Massestrømsanalyse for cadmium English SummaryDuring the period of 1990 to 1996 the consumption of nickel-cadmium batteries and thus the consumption of cadmium was increasing. Nickel-cadmium batteries are especially used for battery-powered hand tools, mobile phones etc. The Danish Environmental Protection Agency decided to following the development for this particular use after 1996, which was the year of reference. In the period of 1996 to 1998 the sales of these batteries have been decreasing, and the consumption of nickel-cadmium batteries seems to have culminated. The increase of the consumption in the period of 1990 to 1996 corresponds to a certain extent to a reduction in the consumption of cadmium with plastic and in fertilisers. In 1996 there was an accumulation of cadmium with the consumers in the Danish community of 10-22 t exceeding the quantity in 1990. The atmospheric fallout on Denmark in 1996 is estimated at 6.2 t, which is round 12 times larger than the emission to the air from Denmark. The regulation of cadmium in Denmark Cadmium and its compounds might be acutely poisonous to men and animals. Cadmium furnishes good grounds for anxiety, because this metal accumulates in the human body, especially in the kidneys. Danish law provides a series of regulations of the use of cadmium; for instance of cadmium-containing soldering fluxes, phosphor-containing fertilisers, cadmium-containing products, packaging, glazing and decorative paints, paints and enamel paints, foodstuffs, stimulants and cosmetics. Additionally there is a regulation providing that cadmium-containing batteries are to be marked with a view to special collection and subsequent re-utilisation or disposal. Furthermore one regulation provides a tax on closed nickel-cadmium batteries. Additionally there is another regulation on collection of closed nickel-cadmium batteries in connection with which the collector obtains remuneration for environmentally safe collection and removal for recycling. The purpose of this mass flow analysis is to achieve an updated overview of the use, the consumption and the distribution of cadmium in Denmark. In addition the future development of cadmium in the waste is assessed. A further aim is to achieve an overview of possible future applications in fields where its use might be increasing. The investigation is to form the basis for the considerations of the Danish Environmental Protection Agency as regards its continuous efforts to restrict the cadmium impact on the population and the environment in Denmark. Also in the early nineties a mass flow analysis of cadmium in Denmark was carried out. A 3-part study of the use and removal of cadmium in Denmark The investigation was carried out and reported in compliance with the guidelines stated in the Environmental Protection Agency's paradigm of this kind of investigations. The level of detailing and reliability of the investigation strived for corresponds to the level characterised as "detailed analyses". The results presented in the project are based on statistics and information from approx. 200 public institutions, private enterprises and information centres. Without their kind attitude this information would not be available. As a principal rule the information is from 1996 which is the reference year. The first part of the study concerns intentional applications of cadmium, i.e. applications for which cadmium has been chosen deliberately because of its technical and economic qualities. The applications in question are: Cadmium as metal, nickel-cadmium batteries, pigments and stabilisers in plastic toys and other plastics, sacrificial anodes, solders, jewellery etc. The unquestionably predominant application of cadmium on the whole is in closed nickel-cadmium batteries, especially used for battery-powered hand tools and mobile phones etc. The second part of the study deals with cadmium as a follow substance, i.e. applications in which cadmium for natural reasons "follows" automatically. Zinc, fertilisers, cement, coal, mortar and oil products were studied. The last part of the study concerns the quantity of cadmium in the waste products of scrap, solid waste, hazardous waste, wastewater and wastewater sludge. On the basis of the above a summarising assessment of the applications and the consumption of cadmium in Denmark, the removal and loss of cadmium to the environment and a cadmium balance for Denmark have been carried out. Principal conclusions The total cadmium consumption is stagnant. An estimate of the consumption of cadmium in 1996 is 43-71 t in round figures. The consumption is dividable as follows:
