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 2023 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) 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 2016 to 2021
  • 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 2016 to 2021
  • 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. 174 of the 2264 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 0 3 3 1 7
no trend 1 3 3 7 3 4 2 23
downward trend 4 2 2 2 2 2 2 16
Greenland-Scotland ridge upward trend 0 0 1 1 1 1 0 4
no trend 0 3 4 1 2 5 2 17
downward trend 3 8 7 10 9 6 6 49
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 2 5 5 1 15
no trend 3 8 10 11 8 12 6 58
downward trend 8 11 10 13 12 9 9 72
2 Norwegian Trench upward trend 0 0 1 2 1 2 1 7
no trend 4 5 5 7 9 9 4 43
downward trend 2 4 10 8 6 6 5 41
Northern North Sea upward trend 0 0 1 3 0 1 1 6
no trend 3 2 12 15 19 23 11 85
downward trend 3 4 2 3 4 2 2 20
Skagerrak and Kattegat upward trend 0 0 0 2 1 1 0 4
no trend 8 10 16 14 17 20 10 95
downward trend 12 14 10 12 9 7 8 72
Southern North Sea upward trend 0 0 0 0 0 1 1 2
no trend 12 20 22 21 20 18 17 130
downward trend 7 4 9 10 11 12 11 64
Channel upward trend 0 0 0 0 0 0 0 0
no trend 18 19 23 23 21 19 22 145
downward trend 4 4 1 1 3 5 2 20
total upward trend 0 0 2 7 2 5 3 19
no trend 45 56 78 80 86 89 64 498
downward trend 28 30 32 34 33 32 28 217
3 Irish and Scottish West Coast upward trend 0 0 1 0 0 0 0 1
no trend 14 10 13 16 18 19 13 103
downward trend 6 8 10 8 6 5 8 51
Irish Sea upward trend 0 0 2 2 1 2 0 7
no trend 19 18 20 17 20 27 19 140
downward trend 9 11 14 18 13 8 12 85
Celtic Sea upward trend 0 0 0 0 0 0 0 0
no trend 19 17 20 18 20 19 19 132
downward trend 5 7 5 7 5 6 5 40
total upward trend 0 0 3 2 1 2 0 8
no trend 52 45 53 51 58 65 51 375
downward trend 20 26 29 33 24 19 25 176
4 Northern Bay of Biscay upward trend 0 0 0 0 0 0 0 0
no trend 21 20 19 20 21 18 20 139
downward trend 0 1 2 1 0 3 1 8
Iberian Sea upward trend 0 0 0 5 0 1 0 6
no trend 14 8 12 14 10 7 9 74
downward trend 5 10 14 7 16 18 13 83
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 0 0 0 5 0 1 0 6
no trend 36 29 31 35 32 26 30 219
downward trend 5 11 17 8 16 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 0 37 33 20 15
no trend 20 60 60 78 38 45 40 50
downward trend 80 40 40 22 25 22 40 35
Greenland-Scotland ridge upward trend 0 0 9 9 8 8 0 6
no trend 0 27 33 8 17 42 25 24
downward trend 100 73 58 83 75 50 75 70
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 8 20 19 6 10
no trend 27 42 46 42 32 46 38 40
downward trend 73 58 45 50 48 35 56 50
2 Norwegian Trench upward trend 0 0 6 12 6 12 10 8
no trend 67 56 31 41 56 53 40 47
downward trend 33 44 63 47 38 35 50 45
Northern North Sea upward trend 0 0 7 14 0 4 7 5
no trend 50 33 80 72 83 88 79 77
