Ecological Risk Assessment of Diffuse and Local Soil Contamination Using Species Sensitivity Distributions - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 677

Time-variant……

Concentration in soil

Equilibr ium

Wet & Dry
Deposition

Manure

Time Time

Ditch
sediment

Human risks

Mixing zone

Degradation

Soil

Ecological risks

Quality products

msPAF per sediment contamination Class
(scenario's of thousands of sediment samples, spread on adjacent land)

Box-plot of Δ

1.0 1.0

0.8

0.6

0.4

0.2

95% protection
criterion

0

-0.2
-0.4
-0.6

Class-0 Class-1 Class-2 Class-3 Class-4

Concentration-based sediment Classification
(low high contaminated)

Fig. 14.16 ( Top ) The conceptual model used in a systems-based approach to address the sediment
disposal problem in the Netherlands. All arrow terms were quantified, and the expected accu-
mulation of compounds in soils and the associated net toxic pressures in soil were predicted for
every sediment volume in the national sediment loads inventory database. ( Bottom ) The predicted
soil concentrations of contaminants, after repeated sediment deposition on land, caused a change
(delta) in the chronic toxic pressure of the mixtures in each of the volumes of a large inventory
list (1356 cases, based on SSD-NOECs). Sometimes, spreading of sediments (particularly class-
0-sediments) on terrestrial soil (using the old classification system) caused decreased rather than
increased toxic pressure in terrestrial soils, when the terrestrial soil was more contaminated than
the sediments. Based on net mixture risk predictions, a new sediment management policy was
developed

14.14.3.4 Management Assessment

A suite of sediment management options were explored, including studies involving
the costs of different management scenarios (Posthuma et al. 2006a , b ; Van Noort
et al. 2006 ). Since the volumes of sediments per site are known, and since the costs
of various handling options are known, it was possible to explore the total costs
of different management options. Based on these insights, a new policy for man-
aging contaminated sediments has been formulated and implemented (Oste et al.