Regional assessment of status and trends in PCB concentrations in biota

  • Overview
  • Summary of individual time series results
  • Regional assessment - methods
  • Regional assessment - availability of time series
  • Regional trends
  • Regional status compared to the Environmental Assessment Criterion (EAC)
  • Regional status compared to the Background Assessment Concentration (BAC)
  • PCB profiles

Overview

The 2024 OSPAR CEMP assessment describes the status and trends of contaminant concentrations in biota and sediment at monitoring stations in the OSPAR area. Assessments are made for a large number of time series, each of a single contaminant in a single species and tissue (for biota) or matrix (for sediment) at a single monitoring station. This document is one of a series that synthesises the results of the individual time series to assess status and trends at the MIME regional level. In particular, it considers PCB concentrations in biota, where the PCBs are CB28, CB52, CB101, CB118, CB138, CB153, CB180. For simplicity, the term ‘region’ is used throughout to describe MIME regions. OSPAR regions are always referred to as such.

The regional status assessments presented in this document are based on environmental thresholds. Regional status assessments based on human health thresholds can be found here.

The regional status assessments presented in this document are integrated with regional status assessments for other contaminants and biological effects using the CHASE approach. Details can be found here.

The following sections:

  • summarise the individual time series results
  • describe the methods used to combine the individual time series results to estimate regional status and trends
  • present the estimates of regional trends
  • present the estimates of regional status


Summary of individual time series results

A time series of PCB concentrations is assessed for status if:

  • there is at least one year with data in the period 2017 to 2022
  • there are at least three years of data over the whole time series
  • a parametric model can be fitted to the data and used to estimate the mean concentration in the final monitoring year (or, occasionally, if a non-parametric test of status is applied)

The conditions are more stringent for trends. Specifically, a time series is assessed for trends if:

  • there is at least one year with data in the period 2017 to 2022
  • there are at least five years of data over the whole time series
  • a parametric model can be fitted to the data and used to estimate the trend in mean concentration

Note that all trend assessments for individual time series and most status assessments are based on the fit of a parametric model. This is important because only the parametric results are passed into the regional assessments in the following sections. 184 of the 2456 PCB time series were assessed for status using a non-parametric test.

The first tab below shows all the monitoring stations where there are individual time series assessments of trend or status for PCBs. The purple circles are stations where there is a trend assessment for at least one PCB, and the light blue cirles are stations where there are only status assessments.

The next set of tabs show the trend and status assessments for each PCB in turn. The colours have the following meaning:

  • blue: the mean concentration is significantly (p < 0.05) below the Background Assessment Concentration (BAC)
  • green: the mean concentration is significantly (p < 0.05) below the Environmental Assessment Criterion (EAC)
  • red: the mean concentration is not signficantly below the EAC
  • black: there are no assessment criteria available

And the shapes have the following meaning:

  • downward triangle: the mean concentration is significantly decreasing (p < 0.05)
  • circle: there is no significant change in mean concentration (p > 0.05) or there are too few years to test for trends
  • upward triangle: the mean concentration is significantly increasing (p < 0.05)

The final set of tabs give:

  • the number of time series with upwards, downwards or no trend in each MIME and OSPAR region
  • the same information presented as proportions
  • the number of time series with blue, green or red status in each MIME and OSPAR region
  • the same information presented as proportions


Stations


CB28


CB52


CB101


CB118


CB138


CB153


CB180


Trend summary (numbers)

Number of time series with upwards, downwards or no trend by MIME and OSPAR region

OSPAR region MIME region status CB28 CB52 CB101 CB118 CB138 CB153 CB180 total
1 Barents Sea upward trend 0 0 0 1 3 4 1 9
no trend 2 3 4 7 4 4 2 26
downward trend 3 2 2 2 2 2 2 15
Greenland-Scotland ridge upward trend 0 0 1 1 1 1 0 4
no trend 0 3 5 0 3 4 3 18
downward trend 4 7 6 11 8 7 5 48
Norwegian Sea upward trend 0 0 1 1 1 1 0 4
no trend 2 2 3 3 3 3 2 18
downward trend 1 1 1 1 1 1 1 7
total upward trend 0 0 2 3 5 6 1 17
no trend 4 8 12 10 10 11 7 62
downward trend 8 10 9 14 11 10 8 70
2 Norwegian Trench upward trend 0 0 0 1 1 3 1 6
no trend 2 4 4 6 8 7 5 36
downward trend 3 4 11 9 7 6 3 43
Northern North Sea upward trend 0 0 1 3 0 1 1 6
no trend 3 2 12 15 19 24 11 86
downward trend 3 4 2 3 4 2 2 20
Skagerrak and Kattegat upward trend 0 1 0 2 1 2 0 6
no trend 9 11 16 15 15 17 10 93
downward trend 9 11 8 9 9 7 8 61
Southern North Sea upward trend 1 0 1 1 0 1 1 5
no trend 10 22 19 19 17 15 15 117
downward trend 10 3 11 11 15 16 13 79
Channel upward trend 0 0 0 0 0 0 0 0
no trend 16 20 23 24 24 22 24 153
downward trend 8 5 4 3 3 5 3 31
total upward trend 1 1 2 7 2 7 3 23
no trend 40 59 74 79 83 85 65 485
downward trend 33 27 36 35 38 36 29 234
3 Irish and Scottish West Coast upward trend 0 0 1 0 0 1 0 2
no trend 27 19 25 27 32 35 21 186
downward trend 5 9 11 11 7 3 10 56
Irish Sea upward trend 0 2 4 2 3 3 0 14
no trend 25 21 22 24 22 30 19 163
downward trend 8 9 14 15 13 8 15 82
Celtic Sea upward trend 0 0 1 0 1 1 0 3
no trend 29 23 26 27 27 25 27 184
downward trend 2 8 6 6 5 7 6 40
total upward trend 0 2 6 2 4 5 0 19
no trend 81 63 73 78 81 90 67 533
downward trend 15 26 31 32 25 18 31 178
4 Northern Bay of Biscay upward trend 0 0 0 0 0 0 0 0
no trend 26 26 25 26 27 23 25 178
downward trend 1 1 2 1 0 4 2 11
Iberian Coast upward trend 1 0 0 1 0 0 0 2
no trend 9 6 12 11 7 5 7 57
downward trend 6 10 10 10 15 17 12 80
Gulf of Cadiz upward trend 0 0 0 0 0 0 0 0
no trend 1 1 0 1 1 1 1 6
downward trend 0 0 1 0 0 0 0 1
total upward trend 1 0 0 1 0 0 0 2
no trend 36 33 37 38 35 29 33 241
downward trend 7 11 13 11 15 21 14 92


Trend summary (proportions)

Proportion of time series with upwards, downwards or no trend by MIME and OSPAR region

