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 published here as a final indicator for the first time in 2024. The data are presented here showing 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 a double update of the data for the H3b indicator this year as we have been awaiting new data from the UK POPs Multi Media Emission Inventory that was not yet available in the previous update.
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 2021
Table H3a: Emissions of mercury to air, land and water, England, 2016 to 2021
| Year | Crematoria | Larger industrial sites |
|---|---|---|
| 2016 | 410.31 | 1,409.31 |
| 2017 | 384.44 | 1,346.66 |
| 2018 | 361.87 | 1,649.88 |
| 2019 | 337.19 | 1,129.26 |
| 2020 | 368.05 | 1,110.63 |
| 2021 | 360.78 | 1,215.89 |
Trend description for H3a
In 2021, emissions of mercury from larger industrial sites and crematoria in England totalled 1,576 kg, with larger industrial sites accounting for 77% 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.
Change since 2018 has been assessed, since 2018 there has been a decrease (improvement) in the emissions of mercury from larger industrial sites, while emissions from crematoria have shown little to no change. However, this is based on only 4 data points so should be considered as indicative and not evidence of a clear trend.
Figure H3b: Emissions of persistent organic pollutants to air, land and water, England, 2000 to 2021
Table H3b: Emissions of persistent organic pollutants to air, land and water, England, 2000 to 2021
| 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 | 88.11 | 97.42 | 87.96 | 72.70 | 94.59 | 88.76 | 89.42 |
| 2002 | 77.00 | 92.45 | 82.78 | 67.14 | 89.43 | 79.39 | 80.50 |
| 2003 | 69.57 | 88.08 | 77.64 | 46.82 | 84.68 | 71.57 | 73.04 |
| 2004 | 62.62 | 87.33 | 98.60 | 43.43 | 80.10 | 65.17 | 66.80 |
| 2005 | 58.17 | 75.83 | 94.16 | 40.45 | 75.74 | 60.37 | 61.35 |
| 2006 | 53.59 | 65.45 | 87.92 | 38.74 | 71.54 | 54.46 | 56.96 |
| 2007 | 49.67 | 59.07 | 74.99 | 37.11 | 67.50 | 50.30 | 53.02 |
| 2008 | 46.24 | 57.38 | 70.18 | 35.24 | 63.71 | 46.42 | 49.45 |
| 2009 | 41.45 | 52.07 | 49.55 | 31.91 | 60.11 | 42.42 | 46.18 |
| 2010 | 33.78 | 51.89 | 47.65 | 31.09 | 56.66 | 39.65 | 44.11 |
| 2011 | 37.52 | 48.23 | 33.88 | 29.81 | 53.37 | 37.68 | 42.34 |
| 2012 | 36.08 | 46.23 | 31.43 | 29.60 | 50.23 | 35.78 | 40.47 |
| 2013 | 34.46 | 45.78 | 26.25 | 31.05 | 47.20 | 34.25 | 39.29 |
| 2014 | 32.55 | 45.85 | 30.84 | 31.65 | 44.30 | 32.88 | 39.05 |
| 2015 | 29.62 | 44.83 | 34.76 | 30.44 | 41.50 | 31.62 | 39.37 |
| 2016 | 25.95 | 43.31 | 41.81 | 28.95 | 38.81 | 30.23 | 39.74 |
| 2017 | 24.94 | 43.09 | 45.50 | 28.68 | 36.20 | 29.37 | 39.64 |
| 2018 | 23.93 | 43.09 | 48.06 | 28.36 | 33.70 | 28.69 | 39.46 |
| 2019 | 23.00 | 42.11 | 46.74 | 28.20 | 31.28 | 27.98 | 39.87 |
| 2020 | 22.26 | 40.32 | 43.81 | 28.30 | 28.95 | 27.20 | 40.55 |
| 2021 | 21.67 | 38.86 | 41.75 | 28.63 | 26.74 | 26.84 | 40.83 |
Trend description for H3b
Emissions attributed to England for all 7 POPs included within this indicator have fallen between 2000 and 2021.
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 48% 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 26% of their 2000 baseline figure but they have risen since then to reach 48% of the baseline by 2018. 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, as such a decrease has been observed down to 42% in the most recent datapoint. Emissions of pentachlorophenol have fallen consistently since 2000 to reach 27% of their baseline figure in 2021. 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 22% and 41% of their baseline figures in 2021. 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, for hexachlorobenzene and polychlorinated Naphthalenes a deteroration (increase) is shown over the short term, with Hexachlorobenzene also showing little to no change over the medium term.
Change since 2018 has also been assessed. Since 2018, there has been a mixed picture with 5 POPs decreasing, Pentachlorobenzine showing little or no change, and Polychlorinated Naphthalenes increasing.
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 | 2015 to 2020 | -24.76 | Loess | Improvement |
| H3b | Dioxin-like Polychlorinated Biphenyls | Medium term | 2010 to 2020 | -43.36 | Loess | Improvement |
| H3b | Dioxin-like Polychlorinated Biphenyls | Long term | 2000 to 2020 | -77.45 | Loess | Improvement |
| H3b | Dioxins and Furans | Short term | 2015 to 2020 | -8.53 | Loess | Improvement |
| H3b | Dioxins and Furans | Medium term | 2010 to 2020 | -19.19 | Loess | Improvement |
| H3b | Dioxins and Furans | Long term | 2000 to 2020 | -60.82 | Loess | Improvement |
| H3b | Hexachlorobenzene | Short term | 2015 to 2020 | 32.82 | Loess | Deterioration |
| H3b | Hexachlorobenzene | Medium term | 2010 to 2020 | 0.28 | Loess | Little or no change |
| H3b | Hexachlorobenzene | Long term | 2000 to 2020 | -49.68 | Loess | Improvement |
| H3b | Pentachlorobenzine | Short term | 2015 to 2020 | -4.40 | Loess | Improvement |
| H3b | Pentachlorobenzine | Medium term | 2010 to 2020 | -10.27 | Loess | Improvement |
| H3b | Pentachlorobenzine | Long term | 2000 to 2020 | -69.12 | Loess | Improvement |
| H3b | Pentachlorophenol | Short term | 2015 to 2020 | -30.16 | Loess | Improvement |
| H3b | Pentachlorophenol | Medium term | 2010 to 2020 | -48.88 | Loess | Improvement |
| H3b | Pentachlorophenol | Long term | 2000 to 2020 | -70.99 | Loess | Improvement |
| H3b | Polychlorinated Biphenyls | Short term | 2015 to 2020 | -12.91 | Loess | Improvement |
| H3b | Polychlorinated Biphenyls | Medium term | 2010 to 2020 | -31.72 | Loess | Improvement |
| H3b | Polychlorinated Biphenyls | Long term | 2000 to 2020 | -72.26 | Loess | Improvement |
| H3b | Polychlorinated Naphthalenes | Short term | 2015 to 2020 | 3.78 | Loess | Deterioration |
| H3b | Polychlorinated Naphthalenes | Medium term | 2010 to 2020 | -8.02 | Loess | Improvement |
| H3b | Polychlorinated Naphthalenes | Long term | 2000 to 2020 | -59.02 | 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.