Model assessment of heavy metal pollution from global to local scales Thematic session 10(c) Model assessment of heavy metal pollution from global to local scales Oleg Travnikov 1

Atmospheric dispersion of heavy metals Properties of heavy metals Property Pb, Cd Hg Atmospheric forms Pbpart, Cdpart Hg0gas, HgIIgas, HgIIpart Atmospheric chemistry not important important Lifetime vs. deposition weeks days-months Geographical scope of pollution regional global-local Accumulation in media significant Secondary emissions (probably) Heavy metal atmospheric transport Pbpart Cdpart Pbpart Cdpart

Atmospheric dispersion of heavy metals Properties of heavy metals Property Pb, Cd Hg Atmospheric forms Pbpart, Cdpart Hg0gas, HgIIgas, HgIIpart Atmospheric chemistry not important important Lifetime vs. deposition weeks days-months Geographical scope of pollution regional global-local Accumulation in media significant Secondary emissions (probably) Heavy metal atmospheric transport HgII gas part Hg0 Hg0 Hg

Multi-model assessment of Hg pollution on a global scale What is known: Spatial patterns Multi-model assessment of Hg pollution on a global scale Air concentration of Hg0 (2015) Hg wet deposition (2015) Model, g/km2/y 1 10 40 Observed, g/km2/y 0.6 2 3 Model, ng/m3 Observed, ng/m3 UN Environment Global Mercury Assessment 2018

Operational model assessment of Hg, Pb, and Cd pollution within EMEP Spatial patterns: Regional scale Operational model assessment of Hg, Pb, and Cd pollution within EMEP Pb in air Hg0 concentration in air Cd in air Output information: Concentration and deposition pattern Source apportionment of deposition Ecosystem-specific deposition

Ecosystem-specific deposition of HMs for evaluation of adverse effects Spatial patterns: Regional scale Ecosystem-specific deposition of HMs for evaluation of adverse effects Hg deposition to forests (2016) Hg deposition inland waters (2016) Harmonization of the land cover data is required within the Convention to avoid inconsistencies in data products

Importance of fine resolution Deposition of Cd within region 2010 Exceedance of critical loads of Cd in 2010 Cd deposition in Central Europe Czech Republic Poland Germany Austria Slovakia Deposition flux Distance Grid cell Detailed and reliable input data are critical for improvement of modelling results with fine spatial resolution Critical loads Deposition

Model assessment of long-term changes of HM pollution What is known: Temporal trends Model assessment of long-term changes of HM pollution Long-term changes of HM deposition Reduction of HM deposition -20 20 40 60 80 100 Pb Cd Hg Overall redcution (1990-2012), % EMEP EU28 EECCA 10 20 30 40 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 Pb deposition, kg/km2/y 0.6 1.2 1.8 2.4 Cd and Hg deposition, g/km2/y Cd Hg Pb

Evaluation of modelling results vs. measurements in mosses What is known: Temporal trends Evaluation of modelling results vs. measurements in mosses Measurement of HM in mosses 0.0 0.1 0.2 0.3 1990 1995 2000 2005 2010 Conc. in mosses, mg/kg 15 30 45 Total deposition, g/km 2 /y Conc. in moss Deposition flux Cd 3 6 9 12 0.6 1.2 1.8 2.4 Total deposition, kg/km Pb

Mercury oxidation and reduction chemistry in the atmosphere Gaps in knowledge : Hg chemistry Mercury oxidation and reduction chemistry in the atmosphere Measurements ECHMERIT GLEMOS GEM-MACH-Hg GEOS-Chem 20 40 60 80 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Wet deposition, ng/m2/day Hg0 + Br Hg0 + O3 Hg0 + OH Hg wet deposition in Europe Travnikov et al. (2017) Hg atmospheric chemistry Br O3 OH NO2 HO2 BrO Cl ClO Br2 HgII gas part Hg0 gas hn (?)

Mercury emissions from legacy and natural sources Gaps in knowledge: Secondary emissions Mercury emissions from legacy and natural sources Source apportionment of Hg deposition (2015) Hg deposition to Europe Direct anthrop. sources (33%) Legacy & natural sources (67%) g/km2/y 5 10 15 20 25 30 35 - legacy and natural sources Available estimates of Hg emission from secondary (re-emission) and natural sources are still very uncertain UN Environment Global Mercury Assessment 2018

Wind re-suspension of particulate heavy metals (Pb, Cd) Gaps in knowledge: Secondary sources Wind re-suspension of particulate heavy metals (Pb, Cd) Wind erosion and dust suspension from arable soils Anthrop. emission and re-suspension of Pb in Europe (1990-2015) Relative contribution of wind re-suspension to total emissions could increase significantly due to strong reduction of direct emissions

Heavy metal accumulation in soil Gaps in knowledge: Accumulation Heavy metal accumulation in soil Pb air concentration Aneboda Gårdsjön Gammtratten Kindla ICP IM sites: mg/kg dw 1980 1990 2000 2010 40 60 80 100 FH 0-5 cm 5-20 cm Pb in soil (Sweden) 1990 1995 2000 2005 2010 3 6 9 12 Conc. in mosses, mg/kg Pb concentration in moss

Mercury bioaccumulation in aquatic environment Gaps in knowledge: Accumulation Mercury bioaccumulation in aquatic environment Hg general cycle in aquatic ecosystems © USGS (ICP Waters report 132/2017) Hg concentration in fish >0.5 mg/kg in 40% of lakes

Evaluation of adverse effects of Hg on ecosystems and human health Gaps in knowledge: Exposure assessment Evaluation of adverse effects of Hg on ecosystems and human health Exceedance of critical loads of Hg (2010) Human exposure via fish consumption © USGS How to establish the proper link between atmospheric deposition and human/ecosystem exposure?

Summary Current status: Monitoring and modelling tools provide acceptable estimates of HM dispersion in the atmosphere, spatial patterns and temporal trends of pollution levels Scientific gaps: Uncertainties in Hg atmospheric chemistry Poorly known process of HM accumulation in soil, water etc. Uncertain estimates of secondary emissions (re-emission, re-suspension) The link between atmospheric deposition and human/ecosystem exposure

Summary Scientific needs: Complex monitoring of HMs in different media (atmosphere, soil, water) to study accumulation and long-term changes Development of multi-media modelling approach for assessment of HM dispersion and cycling (Hg) Development of methods for assessment of HM exposure and adverse effects (critical loads, dynamical modelling etc.)