1. Heavy metals in the soil environment
Titel på præsentation

3. Heavy metal and effect on plants grown in substrate solution.
Metal Deficiency Normal growth Toxicity
Heavy metal and effect on plants grown in substrate solution.
The concentration is mg/L in the substrate solution.

4. Non-point: atmospheric depos. (smoke), fertilizer and sewage sludge
( )1
Sources:
Point: metal plating industries, wood creosoting, gasworks, industries in general….
Non-point: atmospheric depos. (smoke), fertilizer and sewage sludge
From: McLean & Bledsoe, USEPA (1992)
1) Aluminum density 2,7 g/cm3

5. Risk: toxcicity + mobility
Indoor climate (vapours: Hg, As, Se)
Water – solubility (pH, Redox, complex agents..)
Plant uptake (root zone)
Soil ingestion (topsoil - ½ m)

6. Solubility
Key mechanisms that control the distribution of metals between soil water and particle phases. From McLean & Bledsoe (1992).

7. Sorption and soil pH pH dependant reaction: Me(OH)x ↔ Mex+ + x OH-
Mex+ compete with H3O+ on soil particles (cation exchange)

8. Metal solubility pH – pC diagrams

9. pC = -Log([Cd])

10. In EU. From: EEA – 3rd env. assessment, 2003.

11. Heavy metal atmospheric deposits in Denmark
Data from Danish EPA (Miljøstyrelsen). Miljøprojekt 663 “kortlægning af diffuse jordforurening I byområder” (2002)
1984: Unleaded gasoline introduced.
1994: Lead is removed from gasoline
Atm. dep. of lead in the 60’ties approx – μg/m2/year

12. Heavy metal non-point source deposits in Denmark:
“Kunstgødning” : mineral fertiliser
“Spildevandsslam” : Sludge from wastewater treatment plants
Quality criteria DK. Lead (Pb): 40. Arsenic (As) 20. Cadmium (Cd): 0.5 [ mg / Kg DW]
With the present deposition rate it take from 14 to 70 year to increase the 30 cm topsoil metal content with 1 % compared to the present level.

13. Arsenic (As) in Danish soils:
Red: 10 mg/kg Yellow: 5 mg/kg Dark green: 0 mg/kg
From DMU, 1992 survey:

14. Lead in humuslayer of Norwegian natural soils.
Data from www.

15. dk Legislation and approach:
Sensitive areas: top ½ m soil to be clean*
GW areas: no significant leaching
*CF: danish quality criteria for contaminated soil

16. The Usual Suspects… Substances Problem Sources Heavy metalsPb
PCE
The Usual Suspects…
BTX
PAH Cr
Substances
Problem
Sources
Heavy metals
(Hg, Pb, Cd…)
Toxic & chronic effects
Bio accumulation
(strong sorption - Kd)
Industry
Non-point deposition: smoke, sludge and fertilizer
Mineral oil products
(BTX, MTBE, PAH...)
Health. Taste + smell
(indoor climate, water + skin contact)
Gasoline stations + tanks for oil heating
Chlorinated solvents
(PCE, TCE..)
Cancer, toxicity.
Bioaccumulation
(indoor climate + water)
Dry cleaning
Metal processing
Graphic industry