Critical loads

of lead, cadmium and mercury

Gudrun Schuetze

German Federal Environment Agency

gudrun.schuetze@uba.de

CL can be directly compared to deposition rates (but also other input rates)

CL aim at avoidance of any harmful effect to human health and the environment in the long-term perspective (= "sustainability")

CL are derived for receptor areas considering their specific sensitivity against metal inputs. CL maps can be produced.

Why Critical Loads of heavy metals ?

Effects of Pb, Cd, Hg and indicators used in the calculation of critical limits and critical loads

Effect-no.

Effects (indicators) Ecosystems Metals

1 Human health effects (ground water quality in view of use for drinking water supply)

Terrestrial ecosystems

Pb, Cd, Hg

2 Human health effects (food quality)

Terrestrial ecosystems

(arable land only) Cd

3 Ecotoxicological effects Terrestrial ecosystems

Pb, Cd, Hg

4 Ecotoxicological effects Fresh water ecosystems

Pb, Cd

5 Human health effects (food quality)

Fresh water ecosystems

Hg1) 1) Effect 5 is not evaluated by a critical load, but by the critical concentration of Hg in precipitation.

where:

CL(M) = critical load of a heavy metal M (g ha-1 a-1)

Mu = uptake of M in harvestable parts of plants (g ha-1 a-1)

Mle(crit) = critical leaching of M from the considered soil layer (g ha-1 a-1).

CL(M) = Mu + Mle(crit)

CL(M) = Mu + Mle(crit)

Overview on necessary input data:

Land cover (spatial information)

Forest type and increment

Agricultural crops and yields

Metal contents in harvestable parts of plants (Manual / other literature)

Precipitation surplus = Precipitation - Evapotranspiration (National Weather Service)

Soil properties(National Soil Map)

Critical limits Pb, Cd, Hg (Model WHAM W6-MTC, Manual )

5th percentile CL(Cd) to protecthuman health (g ha-1 a-1)

5th percentile CL(Pb) to protecthuman health(g ha-1 a-1)

5th percentile CL(Hg) to protecthuman health(g ha-1 a-1)

5th percentile CL(Cd) to protectEcosystems(g ha-1 a-1)

5th percentile CL(Pb) to protectEcosystems(g ha-1 a-1)

5th percentile CL(Hg) to protectEcosystems(g ha-1 a-1)

Source: CCE SR2005pp. 23 CCE call

for CL(M) data 2005

Areas at risk of health or ecosystem effects in 2000 based on Official Emission data incl. TNO adjustments

Between brackets: Areas at risk based on official 2000 emission data as published in the CCE SR2005 and the TFHM-S&E

Source: CCE

% area at risk ofHealth effects

% area at risk ofEcosystem effects

  Cd Pb Hg Cd Pb Hg

EU25 0.03

(0.1)

24.32

(8.1)

2.4

(3.9)

0.02

(0.0)

48.64

(7.4)

85.75

(51.2)

Europe 0.83

(0.8)

16.65

(8.3)

2.4

(3.9)

0.07

(0.1)

53.44

(28.7)

85.34

(51.0)

Scientific input to the

review of the

Sufficiency and

Effectiveness

of the CLRTAP's

1998 Protocol

on Heavy Metals

Download from the homepage of the Task Force on HM:

http://www.unece.org/env/lrtap/TaskForce/tfhm/Post-Ottawa.htm

Uncertainties in Exceedance calculations are mainly due to uncertainties in emission data.

Conclusion of the Taks Force on Heavy Metals

acting under the Working Group on Strategies and Review

TF chairman's report → ECE.EB.AIR/WG.5/2006/2.

Taking this into account and the fact that Integrated Assessment Models are not available for HM, performing scenario analyses would be a reasonable option for the use of CL(M) data,

Scenario analysis in Europe:

Exceedances of Critical Loads to both public and environmental health

by Cd, Pb and Hg depositions in2000 compared to emission scenarios for 2020

Hettelingh and Sliggers (2006):

Heavy Metal Emissions, Depositions, Critical Loads and Exceedances in Europe, Ministry of the Environment VROM DGM,

Netherlands

including Pb, Cd, Hg,

but also preliminary results on

Cu, Ni, Zn, As, Cr, Se

Download: www.mnp.nl/cce - publications

Exceedance by lead (Pb) depositionIn 2000 and 2020-FIAM

% area at risk in 2000:EMEP region: 42 %EU25: 42 %

% area at risk in 2020-FIAM:EMEP region: 19 %EU25: 27 %

Source: Hettelingh and Sliggers (2006):Heavy Metal Emissions, Depositions, Critical Loads and Exceedances in Europe, Ministry of the Environment VROM DGM, NL

Exceedance by mercury (Hg) depositionIn 2000 and 2020-FIAM

% area at risk:EMEP region: 77 %EU25: 68 %

% area at risk:EMEP region: 74 %EU25: 61 %

Source: Hettelingh and Sliggers (2006):Heavy Metal Emissions, Depositions, Critical Loads and Exceedances in Europe, Ministry of the Environment VROM DGM, NL

Tentative results in 2000 and

in 2020 following CLE, FI and FIAM scenarios

Scenario Percentage of area in Europe at risk caused by exceedance of critical loads of the following heavy metals:

Cr Ni Cu Zn As Se

2000 0.07 0.71 0.76 1.66 0 2.41

2020-CLE 0.08 0.40 0.44 1.06 0 1.09

2020-FI 0.01 0.21 0.34 1.06 0 0.94

2020-FIAM

0.01 0.03 0.25 1.06 0 0.33

Source: Hettelingh and Sliggers (2006):Heavy Metal Emissions, Depositions, Critical Loads and Exceedances in Europe, Ministry of the Environment VROM DGM, NL

If you would like to learn more about

Critical Loads of Pb, Cd, Hg

please have a look to the

Modelling and Mapping Manual

(available in Russian)

www.icpmapping.org

or contact

gudrun schuetze@uba.de