The consumption in 1990 was previously calculated at 50 t. Thus there is no reason to presume that the total consumption of each of the two years has been substantially different. In the 1990-survey the consumption with products was assessed at 39 t, whereas the consumption as a follow-substance was assessed at 11-12 t. That differs from the figures of 1996, when the consumption with products was higher, whereas the consumption as a follow-substance was lower. The principal explanation is a significantly increased supply of closed nickel-cadmium batteries in 1996, see figure 3, and a reduction of cadmium with plastic and in fertilisers. For a series of applications lithium-ion batteries or batteries based on nickel-metal-hydride are replacing the nickel-cadmium batteries. A new type of zinc sacrificial anode with tin and indium instead of cadmium is being patented. If this type of anode gains a footing, the cadmium load on the marine environment will be reduced by 0.6 t cadmium annually. The quantity of solar cells in Denmark is increasing, but the quantity of cadmium is expected to be small - in the area of 75 to 225 kg in year 2005. Also the quantity of electric vehicles with nickel-cadmium batteries in Denmark is increasing. The supply was assessed at 0.8 t cadmium in 1998, and in 1999 a supply of 1.2 t is expected. Figure 3 Look here! .The total loss of cadmium to the environment in 1996 can be assessed at: 0.3-1.6 t cadmium to the air 0.9-2 t cadmium to the water 2.2-3.5 t cadmium to the soil 12-25 t cadmium was deposited, including incineration residue/ash from coal and refuse incineration. Some of the residue/ash is used for embankment and backfilling - roads, dams and the like. In 1996 the loss to the air derived mainly from refuse incineration and flaring of oil products, whereas the loss to the water derived especially from wastewater and storm-water from municipal wastewater and sacrificial anodes. The loss to the soil derived mainly from the use of fertiliser and manure as well as lime from farming. When the total loss is compared to the figures of 1990 the loss to the air has been reduced considerably (from 2 t). The principal reason is that the emissions from the refuse incineration plants and the production of iron and steel have been reduced drastically. However, the loss to the water has increased considerably (from 0.7 t), which is mainly due to an increased loss from sacrificial anodes. The loss to the soil has been reduced (from 5 t); the legislation concerning the maximum content of cadmium in fertiliser is obviously effective. The quantity for deposition must be considered reduced (from 31 t). The explanation of this is that the quantities from the production of iron and steel, the fragmentation of scrap and the direct deposition have decreased. In return the quantities from refuse incineration have increased. From figure 4 showing the cadmium balance of Denmark it appears that the largest item - both as regards imports and exports - is that of nickel-cadmium batteries (clearly dominated by closed batteries). The import was 36-54 t, whereas the export of used batteries for recycling was 13-16 t. Figure 4 Look here! Totalling 1.3-1.4 t the remelting of plastic package is by far the predominant activity for recycling in Denmark. It should be noted that it is a cycle. On the basis of the registration of consumption, export of residues and loss to the environment and the refuse dumps it is estimated that the accumulation in 1996 with the users in the Danish society was 10-22 t. The accumulation in 1990 was estimated at 6.6 t. Thus the accumulation of 1996 is considered higher than that of 1990. On land there was in 1996 atmospheric fallout of cadmium of 3.9 t, whereas the fallout on the Danish waters is estimated at 2.3 t cadmium. It appears that the fallout on Denmark, totalling 6.2 t, is between 4 and 21 times higher than the emission to the air from Denmark. The atmospheric fallout in 1990 was estimated at 4.7 t over land and 4.2 t over the waters - totalling 8.9 t. Compared to that the total fallout in 1996 was reduced by 2.7 t or 30%. Project results Cadmium, with the chemical designation Cd, belongs to the zinc sub-group of the periodic system. Cadmium is widely distributed in the earth. The cadmium content in the earth's crust is estimated between 0.08 and 0.5 ppm. In the upper strata the cadmium content is typically between 0.1 and 1 ppm. Extraction of cadmium is profitable only where it is found in concentrations of 0.05 to 0.8% together with zinc minerals. The found results of 1996 are given below in further detail. In order to illuminate the development trends the results are compared to those of 1990. Intended