downward trend 50 67 13 14 17 8 14 18
Skagerrak and Kattegat upward trend 0 0 0 7 4 4 0 2
no trend 40 42 62 50 63 71 56 56
downward trend 60 58 38 43 33 25 44 42
Southern North Sea upward trend 0 0 0 0 0 3 3 1
no trend 63 83 71 68 65 58 59 66
downward trend 37 17 29 32 35 39 38 33
Channel upward trend 0 0 0 0 0 0 0 0
no trend 82 83 96 96 88 79 92 88
downward trend 18 17 4 4 12 21 8 12
total upward trend 0 0 2 6 2 4 3 3
no trend 62 65 70 66 71 71 67 68
downward trend 38 35 28 28 27 25 30 29
3 Irish and Scottish West Coast upward trend 0 0 4 0 0 0 0 1
no trend 70 56 54 67 75 79 62 66
downward trend 30 44 42 33 25 21 38 33
Irish Sea upward trend 0 0 5 5 3 5 0 3
no trend 68 62 56 46 59 73 61 60
downward trend 32 38 39 49 38 22 39 37
Celtic Sea upward trend 0 0 0 0 0 0 0 0
no trend 79 71 80 72 80 76 79 77
downward trend 21 29 20 28 20 24 21 23
total upward trend 0 0 4 2 1 2 0 1
no trend 72 63 62 59 70 76 67 67
downward trend 28 37 34 39 29 22 33 32
4 Northern Bay of Biscay upward trend 0 0 0 0 0 0 0 0
no trend 100 95 90 95 100 86 95 95
downward trend 0 5 10 5 0 14 5 5
Iberian Sea upward trend 0 0 0 19 0 4 0 4
no trend 74 44 46 54 38 27 41 45
downward trend 26 56 54 27 62 69 59 51
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 0 0 0 10 0 2 0 2
no trend 88 72 65 73 67 54 68 69
downward trend 12 28 35 17 33 44 32 29


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 9 9 11 2 11 11 9 62
red 0 0 0 6 0 0 0 6
Greenland-Scotland ridge blue 7 7 5 5 3 2 7 36
green 3 3 6 5 8 9 3 37
red 0 0 0 0 0 0 0 0
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 8 3 2 7 39
green 17 17 21 8 23 26 16 128
red 0 0 1 11 2 0 1 15
2 Norwegian Trench blue 0 1 2 1 0 0 2 6
green 17 14 13 9 14 16 14 97
red 0 2 2 7 3 1 1 16
Northern North Sea blue 0 0 0 0 0 0 0 0
green 14 21 24 7 30 32 23 151
red 2 2 7 25 1 0 0 37
Skagerrak and Kattegat blue 9 5 0 1 0 0 5 20
green 20 21 25 13 26 28 22 155
red 0 2 4 15 3 1 1 26
Southern North Sea blue 2 1 0 0 0 0 2 5
green 28 32 31 3 30 38 35 197
red 8 4 7 36 6 0 0 61
Channel blue 19 9 0 0 0 0 5 33
green 8 15 22 5 22 27 22 121
red 0 3 5 22 5 1 0 36
total blue 30 16 2 2 0 0 14 64
green 87 103 115 37 122 141 116 721
red 10 13 25 105 18 3 2 176
3 Irish and Scottish West Coast blue 21 19 18 17 4 1 21 101
green 4 6 7 7 21 24 3 72
red 0 0 0 1 0 0 1 2
Irish Sea blue 8 6 0 0 0 0 6 20
green 25 27 32 14 38 40 35 211
red 6 8 9 27 3 1 0 54
Celtic Sea blue 23 18 6 5 1 1 18 72
green 5 11 22 13 28 28 11 118
red 1 0 1 11 0 0 0 13
total blue 52 43 24 22 5 2 45 193
green 34 44 61 34 87 92 49 401
red 7 8 10 39 3 1 1 69
4 Northern Bay of Biscay blue 32 11 0 0 0 0 0 43
green 0 21 32 9 32 32 32 158
red 0 0 0 23 0 0 0 23
Iberian Sea blue 12 14 3 0 1 0 12 42
green 14 12 21 6 22 26 14 115
red 0 0 2 20 3 0 0 25
