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
The data presented here show 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.
Some information is already published: Pollution Inventory, National Atmospheric Emissions Inventory, Persistent Organic Pollutants Multimedia Emissions Inventory (Report CX0115), and National Reports for the Stockholm Convention, Persistent organic pollutants triennial report 2019 to 2021. 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 2022
Table H3a: Emissions of mercury to air, land and water, England, 2016 to 2022
| 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 | 329.37 | 1,215.89 |
| 2022 | 309.75 | 1,244.17 |
Trend description for H3a
In 2022, emissions of mercury from larger industrial sites and crematoria in England totalled 1,554 kg, with larger industrial sites accounting for 80% of this figure.
Assessment of change
Emissions of mercury from crematoria and larger industrial sites decreased (showed an improvement) in the short-term assessment period. Medium- and long-term assessments were not carried out as a suitable time series is not yet available.
Change since 2018 has been assessed. Since 2018 there has been a decrease (improvement) in the emissions of mercury from crematoria and larger industrial sites. However, this is based on only 5 data points so should be considered as indicative and not evidence of a clear trend.
Table H3a: Assessment of change
| Component | Subcomponent | Period | Date range | Percentage change | Smoothing function | Assessment of change |
|---|---|---|---|---|---|---|
| H3a | Crematoria | Short term | 2017 to 2022 | -20.36 | Loess | Improvement |
| H3a | Crematoria | Medium term | N/A | N/A | N/A | Not assessed |
| H3a | Crematoria | Long term | N/A | N/A | N/A | Not assessed |
| H3a | Larger industrial sites | Short term | 2017 to 2022 | -16.68 | Loess | Improvement |
| H3a | Larger industrial sites | Medium term | N/A | N/A | N/A | Not assessed |
| H3a | Larger industrial sites | Long term | N/A | N/A | N/A | Not assessed |
Figure H3b: Emissions of persistent organic pollutants to air, land and water, England, 2000 to 2022
Table H3b: Emissions of persistent organic pollutants to air, land and water, England, 2000 to 2022
| 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 | 85.78 | 97.48 | 88.14 | 71.53 | 94.59 | 85.41 | 85.38 |
| 2002 | 72.83 | 92.42 | 82.93 | 63.96 | 89.43 | 73.21 | 73.02 |
| 2003 | 63.78 | 88.07 | 77.90 | 42.87 | 84.68 | 63.03 | 62.64 |
| 2004 | 55.42 | 87.44 | 98.68 | 38.02 | 80.10 | 54.62 | 53.94 |
| 2005 | 48.89 | 75.65 | 94.30 | 33.83 | 75.74 | 47.21 | 46.44 |
| 2006 | 43.99 | 65.18 | 88.19 | 31.07 | 71.54 | 40.89 | 40.29 |
| 2007 | 39.28 | 58.81 | 75.28 | 28.57 | 67.50 | 35.58 | 34.92 |
| 2008 | 35.12 | 57.09 | 70.42 | 25.88 | 63.71 | 30.79 | 30.20 |
| 2009 | 30.10 | 51.71 | 49.82 | 22.27 | 60.11 | 26.07 | 26.03 |
| 2010 | 27.55 | 51.33 | 47.97 | 21.01 | 56.66 | 22.67 | 23.08 |
| 2011 | 25.23 | 47.56 | 34.30 | 19.22 | 53.37 | 20.20 | 20.59 |
| 2012 | 23.39 | 45.66 | 32.08 | 18.53 | 50.23 | 17.90 | 18.18 |
| 2013 | 21.94 | 45.27 | 26.89 | 19.59 | 47.22 | 16.03 | 16.49 |
| 2014 | 19.87 | 45.58 | 31.26 | 19.82 | 44.32 | 14.39 | 15.70 |
| 2015 | 17.03 | 45.10 | 35.05 | 18.70 | 41.53 | 12.92 | 15.46 |
| 2016 | 13.48 | 43.41 | 41.75 | 17.07 | 38.84 | 11.37 | 15.35 |
| 2017 | 12.34 | 43.30 | 45.34 | 16.66 | 36.24 | 10.39 | 14.85 |
| 2018 | 11.18 | 43.45 | 47.91 | 16.15 | 33.74 | 9.54 | 14.45 |
| 2019 | 10.17 | 42.65 | 46.54 | 15.84 | 31.33 | 8.72 | 14.52 |
| 2020 | 9.33 | 40.79 | 44.57 | 15.79 | 28.99 | 7.82 | 14.88 |
| 2021 | 8.90 | 39.41 | 45.69 | 16.15 | 26.76 | 7.64 | 15.32 |
| 2022 | 7.99 | 42.33 | 45.35 | 15.26 | 24.64 | 7.04 | 15.03 |
Trend description for H3b
Emissions attributed to England for all 7 POPs included within this indicator have fallen between 2000 and 2022.
