Substance flow analysis - lead, 2000
Summary and conclusions
This report presents a detailed analysis of lead consumption and emissions to the environment in Denmark in 2000. The substance flow analysis is an update of a previous analysis from 1994.
The report has been prepared in accordance with the Danish Environmental Protection Agency's paradigm for substance flow analysis. The present knowledge is acquired through information from Statistics Denmark, the Danish Product Register, trade organisations, technical literature, private companies and governmental institutions.
The analysis was undertaken using year 2000 as reference year and presents a comprehensive view of the turnover of lead in Denmark, before the Danish statutory order on lead was coming into force by March 1, 2002. For a number of applications, which according to the statutory order is no longer allowed, the consumption in the time of writing (spring 2003) will be considerably lower than estimated in the investigation.
Consumption
Consumption of lead by applications in 2000 is shown in Table 1. The principal uses of lead, for which no significant changes have taken place, were lead for accumulators, building materials (flashing and roofs), keels, copper and tin compounds, and balancing weights. Cable sheets and lead shots are the only major application areas, in which a significant decrease in consumption has taken place from 1994 to 2000, because other materials have been substituted for lead.
Imported finished goods accounted for the major part of the consumption of lead compounds. The use of lead pigment in paints and plastics, and the use of lead for glass and glazing had nearly come to an end in Danish production of consumer goods. This seems, however, not to be generally true for the rest of Europe. Consequently the import of lead with finished goods is estimated to be significant. The principal applications of lead compounds were lead in crystal glass and cathode ray tubes, pigments in paints and plastics and stabilisers in PVC. In rigid PVC products lead stabilisers were uses in Danish production to the same extent as in the rest of Europe. In soft PVC for cables lead stabilisers have been replaced by other stabilisers, whereas lead stabilisers are still the main choice for this application in Europe as a whole.
The unintentional turnover of lead as impurity is mainly associated with the use of coal, and the total turnover of lead as an impurity was in 2000 slightly less than in 1994 due to a decrease in the consumption of coal.
Table 1
Consumption of lead in Denmark in 2000
Product group |
Consumption |
% of |
Trend |
Lead metal |
|
|
|
Accumulators |
8,300-9,300 |
52 |
Increasing |
Building materials |
3,700-4,100 |
23 |
Stagnant |
Ammunition |
110-200 |
1.0 |
Decreasing |
Keels |
240-740 |
3.0 |
Varying |
Cable sheets |
353-383 |
2.2 |
Decreasing |
Lead-tin alloys |
190-350 |
1.6 |
Stagnant |
Other alloys |
170-350 |
1.5 |
Stagnant |
Fishing tools |
530-910 |
3.8 |
Decreasing |
Other uses as metal |
76-160 |
0.4 |
Stagnant |
Chemical compounds |
|
|
|
Red lead |
0.5-2 |
<0.1 |
Decreasing |
Pigments |
17-70 |
0.3 |
Decreasing |
Cathode ray tubes |
520-640 |
3.0 |
Stagnant |
Other glass (mainly crystal glass) |
140-340 |
1.4 |
Stagnant |
PVC |
440-570 |
3.0 |
Stagnant |
Ceramics |
40-150 |
0.6 |
Stagnant |
Other uses as chemical |
13-74 |
0.3 |
Different |
Turnover as impurity |
|
|
|
Coal |
40-67 |
0.3 |
Decreasing |
Oil products |
<0.12 |
<0.1 |
Stagnant |
Biofuels |
2.7-5.1 |
<0.1 |
Increasing |
Cement |
13-26 |
0.1 |
Stagnant |
Fertilizers and feedstuff |
3.5-9.7 |
<0.1 |
Stagnant |
Lime |
0.5-1.1 |
<0.1 |
Decreasing |
Sand blasting |
2.9-6.1 |
<0.1 |
Stagnant |
Other turnover |
4-24 |
<0.1 |
Different |
Total (rounded) |
14,900-19,000 |
100 |
|
Lead balance
Lead balance for the Danish society is summarised in Figure 1.
Figure 1
Lead balance for the Danish society in 2000. (All figures in tonnes Pb/year)
Small applications
Investigation has had particular focus on the description of a number of minor application areas which have only been briefly described - or not described at all - in the previous substance flow analyses.
Among other applications it includes:
 | Lead as alloying element in zinc used for hot-dip galvanising |
| Lead for balancing windmill wings and ventilators |
| Lead used for radiation shielding |
| Piezoelectric components |
| Lead stabilisers and accelerators for elastomers ("synthetic rubbers") |
| Lead glass for optical applications |
| Fireworks |
| Superconductors |
| Pyrotechnic initiators in airbags, etc. |
For lead used for piezoelectric components, superconductors and pyrotechnic initiators the consumption is increasing, but these applications account for only a modest part of the total consumption. In terms of direct releases to the environment some of the applications are of significance, as fireworks were among the major sources of releases of lead to the air, whereas lead from hotdip galvanised products was a minor source of lead to wastewater. Lead in fireworks is now prohibited according to the statutory order on lead.