OSPAR region MIME region status CB28 CB52 CB101 CB118 CB138 CB153 CB180 total
1 Barents Sea upward trend 0 0 0 10 33 40 20 18
no trend 40 60 67 70 45 40 40 52
downward trend 60 40 33 20 22 20 40 30
Greenland-Scotland ridge upward trend 0 0 8 8 8 9 0 6
no trend 0 30 42 0 25 33 38 26
downward trend 100 70 50 92 67 58 62 68
Norwegian Sea upward trend 0 0 20 20 20 20 0 14
no trend 67 67 60 60 60 60 67 62
downward trend 33 33 20 20 20 20 33 24
total upward trend 0 0 9 11 19 22 6 11
no trend 33 44 52 37 39 41 44 42
downward trend 67 56 39 52 42 37 50 47
2 Norwegian Trench upward trend 0 0 0 6 6 19 11 7
no trend 40 50 27 38 50 44 56 42
downward trend 60 50 73 56 44 37 33 51
Northern North Sea upward trend 0 0 7 14 0 4 7 5
no trend 50 33 80 72 83 89 79 77
downward trend 50 67 13 14 17 7 14 18
Skagerrak and Kattegat upward trend 0 4 0 8 4 8 0 4
no trend 50 48 67 58 60 65 56 58
downward trend 50 48 33 34 36 27 44 38
Southern North Sea upward trend 5 0 3 3 0 3 3 3
no trend 47 88 61 61 53 47 52 58
downward trend 48 12 36 36 47 50 45 39
Channel upward trend 0 0 0 0 0 0 0 0
no trend 67 80 85 89 89 81 89 83
downward trend 33 20 15 11 11 19 11 17
total upward trend 1 1 2 6 2 6 3 3
no trend 54 68 66 65 67 66 67 65
downward trend 45 31 32 29 31 28 30 32
3 Irish and Scottish West Coast upward trend 0 0 3 0 0 2 0 1
no trend 84 68 67 71 82 90 68 76
downward trend 16 32 30 29 18 8 32 23
Irish Sea upward trend 0 6 10 5 8 7 0 5
no trend 76 66 55 58 58 73 56 63
downward trend 24 28 35 37 34 20 44 32
Celtic Sea upward trend 0 0 3 0 3 3 0 1
no trend 94 74 79 82 82 76 82 81
downward trend 6 26 18 18 15 21 18 18
total upward trend 0 2 6 2 4 4 0 3
no trend 84 69 66 70 73 80 68 73
downward trend 16 29 28 28 23 16 32 24
4 Northern Bay of Biscay upward trend 0 0 0 0 0 0 0 0
no trend 96 96 93 96 100 85 93 94
downward trend 4 4 7 4 0 15 7 6
Iberian Coast upward trend 6 0 0 5 0 0 0 1
no trend 56 38 55 50 32 23 37 41
downward trend 38 62 45 45 68 77 63 58
Gulf of Cadiz upward trend 0 0 0 0 0 0 0 0
no trend 100 100 0 100 100 100 100 86
downward trend 0 0 100 0 0 0 0 14
total upward trend 2 0 0 2 0 0 0 1
no trend 82 75 74 76 70 58 70 72
downward trend 16 25 26 22 30 42 30 27


Status summary (numbers)

Number of time series with each status by MIME and OSPAR region

OSPAR region MIME region status CB28 CB52 CB101 CB118 CB138 CB153 CB180 total
1 Barents Sea blue 0 0 0 3 0 0 0 3
green 10 10 11 2 11 11 10 65
red 0 0 0 6 0 0 0 6
Greenland-Scotland ridge blue 7 7 5 6 3 3 7 38
green 3 3 6 3 9 9 3 36
red 0 0 0 1 0 0 0 1
Norwegian Sea blue 0 0 0 0 0 0 0 0
green 5 5 4 1 4 6 4 29
red 0 0 1 5 2 0 1 9
total blue 7 7 5 9 3 3 7 41
green 18 18 21 6 24 26 17 130
red 0 0 1 12 2 0 1 16
2 Norwegian Trench blue 0 1 3 2 0 0 2 8
green 16 13 11 7 14 15 13 89
red 0 2 2 7 2 1 1 15
Northern North Sea blue 0 0 0 0 0 0 0 0
green 13 21 24 7 29 32 23 149
red 2 2 7 25 2 0 0 38
Skagerrak and Kattegat blue 8 5 0 1 0 0 3 17
green 18 19 23 12 24 25 21 142
red 0 1 3 13 2 1 1 21
Southern North Sea blue 3 0 0 0 0 0 1 4
green 28 35 31 7 32 39 37 209
red 8 3 9 34 5 0 0 59
Channel blue 20 9 1 1 0 0 5 36
green 7 17 22 5 23 28 23 125
red 1 2 5 22 5 1 0 36
total blue 31 15 4 4 0 0 11 65
green 82 105 111 38 122 139 117 714
red 11 10 26 101 16 3 2 169
3 Irish and Scottish West Coast blue 33 33 26 22 7 1 36 158
green 7 8 15 17 35 41 4 127
red 0 0 0 2 0 0 1 3
Irish Sea blue 11 8 2 0 0 0 10 31
green 24 30 35 16 45 47 36 233
red 6 8 10 32 3 1 0 60
Celtic Sea blue 28 22 8 6 1 0 24 89
green 8 15 28 16 36 37 13 153
red 1 0 1 15 0 0 0 17
total blue 72 63 36 28 8 1 70 278
green 39 53 78 49 116 125 53 513
red 7 8 11 49 3 1 1 80
4 Northern Bay of Biscay blue 31 11 0 0 0 0 1 43
green 1 21 32 12 32 32 31 161
red 0 0 0 20 0 0 0 20
Iberian Coast blue 14 16 2 3 0 1 11 47
green 11 9 20 11 20 24 14 109
red 0 0 3 11 5 0 0 19
Gulf of Cadiz blue 0 0 0 0 0 0 0 0
green 1 1 1 1 1 1 1 7
red 0 0 0 0 0 0 0 0
total blue 45 27 2 3 0 1 12 90
green 13 31 53 24 53 57 46 277
red 0 0 3 31 5 0 0 39


Status summary (proportions)