applications of cadmium: The supply of cadmium with open nickel-cadmium batteries in 1996 was assessed at 1-2.3 t. That amount cannot be considered substantially different from the 1.6 t assessed for 1990. However, the supply of cadmium with closed batteries in 1996 was assessed at 35-50 t compared to 30 t in 1990. This is the principal increase of the cadmium consumption compared to 1990. The two predominant applications of the closed batteries were battery-powered tools and communication equipment (mobile phones etc), see figure 3. The consumption of cadmium with electronic components (equipped printed circuit boards excluding batteries and solders) was for 1996 assessed at 0.07-0.2 t/year. There is no assessment of the consumption in 1990. For 1990 the consumption was assessed at 6.7 t for plastic excluding toys. For 1996 the consumption is estimated at 0-0.5 t cadmium. Thus the consumption has been reduced substantially. In Denmark cadmium is no longer used as pigment or stabiliser. The legislation has obviously been effective. For 1996 there is an estimated import with plastic products from the Far East of 0-0.5 t. The consumption of cadmium with toys is for 1996 assessed at 0.2-3.6 t, of which the principal part is cadmium as pigment and stabiliser in non-branded toys imported from the Far East. The consumption in 1990 was not registered. Of pigments for other purposes the consumption in 1996 was assessed at 0.04-0.05 t (artists' colours), whereas it was assessed at 0.007-0.012 t for 1990. Obviously this is an increase, but the consumption is very small. For 1996 the consumption for cadmium plating and with cadmium plated parts was assessed at 0.1-0.2 t. For 1990 the consumption was assessed at 0.05-0.235 t. Thus the consumption is considered stagnant. For 1990 the consumption of cadmium containing alloys was assessed at 0.31-0.325 t. For 1996 the consumption was assessed at 0.6-0.8 t. This is a doubling of the consumption. The 0.6 t derives from sacrificial anodes. The remaining part is solders and high-voltage lines. The consumption in jewellery was assessed to be lower than 1.8 t in 1996. The investigation in 1990 did not include jewellery. The jewellery is partly so-called "Indian silver" imported from India and Nepal, and partly silver-plated or gilt bijouterie imported from various countries in the Far East. Finally there are chemicals and solar cells. The consumption in 1996 was assessed at 0.3 t. The consumption with chemicals in 1990 was assessed at 0-0.1 t, whereas solar cells were not included. The consumption must be considered increasing. Cadmium as a follow substance: By nature cadmium exists with zinc, and thus also with zinc oxide. Zinc is used for galvanised products (among other things for passenger cars, lorries and buses), goods of zinc, brass and German silver. Zinc oxide is used as pigment, e.g. in tyres. For 1990 the consumption was assessed at 2.5-2.6 totally, of which 2 t derived from cars etc. The 2 t must be considered a rather high estimate. The consumption in 1996 was assessed at 0.1-1.8 t. The consumption must be considered stagnant. Practically the whole quantity of cadmium derives from cadmium in zinc with galvanised goods, among other things imported cars etc and pure zinc for galvanising. Tyres containing zinc oxide contribute less. The supply of cadmium with fertilisers was assessed at 2.6 t for 1990. For 1996 the total supply was 0.3-1.3 t, of which manure represented approx. 0.2 t. This means clearly a decrease in the cadmium content of the fertiliser as a result of the legislation. The consumption of cadmium with lime was for 1990 assessed at 1.1 t, whereas it was 0.9-1.9 t for 1996. The consumption must be considered stagnant. The consumption of lime for farming purposes is predominant. The lime quantity for flue gas purification increased to 0.3-0.45 million t in 1996, corresponding to 300-450% of the 1990 level, and the quantity of cadmium increased correspondingly. For 1990 the supply of cadmium with coal was assessed at 1.6 t, which is considered equal to that of 1996, assessed at 1.4 t. The supply of cadmium with oil products for 1990 was assessed at 1.2 t. For 1996 the supply was assessed at 0.003-1.3 t; the supply is thus considered stagnant compared to 1990. For cement the supply in 1990 was assessed at 1.2-2.4 t. For 1996 the supply was assessed at 2 t which is considered stagnant compared to 1990. For 1996 the consumption of cadmium as a follow substance in other products (especially wood, paper, straw and food) was assessed at 0.12-0.22 t/year. The corresponding consumption of 1990 was not assessed.
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