BTMIL4 Heavy metals in the soil environment

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

( ) 1 1) Aluminum density 2,7 g/cm 3

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

pH dependant reaction: Me(OH) x ↔ Me x+ + x OH - Me x+ compete with H 3 O + on soil particles (cation exchange)

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

Heavy metal atmospheric deposits in Denmark 1984: Unleaded gasoline introduced. 1994: Lead is removed from gasoline Atm. dep. of Lead in the 60’ties approx – μg/m 2 /year Data from Danish EPA (Miljøstyrelsen). Miljøprojekt 663 “kortlægning af diffuse jordforurening I byområder” (2002)

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.

Arsenic (As) in Danish soil. (red. 10 mg/kg yellow 5 mg/l dark green 0 mg/kg) From DMU, 1992 survey: gmetaller+i+Danmark/Arsen/

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

pC = -Log(C)