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Organiske miljøfremmede stoffer og tungmetaller i havsedimenter

Summary and conclusions

The purpose of this study has been to describe the pollution of marine sediments from selected areas close to and far from pollution sources. The parameters examined were organic pollutants, antifouling compounds and trace elements.

Sediment samples were taken from ten areas:

  • Open Danish sea: Mecklenburg Bight, Øresund south of Ven and Kattegat southeast of Anholt.
  • Coastal areas: Kongedybet (Øresund), Karrebæksminde Bight and Smålandsfarvandet.
  • Bays: Roskilde, Odense, Horsens Bay and Nibe broad (Limfjorden).

All ten sediment samples were analysed for 74 organic pollutants, five antifouling compounds, six trace metals and aluminium. Apart from this, a sediment sample from Marselisborg Marina, which was analysed in the harbour sediment study (Jensen & Gustavson, 2000), was reanalysed as a more sensitive method for analysing the organic pollutants was used in this study.

The new results were in fine accordance with the former results as the majority of the results deviated less than 10-30%. There was a factor of about two in difference for six of the substances.

Many more organic pollutants, which were below the detection limit in the former study, were quantified with the new method. The occurrence of the different substances is summarised in the tables below.

Table 1-3 show number of organic pollutants detected in how many sediment samples. In addition, the tables show average, minimum, maximum and standard deviation for each of the compounds.

Table 4 shows the corresponding values for the trace elements which were found in all samples. The antifouling compound TBT was only found in three samples. The concentrations of the other antifouling compounds DBT, MBT, diuron og irgarol was below the detection limits in all samples.

Generally, the levels found were as expected significant lower the levels found in the harbour sediments (Jensen & Gustavson, 2000).

The highest to third highest concentrations on dry weight of the different group of substances (excluding the harbour sediment) were found in the areas as shown in the table 5. Ranking above the most polluted area based on the frequency of 1st-3rd is: Roskilde Bay together with Mecklenburg Bight and Kattegat, which may be related to the high concentrations of loss on ignition.

Tabel 1 Number of identified organic substances, average, minimum, maximum og standard deviation for content of softener, nonylphenols and P-triesters in sediments.

Marine sediments No. of parameter identified Found in No. of samples Average Minimum Maximum Standard
µg/kg DW           Deviation
Parameter            
Softener 1          
Di-iso-nonylphthalat 0 0   <5    
Di(2-ethylhexyl)adipat 0 0   <5    
Di(2-ethylhexyl)phthalat 0 0   < 10    
Butylbenzylphthalat 0 0   <5    
Diethylphthalat 0 0   <5    
Dimethylphthalat 0 0   <5    
Di-n-butylphthalat 1 2 16 15 17 1,4
Di-n-octylphthalat 0 0   <5    
Nonylphenols 1          
4-Octylphenol 0 0   <20    
Bisphenol A 0 0   <10    
Nonylphenol (+EO1 og EO2) 1 3 20 11 32 11
P-triesters 3          
Tributylphosphat 1 5 8 5,2 18 5,6
Tricresylphosphat 1 1 370 370 370  
Triphenylphosphat 0 0   <10    
Tris-1.3-dichlorisopropylphosphat 1 3 19 7,2 32 12

Tabel 2 Number of identified organic substances, average, minimum, maximum og standard deviation for content of PAH'es¹ in sediments.

