1991. Printedin Great Britain.
0025 326X/ql $3.00+0.00 © 1991PergamonPressplc
Heavy Metal Concentration in Sediments from Pasajes Harbour, Spain Pasajes Harbour is located in the Biscay Gulf coast, in the North of Spain (1°56'W, 43°20'N). It is an inlet connected to the open sea by a narrow strait (Fig. 1). This position protects the bay from the prevailing NW winds and renders Pasajes a safe anchorage. The harbour area inside the bay is 65 000 m 2, with a depth from 5-15 m. The main tributary is the river Oiartzun, with a catchment area of 87 klTl 2 and a mean flow of 3 m 3 s-1. Its source is in a granitic area, and it flows through Triassic shale and, the last 10 km, in Cretaceous limestone. Three small brooks (Lezo, Molinao, Txingurri) discharge also into the bay, their flow mainly due to urban wastewaters of their basin. The fishing fleet based in Pasajes consists of nearly 90 ships and catches, annually, about 12 m million kg of fish, including 4 m kg cod (Gadus morua). Commercial activities involved, for the period 1973-1988, from one to two thousand ships per year and 3-5 m kg of goods (solid and liquid bulk, scrap, steel, motor vehicles, etc.), 20% for coastal traffic and the rest for foreign commerce. The most important sources of pollution are: 1. River Oiartzun: lead and zinc mining in the upper basin, and organic pollution originated from a paper mill and wastewaters from the town of Renteria (population 45 000). 2. Lezo brook: wastewaters of Lezo (population 5000) and a meat factory. 3. Molinao brook: wastewaters of Pasai Antxo (population 2500) and fishing and paint industries. 4. Txingurri brook: wastewaters of Alza and Herrera (population 28 000) and electroplating factories (Cr, Ni, and Zn). Furthermore, there is a population of about 30 000 people whose wastewaters go directly to the bay. Samples of sediments from a depth of 3-5 cm were taken from 1981 to 1989 to follow the evolution of metal pollution in the harbour. Sampling in 1981 and 1982 was by divers and, from 1984, using a Van Veentype dredge. As the harbour is continuously dredged, the samples are considered representative of the last three or four months of sediment deposition. Samples were stored in clean polyethylene bottles and, in the laboratory, they were oven dried (110°C), calcinated (450°C) and wet digested in Teflon bombs, using a mixture of HNO3-HCI-HF (5:3:1) at 120°C (Legorburu et al., 1989). Analysis of the solution was by atomic absorption spectrophotometry (PerkinElmer 2380 with an air-acetylene flame, D2-1amp background correction and a HGA-500 graphite furnace). Organic matter content was calculated from the loss of weight after calcination, and, in the last survey, in 1989, by the chromic acid method (Walkley & Black, 1934). 207
Marine Pollution Bulletin
_•
GULF OF BISCAY
42" 20' N 100m
~
~UI0In
/
1 ~va"
]l'~'w
~ n
- ' ~
Fig. 1 Map of Pasajes Harbour and position of the samplingsites. In some cases, a sample of the < 6 3 Ixm fraction was obtained by wet sieving (F6rstner & Salomons, 1980) and analysed as before. Cleaning of the laboratory glassware followed a special routine to minimize sample contamination (Legorburu & Millan, 1986). The analysis procedure was checked with reference material from the I.A.E.A. Marine sediment, SD-N-1/2. The results are given in Table 1. In most cases, the metal concentrations show a better agreement with the log-normal distribution than with the gaussian distribution (Table 2), hence the geometric average was chosen as a representative parameter for the data. An examination of the pollution levels (Table 3) shows the presence of two areas in the harbour with high level of elements: Sites Nos 1, 2: The organic matter in the sediment is very high (up to 47% dry wt), and its origin has been traced to a p a p e r mill. Wastes from this factory were submitted to restrictions in 1983, and this resulted in a considerable reduction in the organic pollution of the bay. Lead and zinc levels are very high and their concentration is greater in the total sediment than in the fine fraction ( < 6 3 ~tm). This suggests that the river Oiartzun brings down sandy particles (mineral ore debris) derived from the mining operations (mine tailings). The presence of this type of material has been noted in soils of the flood plain in the Oiartzun basin (Ansorena & Marino, 1990). The closing of the mines in 1985 caused a decline of lead and zinc concentrations in the sediment. Site No. 5 is situated in a narrow inlet, where water circulation is slow. The reSult is a build-up of pollutants in the sediments; organic matter, cadmium, chromium, copper, nickel, lead, and zinc are very high in this area. The pollution load in the middle of the bay (Sites Nos 3, 4) is lower and the exit channel contains the cleanest sediments in almost all sampling series. The overall pollution of the bay is declining from the levels of the first surveys (1981-1984) to the last one in 1989. 208
TABLE 1 Analysis of reference material (Marine sediment, SD-N-1/2) from the I.A.E.A.