Proportion of time series with each status by MIME and OSPAR region

OSPAR region MIME region status CB28 CB52 CB101 CB118 CB138 CB153 CB180 total
1 Barents Sea blue 0 0 0 27 0 0 0 4
green 100 100 100 18 100 100 100 88
red 0 0 0 55 0 0 0 8
Greenland-Scotland ridge blue 70 70 45 60 25 25 70 51
green 30 30 55 30 75 75 30 48
red 0 0 0 10 0 0 0 1
Norwegian Sea blue 0 0 0 0 0 0 0 0
green 100 100 80 17 67 100 80 76
red 0 0 20 83 33 0 20 24
total blue 28 28 18 33 10 10 28 22
green 72 72 78 22 83 90 68 69
red 0 0 4 45 7 0 4 9
2 Norwegian Trench blue 0 6 19 12 0 0 13 7
green 100 81 69 44 88 94 81 80
red 0 13 12 44 12 6 6 13
Northern North Sea blue 0 0 0 0 0 0 0 0
green 87 91 77 22 94 100 100 80
red 13 9 23 78 6 0 0 20
Skagerrak and Kattegat blue 31 20 0 4 0 0 12 9
green 69 76 88 46 92 96 84 79
red 0 4 12 50 8 4 4 12
Southern North Sea blue 8 0 0 0 0 0 3 1
green 72 92 78 17 86 100 97 77
red 20 8 22 83 14 0 0 22
Channel blue 71 32 4 4 0 0 18 18
green 25 61 78 18 82 97 82 64
red 4 7 18 78 18 3 0 18
total blue 25 11 3 3 0 0 8 7
green 66 81 79 26 88 98 90 75
red 9 8 18 71 12 2 2 18
3 Irish and Scottish West Coast blue 82 80 63 54 17 2 88 55
green 18 20 37 41 83 98 10 44
red 0 0 0 5 0 0 2 1
Irish Sea blue 27 18 4 0 0 0 22 10
green 58 65 75 33 94 98 78 72
red 15 17 21 67 6 2 0 18
Celtic Sea blue 76 59 21 16 3 0 65 34
green 21 41 76 43 97 100 35 59
red 3 0 3 41 0 0 0 7
total blue 61 51 29 22 6 1 56 32
green 33 43 62 39 91 98 43 59
red 6 6 9 39 3 1 1 9
4 Northern Bay of Biscay blue 97 34 0 0 0 0 3 19
green 3 66 100 38 100 100 97 72
red 0 0 0 62 0 0 0 9
Iberian Coast blue 56 64 8 12 0 4 44 27
green 44 36 80 44 80 96 56 62
red 0 0 12 44 20 0 0 11
Gulf of Cadiz blue 0 0 0 0 0 0 0 0
green 100 100 100 100 100 100 100 100
red 0 0 0 0 0 0 0 0
total blue 78 47 4 5 0 2 21 22
green 22 53 91 41 91 98 79 68
red 0 0 5 54 9 0 0 10


Regional assessment - methods

Tabulating the number of time series with each status category by region provides a quick summary of the individual time series results. However, it does not provide an objective regional assessment of status. Similarly, tabulating the number of time series with an upward or downward trend does not provide an objective regional assessment of trend. This section describes how the individual time series results can by synthesised in a meta-analysis to assess both status and trend at the regional level. For PCBs, the meta-analysis is conducted in two parts: an analysis of the non-planar compounds CB28, CB52, CB101, CB138, CB153, CB180 and a separate analysis of the mono-ortho CB118. The results from the two parts are then combined.

Trends

For a regional trend assessment, the trend in each time series is summarised by the estimated change in log concentration over the last twenty years (or shorter if the time series doesn’t extend that far back). Regional trends for non-planar PCBs are then estimated by fitting the following linear mixed model by restricted maximum likelihood:

  • response: trend (yearly change in log concentration)
  • fixed model: region
  • random model: PCB + region.PCB + station + station.PCB + trend estimation variation + residual variation

The fixed model means that a trend is estimated for each region. Trends in the different non-planar PCBs are assumed to be broadly similar, because inputs and control measures are likely to affect all non-planar PCBs in a similar way. Each regional trend can thus be interpreted as the common trend in non-planar PCB concentrations in that region (i.e. the trend averaged across all non-planar PCBs).

The random model has six terms:

  • PCB allows for variation in trend between PCBs common to all regions
  • region.PCB allows for additional variation in trend between PCBs within regions
  • station allows for variation in trend between stations common to all PCBs
  • station.PCB allows for additional variation in trend between stations and PCBs common to all tissues and species within stations
  • trend estimation variation is the variance of the trend estimates from the individual time series analysis, assumed known and fixed
  • residual variation is the variation that cannot be explained by any of the fixed effects or the other random effects

The model for CB118 is simpler because there is only one compound to consider:

  • response: trend (yearly change in log concentration)
  • fixed model: region
  • random model: station + trend estimation variation + residual variation

The meta-analysis is restricted to time series from monitoring stations that are classified as ‘representative’ or ‘baseline’ (near pristine conditions or only subject to very diffuse inputs). ‘Impacted’ stations (those close to a point source) are omitted because trends there will likely reflect changes due to the point source and will be ‘unrepresentative’ at the regional level.

The meta-analysis is further restricted to:

  • regions with at least three trend stations with good geographic spread. Three stations is considered the minimum required to provide some sort of evidence base at the regional level
  • PCBs with trend information for at least three stations (over all regions): non-planar PCBs are treated as random effects in the meta-anlaysis, so information about trends in one PCB can be ‘borrowed’ from the trend information in the other PCBs

Status

For a regional status assessment, the status of each time series is summarised by the difference between the estimated mean log concentration in the final monitoring year and the log assessment concentration. This ensures that status is always measured on the same scale, even though the assessment concentration might vary between PCBs and species. Essentially the same linear mixed models as for trends are then fitted. For non-planar PCBs:

  • response: status (mean log concentration - log assessment concentration)
  • fixed model: region
  • random model: PCB + region.PCB + station + station.PCB + status estimation variation + residual variation

and for CB118:

  • response: status (mean log concentration - log assessment concentration)
  • fixed model: region
  • random model: station + status estimation variation + residual variation

where status estimation variation is the variation in the status estimates from the individual time series analysis, assumed known and fixed.

There are no restrictions on the time series used in the status meta-analysis based on the classification of the monitoring station; time series from baseline, representative and impacted stations are all included. However, the few time series with a non-parametric assessment of status must be excluded, because there is no summary measure of status to use in the mixed model.

Again, the meta-analysis is restricted to regions with at least three status stations with good geographic spread and to PCBs with status information for at least three stations (over all regions).

Presentation

The results of both the trend and status regional assessments are back-transformed for presentation. The estimated regional trend is then interpreted as the percentage yearly change in concentration and the estimated regional status as the ratio of the mean regional concentration to the assessment concentration. To illustrate the latter, a value of 1 indicates that the mean regional concentration is equal to the assessment concentration; a value of 0.5 indicates that it is half the assessment concentration, and a value of 2 indicates that it is twice the assessment concentration.


Regional assessment - availability of time series

This section provides more detail on the number and geographic spread of the time series available for the meta-analyses. The tabs show the stations with parametric trend and status assessments for each OSPAR region in turn, having excluded trend assessments at impacted stations. The purple circles are stations where there is a trend assessment for at least one PCB, and the light blue cirles are stations where there are only status assessments.