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 44 25 3 0 1 0 12 85
green 15 34 54 16 55 59 47 280
red 0 0 2 43 3 0 0 48


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 87
red 0 0 0 55 0 0 0 9
Greenland-Scotland ridge blue 70 70 45 50 27 18 70 49
green 30 30 55 50 73 82 30 51
red 0 0 0 0 0 0 0 0
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 29 29 18 29 11 7 29 22
green 71 71 78 30 82 93 67 70
red 0 0 4 41 7 0 4 8
2 Norwegian Trench blue 0 6 12 6 0 0 12 5
green 100 82 76 53 82 94 82 82
red 0 12 12 41 18 6 6 13
Northern North Sea blue 0 0 0 0 0 0 0 0
green 88 91 77 22 97 100 100 80
red 12 9 23 78 3 0 0 20
Skagerrak and Kattegat blue 31 18 0 3 0 0 18 10
green 69 75 86 45 90 97 78 77
red 0 7 14 52 10 3 4 13
Southern North Sea blue 5 3 0 0 0 0 5 2
green 74 86 82 8 83 100 95 75
red 21 11 18 92 17 0 0 23
Channel blue 70 33 0 0 0 0 19 17
green 30 56 81 19 81 96 81 64
red 0 11 19 81 19 4 0 19
total blue 24 12 1 1 0 0 11 7
green 68 78 81 26 87 98 88 75
red 8 10 18 73 13 2 1 18
3 Irish and Scottish West Coast blue 84 76 72 68 16 4 84 58
green 16 24 28 28 84 96 12 41
red 0 0 0 4 0 0 4 1
Irish Sea blue 21 15 0 0 0 0 15 7
green 64 66 78 34 93 98 85 74
red 15 19 22 66 7 2 0 19
Celtic Sea blue 79 62 21 17 3 3 62 36
green 17 38 76 45 97 97 38 58
red 4 0 3 38 0 0 0 6
total blue 56 45 25 23 5 2 47 29
green 37 46 64 36 92 97 52 61
red 7 9 11 41 3 1 1 10
4 Northern Bay of Biscay blue 100 34 0 0 0 0 0 19
green 0 66 100 28 100 100 100 71
red 0 0 0 72 0 0 0 10
Iberian Sea blue 46 54 11 0 4 0 46 23
green 54 46 81 23 85 100 54 63
red 0 0 8 77 11 0 0 14
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 75 42 5 0 2 0 20 20
green 25 58 92 27 93 100 80 68
red 0 0 3 73 5 0 0 12


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 -0.33 2.24 -4.73 4.07 -0.33 -4.62 4.15
CB118 -2.15 2.04 -6.15 1.85 -2.13 -5.96 1.86
Greenland-Scotland ridge non-planar PCBs -5.01 1.65 -8.24 -1.79 -4.89 -7.91 -1.77
CB118 -4.11 1.32 -6.70 -1.53 -4.03 -6.48 -1.51
Norwegian Sea non-planar PCBs -4.01 3.05 -9.98 1.97 -3.93 -9.50 1.99
CB118 -7.07 4.04 -14.98 0.84 -6.82 -13.91 0.85
Norwegian Trench non-planar PCBs -1.47 1.78 -4.95 2.01 -1.46 -4.83 2.03
CB118 -1.24 1.50 -4.18 1.70 -1.23 -4.09 1.72
Northern North Sea non-planar PCBs -3.83 1.40 -6.57 -1.09 -3.75 -6.35 -1.08
CB118 -1.30 1.20 -3.65 1.04 -1.30 -3.59 1.05
Skagerrak and Kattegat non-planar PCBs -2.27 1.49 -5.19 0.66 -2.24 -5.06 0.66
CB118 -2.17 1.17 -4.45 0.12 -2.14 -4.36 0.12
Southern North Sea non-planar PCBs -1.96 1.27 -4.46 0.54 -1.94 -4.36 0.54
CB118 -2.47 0.95 -4.33 -0.61 -2.44 -4.24 -0.61
Channel non-planar PCBs -7.29 1.48 -10.19 -4.38 -7.03 -9.69 -4.29
CB118 -4.46 1.77 -7.93 -0.99 -4.36 -7.63 -0.99
Irish and Scottish West Coast non-planar PCBs -7.58 1.42 -10.35 -4.80 -7.30 -9.83 -4.69