Mean concentration og g-i
Element CO Cr Cu Mn Ni Pb Zn
11 149 72.2 777 31 120 439
Confidence interval (ct = 0.05) 10-12 125-161 68.1-75.2 728-801 27-34 112-132 423-452
Laboratory results ~tgg-i 8 147 74 800 45 116 442
TABLE2 Kolmogorov-Smirnovtest for distribution fittingof metal concentration in Pasajes Harbour sediments. Values of two-tailed p.
Total sediment (n = 40) normal log-normal Cd Cr Cu Fe Mn Ni Pb Zn O.M.
0.215 0.438 0.037 0.761 0.009 0.410 0.356 0.198 0.245
0.990 0.495 0.898 0.417 0.337 0.804 0.015 0.998 0.075
Fine fraction (< 6 3 ~tm (n = 17) normal log-normal 0.068 0.240 0.042 0.964 0.732 0.23 l (/.526 0.399 0.381
0.184 0.862 0.536 0.283 0.599 0.837 0.985 0.491 0.850
This study has been financially supported by the Diputacion Foral de Guipuzcoa. We are also grateful for the help provided by the Junta del Puerto de Pasajes in the sampling.
l. LEGORBURU L. CANTON Lab. Contaminacirn (Fac. Quimica-Univ. Pais Vasco), Apdo. 1072, 20080-San Sebastian, Spain
Volume 22/Number 4/April 1991 TABLE 3 Geometric average of metal concentration values (mg kg -~) and organic matter (O.M.) content (%) in Pasajes Harbour sediments (n: number of samples).
Cd
Cr
Cu
1981 (n = 2) Site 2 Site 3 Site 4 Site 5 Site 7
Fe
Mn
Ni
Pb
Zn
O.M.
2.5 2.1 3.4 1.3 1.8
69 144 123 298 98
156 219 214 652 174
15 34 31 36 23
000 500 200 300 300
238 395 259 262 214
34 80 41 102 39
379 387 479 685 252
2350 2100 1770 4610 910
46.0 16.7 18.9 25.5 27.7
1982 (n = 1 ) Site 2 Site 3 Site 4 Site 5 Site 7
4.9 2.7 3.7 4.6 1.9
87 124 140 247 124
200 235 420 596 273
21 35 34 38 26
200 200 500 200 600
313 298 248 212 202
63 93 76 123 69
598 539 518 822 262
5560 340{) 2801/ 562{} 1800
28.5 15.1 14.5 20.5 16.5
1984 (n = 2) Site 2 Site 3 Site 4 Site 5 < 6 3 lain Site 6 Site 7
8.9 14.11 12.(l 14.9 16.t/ l1.0 --
113 142 126 299 290 165 73
483 268 242 633 539 320 2140
78 56 47 58 43 44 25
400 400 300 100 400 200 400
616 600 437 290 291 425 947
85 108 96 107 95 56 153
570 572 483 854 703 489 307
2150 11811 1060 1070 232 42{1 540
17.8 15,8 7,9 18,2 22,1 11,8 1,6
1987 (n = 2) Site I < 63 ~m Site3 < 63 ~tm Site 4 < 6 3 gm
1.7 1.2 3.3 2.2 1.I 1.9
79 55 101 132 128 174
79 59 130 194 153 160
14 3011 7100 15 800 31 800 28 400 25 400
825 102 198 340 330 287
84 105 80 189 162 214
249 149 161 268 124 202
1200 564 536 995 708 804
1989 (n = 2) Site I < 63 mm Site 2 <63 p~m Site 4 < 63 ~tm Site 5 < 63 gm Site 7 < 6 3 Bm
3.9 1.2 2.9 1.2 3.0 2.1 5.8 5.6 6.4 1.2
61 25 74 5tl 127 156 165 130 150 150
255 25 112 228 166 200 372 232 222 356
29 400 3830 8400 12 700 24 300 26 800 35 500 24 300 27 400 31 900
256 64 141 172 250 262 365 221 214 267
43 17 43 35 86 35 99 50 61 71
282 45 159 123 346 179 245 164 287 296
119(I 477 650 613 853 765 1390 970 1310 945
Ansorena, J. • Marino, N. (1990). Agricultura y medio ambiente. Sustrai 18, 51 54. F6rstner, U. & Salomons, W. (1980). Trace metal analysis on polluted sediments. Environ. Technol. Lett. 1,494-505. Legorburu, I. & Millan, E. (1986). Trace metals in air, grass and soil in an urban and industrial area in North Spain: Impact of a steel factory. Environ. Technol. Lett. 7,643-648.
6.9 7.3 5.0 8.2 1.6 6.5 1.3 4.8 3.2 6.5