Releases to the environment
Disposal and releases of lead to the environment are shown in Table 2. The total releases to the environment was 3-17 tonnes lead to air, 170-600 tonnes lead to water and 470-2,200 tonnes lead to soil.
Emission to air
Principal sources of emission to air were fireworks, solid waste incineration, casting and iron and steel reclamation. A major part of the uncertainty of the total estimate is due to the uncertainty of the estimate of the releases from fireworks, which is estimated at 1-8 tonnes lead. In the previous analyses of the turnover of lead in 1985 and 1994, gasoline additives were the major source of lead emission to air. This source was almost completely eliminated in Denmark in 2000.
Discharges to aquatic environments
Main sources of releases to aquatic environments were loss of fishing tools and cables left at the sea floor. The total amounts lost by the use of fishing tools by the fishing trade are quite uncertain, whereas the losses from angling are very certain, as almost all tools used for angling will be lost to the sea. The quantity indicated for cables does not represent the release of lead from the cables to the sea water, but the total quantity taken out of service and left on the sea floor (estimated annual average). During late years more focus has been directed to the issue, and from now on removal of submarine cables taken out of service will be required. Cables taken out of service are recorded in a centralised register.
Compared to those two sources the discharge with wastewater is small. Storm water drained directly to recipients represented the main part of lead discharge with wastewater/storm water, as more than 90% of the lead entering sewage treatment plants was retained with the sludge. The predominant source of lead to municipal wastewater is in accordance with the previous analyses estimated to be lead oxides corroded from lead flashing and lead roofs on historical buildings. It should be noted that the estimate of these sources is encumbered with significant uncertainty, and the sources are on the basis of the present knowledge estimated to be larger than the total amount of lead entering sewage treatment plants. However, it does not affect the fact that corrosion from flashing and roofing is estimated to be the major source of lead to wastewater - a result which is in agreement with results obtained in other countries.
Releases to soil
Cables left in the ground account for the major loss of lead to the soil environment but it should be noted that it is difficult to state how many of the cables that will later be removed by future excavation activities. In total some 150,000 tonnes lead in cables are placed in the earth in Denmark, and in recent years more focus has been attached to the removal of cables, which are abandoned. The recommended practice is to remove abandoned cables, when the track is later excavated, but it is unclear how many of the cables will actually be removed eventually. As it is the case for the submarine cables the estimated amount represents the amount left in the ground, not the release of lead from cables to the surrounding ground.
Besides cables, ammunition is the principal source of led releases to the soil. Compared to the previous substance flow analyses the amount of lead spread by ammunition has decreased substantially; primarily as a consequence of the ban of the use of lead shot. Other sources of releases to soil are releases from scrap storages and releases from broken accumulators. As these activities are rather dispersed, the estimation of these sources is very difficult and the estimates consequently very uncertain.
Recycling
An extensive collection of waste containing lead metal and dust takes place in Denmark. Besides ashes and dust from steel reclamation and foundries (490- 670 tonnes lead) considerable amounts of lead accumulators (10,000-11,000) tonnes lead), lead flashing (600-1,200 tonnes lead), copper alloys (370-650 tonnes) and cables (580-690 tonnes lead) were collected. Collection of lead glass from cathode ray tubes for recovery abroad accounted for 90-260 tonnes, whereas 18-50 tonnes lead was collected with PVC for recovery.
In total 12,800-15,600 tonnes lead were collected for recovery in Denmark in 2000.
The major part of the scrap was exported for recovery abroad. However, a significant part of the cables were recovered in Denmark, and cables were imported as well for recovery in Denmark. The products of the recovery were mainly exported. Recycling of lead within the Danish society is estimated at 420-840 tonnes.
Landfilling
About 1,300-2,300 tonnes lead was landfilled (including deposits, construction work etc.). The main sources were residues from solid waste incineration (630-980 tonnes lead) and shredder waste (380-700 tonnes lead) and fishing tools (170-340 tons bly).
Stock building
Due to the uncertainty of the estimated consumption, disposal of waste, export of scrap and waste products, and releases to the environment it is not possible to estimate whether the total amount of lead accumulated in products in use in the society was slightly increased or decreased in 2000. The stock in the society comprises lead in cables (100,000 -200,000 tonnes lead), roofs and flashing (80,000-120,000 tonnes lead corresponding to 30 years' consumption) and batteries (30,000- 40,000 tonnes corresponding to four years' consumption). Additionally 40,000-100,000 tons are accumulated in keels, X-ray laboratories, electronics, PVC, glass and other products. In total, the stock is estimated at 220,000- 410,000 tonnes lead.