CB118 -6.96 1.30 -9.51 -4.40 -6.72 -9.08 -4.31
Irish Sea non-planar PCBs -3.51 1.22 -5.90 -1.13 -3.45 -5.73 -1.12
CB118 -4.09 0.86 -5.77 -2.41 -4.01 -5.61 -2.38
Celtic Sea non-planar PCBs -5.15 1.39 -7.87 -2.43 -5.02 -7.57 -2.41
CB118 -3.50 1.21 -5.87 -1.13 -3.44 -5.70 -1.12
Northern Bay of Biscay non-planar PCBs -5.47 1.57 -8.54 -2.40 -5.32 -8.18 -2.37
CB118 -5.39 2.27 -9.84 -0.95 -5.25 -9.37 -0.94
Iberian Sea non-planar PCBs -8.15 1.32 -10.73 -5.57 -7.82 -10.17 -5.41
CB118 -0.97 1.14 -3.20 1.25 -0.97 -3.15 1.26


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 -2.10 2.23 -6.47 2.28 -2.07 -6.27 2.31
CB52 -1.54 2.26 -5.96 2.89 -1.52 -5.79 2.93
CB101 -1.26 2.30 -5.76 3.25 -1.25 -5.60 3.30
CB118 -2.15 2.04 -6.15 1.85 -2.13 -5.96 1.86
CB138 1.15 2.14 -3.05 5.34 1.16 -3.00 5.49
CB153 1.43 2.14 -2.76 5.62 1.44 -2.72 5.78
CB180 0.33 2.33 -4.23 4.89 0.33 -4.14 5.02
Greenland-Scotland ridge CB28 -6.96 1.63 -10.14 -3.77 -6.72 -9.64 -3.70
CB52 -5.92 1.48 -8.82 -3.02 -5.75 -8.44 -2.97
CB101 -4.49 1.46 -7.35 -1.63 -4.39 -7.09 -1.61
CB118 -4.11 1.32 -6.70 -1.53 -4.03 -6.48 -1.51
CB138 -4.38 1.45 -7.21 -1.54 -4.28 -6.96 -1.53
CB153 -3.67 1.45 -6.51 -0.83 -3.60 -6.30 -0.83
CB180 -4.67 1.52 -7.65 -1.69 -4.56 -7.36 -1.68
Norwegian Sea CB28 -6.52 3.18 -12.75 -0.29 -6.31 -11.97 -0.29
CB52 -5.77 3.19 -12.03 0.49 -5.61 -11.33 0.49
CB101 -3.94 3.13 -10.08 2.20 -3.86 -9.59 2.22
CB118 -7.07 4.04 -14.98 0.84 -6.82 -13.91 0.85
CB138 -2.44 3.12 -8.56 3.67 -2.41 -8.20 3.74
CB153 -1.85 3.12 -7.96 4.25 -1.84 -7.65 4.34
CB180 -3.50 3.23 -9.82 2.83 -3.44 -9.36 2.87
Norwegian Trench CB28 -3.77 1.79 -7.27 -0.27 -3.70 -7.02 -0.27
CB52 -3.31 1.78 -6.79 0.18 -3.25 -6.57 0.18
CB101 -2.22 1.61 -5.38 0.94 -2.20 -5.24 0.94
CB118 -1.24 1.50 -4.18 1.70 -1.23 -4.09 1.72
CB138 -0.60 1.59 -3.72 2.53 -0.59 -3.65 2.56
CB153 0.50 1.60 -2.63 3.64 0.50 -2.60 3.71
CB180 0.57 1.72 -2.80 3.94 0.57 -2.76 4.02
Northern North Sea CB28 -6.56 1.45 -9.41 -3.72 -6.35 -8.98 -3.65
CB52 -6.67 1.65 -9.89 -3.44 -6.45 -9.42 -3.38
CB101 -3.29 1.35 -5.93 -0.65 -3.23 -5.75 -0.65
CB118 -1.30 1.20 -3.65 1.04 -1.30 -3.59 1.05
CB138 -2.41 1.15 -4.66 -0.16 -2.38 -4.55 -0.16
CB153 -1.87 1.13 -4.09 0.36 -1.85 -4.01 0.36
CB180 -2.17 1.30 -4.71 0.38 -2.14 -4.60 0.38
Skagerrak and Kattegat CB28 -3.78 1.33 -6.39 -1.17 -3.71 -6.19 -1.16
CB52 -3.56 1.30 -6.11 -1.01 -3.50 -5.93 -1.01
CB101 -2.72 1.27 -5.21 -0.22 -2.68 -5.08 -0.22
CB118 -2.17 1.17 -4.45 0.12 -2.14 -4.36 0.12
CB138 -1.16 1.27 -3.65 1.33 -1.15 -3.58 1.34
CB153 -0.49 1.27 -2.97 1.99 -0.49 -2.93 2.01
CB180 -1.89 1.35 -4.54 0.75 -1.88 -4.44 0.76
Southern North Sea CB28 -2.30 1.08 -4.43 -0.18 -2.28 -4.33 -0.18
CB52 -0.97 1.09 -3.10 1.15 -0.97 -3.05 1.16
CB101 -1.83 1.01 -3.80 0.15 -1.81 -3.73 0.15
CB118 -2.47 0.95 -4.33 -0.61 -2.44 -4.24 -0.61
