The extent to which a satisfactory basis exists for the application of an effects-

based approach for Pb, Cd, Hg

Report of the Working Group on Effects

H.-D Gregor

Main advantages of the critical load approach in the framework of the CLRTAP:

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.

There are different effects-based approaches, one of them is the critical load approach.

End of 1980s:

Because of rising concern about possible harmful accumulation of metals in the environment due to LRTAP the idea arose to adapt the CL approach for application for heavy metals

The critical load approach has been successfully applied for policies to reduce acidification and eutrophication.

1994: 2. Sulfur Protocol27 Parties

15 countries delivered national CL data

1999: Gothenburg Protocol20 Parties

24 countries delivered national CL data

CL(M) History:

1989: Sweden WS

1994: ESQUAD Study published

1996: First draft Manuals published (NL)

1997: Workshop Bad Harzburg

1998: Revised Manuals

1999: Workshop Schwerin

2000: Ad-hoc Expert Group on critical limits, Bratislava

2001: Mapping guidance

2001: Expert Panel on HM established

2001/2: voluntary call for CL(M) data

2002: Berlin WS

2003: Expert Panel meeting

2004: WS Potsdam

2004: HM chapter of the M&M Manual

2004: call for data

2006: Expert Panel meeting

CL(M) updates

A CL(M) approach was developed in a 16 years process (1990 - 2006) of discussion and sophistication.

The Arhus Protocol on HM (1998), Article 6g encourages its Parties to develop an effects-based approach...

The Arhus Protocol on HM (1998), Article 6g

"... which integrates appropriate information ... on modelled or measured environmental levels, pathways, and effects on human health and the environment, for the purpose of formulating future optimised control strategies..."

LRTAP contributes a considerable portion of the load.

Cd input and output at DE01 Pb input and output at FI03

Hg input and output at SE04

Metal accumulation in catchments monitored by ICP Integrated Monitoring (EB.AIR/WG.1/2006/9)

Cd accumulation in agricultural soils, P supplied with "low-Cd" fertilizer(TF Health 2006 update - draft)

+ 0.03 % + 0.05 %

Metals further accumulate in agricultural and forest soils and in whole catchments,

Human health pathways and effects:

Air - soil - groundwater - drinking water (Pb, Cd, Hg - WHO 2004)

Air - soil - food (Cd - De Vries et al. 2005)

Air - precipitation - catchment - fish (Hg - WHO/FAO 2003)

Ecotoxicological pathways and effects:

Air - soil - plants, invertebrates, microbiota

Pb, Cd: critical limit function for free metal ions (Lofts et al. 2003)

Hg: critical limits related to the Hg concentration in soil organic matter (Meili et al. 2003)

The current CL methodology:

CL(M) = Mu + Mle(crit)

where: CL(M) = critical load of a heavy metal M (g ha-1 a-1) Mu = metal net uptake in harvestable parts of plants under critical load conditions (g ha-1 a-1) Mle(crit) = critical leaching flux of heavy metal M from the considered soil layer (g ha-1 a-1), whereby only the vertical drainage flux is considered

Laboratory experiments and field tests (Hg) on effects on plants, microbiota

Some selected results:

Metal Species/group Effect (reduction/inhibition)

value [mg/kg]

Endpoint Reference

Cd Hordeum vulgare root growth 5.0 NOEC Aery and Jagetiya (1997)

Lycospermium esculentum

growth 3.2 NOEC Adema and Henzen (1989)

Triticum aestivum growth 0.9 NOEL Reber (1989

Microbiota Fe(III) reduction 1.0 EC10 Welp (1987)

Pb Allium cepa growth 25.0 NOEC Lighthart et al. (1983)

Fosomia candida reproduction 400.0 NOEC Sandifer and Hopkin (1996)

Microbiota substrate induced respiration 89.0 EC10 Saviozzi et al. (1997)

Microbiota urease activity 80.0 EC10 Doelmanm and Hanstra (1986)

Hg Microbiota Fe(III)reduction 2.0 LOEC Zelles et al. (1989)

Microbiota C-mineralisation 0.3 LOEC Bringmark and Bringmark (2001)

Ecotoxicological effects:

log[M]free,sdw = a + b∙log[OM]s +c∙pHsdw + m∙log[M]re [M]free,sdw = the free metal ion concentration (mol l-1) [M]re = the reactive metal content in the solid phase (mol g-1) [OM]s = organic matter (%) pHsdw = soil drainage water pH Table A1.4: Values for the regression coefficients for the free ion concentration – reactive metal content relationship (Eq.A1.4) and statistical measures R2 and se(Y) based on results of studies carried out in Canada, the Netherlands and the UK. Values in brackets are the standard errors for the coefficients. Metal a b c m R2 se(Y) ([OM])s (pHsdw) (log[M]re) Cd -0.08 (0.65) -0.60 (0.08) -0.53 (0.03) 0.60 (0.06) 0.624 0.53 Pb 4.32 (0.49) -0.69 (0.07) -1.02 (0.03) 1.05 (0.06) 0.854 0.60

Human health effects(Results from EB.AIR/WG.1/2006/12):

Hg effects:neurotoxic effects, unborn children are most susceptible group, exposed mainly due to fish consumption of the mother.