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 49%, before falling more gradually up until 2022. Emissions post-2010 are largely linked to more diffuse sources such as domestic combustion of solid fossil fuels, accidental fire, and illegal burning of waste. From 2021 to 2022, emissions of dioxins and furans showed a slight uptick from 39% to 42%. This is likely due to industry and society returning to normal rates of activity following the COVID-19 lockdown period in 2020, though this is uncertain, and recent trends should be interpretated with care. Future data will aid interpretation.
By 2013, emissions of hexachlorobenzene had fallen to 27% 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 45% of the baseline in 2022. Emissions of pentachlorophenol have fallen consistently since 2000 to reach 25% of their baseline figure in 2022. 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 8% and 15% of their baseline figures in 2022. 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
Over the medium- and long-term assessment periods, a decrease (improvement) was observed for all emissions of persistent organic pollutants (POPs) to air, land and water covered by the interim H3 indicator - except hexachlorobenzene, which increased (deteriorated) over the medium term.
Over the short-term assessment period, most of the 7 POPs decreased (improved) - except hexachlorobenzene and polychlorinated naphthalenes, which increased (deteriorated).
Change since 2018 has also been assessed. Since 2018, there has been a mixed picture with 4 POPs decreasing (improving), dioxins and furans showing little or no change, and hexachlorobenzene and polychlorinated naphthalenes increasing (deteriorating).
Smoothing is applied across the whole time series in our assessments to account for natural interannual variability. The assessment of these smoothed trends therefore may differ from the percentage changes over the same year ranges for the unsmoothed time series.
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 | 2017 to 2022 | -39.62 | Loess | Improvement |
| H3b | Dioxin-like Polychlorinated Biphenyls | Medium term | 2012 to 2022 | -65.67 | Loess | Improvement |
| H3b | Dioxin-like Polychlorinated Biphenyls | Long term | 2000 to 2022 | -91.88 | Loess | Improvement |
| H3b | Dioxins and Furans | Short term | 2017 to 2022 | -4.15 | Loess | Improvement |
| H3b | Dioxins and Furans | Medium term | 2012 to 2022 | -11.22 | Loess | Improvement |
| H3b | Dioxins and Furans | Long term | 2000 to 2022 | -60.44 | Loess | Improvement |
| H3b | Hexachlorobenzene | Short term | 2017 to 2022 | 26.23 | Loess | Deterioration |
| H3b | Hexachlorobenzene | Medium term | 2012 to 2022 | 43.83 | Loess | Deterioration |
| H3b | Hexachlorobenzene | Long term | 2000 to 2022 | -46.16 | Loess | Improvement |
| H3b | Pentachlorobenzine | Short term | 2017 to 2022 | -9.29 | Loess | Improvement |
| H3b | Pentachlorobenzine | Medium term | 2012 to 2022 | -20.34 | Loess | Improvement |
| H3b | Pentachlorobenzine | Long term | 2000 to 2022 | -83.11 | Loess | Improvement |
| H3b | Pentachlorophenol | Short term | 2017 to 2022 | -31.86 | Loess | Improvement |
| H3b | Pentachlorophenol | Medium term | 2012 to 2022 | -50.87 | Loess | Improvement |
| H3b | Pentachlorophenol | Long term | 2000 to 2022 | -75.29 | Loess | Improvement |
| H3b | Polychlorinated Biphenyls | Short term | 2017 to 2022 | -28.48 | Loess | Improvement |
| H3b | Polychlorinated Biphenyls | Medium term | 2012 to 2022 | -58.79 | Loess | Improvement |
| H3b | Polychlorinated Biphenyls | Long term | 2000 to 2022 | -92.53 | Loess | Improvement |
| H3b | Polychlorinated Naphthalenes | Short term | 2017 to 2022 | 10.46 | Loess | Deterioration |
| H3b | Polychlorinated Naphthalenes | Medium term | 2012 to 2022 | -13.82 | Loess | Improvement |
| H3b | Polychlorinated Naphthalenes | Long term | 2000 to 2022 | -83.89 | Loess | Improvement |
Note that assessment categories for the short, medium and long term were assigned based on smoothed data, so percentage change figures in Tables H3bi to H3bvii may differ from unsmoothed values quoted elsewhere. Percentage change refers to the difference seen from the first to last year in the specified date range.