CB138 -2.71 1.01 -4.69 -0.73 -2.67 -4.58 -0.72
CB153 -1.23 1.00 -3.18 0.72 -1.22 -3.13 0.72
CB180 -2.71 1.04 -4.76 -0.67 -2.68 -4.64 -0.67
Channel CB28 -10.24 1.69 -13.55 -6.93 -9.73 -12.67 -6.70
CB52 -9.29 1.59 -12.42 -6.17 -8.87 -11.68 -5.98
CB101 -6.16 1.49 -9.08 -3.24 -5.97 -8.68 -3.19
CB118 -4.46 1.77 -7.93 -0.99 -4.36 -7.63 -0.99
CB138 -5.93 1.44 -8.76 -3.11 -5.76 -8.39 -3.06
CB153 -5.58 1.39 -8.30 -2.85 -5.42 -7.96 -2.81
CB180 -6.54 1.49 -9.45 -3.62 -6.33 -9.02 -3.55
Irish and Scottish West Coast CB28 -11.11 1.56 -14.17 -8.06 -10.52 -13.21 -7.74
CB52 -11.49 1.46 -14.36 -8.62 -10.86 -13.38 -8.26
CB101 -8.80 1.30 -11.34 -6.26 -8.43 -10.72 -6.07
CB118 -6.96 1.30 -9.51 -4.40 -6.72 -9.08 -4.31
CB138 -3.41 1.22 -5.79 -1.03 -3.35 -5.63 -1.02
CB153 -3.06 1.19 -5.39 -0.73 -3.02 -5.25 -0.73
CB180 -7.57 1.47 -10.46 -4.69 -7.29 -9.93 -4.58
Irish Sea CB28 -4.55 1.09 -6.68 -2.42 -4.45 -6.46 -2.39
CB52 -4.98 1.03 -7.00 -2.97 -4.86 -6.76 -2.92
CB101 -3.05 0.93 -4.87 -1.23 -3.00 -4.75 -1.22
CB118 -4.09 0.86 -5.77 -2.41 -4.01 -5.61 -2.38
CB138 -2.58 0.92 -4.38 -0.78 -2.55 -4.29 -0.78
CB153 -1.83 0.91 -3.61 -0.05 -1.81 -3.54 -0.05
CB180 -4.10 0.97 -6.00 -2.19 -4.02 -5.83 -2.17
Celtic Sea CB28 -7.29 1.45 -10.13 -4.45 -7.03 -9.63 -4.35
CB52 -8.56 1.39 -11.29 -5.83 -8.20 -10.68 -5.66
CB101 -3.74 1.22 -6.12 -1.35 -3.67 -5.94 -1.34
CB118 -3.50 1.21 -5.87 -1.13 -3.44 -5.70 -1.12
CB138 -3.10 1.18 -5.40 -0.80 -3.05 -5.26 -0.79
CB153 -2.82 1.14 -5.06 -0.58 -2.78 -4.93 -0.58
CB180 -5.40 1.30 -7.96 -2.85 -5.26 -7.65 -2.81
Northern Bay of Biscay CB28 -7.84 1.81 -11.38 -4.30 -7.54 -10.76 -4.20
CB52 -7.44 1.76 -10.88 -4.00 -7.17 -10.31 -3.92
CB101 -5.16 1.64 -8.37 -1.95 -5.03 -8.03 -1.93
CB118 -5.39 2.27 -9.84 -0.95 -5.25 -9.37 -0.94
CB138 -3.92 1.65 -7.16 -0.69 -3.85 -6.91 -0.68
CB153 -4.27 1.53 -7.26 -1.28 -4.18 -7.00 -1.27
CB180 -4.16 1.69 -7.47 -0.86 -4.08 -7.20 -0.86
Iberian Sea CB28 -8.38 1.26 -10.85 -5.92 -8.04 -10.28 -5.75
CB52 -10.85 1.18 -13.16 -8.54 -10.28 -12.33 -8.19
CB101 -7.31 1.08 -9.42 -5.19 -7.05 -8.99 -5.06
CB118 -0.97 1.14 -3.20 1.25 -0.97 -3.15 1.26
CB138 -6.64 1.04 -8.68 -4.59 -6.42 -8.32 -4.49
CB153 -6.06 1.04 -8.10 -4.01 -5.88 -7.78 -3.93
CB180 -9.65 1.14 -11.88 -7.42 -9.20 -11.20 -7.16


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 -3.19 0.46 -2.44 0.04 0.09
CB118 -0.64 0.27 -0.19 0.53 0.82
Greenland-Scotland ridge non-planar PCBs -4.52 0.45 -3.78 0.01 0.02
CB118 -1.83 0.28 -1.37 0.16 0.25
Norwegian Sea non-planar PCBs -2.44 0.52 -1.58 0.09 0.21
CB118 0.48 0.37 1.09 1.61 2.96
Norwegian Trench non-planar PCBs -3.10 0.42 -2.41 0.04 0.09
CB118 -0.44 0.22 -0.07 0.65 0.93
Northern North Sea non-planar PCBs -2.75 0.40 -2.10 0.06 0.12
CB118 0.02 0.17 0.30 1.02 1.35
Skagerrak and Kattegat non-planar PCBs -2.69 0.40 -2.03 0.07 0.13