Legorburu, I., Ramos, A. & Sola, M. J. (1989). Heavy metals in coastal sediments in Guipuzcoa (Spain). Toxicol. Environ. Chem. 23, 129134. Walkey, A. & Black, I. A. (1978). SoilSci. 3% 29-38 (1934) cited by A. A. Sobek, W. A. Schuller, J. R. Freeman & R. M Smith in Field and Laboratory Methods Applicable to Overburdens and Minesoils, Tech. Rep. EPA-60/2-78-054. US-EPA 1978. Cincinnati, USA.
209
the maximum permissible limits prescribed for seafoods for human consumption (10 ppm, 50 ppm respectively) in India (FAO, 1983). No seaweed investigated in the present study is used as food in the study areas. The authors thank Prof. A. Subramanian, Director, Centre of Advanced Study in Marine Biology and authorities of the Annamalai University for facilities and encouragement. They also thank Dr. A. N. Subramanian for his helpful suggestions. They are grateful to the Department of Ocean Development, Government of India, New Delhi for financial support with which the present investigation was carried OUt.
M. GANESAN R. K A N N A N K. RAJENDRAN C. GOVINDASAMY P. SAMPATHK UMAR L. KANNAN Centre of Advanced Study in Marine Biology, Annamalai University, Parangipettai, 608 502, Tamil Nadu, India Agadi, V. V., Bhosle, N. B. & Untawale, A. G. (1978). Metal concentration in some seaweeds of Goa (India) Bot. Mar. 21,247-250. Bryan, G. W. (1969). The absorption of Zinc and other metals by the brown seaweed Laminaria digitata. J. mar. biol. Ass. U.K. 49, 225243. Eisler, R. (1981). Trace Metal Concentration in Marine Organisms. Pergamon Press, New York. FAO (1983). Compilation of legal limits for hazardous substances in fish and fishery products. Goldberg, E. D. (1952). Iron assimilation by marine diatoms. Biol. Bull. 102,243-248. Ho, Y. B. (1988). Metal levels in three intertidal macroalgae in Hong Kong waters. Aquat. Bot. 29, 367-372. Lobban, C. S., Harrison, P. J. & Duncan, M. J. (1985). The Physiological Ecology of Seaweeds. Cambridge University Press, New York. Luoma, S. N., Bryan, G. W. & Longston, W. J. (1982). Scavenging of heavy metals from particulate by brown seaweed. Mar. Pollut. Bull. 13,392-396. Kesava Rao, C. H. & Indusekar, V. K. (1986). Manganese, Zinc, Copper, Nickel and Cobalt content in seawater and seaweeds from Saurashtra coast. Mahasagar. Bull-Natn. Inst. Oceanogr. 19(2), 129-136. Patel, B., Pawar, S., Balani, M. C. & Patel, S. (1980). Maeroalgae as sentinel of trace and heavy metals in the management of coastal environment. In Management of Environment (B. Patel, ed.), pp. 371-388. Wiley Eastern Ltd, New Delhi. Say, P. J., Burrows, I. G,, Whitton, B. A. & Harding, J. P. L. (1986). A method for the sampling, treatment and analysis of the seaweed Enteromorpha to monitor heavy metals in estuarine and coastal waters. In Enteromorpha as monitor of heavy metals in estuarine and coastal waters, pp. 1-20. Northern Environmental Consultants Ltd, Durham, England. Sivalingam, E M. (1978). Biodeposited trace metals and mineral content studies of some tropical marine algae. Bot. Mar. 21,327-330. Tewari, A., Thampan, S. & Joshi, H. V. (1990). Effect of chlor-alkali industry effluent on growth and biochemical composition of two marine macro algae. Mar. Pollut. Bull. 21, 33-88. Zingde, M. D., Singbal, S. Y. S., Moroses, C. E & Reddy, C. V. G. (1976). Arsenic, Copper, Zinc and Manganese in marine flora and fauna of coastal estuarine waters around Goa. Indian J. mar. Sci. 5,212-217.
