Changes made since the 2014 Assessment are described below:
Inflation factors were historically used in the estimation of uncertainties when these were not reported with the monitoring data. The inflation factors were designed to down-weight data with poor analytical quality and were based on QUASIMEME Z-scores supplied to ICES on CD by analytical laboratories and Certified Reference Material (CRM) concentrations held in the ICES database. The inflation factors were bounded below by 1 (good quality) and above by 3 (bad quality or no Z-scores or CRM data).
Inflation factors were applied to all years until the 2021 assessment when they were restricted to years up to 2010 (see justification below). From the current assessment onwards, inflation factors are not used. This change brings the OSPAR methodology in line with that used by HELCOM and AMAP.
Assessment code has been developed for modelling time series of neutral red retention time, lysosomal labilisation period, stress on stress, comet assay and micronucleus assay. These responses have distributions which differ from the log normal distribution used for chemical contaminants and ‘contaminant-like’ biological effects (such as PAH metabolites). Details can be found in the help file describing methods for biological effects.
Historically, imposex in Buccinum undatum has been assessed using the imposex stage (IMPS). From this assessment onwards, the vas deferens sequence (VDS) is used. This aligns the OSPAR and HELCOM assessments.
The Background Assessment Concentrations (BACs) for arsenic and nickel in sediment are 25 and 36 mg kg\(^{-1}\) dw normalised to 5% aluminium. These are applicable to all regions apart from the Iberian Sea and the Gulf of Cadiz where there are no BACs. The ERLs for arsenic and nickel are 8.2 and 21 mg kg\(^{-1}\) dw, which are lower than the corresponding BACs. In the past, the ERLs have been applied in the Iberian Sea and the Gulf of Cadiz (where there are no BACs) but ignored in all other regions (where the BACs are greater than the ERLs). From now on, the ERLs are not used anywhere.
The following determinands were assessed for the first time:
Several determinands that had previously been assessed in biota were extended to sediment and water. In particular, many more PAHs, CBs and other organochlorines were assessed in water for the first time.
In previous assessments, cadmium, mercury and lead concentrations in biota were compared to the Background Assessment Concentration (BAC) and the Maximum Permissible Concentration (MPC). The BAC is an environmental threshold and the MPC is a human health threshold, but the distinction was blurred when interpretating the data. In this assessment, thresholds were explicitly stated to be for environmental or human health purposes. Thus, the environmental status of cadmium and lead was assessed using the BAC only and the environmental status of mercury was assessed using the BAC and the Quality Standard secondary poisoning (QSsp.) The human health status of all three metals was assessed using the MPC.
Other human health thresholds were for SCB7 (MPC) and for TBSN+, fluoranthene, benzo[a]pyrene, SBDE6, PFOS, the WHO TEQDFP, \(\gamma\)-HCH and HCB (Quality Standard human health).
The QSsp was used for the first time to asssess the environmental status of HBCD, PFOS, the WHO TEQDFP and HCB.
No- and low-risk concentrations were used as environmental thresholds for mercury concentrations in mammal hair and liver and in bird egg homogenate, liver, feather and blood. OSPAR Ecological Quality Criteria were used as environmental thresholds for SCB7, HCB and HCH concentrations in egg homogenate in common tern (Sterna hirundo) and Eurasian oystercatcher (Haematopus ostralegus).
Details on how the various thresholds were applied to different species and tissues are described in the relevant help file.
The 2020 assessment of organobromine (PBDEs, HBCD and TBBP-A) concentrations in fish changed from a wet weight to a lipid weight basis, provided the typical lipid content for the species / tissue was > 3% – essentially for all fish liver and herring muscle. Organobromine concentrations in species / tissues with < 3% lipid continued to be assessed on a wet weight basis. All other organic contaminants in fish were assessed on a wet weight basis.
In this assessment, all
A detailed description of the rationale behind these changes can be found in Annex 3 of the OSPAR MIME 2020 Summary Record.
Contaminants in bivalves were assessed on a dry weight basis in assessments up to and including 2012. They were then assessed on a wet weight basis from 2013 to 2020. In the 2021 assessment, contaminants in bivalves reverted to being assessed on a dry weight basis. A detailed description of the rationale behind these changes can be found in Annex 4 of the OSPAR MIME 2020 Summary Record.
Inflation factors are used in the estimation of uncertainties when these are not reported with the monitoring data. The inflation factors are designed to down-weight data when analytical quality is poor and are based on QUASIMEME Z-scores supplied to ICES on CD by analytical laboratories and Certified Reference Material (CRM) concentrations held in the ICES database. The inflation factors are bounded below by 1 (good quality) and above by 3 (bad quality or no Z-scores or CRM data).
