H3: Emissions of mercury and persistent organic pollutants to the environment

Short Description

This indicator shows changes in emissions of mercury and persistent organic pollutants (POPs) to air, land, and water from measured, calculated, and modelled sources.

Mercury is toxic, causes damage to human health and accumulates in the environment and the food chain. For mercury, which is covered by the Minamata Convention, combustion sources are particularly significant, and information on emissions is provided annually by larger industrial sites. Other major sources of mercury to air will be gathered from different data sources.

POPs are chemicals that are extremely persistent in the environment, become widely distributed geographically, are able to accumulate in the tissues of humans and wildlife, and have harmful impacts on human health and the environment. POPs within this indicator refers to pollutants listed under Annex C (unintentional produced) of the Stockholm Convention. The Convention covers a range of substances spanning industrial uses, pesticides, and unintentionally produced substances.

Readiness and links to data

This indicator is not available for reporting in a final format in 2023 as further development is required to bring data together from a number of different sources. A revised interim indicator is presented here that shows annual England-level emissions of (a) mercury from larger industrial sites and crematoria, and (b) 7 unintentionally produced POP substances (as listed in the Stockholm Convention Annex C): polychlorinated biphenyls; dioxin-like polychlorinated biphenyls; dioxins and furans; hexachlorobenzene; polychlorinated naphthalenes; pentachlorophenol; and pentachlorobenzene from a wide range of sources to air, land, and water. These POPs data are a disaggregation of the annual UK-level data previously presented in this indicator. There is no update for the H3b indicator this year as we have been awaiting new data from the UK POPs Multi Media Emission Inventory. There will be an update covering 2 years produced for the next issue of this report.

Some information is already published: Pollution Inventory, National Atmospheric Emissions Inventory, Persistent Organic Pollutants Multimedia Emissions Inventory, and National Reports for the Stockholm Convention. Population estimates used to apportion some UK emissions of POPs at an England level are also published annually.

For further information on the methodology used to produce this indicator email chemicalrestrictions@environment-agency.gov.uk.

Indicator components

Figure H3a: Emissions of mercury to air, land and water, England, 2016 to 2020

Table H3a: Emissions of mercury to air, land and water, England, 2016 to 2020

Year Crematoria Larger industrial sites
2016 410.31 1,409.31
2017 384.44 1,346.66
2018 362.17 1,649.88
2019 337.19 1,295.26
2020 368.01 1,110.63

Trend description for H3a

In 2020, emissions of mercury from larger industrial sites and crematoria in England totalled 1,478 kg, with larger industrial sites accounting for 75% of this figure.

Assessment of change

No assessment of change was undertaken for this component as a suitable time series is not yet available in the Outcome Indicator Framework.

Figure H3b: Emissions of persistent organic pollutants to air, land and water, England, 2000 to 2019

Table H3b: Emissions of persistent organic pollutants to air, land and water, England, 2000 to 2019

Year Dioxin-like Polychlorinated Biphenyls Dioxins and Furans Hexachlorobenzene Pentachlorobenzine Pentachlorophenol Polychlorinated Biphenyls Polychlorinated Naphthalenes
2000 100.00 100.00 100.00 100.00 100.00 100.00 100.00
2001 83.70 97.90 87.97 73.20 94.59 83.55 83.22
2002 69.41 92.53 82.78 62.92 89.43 70.25 69.59
2003 59.26 88.26 77.66 43.95 84.68 59.41 58.59
2004 50.50 87.53 98.64 37.51 80.10 50.85 49.73
2005 43.70 76.82 94.28 32.37 75.74 43.57 42.38
2006 38.73 66.84 87.95 28.65 71.54 37.47 36.63
2007 34.15 61.02 75.17 25.39 67.50 32.56 31.77
2008 30.46 60.14 70.40 23.15 63.71 28.30 27.64
2009 26.15 55.08 49.78 20.03 60.11 24.19 24.09
2010 24.18 56.63 47.90 18.74 56.66 21.41 21.81
2011 22.14 52.23 34.17 17.10 53.37 19.43 19.99
2012 20.94 51.14 31.84 16.83 50.23 17.63 18.18
2013 20.42 51.20 26.72 18.28 47.20 16.23 17.08
2014 19.01 50.12 31.24 18.37 44.30 15.00 16.91
2015 16.54 49.88 35.14 17.29 41.50 13.91 17.28
2016 13.27 48.49 42.30 15.39 38.81 12.73 17.72
2017 12.14 48.26 45.86 14.42 36.20 12.03 17.75
2018 11.40 48.56 48.49 14.18 33.70 11.48 17.78
2019 10.74 47.89 51.50 14.07 31.28 10.91 18.26

Trend description for H3b

Emissions attributed to England for all 7 POPs included within this indicator have fallen between 2000 and 2019.