MarinePollutionBulletin. Volume22, No. 4. pp. 207-209. 1991. Printedin Great Britain.
0025 326X/ql $3.00+0.00 © 1991PergamonPressplc
Heavy Metal Concentration in Sediments from Pasajes Harbour, Spain Pasajes Harbour is located in the Biscay Gulf coast, in the North of Spain (1°56'W, 43°20'N). It is an inlet connected to the open sea by a narrow strait (Fig. 1). This position protects the bay from the prevailing NW winds and renders Pasajes a safe anchorage. The harbour area inside the bay is 65 000 m 2, with a depth from 5-15 m. The main tributary is the river Oiartzun, with a catchment area of 87 klTl 2 and a mean flow of 3 m 3 s-1. Its source is in a granitic area, and it flows through Triassic shale and, the last 10 km, in Cretaceous limestone. Three small brooks (Lezo, Molinao, Txingurri) discharge also into the bay, their flow mainly due to urban wastewaters of their basin. The fishing fleet based in Pasajes consists of nearly 90 ships and catches, annually, about 12 m million kg of fish, including 4 m kg cod (Gadus morua). Commercial activities involved, for the period 1973-1988, from one to two thousand ships per year and 3-5 m kg of goods (solid and liquid bulk, scrap, steel, motor vehicles, etc.), 20% for coastal traffic and the rest for foreign commerce. The most important sources of pollution are: 1. River Oiartzun: lead and zinc mining in the upper basin, and organic pollution originated from a paper mill and wastewaters from the town of Renteria (population 45 000). 2. Lezo brook: wastewaters of Lezo (population 5000) and a meat factory. 3. Molinao brook: wastewaters of Pasai Antxo (population 2500) and fishing and paint industries. 4. Txingurri brook: wastewaters of Alza and Herrera (population 28 000) and electroplating factories (Cr, Ni, and Zn). Furthermore, there is a population of about 30 000 people whose wastewaters go directly to the bay. Samples of sediments from a depth of 3-5 cm were taken from 1981 to 1989 to follow the evolution of metal pollution in the harbour. Sampling in 1981 and 1982 was by divers and, from 1984, using a Van Veentype dredge. As the harbour is continuously dredged, the samples are considered representative of the last three or four months of sediment deposition. Samples were stored in clean polyethylene bottles and, in the laboratory, they were oven dried (110°C), calcinated (450°C) and wet digested in Teflon bombs, using a mixture of HNO3-HCI-HF (5:3:1) at 120°C (Legorburu et al., 1989). Analysis of the solution was by atomic absorption spectrophotometry (PerkinElmer 2380 with an air-acetylene flame, D2-1amp background correction and a HGA-500 graphite furnace). Organic matter content was calculated from the loss of weight after calcination, and, in the last survey, in 1989, by the chromic acid method (Walkley & Black, 1934). 207
Marine Pollution Bulletin
_•
GULF OF BISCAY
42" 20' N 100m
~
~UI0In
/
1 ~va"
]l'~'w
~ n
- ' ~
