2.11 Uncertainties

Posted by Arne Skov on 2015-09-10

2.11    Uncertainties


Systematic updating of the data in the product registers is important, since experience has shown that the general requirement to notify changes does not give satisfactory results. Experience has shown that when the composition of a product is changed, the companies do often not report this to the product registers. This error maybe is smaller in Norway where companies are asked each year if they have updated their composition data.


The total amount of a substance in SPIN is the added quantities of the substance in all products, the export amount subtracted. That is to say that if a substance is registered first as the imported raw material and then as part of the final preparation the quantity will be counted twice. Substances that are used for formulation of chemical products and that are imported, and most are in the Nordic countries, will thus be accounted for with maybe double the actual amount. The accuracy of the total net turnover will be dependent on the use of the substance; a substance imported only for use in synthesis will appear with a more correct quantity. The more disintegrated the use is, the more correct the figure will be, as it is hardly likely that the same molecule will act both as raw material to a trade, formulated and then sold to the same trade again.


Another factor giving a distortion of the quantity value is when concentration has been registered as an interval. The upper limit has been chosen for calculations of the substance amount in Denmark, Finland and Norway. The Swedish data are given as the mean percentage. Depending on how wide the allowed interval is in the different countries the discrepancy between the given value and the true value will vary.


In Sweden the possibility to not declare all ingredients in all concentrations causes uncertainty in the substance quantity figure. This is particularly important when trying to estimate substances that, however hazardous, are active in low percentage. On the other hand the other Nordic product registers mainly contain hazardous chemical products, thus giving an underestimation of both hazardous and not hazardous substances, as they don’t account for quantities in non-hazardous chemical products.


Secrecy rules have made it necessary to exclude data on many substances in SPIN. Thus, addition of subsets will not give a correct answer and can not be compared to the total amount of the substance. Moreover, Danish and Finnish industrial category quantities have been distributed with the entire substance amount for each product on each of the industrial categories given for that product. An addition of such industrial category quantities can give a value both double and triple the total substance amount.


Another obstacle when evaluating industrial category quantities is that in Sweden some industrial categories are only registered on the one digit level. This one digit level substance quantity has been distributed on the underlying two digit levels which may cause an error in allocation, some sub-category getting to much and others too little.


As a result of secrecy considerations some substances in the Nordic product registers are only mentioned in SPIN by their name. Total quantities and the total number of products have not been reported to SPIN if the substance is contained in less than 4 products and is registered by less than 3 companies. To show that the lack of information is due to confidentiality, a “Yes” is stated under the column heading “Confidential” in the “Total use”-window.


Finally it should be mentioned that information about specific substances and polymers only has been reported to SPIN when they have an unambiguous CAS-number.


Please also refer to section 2.12 “limits in the use of data”.