Table 1 Values of environment indicators for cadmium, copper, lead and zinc in The Netherlands, for 1990 and the steady-state SS
Copper Lead
Zinc Indicators
Cadmium SS
1990 1990
SS 1990
SS 1990
SS 64
27 22
1. Relative environmental accumulation 57
2a. Risk ratio 0.7
0.2 2.0
Human toxicity 3.2
0.3 41
0.8 2.2
Aquatic ecotoxicity 20
0.4 157
0.8 8
74 Concentration } reference value
1.4 55
3.3 0.3
12 Concentration } limit value
0.1 1.3
11 0.4
0.5 0.3
105 0.0
0.2 1.4
Concentration } MPC 0.3
11 Terrestrial ecotoxicity
1.6 0.7
7.9 0.5
0.7 6.9
Concentration } reference value 0.7
3.1 0.0
Concentration } limit value 0.1
0.1 1.7
0.1 1.2
0.1 0.6
0.7 0.6
7.1 0.3
4.2 0.6
2.7 Concentration } MPC
0.3 2b. Transition period years
460 Human toxicity
130 Aquatic ecotoxicity
2 Concentration } reference value
13 3
90 Concentration } limit value
12 3
Concentration } MPC 1000
16 Terrestrial ecotoxicity
Concentration } reference value 200
19 200
90 720
80000 Concentration } limit value
30 550
Concentration } MPC 120
flows within the environment when analysing the ultimate sinks of the system. Here, part of the soil
and the sediment — the deep soil below 0.20 m and the deep sediment below 0.03 m — are re-
garded as immobile sinks for metals.
The indicators as defined above form the kernel of the following presentation of results.
3. Metals in The Netherlands
In this section the results of a case study on the environmental risks relating to the metabolism of
cadmium, copper, lead and zinc for the total Dutch economy are presented. The situation for
1990 is compared with the steady-state situation calculated with FLUX. Input data for 1990 such
as data on flows in the economy, accumulations, emissions and transboundary pollution have been
taken mainly from Annema et al. 1995. The economy indicators and the environmental accu-
mulation for 1990 have been calculated by simple spreadsheet manipulations of FLUX results. The
risk indicators have been calculated using the multi-media model DYNABOX Heijungs et al.,
1998. All the indicators discussed in Section 2 are applied in this case study. The results for 1990
and for the steady-state situation are presented below per group of indicators.
3.1.
En6ironment indicators indicators
1
,
2
a and
2
b The results for the relative environmental accu-
mulation Table 1 show that about 50 of the environmental inflow of copper and zinc and
about 25 of the inflow of cadmium and lead accumulated in the environment in 1990.
Table 1 shows the risk ratios for human toxicity and aquatic and terrestrial ecotoxicity. Acceptable
daily intake ADI values defined by the World Health Organization and tolerable daily intake
Table 2 Concentrations in water and soil as used in the calculation of the risk ratios
Cadmium Copper
Lead Zinc
1990 SS
1990 SS
1990 SS
1990 SS
2.8 101
Water concentration mgl 0.08
15 0.2
0.4 157
0.2 624
442 Soil concentration mgkg dry weight
0.6 1.3
26 328
38 88
TDI values similarly defined by Vermeire et al. 1991 and Cleven et al. 1992 have been applied
in calculating the risk ratio for human toxicity. Three different standards have been applied in
calculating the risk ratio for aquatic and terres- trial ecotoxicity: the Dutch reference value, the
Dutch limit value and the Dutch maximum per- missible concentration MPC. The reference
value is the concentration at which the risk of adverse ecotoxic effects is considered negligible; it
indicates the final quality level to be reached and it does not take into account the natural back-
ground concentration. The limit value is the con- centration of a chemical in a medium which
should not be exceeded; it indicates the short-term ecotoxic quality level to be reached. Reference
and limit values are policy standards. The MPC is defined as the sum of the maximum permissible
addition MPA and the existing background con- centration in The Netherlands, with the MPA
defined as the amount of a metal originating from antropogenic sources that is allowed on top of the
natural background concentration. The MPC is an ecotoxicological value.
5
Reference and limit values are taken from Janus et al. 1994; MPC values are taken from
Crommentuijn et al. 1997; background concen- trations are taken from Crommentuijn et al.
1997 and Van Drecht et al. 1996. All standards are used as risk indicators; it has not been
analysed which exposure levels and effects are actually found at the concentrations calculated.
The concentrations in water and soil used for calculation of the risk ratios are shown in Table 2.
It appears that several risk ratios are expected to be above 1, depending on the type of environmen-
tal standard applied. For human toxicity the risk ratio of lead is already above 1 for 1990 and the
risk ratio for the steady-state situation is above 1 for lead, zinc and copper, in decreasing order of
magnitude. For aquatic and terrestrial ecotoxicity copper gives the highest risk ratios, then lead and
zinc, and then cadmium. These results mean that the current metabolism of these metals is gener-
ally not sustainable.