Marine sediments No. of parameter identified Found in No. of samples Average Minimum Maximum Standard
µg/kg DW           Deviation
Parameter            
PAH 32          
Naphthalen 1 9 11 3,4 39 11
2-Methylnaphthalen 1 9 13 3,1 57 17
1-Methylnaphthalen 1 7 10 3,1 37 12
Biphenyl 1 6 6,7 3,1 18 5,8
1.5-Dimethylnaphthalen 1 6 9,4 3,1 32 11
Acenaphthylen 1 9 6,3 3,1 11 2,3
Acenaphthen 1 7 7,4 3,8 12 3,0
Dibenzofuran 1 9 12 3,8 37 11
2.3.5-trimethylnaphthalen 1 9 10 4,1 37 10
Fluoren 1 7 8,9 4,6 14 4,3
1-Methylfluoren 1 4 6,4 3,4 14 5,1
Dibenzothiophen 1 8 4,8 3,1 7,5 1,8
Phenanthren 1 9 46 25 67 16
Anthracen 1 9 11 6,7 18 3,4
Carbazol 1 5 5,9 5,4 6,6 0,5
2-Methylphenanthren 1 9 14 7,3 23 4,9
2-Methylanthracen 1 5 4,2 3,1 6,5 1,3
1-Methylphenanthren 1 9 7,6 3,8 12 2,6
3.6-Dimethylphenanthren 1 5 4,6 3,5 7,1 1,5
Fluoranthen 1 9 130 49 270 61
Pyren 1 9 116 49 240 54
1-Benzofluoren 1 9 23 11 44 9,7
1-Methylpyren 1 9 6,9 3,9 10 2,2
Benz(a)anthracen 1 9 80 34 130 31
Chrysen/Triphenylen 1 9 92 42 150 42
Benzo(b+k+j)flouranthen 1 10 295 6,9 600 221
Benz(e)pyren 1 10 122 4,8 260 91
Benz(a)pyren 1 7 73 14 130 42
Perylen 1 6 21 12 31,5 8,2
Indeno(1.2.3-cd)pyren 1 10 121 3,3 390 128
Dibenzo(a,h)anthracen 1 9 23 5,2 130 40
Benzo(ghi)perylen 1 9 114 7 320 107
Sum PAH 32 10 1288 15 2643 865

1 In one sample is only three of the PAH'es above the detection limit.

Tabel 3 Number of identified organic substances, average, minimum, maximum og standard deviation for content of CB's¹, pesticides, LAS and total hydrocarbons in sediments.

Marine sediments No. of parameter identified Found in No. of samples Average Minimum Maximum Standard
µg/kg DW           Deviation
Parameter            
Individuel chloro0biphenyls (PCB) 7          
CB#28 1 9 0,35 0,12 0,75 0,22
CB#52 1 9 0,32 0,16 0,61 0,19
CB#101 1 9 0,50 0,14 0,94 0,28
CB#118 1 9 0,56 0,19 1,3 0,33
CB#138 1 9 1,3 0,41 3,8 1,07
CB#153 1 9 1,3 0,41 3,7 1,05
CB#180 1 6 0,70 0,36 1,085 0,28
Sum CB-7   10 4,32 0,39 11,0 3,21
Pesticides 14          
Aldrin 1 2 0,27 0,16 0,38 0,16
HCH, alpha- 1 1 12 12 12  
HCH, beta- 1 2 6,6 1,2 12 7,64
HCH, delta- 1 6 0,85 0,29 1,6 0,56
HCH, gamma- 1 9 3,3 1,3 5,8 1,55
DDD, p,p'- 1 7 0,95 0,34 1,5 0,52
DDE, p,p'- 1 9 0,67 0,14 1,8 0,50
DDT, p,p'- 1 10 2,2 0,92 3,5 0,90
Dieldrin 1 1 0,64 0,64 0,64  
Endosulfan I 1 8 2,2 1,2 3,8 0,80
Endosulfan II 1 5 1,7 0,69 4,5 1,58
Endosulfan sulfat 1 1 0,39 0,39 0,39  
Endrin 1 1 2 2 2  
Endrin Aldehyd 0 0   <0.1    
Endrin Keton 0 0   <0.1    
Heptachlor 0 0   <0.1    
Heptachlorepoxid 1 2 0,36 0,34 0,38 0,03
Methoxychlor 0 0   <0.1    
Sum pesticides   10 12,6 4,23 29,9 7,41
LAS 1 2 3020 540 5500 3507
Total hydrocarbons mµg/kg DW 1 10 56 3 480 149

1 In one sample is only identified CB #52.

Tabel 4 Average, minimum, maximum og standard deviation for content of trace elements (mg/kg dry weight).