In some populations consuming large amounts of fish, or contaminated fish, harzardous levels may be reached. Decreasing the Hg concentration in fish should be treated as a high priority.

Pb effects: impairment of neurodevelopment in children - even at blood

concentrations below 100 µg/lThere may be no threshold for the effects.

In the long term the rise of lead levels in soils is a matter of concern and should be avoided.

Cd effects: increased protein excretion as result of tubular cell damage,increased risk of osteoporosis

Safety margin between present daily intake and effects thresholds small or not existing (sensitive parts of population)

effects presentlypossible!

effects presently possible!

The CL(M) methodology takes the most recently available state of knowledge into account.

Expert Panel on Heavy Metals (under ICP M&M), January 2006 (Minutes)3 a) The Expert Panel supports the practice to start effects-based approaches for HM by calculating critical loads and their exceedances and to use the results in policy. Dynamic models are more complex and should be used as a complement.

The 24 WGE (2005), later confirmed by EB.AIR/WG.1/2005/87, No 19 (g):44. (d) Took note of ICP Modelling and Mapping analyses of critical loads of heavy metals (EB.AIR/WG.1/2005/10/Add.1) and recommended that the results be used in work under the Convention.

The 23 WGE (2004), later confirmed by EB.AIR/WG.1/2005/83, No 20 (i):33. (c) Took note of the recent developments and the report of the ICP M&M workshop on critical loads of heavy metals (EB.AIR/WG.1/2004/10/ Add.1) concluding that effects-based approaches for heavy metals were sound and recommending the results for use in work under the Convention.

Potsdam 2004 (Minutes):10. During the discussion it was stressed that uncertainties in input data or parts of the models do not question the scientific soundness and applicability of the critical loads approach for heavy metals as a whole.

The CL(M) methodology is applicable (at least) in the entire EMEP domain

CL maps for whole Europe can be produced based on a background database (forests) for Europe

2004/2006 18 countries delivered data for critical loads (Pb, Cd, Hg) or critical Hg concentrations in precipitation, respectively

Cd Pb

Hg

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

Taking this into account and the fact that IAM are not available for HM, performing scenario analyses would be a reasonable option for the use of CL(M) data, see ECE.EB.AIR/WG.5/2006/2, No 75.

The 25 WGE (2006), paragraph 41.:

(c) took note of ICP Modelling and Mapping's new critical loads for heavy metals (EB.AIR/WG.1/2006/10) and recommended that the results be used in work under the Convention

(d) Approved the update of critical loads on heavy metals (EB.AIR/ WG.1/2006/10); confirmed again the underlying methodology was scientifically sound and formed a satisfactory basis for the application of an effects-based approach as described in EB.AIR/WG.5/2006/2 para 75. It noted that uncertainties in critical loads exceedance calculations were mainly found in emissions data. It recommended that the results be used in work under the Convention , in particular in the review of the Protocol on Heavy Metals and entrusted its Chairman to include these conclusions in his report to the thirty eight session of the WGSR.

PbHg

Thank you!

CdHg

PbThank You!

Results from the Working Group on Effects:

Recent/current ICP activities concerning heavy metals:

ICP Forests, HM in Forest soils (eg For.Cond.Rep.) Pb, Cd, Zn, Cu, Fe, Cr, Ni, Mn

ICP Waters, Heavy Metals in Surface Waters Pb, Cd, Zn, others

ICP Vegetation/ Pb, Cd, Cu, As, Cr,Ni/ Moss Survey deposition to mosses

ICP IM, Pools and Fluxes Pb, Cd, Cu, As, Cr,Ni, Zn, V

TFH, Health Risks of HM from LRTAP Pb, Cd, Hg

ICP M&M +EMEP MSC-E, First preliminary maps Pb, Cd

ICP Materials 2003, Release of HM due to corrosion (source !!) Zn, Cu

22WGE report to HM workshop Langen 17-18 November 2003