Fig. 1 Map of Pasajes Harbour and position of the samplingsites. In some cases, a sample of the < 6 3 Ixm fraction was obtained by wet sieving (F6rstner & Salomons, 1980) and analysed as before. Cleaning of the laboratory glassware followed a special routine to minimize sample contamination (Legorburu & Millan, 1986). The analysis procedure was checked with reference material from the I.A.E.A. Marine sediment, SD-N-1/2. The results are given in Table 1. In most cases, the metal concentrations show a better agreement with the log-normal distribution than with the gaussian distribution (Table 2), hence the geometric average was chosen as a representative parameter for the data. An examination of the pollution levels (Table 3) shows the presence of two areas in the harbour with high level of elements: Sites Nos 1, 2: The organic matter in the sediment is very high (up to 47% dry wt), and its origin has been traced to a p a p e r mill. Wastes from this factory were submitted to restrictions in 1983, and this resulted in a considerable reduction in the organic pollution of the bay. Lead and zinc levels are very high and their concentration is greater in the total sediment than in the fine fraction ( < 6 3 ~tm). This suggests that the river Oiartzun brings down sandy particles (mineral ore debris) derived from the mining operations (mine tailings). The presence of this type of material has been noted in soils of the flood plain in the Oiartzun basin (Ansorena & Marino, 1990). The closing of the mines in 1985 caused a decline of lead and zinc concentrations in the sediment. Site No. 5 is situated in a narrow inlet, where water circulation is slow. The reSult is a build-up of pollutants in the sediments; organic matter, cadmium, chromium, copper, nickel, lead, and zinc are very high in this area. The pollution load in the middle of the bay (Sites Nos 3, 4) is lower and the exit channel contains the cleanest sediments in almost all sampling series. The overall pollution of the bay is declining from the levels of the first surveys (1981-1984) to the last one in 1989. 208
TABLE 1 Analysis of reference material (Marine sediment, SD-N-1/2) from the I.A.E.A.
Mean concentration og g-i
Element CO Cr Cu Mn Ni Pb Zn
11 149 72.2 777 31 120 439
Confidence interval (ct = 0.05) 10-12 125-161 68.1-75.2 728-801 27-34 112-132 423-452
Laboratory results ~tgg-i 8 147 74 800 45 116 442
TABLE2 Kolmogorov-Smirnovtest for distribution fittingof metal concentration in Pasajes Harbour sediments. Values of two-tailed p.
Total sediment (n = 40) normal log-normal Cd Cr Cu Fe Mn Ni Pb Zn O.M.
0.215 0.438 0.037 0.761 0.009 0.410 0.356 0.198 0.245
0.990 0.495 0.898 0.417 0.337 0.804 0.015 0.998 0.075
Fine fraction (< 6 3 ~tm (n = 17) normal log-normal 0.068 0.240 0.042 0.964 0.732 0.23 l (/.526 0.399 0.381
0.184 0.862 0.536 0.283 0.599 0.837 0.985 0.491 0.850
This study has been financially supported by the Diputacion Foral de Guipuzcoa. We are also grateful for the help provided by the Junta del Puerto de Pasajes in the sampling.
l. LEGORBURU L. CANTON Lab. Contaminacirn (Fac. Quimica-Univ. Pais Vasco), Apdo. 1072, 20080-San Sebastian, Spain
Volume 22/Number 4/April 1991 TABLE 3 Geometric average of metal concentration values (mg kg -~) and organic matter (O.M.) content (%) in Pasajes Harbour sediments (n: number of samples).