CB118 -0.01 0.17 0.27 0.99 1.31
Southern North Sea non-planar PCBs -2.33 0.39 -1.69 0.10 0.18
CB118 0.38 0.15 0.64 1.46 1.89
Channel non-planar PCBs -2.51 0.40 -1.86 0.08 0.16
CB118 0.55 0.18 0.84 1.73 2.31
Irish and Scottish West Coast non-planar PCBs -4.85 0.40 -4.18 0.01 0.02
CB118 -2.22 0.19 -1.91 0.11 0.15
Irish Sea non-planar PCBs -2.44 0.39 -1.81 0.09 0.16
CB118 0.08 0.14 0.32 1.08 1.38
Celtic Sea non-planar PCBs -3.54 0.40 -2.89 0.03 0.06
CB118 -0.69 0.16 -0.42 0.50 0.66
Northern Bay of Biscay non-planar PCBs -2.83 0.39 -2.19 0.06 0.11
CB118 -0.12 0.16 0.14 0.89 1.15
Iberian Sea non-planar PCBs -3.02 0.40 -2.36 0.05 0.09
CB118 0.10 0.18 0.40 1.11 1.49


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 -3.88 0.33 -3.33 0.02 0.04
CB52 -3.22 0.33 -2.67 0.04 0.07
CB101 -2.11 0.32 -1.59 0.12 0.20
CB118 -0.64 0.27 -0.19 0.53 0.82
CB138 -2.36 0.30 -1.86 0.09 0.16
CB153 -3.63 0.30 -3.13 0.03 0.04
CB180 -3.94 0.34 -3.38 0.02 0.03
Greenland-Scotland ridge CB28 -4.87 0.37 -4.26 0.01 0.01
CB52 -4.23 0.31 -3.73 0.01 0.02
CB101 -3.52 0.30 -3.03 0.03 0.05
CB118 -1.83 0.28 -1.37 0.16 0.25
CB138 -3.81 0.30 -3.31 0.02 0.04
CB153 -4.95 0.30 -4.45 0.01 0.01
CB180 -5.76 0.33 -5.22 0.00 0.01
Norwegian Sea CB28 -3.38 0.44 -2.66 0.03 0.07
CB52 -2.86 0.44 -2.13 0.06 0.12
CB101 -1.35 0.42 -0.66 0.26 0.52
CB118 0.48 0.37 1.09 1.61 2.96
CB138 -1.34 0.41 -0.67 0.26 0.51
CB153 -2.56 0.41 -1.89 0.08 0.15
CB180 -3.15 0.44 -2.43 0.04 0.09
Norwegian Trench CB28 -3.83 0.29 -3.35 0.02 0.04
CB52 -3.07 0.27 -2.62 0.05 0.07
CB101 -2.16 0.25 -1.76 0.11 0.17
CB118 -0.44 0.22 -0.07 0.65 0.93
CB138 -2.26 0.24 -1.86 0.10 0.16
CB153 -3.48 0.25 -3.08 0.03 0.05
CB180 -3.81 0.27 -3.37 0.02 0.03
Northern North Sea CB28 -3.31 0.22 -2.94 0.04 0.05
CB52 -3.26 0.21 -2.91 0.04 0.05
CB101 -1.92 0.20 -1.60 0.15 0.20
CB118 0.02 0.17 0.30 1.02 1.35
CB138 -1.82 0.19 -1.51 0.16 0.22
CB153 -3.06 0.18 -2.76 0.05 0.06
CB180 -3.10 0.21 -2.76 0.05 0.06
Skagerrak and Kattegat CB28 -3.03 0.20 -2.70 0.05 0.07
CB52 -2.66 0.20 -2.33 0.07 0.10
CB101 -1.80 0.19 -1.48 0.17 0.23
CB118 -0.01 0.17 0.27 0.99 1.31
CB138 -1.85 0.19 -1.53 0.16 0.22
CB153 -3.04 0.19 -2.73 0.05 0.07
CB180 -3.76 0.20 -3.42 0.02 0.03
Southern North Sea CB28 -2.92 0.18 -2.62 0.05 0.07
CB52 -2.34 0.18 -2.05 0.10 0.13
CB101 -1.33 0.17 -1.05 0.26 0.35
CB118 0.38 0.15 0.64 1.46 1.89
CB138 -1.49 0.17 -1.22 0.22 0.30
CB153 -2.53 0.17 -2.26 0.08 0.10
CB180 -3.38 0.17 -3.09 0.03 0.05
Channel CB28 -3.75 0.20 -3.42 0.02 0.03
CB52 -2.67 0.20 -2.35 0.07 0.10
CB101 -1.19 0.20 -0.87 0.30 0.42
CB118 0.55 0.18 0.84 1.73 2.31
CB138 -1.34 0.20 -1.01 0.26 0.36
CB153 -2.38 0.20 -2.06 0.09 0.13
CB180 -3.75 0.20 -3.42 0.02 0.03
Irish and Scottish West Coast CB28 -4.96 0.23 -4.58 0.01 0.01
CB52 -4.87 0.23 -4.50 0.01 0.01