The reporting of uncertainties became mandatory for the 2010 monitoring year, at which point the collection of QUASIMEME data stopped and the reporting of CRM information became optional. However, some uncertainties are still not reported (or are reported unreliably) and have to be estimated as part of the assessment process. In previous assessments, the inflation factors for these data were often set to 3 (because there were no associated Z-scores or CRM data) even though it is known that they are missing due to inadequacies in national databases rather than in the quality of the concentration measurements. Therefore, in this assessment, inflation factors from 2010 onwards were always set to 1.
This change brings the OSPAR methodology more in line with that used by HELCOM and AMAP where inflation factors are not used.
The following determinands were assessed for the first time:
Arsenic, chromium, nickel, BDE66, BDE85, BD183 and BD209 are already routinely assessed in sediment.
HBCD (the sum of HBCDA, HBCDB and HBCDG) has been routinely assessed in biota and sediment in previous assessments and will continue to be assessed in addition to the individual compounds.
In previous assessments, mercury concentrations in fish were assessed in muscle and other contaminant concentrations (metals and organics) were assessed in liver (with a few exceptions, notably for herring). From now on, when data for the same contaminant have been reported in both muscle and liver, separate time series will be constructed and both will be assessed. The application of assessment criteria to time series in different tissues has been rationalised and is explained in the relevant help files.
Time series of contaminant concentrations in bird (egg) tissue were assessed for the first time. There were time series in egg homogenate of yolk and albumen (EH), blood (BL), red blood cells (ER), feathers (FE), liver (LI) and muscle (MU). No assessment criteria were applied to bird data.
Arctic Monitoring and Assessment Programme (AMAP) data on mercury concentrations in OSPAR Region 1 were included in the assessment. Some of these data were extracted from the ICES data base, whilst others were provided directly by AMAP. The time series were of concentrations in shellfish, fish, birds and mammals. Some mammal time series were split according to sex / age as directed by AMAP. No assessment criteria were applied to bird or mammal data.
Organobromine concentrations in fish were assessed on a lipid weight basis when the typical species-tissue lipid weight was \(\ge\) 3% and on a wet weight basis otherwise. Organobromines in shellfish (soft body) were assessed on a wet weight basis (as in previous assessments). Organobromines in birds (egg homogenate of yolk and albumen) were assessed on a lipid weight basis.
The Canadian Federal Environmental Quality Guidelines (FEQGs) for selected PBDEs were converted to a lipid weight basis by assuming that they had been developed on fish with a lipid content of 5%. They were applied directly to the fish time series assessed on a lipid weight basis, and converted using species-tissue conversion factors to a wet weight basis for the shellfish and remaining fish time series.
New Background Assessment Concentrations (BACs) for PBDEs in fish and shellfish were developed. These were expressed on a lipid weight basis and, as with the FEQGs, applied directly to the fish time series assessed on a lipid weight basis, and converted to a wet weight basis for the shellfish and remaining fish time series.
The EAC for \(\gamma\)-HCH in mussels and oysters was converted from a wet weight basis to a dry weight basis by multiplying it by 5 in the 2005 CEMP Assessment and was expressed on a dry weight basis in all subsequent assessments. However, this is inconsistent with the current practice of using species-tissue conversion factors estimated from the data to convert assessment criteria betweeen bases. The EAC has therefore reverted to its original value of 0.29 \(\mu\)g kg\(^{-1}\) ww.
Background Assessment Concentrations (BACs) were trialled for all organobromines in fish and sediment and for BDE47 in shellfish. In the previous assessment, BACs were trialled for BDE47 only.
When uncertainties are not reported with concentration measurements, they are estimated from values derived from the ICES data base. These values were first derived in the 2016 assessment based on an extraction on 14 December 2015, and the same values were used in the 2017 and 2018 assessments. For the 2019 assessment onwards the values will be derived from the most recent extraction, using uncertainties for measurements from the last twenty monitoring years. For example, the values for the 2019 assessment were derived from an extraction on 15 February 2019 using uncertainties for measurements in monitoring years 1998 through 2017 inclusive.
From this assessment onwards, the species-specific factors for converting the basis of assessment concentrations in biota will be updated annually, using the most recent extraction and data from the last twenty monitoring years (see above).
Time series of contaminant concentrations in water were assessed for the first time. To keep things simple, attention was restricted to concentrations of CD, PB and NI in filtered samples, and BAP, TBTIN and PFOS in unfiltered samples. The fitted mean concentration in the final year was compared to the Annual Average Environmental Quality Standard for 'other surface waters'.
Organobromine concentrations were assessed for status for the first time. Canadian Federal Environmental Quality Guidelines (FEQGs) were used as EAC equivalents for biota and sediment. Background Assessment Concentrations (BACs) were trialled for BDE47 in biota and sediment.