Variabel på tørstofbasis Hg Cd Cu Ni Pb Zn Al
%		 Glødetab
%
'Gennemsnit 0,11 0,64 27 16,6 32 96 1,18 7,35
Minimum 0,03 0,05 1,1 1,6 1,7 6,1 0,12 0,60
Maximum 0,21 1,80 141 35 63,0 277 2,36 14,50
Standardafvigelse 0,05 0,60 39 11,6 22,5 78 0,82 4,96

Table 5 Overview of areas ranked 1-3 for the level of examined substances

Group of substances Area with
  Highest level Second highest level Third highest level
Softener Mecklenburg Bight Roskilde Bay Not found in other areas
Nonylphenols Roskilde Bay Horsens Bay Not found in other areas
P-triesters Roskilde Bay Odense Bay Kongedybet
Sum PAH Smålandsfarvandet Kattegat Mecklenburg Bight
Sum PCB Horsens Bay Roskilde Bay Mecklenburg Bight
Sum chlorinated pesticides Kongedybet Roskilde Bay Kattegat og Mecklenburg Bight
LAS Horsens Bay Mecklenburg Bight Not found in other areas
Hydrocarbons Horsens Bay Kongedybet Kattegat
TBT¹ Roskilde Bay Odense Bay Kongedybet
Mercury Horsens Bay Kattegat Mecklenburg Bight
Cadmium Smålandsfarvandet Roskilde Bay Horsens Bay
Copper Roskilde Bay Smålandsfarvandet Mecklenburg Bight
Nikkel Kattegat Smålandsfarvandet Mecklenburg Bight
Lead Mecklenburg Bight Smålandsfarvandet Roskilde Bay
Zinc Smålandsfarvandet Mecklenburg Bight Kattegat

1 TBT was only found in these three samples. The concentrations of DBT, MBT, diuron og irgarol was below the detection limits in all samples.

The measured concentrations have also been calculated on loss on ignition (equivalent to organic matter) as both the organic pollutants and trace metals have a high affinity to organic carbon. The sequence of the most polluted sediments was often changed when the comparisons were done on loss on ignition instead of on dry matter. It is relevant from a biological viewpoint to use this expression because the animals living in the sediments mainly eat the organic matter.

The trace elements were also normalised to aluminium (table 6) as this unit is often applied to compensate for geological differences.

Tabel 6 Average, minimum, maximum og standard deviation for content of trace elements normalisered to Al (mg/kg Al).

Trace elements normalised to Al Hg Cd Cu Ni Pb Zn
Average 14,0 57,5 2053 1383 2733 7993
Minimum 5,4 6,0 750 1123 1394 5079
Maximum 41 144 7542 1858 5070 14756
Standard deviation 10,5 38 1914 235 1116 2887

The levels of trace metals calculated as loss on ignition (table 7) were compared with the limit values calculated on loss on ignition developed by the Danish EPA for diffuse impacted sediments. Levels below twice these values are only considered as diffuse impacted sediments.

Tabel 7 Average, minimum, maximum og standard deviation for content of trace elements (mg/kg loss on ignition).

Trace elements normalised to loss on ignition Hg Cd Cu Ni Pb Zn
Average 2,5 8,4 330 233 450 1304
Minimum 0,64 1,4 170 120 224 743
Maximum 7,4 14 1262 311 710 2470
Standard deviation 2,1 3,6 314 58 172 435

The following areas exceed these values:

  • Hg: Kongedybet, Nibe Broad and Øresund;
  • Pb: Mecklenburg Bight and Kongedybet.

These values are not exceeded for Cd, Cu and Zn. No value exists for Ni. Generally, it may be concluded that the detected level of trace elements in the sediments were equivalent to diffuse impacted areas.

A correlation analysis showed that the level of trace elements were significantlycorrelated with loss on ignition and Al with the exception of Cd normalised to Al. The trace elements correlate with each other with the exception of Cd-Hg, Cd-Ni and Cd-Pb. This may be due to

caused by the fact that Cd in the marine environment is more mobile than the other trace elements.

 

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Version 1.0 Januar 2006, © Miljøstyrelsen.