CB101 -3.95 0.21 -3.60 0.02 0.03
CB118 -2.22 0.19 -1.91 0.11 0.15
CB138 -3.92 0.21 -3.57 0.02 0.03
CB153 -4.95 0.21 -4.61 0.01 0.01
CB180 -6.43 0.22 -6.06 0.00 0.00
Irish Sea CB28 -2.60 0.17 -2.32 0.07 0.10
CB52 -2.36 0.17 -2.08 0.09 0.13
CB101 -1.52 0.16 -1.25 0.22 0.29
CB118 0.08 0.14 0.32 1.08 1.38
CB138 -1.82 0.16 -1.55 0.16 0.21
CB153 -2.94 0.16 -2.67 0.05 0.07
CB180 -3.42 0.17 -3.15 0.03 0.04
Celtic Sea CB28 -4.16 0.19 -3.84 0.02 0.02
CB52 -3.66 0.19 -3.35 0.03 0.04
CB101 -2.34 0.19 -2.03 0.10 0.13
CB118 -0.69 0.16 -0.42 0.50 0.66
CB138 -2.64 0.19 -2.33 0.07 0.10
CB153 -3.63 0.18 -3.33 0.03 0.04
CB180 -4.81 0.19 -4.50 0.01 0.01
Northern Bay of Biscay CB28 -4.09 0.18 -3.80 0.02 0.02
CB52 -2.98 0.18 -2.68 0.05 0.07
CB101 -1.58 0.18 -1.29 0.21 0.28
CB118 -0.12 0.16 0.14 0.89 1.15
CB138 -1.94 0.18 -1.65 0.14 0.19
CB153 -2.56 0.18 -2.27 0.08 0.10
CB180 -3.85 0.18 -3.56 0.02 0.03
Iberian Sea CB28 -3.47 0.21 -3.11 0.03 0.04
CB52 -3.72 0.21 -3.36 0.02 0.03
CB101 -1.94 0.20 -1.61 0.14 0.20
CB118 0.10 0.18 0.40 1.11 1.49
CB138 -1.85 0.20 -1.52 0.16 0.22
CB153 -2.92 0.20 -2.60 0.05 0.07
CB180 -4.22 0.21 -3.88 0.01 0.02


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 1.92 0.77 3.19 6.84 24.22
CB118 2.16 0.48 2.95 8.71 19.07
Greenland-Scotland ridge non-planar PCBs -0.12 0.77 1.14 0.88 3.12
CB118 0.43 0.50 1.25 1.54 3.50
Norwegian Sea non-planar PCBs 2.82 0.89 4.29 16.79 72.70
CB118 3.44 0.65 4.50 31.03 90.19
Norwegian Trench non-planar PCBs 1.33 0.71 2.50 3.80 12.18
CB118 1.79 0.39 2.42 5.98 11.27
Northern North Sea non-planar PCBs 1.68 0.66 2.76 5.35 15.76
CB118 2.32 0.30 2.82 10.21 16.71
Skagerrak and Kattegat non-planar PCBs 1.75 0.67 2.86 5.77 17.39
CB118 2.21 0.31 2.73 9.13 15.27
Southern North Sea non-planar PCBs 2.46 0.65 3.53 11.67 33.97
CB118 3.05 0.28 3.52 21.14 33.71
Channel non-planar PCBs 1.26 0.67 2.35 3.51 10.53
CB118 2.12 0.31 2.63 8.33 13.94
Irish and Scottish West Coast non-planar PCBs -1.19 0.67 -0.08 0.30 0.92
CB118 -0.73 0.33 -0.20 0.48 0.82
Irish Sea non-planar PCBs 2.01 0.64 3.07 7.49 21.59
CB118 2.36 0.26 2.78 10.58 16.10
Celtic Sea non-planar PCBs 0.19 0.66 1.27 1.21 3.57
CB118 0.85 0.29 1.33 2.35 3.79
Northern Bay of Biscay non-planar PCBs 0.82 0.65 1.90 2.28 6.67
CB118 1.36 0.28 1.82 3.90 6.17
Iberian Sea non-planar PCBs 0.69 0.67 1.79 2.00 6.00
CB118 1.64 0.32 2.16 5.14 8.65


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 0.53 0.75 0.88 2.11
CB52 1.18 0.53 2.06 3.27 7.82
CB101 2.36 0.52 3.21 10.54 24.84
CB118 2.16 0.48 2.95 8.71 19.07
CB138 3.06 0.51 3.89 21.29 49.15
CB153 3.35 0.51 4.19 28.64 66.15
CB180 1.71 0.53 2.59 5.54 13.35
Greenland-Scotland ridge CB28 -1.86 0.55 -0.94 0.16 0.39
CB52 -0.70 0.51 0.15 0.50 1.16
CB101 0.19 0.51 1.03 1.21 2.80
CB118 0.43 0.50 1.25 1.54 3.50
CB138 0.95 0.51 1.79 2.60 5.99