The Dogger Bank sub-region was subsumed within the Southern North Sea sub-region.
Stress on stress, comet assay, micronucleus assay, neutral red retention time and lysosomal labilisation period were assessed for the first time. However, as there was no time series with more than two years of data (for any of these effects), no models were fitted and only an ad-hoc assessment of status was possible.
The individual time series assessments were synthesised in a meta analysis to make regional assessments of metals, PAHs, chlorobiphenyls, organo-bromines, organo-metals (sediment only) and imposex. The regional assessments can be found in the links under 'More information' to the right of the maps.
There were major changes in the way contaminant and biological effects time series were assessed. These included
The changes were so wide-ranging that, to understand them properly, it is probably best to compare the current help files with the 2015 help files:
There were also major changes in the assessment of imposex time series when submitted as individual VDS measurements. These included
Again, to undestand the changes properly, it is best to compare the current help files with the 2015 help file: assessment of imposex.
The definition of recent trends was extended from 10 to 20 years for contaminants and biological effects (other than imposex) in biota. This brings it into line with the definition for contaminants in sediment and reflects the increasing use of year-skipping monitoring strategies, particularly for stations with low concentrations. A recent trend thus indicates a significant change in concentration in the period 1994 to 2013 (for the 2015 assessment).
Loess smoothers are used to model smooth changes in contaminant concentrations (for both biota and sediment) and biological effects measurements (apart from imposex) when there are 7+ years of data. The amount of smoothing is determined by the type and width of the neighbourhood of contaminant indices that is used to estimate each \(f(t)\) as \(t\) runs from 1 to \(T\). Previously, a fixed-width neighbourhood (Fryer & Nicholson, 1999) was used with, for example, a width of 9 meaning that only the indices in the 9 years closest to \(t\) were used to estimate \(f(t)\). This worked well if there was annual monitoring, but was less effective when monitoring was less frequent since some parts of the fit were sometimes based on only a few indices. This has been replaced by a neighbourhood in which a fixed number of indices are used to estimate each \(f(t)\). For example, a neighbourhood of 9 now uses the 9 indices that are closest to \(t\) to estimate \(f(t)\). The fit in year \(t\) can now be influenced by indices from years relatively distant to \(t\), but the fit is always based on the same number of indices. This type of neighbourhood was used in the original development of loess smoothers (Cleveland, 1979).
A greater range of neighbourhood widths are also now considered. Previously, widths of 7, 9, and 11 years were considered, with the final choice being the width giving the smallest Akaike’s Information Criterion corrected for small sample size (AICc). Now, widths of 7, 9, 11 up to \(T\) (if \(T\) is odd) or \(T+1\) (if \(T\) is even) are considered, with the final choice again based on AICc. However, if there is no evidence of nonlinearity in the data (i.e. if the AICc of the linear model is lower than that of the best smoother) then the linear model
\(f(t) = \mu + \beta t\) is used instead.
Cleveland WS, 1979. Robust locally-weighted regression and smoothing scatterplots. Journal of the American Statistical Association 74: 829-836.
Fryer RJ & Nicholson MD, 1999. Using smoothers for comprehensive assessments of contaminant time series in marine biota. ICES Journal of Marine Science 56: 779-790.
Organofluorines (PFOS) were introduced as a group of contaminants for biota.
Scope for growth and glutathionine transferase were introduced as biological effects for biota. For both, high values indicate healthy organisms. Glutathionine transferase is assessed in exactly the same way as chemical contaminants in biota, except that the lower confidence limit on the fitted value in the last monitoring year is used to assess status. For scope for growth, the annual indices are the median values of the scope for growth measurements in each year (there is no log transformation). This is because scope for growth can be negative (with negative values indicating bad status). The annual indices are then modelled in the same way as chemical contaminant indices, except that the lower confidence limit is used to assess status.
The ERLs for C1-naphthalene, C2-naphthalene, C1-phenanthrene, C2-phenanthrene and C1-dibenzothiophene were not used as it was not possible to find sufficient justification for them in the literature.
Previously, environmental status of imposex levels was assessed using the model fitted to the annual indices. The upper one-sided 95% confidence limit on the fitted value in the most recent monitoring year was compared to the available assessment criteria. However, in many time series, imposex levels have declined so rapidly that the linear models used to assess trends cannot track the change completely. The linear models correctly show evidence of a decline, but over-estimate imposex levels in the final monitoring year suggesting that environmental status is worse than it actually is. To overcome this, an alternative test of status is now used when there are individual measurements in the final monitoring year. A proportional odds model is fitted to the individual measurements and used to place an upper one-sided 95% confidence limit on the annual index in the final monitoring year. This confidence limit is then compared to the available assessment criteria.