The variables in sediment_data.csv describe the contaminant data in sediment used in the 2017 assessment of the UK's Clean Seas Environment Monitoring Programme. The column headers are:
seriesID
Description: timeseries identifier
Unit:
Type: categorical
Levels: 4293
Note: identifies the data (a station / contaminant combination) that were grouped together into a timeseries and modelled to assess status and trends
station
Description: station identifier
Unit:
Type: categorical
Levels: 109
Note: monitoring station – links to station information in sediment_stations.csv
year
Description: monitoring year
Unit:
Type: discrete
Range: 1999, 2016
Note: for some data suppliers, monitoring is in winter and e.g. sampling in December 2015 and January 2016 would be regarded as having come from the same monitoring year
date
Description: sampling date
Unit:
Type: discrete
Range: 1999-01-18, 2016-10-26
Note:
sampleID
Description: sample identifier
Unit:
Type: categorical
Levels: 4053
Note:
matrix
Description: sample matrix
Unit:
Type: categorical
Levels: SED63, SEDTOT
Note: see ICES reference codes for MATRX
group
Description: contaminant group
Unit:
Type: categorical
Levels: BDE, CB, metal, organoMetal, PAH.alkylated, PAH.parent
Note:
BDE = polybrominated diphenyl ethers
CB = polychlorinated biphenyls
organoMetal = tributyltin and derivatives
PAH.alkylated = alkylated polycyclic aromatic hydrocarbons
PAH.parent = parent polycyclic aromatic hydrocarbons
determinand
Description: contaminant
Unit:
Type: categorical
Levels: 49
Note: see ICES reference codes for PARAM; data submitted as CHRTR have been relabelled as CHR
metoa
Description: method of chemical analysis
Unit:
Type: categorical
Levels: 15
Note: see ICES reference codes for METOA
concentration
Description: concentration of contaminant
Unit: mg/kg dw (metals), ug/kg dw (organics)
Type: continuous
Range: 0.00027, 314000
Note: all contaminant concentrations are expressed on a dry weight basis
qflag
Description: less-than qualifier for the concentration measurement
Unit:
Type: categorical
Levels: "", "<"
Note:
“<” indicates a value below the limit of detection
"” indicates a value above the limit of detection
uncertainty
Description: uncertainty in the concentration measurement
Unit: as for concentration
Type: continuous
Range: 0.0000035, 23680
Note: analytical uncertainty expressed as the standard deviation
normConc
Description: normalised concentration of contaminant
Unit: as for concentration
Type: continuous
Range: 0.0047, 473765
Note: the concentration normalised to 5% aluminium (metals) or 2.5% organic carbon (organics); the normalisation process is explained here; some normalised concentrations are ‘missing’ because the normaliser (aluminium or organic carbon) concentration was not reported or because the uncertainty in the normalised concentration was greater than the normalised concentration
normConc.qflag
Description: less-than qualifier for the normalised measurement
Unit:
Type: categorical
Levels: "", "<"
Note: see qflag
normConc.uncertainty
Description: uncertainty in the normalised measurement
Unit: as for concentration
Type: continuous
Range: 0.0000099, 47494
Note: analytical uncertainty expressed as the standard deviation
AL
Description: aluminium concentration
Unit: %
Type: continuous
Range: 0.013, 48.2
Note: all values are above the limit of detection
AL.uncertainty
Description: uncertainty in the aluminium measurement
Unit: %
Type: continuous
Range: 0.0005, 5.49
Note: analytical uncertainty expressed as the standard deviation
CORG
Description: organic carbon concentration
Unit: %
Type: continuous
Range: 0.03, 9.7
Note:
CORG.qflag
Description: less-than qualifier for the organic carbon measurement
Unit:
Type: categorical
Levels: "", "<"
Note: see qflag
CORG.uncertainty
Description: uncertainty in the organic carbon measurement
Unit: %
Type: continuous
Range: 0.001, 17.1
Note: analytical uncertainty expressed as the standard deviation
DRYWT
Description: dry weight of the sample
Unit: %
Type: continuous
Range: 8.33, 94.8
Note: all values are above the limit of detection
DRYWT.uncertainty
Description: uncertainty in the dry weight measurement
Unit: %
Type: continuous
Range: 0.036, 3.35
Note: analytical uncertainty expressed as the standard deviation