The following regions have an insufficient number of time series or spread of stations and are excluded from the regional assessment:

  • trend: Gulf of Cadiz
  • status: Gulf of Cadiz


OSPAR region 1


OSPAR region 2


OSPAR region 3


OSPAR region 4


Regional trends

The first 4 tabs show:

  • Regional trends: estimates of the regional trend for non-planar PCBs and CB118 with pointwise 95% confidence intervals
  • Regional trends by PCB: regional trend estimates for each PCB with pointwise 95% confidence intervals plotted by PCB
  • Regional trends by region: regional trend estimates for each PCB with pointwise 95% confidence intervals plotted by region
  • Individual time series: the trend estimates from the individual time series on which the regional assessment is based. The estimates for regions with insufficient geographic spread (and excluded from the meta-analysis) are also shown.

The symbols in all these plots have the following interpretation:

  • downward triangle: the mean concentration is significantly decreasing (p < 0.05)
  • circle: there is no significant change in mean concentration (p > 0.05)
  • upward triangle: the mean concentration is significantly increasing (p < 0.05)

The final 2 tabs show the estimates of the regional trend for non-planar PCBs and CB118 and the regional trend by PCB.


Regional trends


Regional trends by PCB


Regional trends by region


Individual time series


Estimates by region

This table shows the estimates of the regional trend:

  • trend: the estimated mean yearly change in log concentration across the region (multiplied by 100 for presentation)
  • se: the corresponding standard error
  • lower, upper: the corresponding pointwise 95% confidence limits
  • % yearly change: the estimated mean % yearly change in concentration across the region
  • %yc lower, %yc upper: the corresponding pointwise 95% confidence limits


MIME region PCB trend se lower upper % yearly change %yc lower %yc upper
Barents Sea non-planar PCBs 0.35 1.92 -3.40 4.11 0.35 -3.35 4.20
CB118 -1.87 1.86 -5.51 1.77 -1.86 -5.37 1.78
Greenland-Scotland ridge non-planar PCBs -3.98 1.47 -6.86 -1.11 -3.91 -6.63 -1.10
CB118 -4.18 1.23 -6.58 -1.77 -4.09 -6.37 -1.76
Norwegian Sea non-planar PCBs -3.15 2.56 -8.17 1.87 -3.10 -7.84 1.89
CB118 -5.12 3.44 -11.86 1.62 -4.99 -11.19 1.64
Norwegian Trench non-planar PCBs -1.21 1.64 -4.43 2.00 -1.21 -4.33 2.02
CB118 -1.09 1.43 -3.88 1.70 -1.08 -3.81 1.72
Northern North Sea non-planar PCBs -3.67 1.32 -6.26 -1.08 -3.60 -6.07 -1.08
CB118 -1.26 1.14 -3.50 0.98 -1.25 -3.44 0.98
Skagerrak and Kattegat non-planar PCBs -1.90 1.38 -4.60 0.81 -1.88 -4.49 0.81
CB118 -1.22 1.04 -3.26 0.83 -1.21 -3.21 0.83
Southern North Sea non-planar PCBs -2.90 1.19 -5.23 -0.57 -2.85 -5.09 -0.56
CB118 -2.99 0.84 -4.63 -1.36 -2.95 -4.53 -1.35
Channel non-planar PCBs -7.67 1.30 -10.22 -5.13 -7.39 -9.72 -5.00
CB118 -6.05 1.44 -8.87 -3.24 -5.87 -8.49 -3.18
Irish and Scottish West Coast non-planar PCBs -6.90 1.20 -9.26 -4.54 -6.67 -8.84 -4.44
CB118 -5.49 1.01 -7.47 -3.52 -5.35 -7.20 -3.46
Irish Sea non-planar PCBs -2.50 1.14 -4.72 -0.27 -2.47 -4.61 -0.27
CB118 -2.90 0.77 -4.41 -1.38 -2.86 -4.32 -1.38
Celtic Sea non-planar PCBs -3.30 1.21 -5.66 -0.93 -3.24 -5.51 -0.93
CB118 -2.03 0.99 -3.96 -0.10 -2.01 -3.89 -0.10
Northern Bay of Biscay non-planar PCBs -5.13 1.32 -7.73 -2.54 -5.01 -7.43 -2.51
CB118 -4.43 1.70 -7.76 -1.09 -4.33 -7.47 -1.09
Iberian Coast non-planar PCBs -7.36 1.28 -9.86 -4.86 -7.10 -9.39 -4.75
CB118 -7.10 1.15 -9.35 -4.84 -6.85 -8.93 -4.73


Estimates by region and PCB

This table shows the estimates of the regional trend by determinand:

  • trend: the estimated mean yearly change in log concentration across the region (multiplied by 100 for presentation)
  • se: the corresponding standard error
  • lower, upper: the corresponding pointwise 95% confidence limits
  • % yearly change: the estimated mean % yearly change in concentration across the region
  • %yc lower, %yc upper: the corresponding pointwise 95% confidence limits