Dioxins and furans are a family of chemicals strongly associated with thermal processes linked to combustion (particularly of waste) and manufacture of metals. Their emissions were already reduced by over 60% between 1990 and 2000, with improvements in technology and tighter environmental regulations contributing to this fall. Between 2000 and 2010, emissions of dioxins and furans fell by a further 43% but have since levelled out, with emissions post-2010 largely linked to more diffuse sources such as domestic combustion of solid fossil fuels, accidental fire, and illegal burning of waste.

By 2013, emissions of hexachlorobenzene had fallen to 27% of their 2000 baseline figure but they have risen annually since then to reach 52% of emissions in 2000. This is linked to waste incineration and the increasing use of a specific pesticide (chlorothalonil) for which it is a by-product. Since 2019, Chlorothalonil is no longer an approved active substance in Great Britain, so use will decline. Emissions of pentachlorophenol have fallen consistently since 2000 to reach 31% of their baseline figure in 2019. Emissions of the remaining 4 POPs have followed a very similar pattern to each other, falling sharply in the first 10 years and then levelling out to between 11% and 18% of their baseline figures in 2019. In particular for polychlorinated biphenyls and dioxin-like polychlorinated biphenyls, this relates to remaining final in-use stocks of heat-transfer fluids in di-electric equipment in the energy transmission networks.

Assessment of change

A decrease (or improvement) was observed for all emissions of persistent organic pollutants (POPs) to air land and water covered by the interim H3 indicator, over the medium and long term. Most POPs also decrease over the short term; however, there was an increase (deterioration) in hexachlorobenzene.

Change since 2018 has also been assessed. Since 2018, there has been a mixed picture with 3 POPs decreasing, 3 showing little or no change, and hexachlorobenzene increasing. However, this is based on only 2 data points so should be considered as indicative and not evidence of a clear trend.

Further information on this assessment, along with details on the methodology, is provided in the Assessment background. Summaries by 25 Year Environment Plan goal and information on indicator links are presented in the Assessment results.

Table H3b: Assessment of change

Component Subcomponent Period Date range Percentage change Smoothing function Assessment of change
H3b Dioxin-like Polychlorinated Biphenyls Short term 2013 to 2018 -40.32 Loess Improvement
H3b Dioxin-like Polychlorinated Biphenyls Medium term 2008 to 2018 -61.44 Loess Improvement
H3b Dioxin-like Polychlorinated Biphenyls Long term 2000 to 2018 -88.21 Loess Improvement
H3b Dioxins and Furans Short term 2013 to 2018 -5.00 Loess Improvement
H3b Dioxins and Furans Medium term 2008 to 2018 -19.16 Loess Improvement
H3b Dioxins and Furans Long term 2000 to 2018 -53.14 Loess Improvement
H3b Hexachlorobenzene Short term 2013 to 2018 57.22 Loess Deterioration
H3b Hexachlorobenzene Medium term 2008 to 2018 -27.94 Loess Improvement
H3b Hexachlorobenzene Long term 2000 to 2018 -46.42 Loess Improvement
H3b Pentachlorobenzine Short term 2013 to 2018 -15.47 Loess Improvement
H3b Pentachlorobenzine Medium term 2008 to 2018 -34.17 Loess Improvement
H3b Pentachlorobenzine Long term 2000 to 2018 -84.58 Loess Improvement
H3b Pentachlorophenol Short term 2013 to 2018 -28.59 Loess Improvement
H3b Pentachlorophenol Medium term 2008 to 2018 -47.13 Loess Improvement
H3b Pentachlorophenol Long term 2000 to 2018 -66.26 Loess Improvement
H3b Polychlorinated Biphenyls Short term 2013 to 2018 -28.30 Loess Improvement
H3b Polychlorinated Biphenyls Medium term 2008 to 2018 -59.10 Loess Improvement
H3b Polychlorinated Biphenyls Long term 2000 to 2018 -88.30 Loess Improvement
H3b Polychlorinated Naphthalenes Short term 2013 to 2018 2.69 Loess Little or no change
H3b Polychlorinated Naphthalenes Medium term 2008 to 2018 -34.87 Loess Improvement
H3b Polychlorinated Naphthalenes Long term 2000 to 2018 -81.71 Loess Improvement

Note that assessment categories for the short, medium and long term were assigned based on smoothed data, so percent change figures in Tables H3bi to H3bvii may differ from unsmoothed values quoted elsewhere. Percent change refers to the difference seen from the first to last year in the specified date range.

Indicator Metadata