Cd
Cr
Cu
1981 (n = 2) Site 2 Site 3 Site 4 Site 5 Site 7
Fe
Mn
Ni
Pb
Zn
O.M.
2.5 2.1 3.4 1.3 1.8
69 144 123 298 98
156 219 214 652 174
15 34 31 36 23
000 500 200 300 300
238 395 259 262 214
34 80 41 102 39
379 387 479 685 252
2350 2100 1770 4610 910
46.0 16.7 18.9 25.5 27.7
1982 (n = 1 ) Site 2 Site 3 Site 4 Site 5 Site 7
4.9 2.7 3.7 4.6 1.9
87 124 140 247 124
200 235 420 596 273
21 35 34 38 26
200 200 500 200 600
313 298 248 212 202
63 93 76 123 69
598 539 518 822 262
5560 340{) 2801/ 562{} 1800
28.5 15.1 14.5 20.5 16.5
1984 (n = 2) Site 2 Site 3 Site 4 Site 5 < 6 3 lain Site 6 Site 7
8.9 14.11 12.(l 14.9 16.t/ l1.0 --
113 142 126 299 290 165 73
483 268 242 633 539 320 2140
78 56 47 58 43 44 25
400 400 300 100 400 200 400
616 600 437 290 291 425 947
85 108 96 107 95 56 153
570 572 483 854 703 489 307
2150 11811 1060 1070 232 42{1 540
17.8 15,8 7,9 18,2 22,1 11,8 1,6
1987 (n = 2) Site I < 63 ~m Site3 < 63 ~tm Site 4 < 6 3 gm
1.7 1.2 3.3 2.2 1.I 1.9
79 55 101 132 128 174
79 59 130 194 153 160
14 3011 7100 15 800 31 800 28 400 25 400
825 102 198 340 330 287
84 105 80 189 162 214
249 149 161 268 124 202
1200 564 536 995 708 804
1989 (n = 2) Site I < 63 mm Site 2 <63 p~m Site 4 < 63 ~tm Site 5 < 63 gm Site 7 < 6 3 Bm
3.9 1.2 2.9 1.2 3.0 2.1 5.8 5.6 6.4 1.2
61 25 74 5tl 127 156 165 130 150 150
255 25 112 228 166 200 372 232 222 356
29 400 3830 8400 12 700 24 300 26 800 35 500 24 300 27 400 31 900
256 64 141 172 250 262 365 221 214 267
43 17 43 35 86 35 99 50 61 71
282 45 159 123 346 179 245 164 287 296
119(I 477 650 613 853 765 1390 970 1310 945
Ansorena, J. • Marino, N. (1990). Agricultura y medio ambiente. Sustrai 18, 51 54. F6rstner, U. & Salomons, W. (1980). Trace metal analysis on polluted sediments. Environ. Technol. Lett. 1,494-505. Legorburu, I. & Millan, E. (1986). Trace metals in air, grass and soil in an urban and industrial area in North Spain: Impact of a steel factory. Environ. Technol. Lett. 7,643-648.
6.9 7.3 5.0 8.2 1.6 6.5 1.3 4.8 3.2 6.5
Legorburu, I., Ramos, A. & Sola, M. J. (1989). Heavy metals in coastal sediments in Guipuzcoa (Spain). Toxicol. Environ. Chem. 23, 129134. Walkey, A. & Black, I. A. (1978). SoilSci. 3% 29-38 (1934) cited by A. A. Sobek, W. A. Schuller, J. R. Freeman & R. M Smith in Field and Laboratory Methods Applicable to Overburdens and Minesoils, Tech. Rep. EPA-60/2-78-054. US-EPA 1978. Cincinnati, USA.
209