MIME region PCB trend se lower upper % yearly change %yc lower %yc upper
Barents Sea CB28 -1.62 2.00 -5.53 2.30 -1.60 -5.38 2.33
CB52 -0.80 2.01 -4.74 3.15 -0.79 -4.63 3.20
CB101 -0.11 2.07 -4.17 3.95 -0.11 -4.08 4.03
CB118 -1.87 1.86 -5.51 1.77 -1.86 -5.37 1.78
CB138 1.97 1.81 -1.57 5.52 1.99 -1.56 5.67
CB153 2.01 1.81 -1.52 5.55 2.03 -1.51 5.71
CB180 0.65 2.10 -3.46 4.77 0.66 -3.40 4.88
Greenland-Scotland ridge CB28 -4.87 1.48 -7.76 -1.97 -4.75 -7.47 -1.95
CB52 -4.96 1.30 -7.51 -2.41 -4.84 -7.24 -2.38
CB101 -3.49 1.27 -5.98 -1.00 -3.43 -5.81 -0.99
CB118 -4.18 1.23 -6.58 -1.77 -4.09 -6.37 -1.76
CB138 -3.48 1.26 -5.94 -1.02 -3.42 -5.77 -1.01
CB153 -2.65 1.26 -5.11 -0.19 -2.62 -4.99 -0.19
CB180 -4.45 1.37 -7.15 -1.76 -4.36 -6.90 -1.75
Norwegian Sea CB28 -5.87 2.78 -11.31 -0.42 -5.70 -10.70 -0.42
CB52 -4.65 2.80 -10.14 0.84 -4.55 -9.65 0.84
CB101 -2.71 2.76 -8.12 2.70 -2.67 -7.80 2.74
CB118 -5.12 3.44 -11.86 1.62 -4.99 -11.19 1.64
CB138 -1.65 2.68 -6.90 3.61 -1.63 -6.67 3.67
CB153 -1.13 2.68 -6.39 4.12 -1.13 -6.19 4.21
CB180 -2.89 2.86 -8.49 2.70 -2.85 -8.14 2.74
Norwegian Trench CB28 -3.79 1.78 -7.28 -0.30 -3.72 -7.02 -0.30
CB52 -3.13 1.76 -6.58 0.32 -3.08 -6.37 0.33
CB101 -1.93 1.46 -4.79 0.92 -1.91 -4.68 0.93
CB118 -1.09 1.43 -3.88 1.70 -1.08 -3.81 1.72
CB138 -0.43 1.43 -3.24 2.37 -0.43 -3.19 2.40
CB153 1.12 1.45 -1.72 3.96 1.13 -1.71 4.04
CB180 0.89 1.70 -2.44 4.21 0.89 -2.41 4.30
Northern North Sea CB28 -6.32 1.46 -9.19 -3.45 -6.13 -8.78 -3.39
CB52 -6.66 1.69 -9.97 -3.35 -6.44 -9.49 -3.30
CB101 -3.03 1.29 -5.56 -0.51 -2.99 -5.40 -0.51
CB118 -1.26 1.14 -3.50 0.98 -1.25 -3.44 0.98
CB138 -2.24 1.04 -4.28 -0.20 -2.21 -4.19 -0.20
CB153 -1.79 1.02 -3.78 0.20 -1.77 -3.71 0.21
CB180 -1.98 1.23 -4.39 0.43 -1.96 -4.30 0.44
Skagerrak and Kattegat CB28 -3.15 1.25 -5.60 -0.70 -3.10 -5.45 -0.70
CB52 -3.09 1.18 -5.40 -0.78 -3.04 -5.25 -0.78
CB101 -2.27 1.14 -4.51 -0.03 -2.24 -4.41 -0.03
CB118 -1.22 1.04 -3.26 0.83 -1.21 -3.21 0.83
CB138 -1.07 1.14 -3.30 1.16 -1.07 -3.24 1.16
CB153 -0.28 1.13 -2.50 1.94 -0.28 -2.46 1.96
CB180 -1.52 1.26 -3.99 0.96 -1.50 -3.91 0.96
Southern North Sea CB28 -2.64 0.98 -4.56 -0.72 -2.60 -4.45 -0.71
CB52 -2.26 0.95 -4.12 -0.41 -2.24 -4.04 -0.41
CB101 -2.64 0.88 -4.36 -0.92 -2.61 -4.26 -0.92
CB118 -2.99 0.84 -4.63 -1.36 -2.95 -4.53 -1.35
CB138 -3.84 0.86 -5.54 -2.15 -3.77 -5.39 -2.13
CB153 -2.50 0.85 -4.18 -0.83 -2.47 -4.09 -0.83
CB180 -3.49 0.92 -5.30 -1.69 -3.43 -5.16 -1.68
Channel CB28 -11.04 1.53 -14.04 -8.05 -10.45 -13.10 -7.73
CB52 -9.40 1.40 -12.15 -6.65 -8.97 -11.44 -6.43
CB101 -6.75 1.24 -9.18 -4.32 -6.53 -8.77 -4.23
CB118 -6.05 1.44 -8.87 -3.24 -5.87 -8.49 -3.18
CB138 -6.35 1.21 -8.72 -3.99 -6.15 -8.35 -3.91
CB153 -5.80 1.14 -8.05 -3.56 -5.64 -7.73 -3.50
CB180 -6.69 1.24 -9.11 -4.27 -6.47 -8.71 -4.18
Irish and Scottish West Coast CB28 -10.64 1.43 -13.44 -7.83 -10.09 -12.58 -7.53
CB52 -12.76 1.16 -15.04 -10.49 -11.98 -13.97 -9.96
CB101 -6.65 0.99 -8.58 -4.71 -6.43 -8.22 -4.60
CB118 -5.49 1.01 -7.47 -3.52 -5.35 -7.20 -3.46
CB138 -2.28 0.92 -4.07 -0.48 -2.25 -3.99 -0.48
CB153 -1.23 0.86 -2.92 0.46 -1.23 -2.88 0.46
CB180 -7.83 1.24 -10.26 -5.40 -7.53 -9.75 -5.25
Irish Sea CB28 -3.18 1.00 -5.14 -1.23 -3.13 -5.01 -1.22
CB52 -2.80 0.94 -4.64 -0.95 -2.76 -4.54 -0.95
CB101 -1.80 0.78 -3.33 -0.28 -1.79 -3.27 -0.28
CB118 -2.90 0.77 -4.41 -1.38 -2.86 -4.32 -1.38
CB138 -1.92 0.79 -3.46 -0.37 -1.90 -3.40 -0.37
CB153 -1.08 0.76 -2.58 0.41 -1.08 -2.54 0.41
CB180 -4.21 0.86 -5.89 -2.53 -4.12 -5.72 -2.49
Celtic Sea CB28 -5.10 1.26 -7.56 -2.63 -4.97 -7.29 -2.60
CB52 -5.95 1.12 -8.13 -3.76 -5.77 -7.81 -3.69
CB101 -1.91 0.97 -3.81 -0.02 -1.89 -3.73 -0.02
CB118 -2.03 0.99 -3.96 -0.10 -2.01 -3.89 -0.10
CB138 -1.34 0.92 -3.15 0.46 -1.34 -3.10 0.46
CB153 -1.34 0.89 -3.08 0.40 -1.33 -3.03 0.40
CB180 -4.15 1.06 -6.23 -2.06 -4.06 -6.04 -2.04
Northern Bay of Biscay CB28 -7.23 1.59 -10.35 -4.11 -6.97 -9.83 -4.03
CB52 -5.97 1.48 -8.86 -3.08 -5.79 -8.48 -3.03
CB101 -5.09 1.36 -7.75 -2.43 -4.96 -7.45 -2.40
CB118 -4.43 1.70 -7.76 -1.09 -4.33 -7.47 -1.09
CB138 -4.13 1.36 -6.80 -1.45 -4.04 -6.58 -1.44
CB153 -3.63 1.22 -6.02 -1.24 -3.56 -5.84 -1.23
CB180 -4.77 1.39 -7.48 -2.05 -4.66 -7.21 -2.03
Iberian Coast CB28 -6.94 1.19 -9.27 -4.60 -6.70 -8.86 -4.50
CB52 -9.07 1.14 -11.30 -6.83 -8.67 -10.69 -6.61
CB101 -5.36 1.03 -7.37 -3.34 -5.22 -7.10 -3.29
CB118 -7.10 1.15 -9.35 -4.84 -6.85 -8.93 -4.73
CB138 -5.68 1.00 -7.64 -3.71 -5.52 -7.36 -3.64
CB153 -6.74 1.00 -8.69 -4.79 -6.52 -8.32 -4.67
CB180 -10.41 1.10 -12.56 -8.25 -9.88 -11.80 -7.92


Regional status compared to the Environmental Assessment Criterion (EAC)

The first 4 tabs show:

  • Regional status: estimates of the regional status for non-planar PCBs and CB118 with pointwise upper one-sided 95% confidence intervals
  • Regional status by PCB: regional status estimates for each PCB with pointwise upper one-sided 95% confidence intervals plotted by PCB
  • Regional status by region: regional status estimates for each PCB with pointwise upper one-sided 95% confidence intervals plotted by region
  • Individual time series: the status estimates from the individual time series on which the regional assessment is based. The estimates for regions with insufficient geographic spread (and excluded from the meta-analysis) are also shown.