The transition periods for the various metals are also shown in Table 1. In calculating the
transition periods, current background levels in the various environmental media have been taken
into due account. The transition periods vary from 0 years for cadmium in water to reach the
reference and the limit value, to 8000 years for lead in soil to reach the limit value.
6
The results for soil have been compared with the results of
the more sophisticated DB model for cadmium see Section 5 and appear to be fairly similar. The
results for human toxicity and aquatic ecotoxicity could not be compared with any other model. For
aquatic ecotoxicity the risk ratios for the steady- state situation note: based on the steady-state
emissions as calculated by FLUX and not on the 1990 emissions seem quite high. This may be due
to uncertainties attached to the partitioning coeffi- cients used and the solubility value used, which is
different for different metal species.
6
The transition periods are calculated by DYNABOX and based on the steady-state emissions presented in Table 1. Note,
however, that FLUX and DYNABOX are separate and not integrated models, which makes consistent analysis of the
transition periods in relation to the flows in the economy unfeasible at present.
5
In The Netherlands a discussion is being held on the derivation of ecotoxicological values for zinc, also taking into
account the essential meaning of zinc for human and other life. The discussion may result in new ecotoxicological values, but
these have not yet been proposed Gezondheidsraad, 1998.
Table 3 Values of economy–environment indicators for cadmium, copper, lead and zinc in The Netherlands, for 1990 and the steady-state
SS Copper
Indicators Lead
Cadmium Zinc
SS 1990
SS 1990
1990 SS
1990 SS
3. Total emissions 17.1
148.9 1203
69044 1136
52716 5192
73060 Air
5.5 4.2
52 93
152 156
183 160
5.0 152
477 185
4.8 191
Water 617
1221 6.2
Agricultural soil 9.4
987 1914
266 510
1992 3124
1.9 Non-agricultural soil
129.1 12
66560 533
51859 2400
68555 127.1
0.04 66521
0.12 0.04
51230 Landfill
2 61276
Other sources 2.0
1.9 12
39 533
559 2398
7278 4. Pollution export
− 14.3
− 10.0
− 5086
− 7665
n.a. n.a.
− 6644
− 7434
Values are given in tonnesyear. n.a. = not applicable.
3.2.
Indicators on emissions and exports indicator
3
and
4
The results for the emission indicators Table 3 show, for almost all media and all metals, an
increase of emissions in the steady-state situation compared to the 1990 situation. The increase of
air emissions in the steady-state situation com- pared to the 1990 situation is generally moderate.
The increase for cadmium is caused by the incin- eration of spent NiCad batteries; the increase for
copper is due to overhead railway wires. For zinc, air emissions for the steady-state compared to
1990 decrease, since the amount of zinc in gal- vanised iron is decreasing. Besides emissions,
transboundary pollution via air from foreign countries is an important source for the total
input to air for all four metals; this source is not included in the emissions indicator, however.
For all four metals, the increase of water emis- sions in the steady-state situation compared to the
1990 situation is due mainly to the corrosion of metals in building materials e.g. zinc gutters,
galvanised steel, tapwater heating equipment and bulk materials such as concrete. However, with
respect to the total input to water, it is not emissions within The Netherlands but inflow of
metals from outside The Netherlands via rivers like the Rhine and Meuse that constitute the
dominant source for all four metals up to over 70.
The increase of steady-state emissions to agri- cultural soils compared to 1990 emissions is sig-
nificant for all metals and is due to increasing flows of organic manure and of source-separated
vegetable, fruit and garden waste the latter being less relevant for lead. The ultimate source behind
these increasing flows of copper and zinc is animal fodder. It appears that in the steady-state situa-
tion the agricultural soil emissions of copper and zinc are due overwhelmingly about 80 – 90 to
the addition to fodder of copper and zinc, respec- tively. This is an example of closed-loop accumu-
lation: copper and zinc are added to fodder, which is imported from abroad and fed to Dutch
cattle. The manure produced by the cattle, includ- ing its copper and zinc content, is spread on
agricultural land as an organic fertiliser. Soil con- centrations of copper and zinc consequently rise
and, with them, the copper and zinc concentra- tions in maize, pit grass, fresh grass and hay. The
livestock are additionally fed with maize, pit grass, fresh grass and hay, and the metals are thus
returned to the economy. The eventual steady- state soil concentration due to this cycling of
copper and zinc leads to several risk ratios above 1.