CB153 1.40 0.51 2.24 4.06 9.36
CB180 -0.73 0.53 0.14 0.48 1.15
Norwegian Sea CB28 0.51 0.71 1.68 1.66 5.34
CB52 1.66 0.71 2.83 5.25 16.91
CB101 3.23 0.69 4.38 25.36 79.46
CB118 3.44 0.65 4.50 31.03 90.19
CB138 4.24 0.69 5.37 69.46 215.24
CB153 4.59 0.69 5.72 98.60 305.67
CB180 2.69 0.71 3.85 14.77 47.20
Norwegian Trench CB28 -0.78 0.44 -0.05 0.46 0.95
CB52 0.56 0.43 1.26 1.75 3.54
CB101 1.58 0.41 2.25 4.83 9.53
CB118 1.79 0.39 2.42 5.98 11.27
CB138 2.53 0.41 3.20 12.54 24.63
CB153 2.88 0.41 3.56 17.85 35.10
CB180 1.24 0.42 1.94 3.46 6.96
Northern North Sea CB28 -0.22 0.33 0.32 0.80 1.38
CB52 0.36 0.33 0.90 1.43 2.45
CB101 1.86 0.31 2.37 6.40 10.72
CB118 2.32 0.30 2.82 10.21 16.71
CB138 2.93 0.31 3.43 18.64 30.98
CB153 3.25 0.31 3.76 25.87 42.78
CB180 1.89 0.32 2.42 6.63 11.24
Skagerrak and Kattegat CB28 -0.01 0.34 0.56 0.99 1.75
CB52 1.03 0.34 1.60 2.81 4.93
CB101 2.06 0.34 2.62 7.88 13.77
CB118 2.21 0.31 2.73 9.13 15.27
CB138 2.92 0.34 3.48 18.54 32.34
CB153 3.29 0.34 3.84 26.75 46.61
CB180 1.22 0.35 1.79 3.38 5.97
Southern North Sea CB28 0.45 0.30 0.95 1.57 2.58
CB52 1.75 0.30 2.24 5.77 9.44
CB101 2.82 0.29 3.30 16.73 27.11
CB118 3.05 0.28 3.52 21.14 33.71
CB138 3.61 0.29 4.09 36.79 59.51
CB153 4.14 0.29 4.61 62.50 100.87
CB180 1.98 0.30 2.47 7.27 11.83
Channel CB28 -1.38 0.33 -0.84 0.25 0.43
CB52 0.18 0.33 0.73 1.20 2.08
CB101 1.85 0.33 2.39 6.34 10.95
CB118 2.12 0.31 2.63 8.33 13.94
CB138 2.80 0.33 3.34 16.38 28.25
CB153 3.35 0.33 3.89 28.52 49.13
CB180 0.75 0.33 1.30 2.11 3.65
Irish and Scottish West Coast CB28 -2.70 0.36 -2.11 0.07 0.12
CB52 -2.11 0.36 -1.52 0.12 0.22
CB101 -1.01 0.35 -0.43 0.37 0.65
CB118 -0.73 0.33 -0.20 0.48 0.82
CB138 0.10 0.35 0.67 1.11 1.96
CB153 0.66 0.35 1.23 1.94 3.42
CB180 -2.08 0.36 -1.49 0.13 0.23
Irish Sea CB28 0.47 0.28 0.94 1.60 2.55
CB52 1.29 0.28 1.75 3.64 5.78
CB101 2.28 0.28 2.73 9.73 15.37
CB118 2.36 0.26 2.78 10.58 16.10
CB138 2.97 0.28 3.42 19.44 30.66
CB153 3.42 0.28 3.88 30.56 48.21
CB180 1.65 0.28 2.11 5.23 8.28
Celtic Sea CB28 -1.83 0.32 -1.31 0.16 0.27
CB52 -0.84 0.32 -0.32 0.43 0.73
CB101 0.65 0.31 1.17 1.92 3.23
CB118 0.85 0.29 1.33 2.35 3.79
CB138 1.45 0.31 1.97 4.28 7.16
CB153 2.06 0.31 2.57 7.82 13.09
CB180 -0.36 0.32 0.16 0.70 1.17
Northern Bay of Biscay CB28 -1.84 0.30 -1.35 0.16 0.26
CB52 -0.24 0.30 0.25 0.78 1.28
CB101 1.33 0.30 1.82 3.79 6.19
CB118 1.36 0.28 1.82 3.90 6.17
CB138 2.08 0.30 2.57 8.00 13.06
CB153 3.07 0.30 3.56 21.45 35.02
CB180 0.56 0.30 1.05 1.75 2.86
Iberian Sea CB28 -1.17 0.34 -0.61 0.31 0.55
CB52 -0.92 0.34 -0.36 0.40 0.70
CB101 1.04 0.33 1.59 2.84 4.91
CB118 1.64 0.32 2.16 5.14 8.65
CB138 2.24 0.33 2.78 9.36 16.13
CB153 2.76 0.33 3.31 15.82 27.28
CB180 0.21 0.34 0.77 1.24 2.15


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.