The symbols in all the plots have the following interpretation:

  • blue: the mean concentration is significantly (p < 0.05) below the Background Assessment Concentration (BAC)
  • green: the mean concentration is significantly (p < 0.05) below the EAC
  • red: the mean concentration is not significantly below the EAC

Note that to see why some points might be coloured blue, it is necessary to look ahead to the next section, where status is compared to the BAC. Unfortunately, it isn’t easy to present the assessment of status relative to the EAC with the assessment of status relative to the BAC because the ratio of the BAC to the EAC can vary between PCBs and species.

The final 2 tabs shows the estimates of the regional status for non-planar PCBs and CB118 and the regional status by PCB.


Regional status


Regional status by PCB


Regional status by region


Individual time series


Estimates by region

This table shows the estimates of the regional status:

  • status: the estimated mean log concentration minus the log EAC
  • se: the corresponding standard error
  • upper: the corresponding pointwise upper one-sided 95% confidence limit
  • concentration: the estimated mean concentration relative to the EAC
  • conc upper: the corresponding pointwise upper one-sided 95% confidence limit


MIME region PCB status se upper concentration conc upper
Barents Sea non-planar PCBs -3.17 0.45 -2.42 0.04 0.09
CB118 -0.65 0.28 -0.20 0.52 0.82
Greenland-Scotland ridge non-planar PCBs -4.56 0.45 -3.83 0.01 0.02
CB118 -1.79 0.29 -1.31 0.17 0.27
Norwegian Sea non-planar PCBs -2.43 0.52 -1.57 0.09 0.21
CB118 0.52 0.38 1.13 1.68 3.11
Norwegian Trench non-planar PCBs -3.17 0.43 -2.47 0.04 0.08
CB118 -0.49 0.23 -0.11 0.61 0.90
Northern North Sea non-planar PCBs -2.77 0.40 -2.12 0.06 0.12
CB118 -0.01 0.17 0.27 0.99 1.31
Skagerrak and Kattegat non-planar PCBs -2.74 0.40 -2.07 0.06 0.13
CB118 -0.02 0.18 0.28 0.98 1.32
Southern North Sea non-planar PCBs -2.40 0.39 -1.75 0.09 0.17
CB118 0.26 0.16 0.52 1.30 1.68
Channel non-planar PCBs -2.66 0.40 -2.01 0.07 0.13
CB118 0.39 0.17 0.68 1.47 1.96
Irish and Scottish West Coast non-planar PCBs -4.92 0.39 -4.28 0.01 0.01
CB118 -2.20 0.15 -1.94 0.11 0.14
Irish Sea non-planar PCBs -2.55 0.39 -1.91 0.08 0.15
CB118 -0.01 0.14 0.21 0.99 1.24
Celtic Sea non-planar PCBs -3.64 0.39 -3.00 0.03 0.05
CB118 -0.79 0.15 -0.54 0.46 0.58
Northern Bay of Biscay non-planar PCBs -2.89 0.39 -2.24 0.06 0.11
CB118 -0.15 0.16 0.11 0.86 1.12
Iberian Coast non-planar PCBs -3.30 0.41 -2.63 0.04 0.07
CB118 -0.80 0.21 -0.45 0.45 0.64


Estimates by region and PCB

This table shows the estimates of the regional trend by determinand:

  • status: the estimated mean log concentration minus the log EAC
  • se: the corresponding standard error
  • upper: the corresponding pointwise upper one-sided 95% confidence limit
  • concentration: the estimated mean concentration relative to the EAC
  • conc upper: the corresponding pointwise upper one-sided 95% confidence limit