The increase of steady-state emissions com- pared to 1990 emissions is most eye-catching for
non-agricultural soil. For all metals, the increase of emissions at steady-state is completely domi-
nated by emissions from landfill sites, which are
Table 4 Values of economy indicators for cadmium, copper, lead and zinc in The Netherlands, for 1990 and the steady-state SS
Zinc Indicators
Cadmium Copper
Lead 1990
1990 SS
1990 SS
SS SS
1990 5. Technical efficiency
99 99
3 3
98 98
Extraction 98
98 93
99 99
100 100
97 Production
97 96
95 91
99 96
79 100
98 83
Use 94
88 85
95 95
91 Waste management
87 83
6a. Functional recycling rate Extraction
7 7
Production Use
92 88
93 94
80 47
85 66
Waste management 6b. Non-functional recycling rate
Extraction Production
Use 3
5 1
1 2
3 Waste management
34 17
14 7
11 7. Economy accumulation } total economy inflow
12
assumed to be quite low in 1990. In a steady-state the outflow equals the inflow. Since it is assumed
that emissions to non-agricultural soil are the only outflow from a landfill, the emission to non-agri-
cultural soil at steady-state will equal the inflow at steady-state. In the end any leakage to the envi-
ronment from a waste storage site will lead to a non-sustainable situation, but the time this will
take may be very long up to thousands of years. For the risk ratios, however, emissions to non-
agricultural soil make a contribution of only about 10 and are thus not a major source, even
in the steady-state situation.
The results for the pollution export indicator in Table 3 indicate that The Netherlands is, and will
remain, a net importer of pollution for cadmium, copper and zinc. This means there is no net
shifting of problems to other countries. For lead this indicator is not useful, since it only gives
useful information if the economic processes in the region are more or less representative of the
average economic processes in the world. The latter is not the case for lead extraction and
refining processes in The Netherlands see below.
3.3.
Economy indicators indicators
5
,
6
a,
6
b and
7
The results on technical efficiency Table 4 show that the efficiency of the extraction and
production stages is generally high. This indicates that, in order to prevent emissions, not much can
be gained by a further boost of industrial effi- ciency. An exception is the extraction stage of
lead 3.
7
Comparing the steady-state efficiencies to the 1990 efficiencies, the decrease in use and
waste-management efficiencies — due, for exam- ple, to corrosion of asphalt, cement and concrete
in utility buildings, overhead rail wires, cement
7
This is due to the definition of extraction, which includes non-functional extraction and refining, and the fact that no
primary extraction of metals takes place in The Netherlands. The non-functional lead flow, which is separated from the iron
and disposed of in a landfill during the process of iron refining, is also included in this indicator. Thus, the low extraction
efficiency value indicates the potential for useful application of this lead flow.
and landfill emissions — is the most eye-catching result for all metals.
Table 4 shows that functional recycling takes place mainly in the waste-management stage; to a
large extent, this is due to the definition of this stage, which is taken to include collection and
storage of waste flows. For copper, lead and zinc the recycling rate is determined largely by the
recycling of building materials, and for cadmium by the recycling of various types of NiCad batter-
ies. Furthermore, Table 4 shows that non-func- tional recycling is highest for cadmium and lowest
for zinc. Note that the efficiency of the waste- management stage is determined by the functional
and non-functional recycling rate and by the ac- cumulation rate which, by definition, is 0 for the
steady-state situation.
The results for the relative accumulation in the economy show that it ranges between 7 and 14,
being highest for copper and lowest for lead. An indication of the time it will take to reach the
steady-state situation in the economy can be ob- tained from the lifespans of the products and
applications involved. For example, the average lifespan of functional applications as building ma-
terials lies somewhere between 30 and 50 years, while for non-functional flows of metals in bulk
building materials such as concrete this may be over 100 years. Thus, 100 years seems a reason-
able estimate of the time it will take to reach steady-state for the metal flows in the economy.
It should be noted, however, that all steady- state indicators presented in this section are based
on 1990 data and do not take into account any effects of policy measures taken since. For exam-
ple, the decrease of lead in fuel and the decrease of cadmium in zinc gutters have not been taken
into account in the current steady-state results. The use of copper and zinc in fodder has also
been reduced since 1990, but this has been neu- tralised by an increase of the Dutch pig stock,
resulting in a higher flow of copper and an equal flow of zinc in fodder in 1994 Westhoek et al.,
1997 compared with 1990. The closed-loop accu- mulation example of copper and zinc in fodder is
thus still valid.
3.4.
Conclusions From this case study the following conclusions
can be drawn:
The 1990 flows and accumulations of cad- mium, copper, lead and zinc pose significant
long-term risks to human health and ecosystem health.
For all metals, the built environment, agricul- ture and landfills are the most important
sources of the increase in emissions for the steady-state
situation based
on the
1990 regime.
In contrast to the apparent general view that these metal flows are well under control, the
conclusions of this case study points in a different direction. The problem is all the more pressing
since the recycling rates of the metals are already quite high.
4. Copper in the Dutch housing sector