MIME region PCB status se upper concentration conc upper
Barents Sea CB28 -3.89 0.33 -3.35 0.02 0.04
CB52 -3.19 0.33 -2.64 0.04 0.07
CB101 -2.10 0.31 -1.59 0.12 0.20
CB118 -0.65 0.28 -0.20 0.52 0.82
CB138 -2.31 0.30 -1.82 0.10 0.16
CB153 -3.61 0.30 -3.12 0.03 0.04
CB180 -3.92 0.34 -3.37 0.02 0.03
Greenland-Scotland ridge CB28 -4.74 0.34 -4.18 0.01 0.02
CB52 -4.31 0.29 -3.84 0.01 0.02
CB101 -3.67 0.29 -3.19 0.03 0.04
CB118 -1.79 0.29 -1.31 0.17 0.27
CB138 -3.84 0.28 -3.37 0.02 0.03
CB153 -4.98 0.28 -4.52 0.01 0.01
CB180 -5.84 0.32 -5.31 0.00 0.00
Norwegian Sea CB28 -3.41 0.44 -2.70 0.03 0.07
CB52 -2.85 0.44 -2.13 0.06 0.12
CB101 -1.33 0.41 -0.65 0.26 0.52
CB118 0.52 0.38 1.13 1.68 3.11
CB138 -1.33 0.40 -0.67 0.26 0.51
CB153 -2.54 0.40 -1.89 0.08 0.15
CB180 -3.09 0.43 -2.39 0.05 0.09
Norwegian Trench CB28 -3.93 0.30 -3.43 0.02 0.03
CB52 -3.12 0.28 -2.66 0.04 0.07
CB101 -2.26 0.25 -1.85 0.10 0.16
CB118 -0.49 0.23 -0.11 0.61 0.90
CB138 -2.37 0.25 -1.97 0.09 0.14
CB153 -3.54 0.25 -3.14 0.03 0.04
CB180 -3.78 0.27 -3.33 0.02 0.04
Northern North Sea CB28 -3.38 0.22 -3.01 0.03 0.05
CB52 -3.25 0.21 -2.90 0.04 0.05
CB101 -1.94 0.19 -1.62 0.14 0.20
CB118 -0.01 0.17 0.27 0.99 1.31
CB138 -1.87 0.18 -1.57 0.15 0.21
CB153 -3.08 0.18 -2.79 0.05 0.06
CB180 -3.11 0.20 -2.78 0.04 0.06
Skagerrak and Kattegat CB28 -3.08 0.21 -2.73 0.05 0.06
CB52 -2.71 0.21 -2.38 0.07 0.09
CB101 -1.86 0.20 -1.53 0.16 0.22
CB118 -0.02 0.18 0.28 0.98 1.32
CB138 -1.92 0.20 -1.60 0.15 0.20
CB153 -3.10 0.20 -2.77 0.05 0.06
CB180 -3.76 0.21 -3.41 0.02 0.03
Southern North Sea CB28 -2.93 0.18 -2.63 0.05 0.07
CB52 -2.38 0.17 -2.09 0.09 0.12
CB101 -1.41 0.17 -1.14 0.24 0.32
CB118 0.26 0.16 0.52 1.30 1.68
CB138 -1.62 0.17 -1.35 0.20 0.26
CB153 -2.62 0.16 -2.35 0.07 0.10
CB180 -3.42 0.17 -3.14 0.03 0.04
Channel CB28 -3.93 0.19 -3.61 0.02 0.03
CB52 -2.80 0.19 -2.49 0.06 0.08
CB101 -1.38 0.19 -1.07 0.25 0.34
CB118 0.39 0.17 0.68 1.47 1.96
CB138 -1.48 0.19 -1.17 0.23 0.31
CB153 -2.51 0.18 -2.21 0.08 0.11
CB180 -3.87 0.19 -3.56 0.02 0.03
Irish and Scottish West Coast CB28 -5.03 0.19 -4.73 0.01 0.01
CB52 -4.90 0.17 -4.62 0.01 0.01
CB101 -3.96 0.16 -3.69 0.02 0.02
CB118 -2.20 0.15 -1.94 0.11 0.14
CB138 -4.02 0.16 -3.76 0.02 0.02
CB153 -4.96 0.16 -4.70 0.01 0.01
CB180 -6.63 0.18 -6.34 0.00 0.00
Irish Sea CB28 -2.67 0.16 -2.40 0.07 0.09
CB52 -2.44 0.16 -2.18 0.09 0.11
CB101 -1.60 0.15 -1.36 0.20 0.26
CB118 -0.01 0.14 0.21 0.99 1.24
CB138 -1.92 0.15 -1.68 0.15 0.19
CB153 -3.02 0.15 -2.77 0.05 0.06
CB180 -3.63 0.15 -3.38 0.03 0.03
Celtic Sea CB28 -4.16 0.17 -3.87 0.02 0.02
CB52 -3.64 0.17 -3.36 0.03 0.03
CB101 -2.47 0.17 -2.20 0.08 0.11
CB118 -0.79 0.15 -0.54 0.46 0.58
CB138 -2.81 0.16 -2.54 0.06 0.08
CB153 -3.76 0.16 -3.49 0.02 0.03
CB180 -5.01 0.17 -4.73 0.01 0.01
Northern Bay of Biscay CB28 -4.16 0.18 -3.87 0.02 0.02
CB52 -3.00 0.18 -2.71 0.05 0.07
CB101 -1.64 0.17 -1.36 0.19 0.26
CB118 -0.15 0.16 0.11 0.86 1.12
CB138 -2.00 0.17 -1.72 0.13 0.18
CB153 -2.59 0.17 -2.31 0.07 0.10
CB180 -3.94 0.17 -3.65 0.02 0.03
Iberian Coast CB28 -3.84 0.23 -3.46 0.02 0.03
CB52 -3.97 0.23 -3.59 0.02 0.03
CB101 -2.03 0.21 -1.68 0.13 0.19
CB118 -0.80 0.21 -0.45 0.45 0.64
CB138 -2.04 0.21 -1.69 0.13 0.18
CB153 -3.31 0.21 -2.96 0.04 0.05
CB180 -4.65 0.22 -4.29 0.01 0.01


Regional status compared to the Background Assessment Concentration (BAC)

The first 4 tabs show:

  • Regional status: estimates of the regional status for non-planar PCBs and CB118 with pointwise upper one-sided 95% confidence intervals
  • Regional status by PCB: regional status estimates for each PCB with pointwise upper one-sided 95% confidence intervals plotted by PCB
  • Regional status by region: regional status estimates for each PCB with pointwise upper one-sided 95% confidence intervals plotted by region
  • Individual time series: the status estimates from the individual time series on which the regional assessment is based. The estimates for regions with insufficient geographic spread (and excluded from the meta-analysis) are also shown.

The symbols in all the plots have the following interpretation:

  • blue: the mean concentration is significantly (p < 0.05) below the BAC
  • green: the mean concentration is significantly (p < 0.05) below the Environmental Assessment Criterion (EAC)
  • red: the mean concentration is not significantly below the EAC

The final 2 tabs shows the estimates of the regional status for non-planar PCBs and CB118 and the regional status by PCB.


Regional status


Regional status by PCB


Regional status by region


Individual time series


Estimates by region

This table shows the estimates of the regional status:

  • status: the estimated mean log concentration minus the log BAC
  • se: the corresponding standard error
  • upper: the corresponding pointwise upper one-sided 95% confidence limit
  • concentration: the estimated mean concentration relative to the BAC
  • conc upper: the corresponding pointwise upper one-sided 95% confidence limit


MIME region PCB status se upper concentration conc upper
Barents Sea non-planar PCBs 1.95 0.76 3.19 7.00 24.34
CB118 2.17 0.47 2.95 8.72 19.02
Greenland-Scotland ridge non-planar PCBs -0.23 0.74 0.99 0.79 2.70
CB118 0.51 0.50 1.33 1.66 3.77
Norwegian Sea non-planar PCBs 2.84 0.88 4.28 17.15 72.36
CB118 3.49 0.64 4.55 32.69 94.19
Norwegian Trench non-planar PCBs 1.18 0.71 2.34 3.25 10.42
CB118 1.65 0.39 2.30 5.23 9.99
Northern North Sea non-planar PCBs 1.66 0.65 2.73 5.27 15.39
CB118 2.26 0.29 2.74 9.57 15.50
Skagerrak and Kattegat non-planar PCBs 1.72 0.67 2.83 5.61 17.01
CB118 2.22 0.33 2.76 9.20 15.87
Southern North Sea non-planar PCBs 2.43 0.65 3.50 11.40 32.99
CB118 2.92 0.28 3.38 18.63 29.50
Channel non-planar PCBs 1.18 0.66 2.26 3.27 9.62
CB118 2.01 0.30 2.51 7.48 12.28
Irish and Scottish West Coast non-planar PCBs -1.24 0.64 -0.19 0.29 0.83
CB118 -0.68 0.26 -0.25 0.51 0.78
Irish Sea non-planar PCBs 1.77 0.63 2.80 5.84 16.49
CB118 2.11 0.23 2.50 8.27 12.15
Celtic Sea non-planar PCBs 0.07 0.64 1.12 1.07 3.07
CB118 0.74 0.26 1.17 2.09 3.21
Northern Bay of Biscay non-planar PCBs 0.77 0.65 1.84 2.17 6.28
CB118 1.33 0.28 1.79 3.80 5.99
Iberian Coast non-planar PCBs 0.47 0.68 1.58 1.60 4.85
CB118 0.77 0.35 1.35 2.17 3.84


Estimates by region and PCB

This table shows the estimates of the regional trend by determinand:

  • status: the estimated mean log concentration minus the log BAC
  • se: the corresponding standard error
  • upper: the corresponding pointwise upper one-sided 95% confidence limit
  • concentration: the estimated mean concentration relative to the BAC
  • conc upper: the corresponding pointwise upper one-sided 95% confidence limit


MIME region PCB status se upper concentration conc upper
Barents Sea CB28 -0.13 0.52 0.72 0.88 2.05
CB52 1.23 0.52 2.08 3.41 7.99
CB101 2.36 0.50 3.19 10.61 24.34
CB118 2.17 0.47 2.95 8.72 19.02
CB138 3.11 0.50 3.92 22.43 50.65
CB153 3.38 0.50 4.19 29.35 66.27
CB180 1.73 0.52 2.58 5.63 13.26
Greenland-Scotland ridge CB28 -1.80 0.51 -0.96 0.17 0.38
CB52 -0.83 0.48 -0.05 0.44 0.96
CB101 -0.03 0.48 0.76 0.97 2.13
CB118 0.51 0.50 1.33 1.66 3.77
CB138 0.86 0.47 1.64 2.36 5.15
CB153 1.30 0.47 2.08 3.68 8.02
CB180 -0.88 0.50 -0.06 0.42 0.94
Norwegian Sea CB28 0.49 0.69 1.63 1.64 5.11
CB52 1.69 0.69 2.83 5.43 16.99
CB101 3.25 0.68 4.37 25.92 78.81
CB118 3.49 0.64 4.55 32.69 94.19
CB138 4.25 0.67 5.35 70.35 211.19
CB153 4.61 0.67 5.71 100.56 301.98
CB180 2.74 0.69 3.87 15.56 48.12
Norwegian Trench CB28 -0.96 0.45 -0.23 0.38 0.80
CB52 0.42 0.43 1.12 1.52 3.08
CB101 1.38 0.41 2.06 3.98 7.86
CB118 1.65 0.39 2.30 5.23 9.99
CB138 2.32 0.41 3.00 10.20 20.07
CB153 2.74 0.41 3.41 15.43 30.37
CB180 1.19 0.43 1.89 3.27 6.62
Northern North Sea CB28 -0.27 0.33 0.26 0.76 1.30
CB52 0.38 0.32 0.91 1.47 2.48
CB101 1.85 0.31 2.35 6.34 10.49
CB118 2.26 0.29 2.74 9.57 15.50
CB138 2.89 0.30 3.38 17.91 29.36
CB153 3.24 0.30 3.73 25.58 41.76
CB180 1.88 0.31 2.40 6.58 11.01
Skagerrak and Kattegat CB28 -0.04 0.36 0.55 0.96 1.73
CB52 1.01 0.35 1.59 2.75 4.91
CB101 2.03 0.35 2.61 7.60 13.55
CB118 2.22 0.33 2.76 9.20 15.87
CB138 2.87 0.35 3.44 17.58 31.24
CB153 3.25 0.35 3.82 25.77 45.80
CB180 1.23 0.36 1.82 3.42 6.17
Southern North Sea CB28 0.50 0.30 0.98 1.64 2.67
CB52 1.74 0.29 2.22 5.70 9.23
CB101 2.78 0.29 3.25 16.09 25.79
CB118 2.92 0.28 3.38 18.63 29.50
CB138 3.54 0.29 4.01 34.47 55.26
CB153 4.09 0.29 4.56 59.51 95.20
CB180 1.96 0.29 2.44 7.10 11.46
Channel CB28 -1.49 0.31 -0.97 0.23 0.38
CB52 0.13 0.31 0.64 1.13 1.90
CB101 1.75 0.31 2.26 5.75 9.60
CB118 2.01 0.30 2.51 7.48 12.28
CB138 2.73 0.31 3.24 15.32 25.54
CB153 3.29 0.31 3.80 26.92 44.83
CB180 0.70 0.31 1.21 2.02 3.37
Irish and Scottish West Coast CB28 -2.77 0.28 -2.30 0.06 0.10
CB52 -2.12 0.27 -1.67 0.12 0.19
CB101 -1.01 0.27 -0.57 0.36 0.57
CB118 -0.68 0.26 -0.25 0.51 0.78
CB138 0.02 0.27 0.46 1.02 1.58
CB153 0.68 0.26 1.11 1.97 3.05
CB180 -2.24 0.27 -1.79 0.11 0.17
Irish Sea CB28 0.27 0.26 0.69 1.31 2.00
CB52 1.05 0.25 1.47 2.86 4.34
CB101 2.03 0.25 2.44 7.62 11.46
CB118 2.11 0.23 2.50 8.27 12.15
CB138 2.73 0.25 3.14 15.32 23.02
CB153 3.20 0.25 3.61 24.65 37.03
CB180 1.31 0.25 1.72 3.69 5.57
Celtic Sea CB28 -1.85 0.28 -1.39 0.16 0.25
CB52 -0.84 0.28 -0.38 0.43 0.68
CB101 0.50 0.27 0.96 1.66 2.60
CB118 0.74 0.26 1.17 2.09 3.21
CB138 1.26 0.27 1.71 3.53 5.53
CB153 1.92 0.27 2.37 6.80 10.66
CB180 -0.58 0.28 -0.12 0.56 0.89
Northern Bay of Biscay CB28 -1.91 0.29 -1.43 0.15 0.24
CB52 -0.27 0.29 0.21 0.77 1.24
CB101 1.27 0.29 1.75 3.56 5.74
CB118 1.33 0.28 1.79 3.80 5.99
CB138 2.02 0.29 2.50 7.57 12.19
CB153 3.04 0.29 3.52 20.93 33.72
CB180 0.47 0.29 0.95 1.60 2.58
Iberian Coast CB28 -1.47 0.36 -0.87 0.23 0.42
CB52 -1.09 0.36 -0.49 0.34 0.61
CB101 1.01 0.35 1.59 2.76 4.93
CB118 0.77 0.35 1.35 2.17 3.84
CB138 2.10 0.35 2.68 8.14 14.52
CB153 2.43 0.35 3.01 11.34 20.22
CB180 -0.17 0.36 0.42 0.84 1.52


PCB profiles

The profile of concentrations across PCBs can sometimes be useful for examining sources, and for comparing concentrations across regions where assessment criteria are not available. Profiles were examined by fitting the following linear mixed model to the non-planar PCBs by restricted maximum likelihood:

  • response: mean log concentration
  • fixed model: region
  • random model: PCB + region.PCB + station + station.PCB + estimation variance + residual variation

where, for each time series, the mean log concentration is the estimated mean log concentration in the final monitoring year and the estimation variance is the variance associated with this estimate. The usual simplified model was also fitted to CB118 and the results combined.

The estimated PCB concentration profiles by region are shown below with pointwise 95% confidence limits. The units are ug/kg lw.