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Inventory of biocides used in Denmark

4. Main group 2: Preservatives

4.1 Product-type 6: In-can preservatives

In-can preservatives are biocidal-products used for the preservation of manufactured products, other than foodstuff or feedingstuff, in containers by the control of microbial deterioration to ensure their shelf life.

In-can preservatives are used in virtually all water-based non-food products.

The product-type can based on application areas be organised into four application areas:

	In-can preservatives for paints
	In-can preservatives for inks, fountain water, adhesives and sealants
	In-can preservatives for cleaning materials
	In-can preservatives for other products

In-can preservatives for medicine, toys, cosmetics and human hygiene products are not included, as these products are covered by other directives.

There is a large number of in-can preservatives in use in many different products, and in this project it has not been possible to carry out a comprehensive assessment of all preservatives and applications.

In PROBAS, 236 different CAS No’s are registered as used as preservatives. As many of the water-based products are not registered in PROBAS, the actual number of preservatives may be higher.

It is in PROBAS not possible to distinguish between in-can preservatives and other preservatives. In total, 144 CAS No’s are registered as preservatives in the following product groups: Paint, inks, dyes, binders, adhesives, maintenance products, photographic products, cleaning agents and sealants. The preservatives in these products will either be in-can preservatives covered by this section or film preservatives covered by the next section. In-can preservatives may also be used in other product groups, and the list is consequently not comprehensive.

Of the 144 CAS No’s, 75 is used in less than 3 registered products and are not shown due to confidentiality. The remaining 68 preservatives are shown in Table 4.1 with the number of registered products indicated.

It should be noted that the preservatives registered in a large number of products are not necessarily the preservatives used in largest quantities. As mentioned, most water-based products as paint and cleaning agents are not registered in PROBAS.

The table, however, gives an indication of the large number of preservatives in use, and indicates some of the most widespread. Of the upper 12 compounds as regards product groups, the isothiazolones(4), 1,3-,2-bromo-2-nitro-propanediol and quaternary ammonium compounds (2) are some of the preservatives estimated to account for the major part of the consumption. As regards formaldehyde, the current inventory indicates that formaldehyde is not very widespread as in-can preservative today.

The consumption figures for the different application areas are assessed in the following sections.

Table 4.1
Preservatives registered in >2 products in PROBAS under the product groups: Paint, inks, dyes, binders, adhesives, maintenance products, photographic products, cleaning agents and sealants

4.1.1 In-can preservatives for paints

In-can preservatives are used for preservation of all types of water-based paints.

4.1.1.1 Actors on the market

There is no Danish production of in-can preservatives for paints. The main suppliers of the preservatives are Thor Chemie GmbH and Rohm & Haas; both without Danish offices.

Producers and suppliers of paints containing in-can preservatives are organised in the trade organisation 'The Danish Paintmakers Association' ('Foreningen for Danmarks Lak- og Farveindustri').

The content of biocides in paints has as a part of another ongoing project supported by the Danish EPA been assessed by a panel of experts from the paint industry. The following information on in-can preservatives in paint is based on this work, if nothing else is mentioned.

The main biocides registered in PROBAS for the application is listed in Table 4.2. According to the industry only a limited number of the biocides (indicated in the table) accounts for the main part of the consumption. Basically, the same biocides are used for both indoor and outdoor water-based paints for both masonry and wood.

There are more than 39 biocides registered as preservatives in paints in PROBAS. The list of preservatives is not shown due to confidentiality. For most water-based paints, there is no obligation to declare the products to PROBAS, and the register cannot be used for estimation of the total content of biocides in paint.

Table 4.2
Main biocides used as in-can preservatives for paint in Denmark ¹⁾

1) The list includes the main biocides registered in PROBAS for the application. Some of the biocides may, however, not be in use today. According to the industry a limited number of biocides accounts for the main part of the consumption (indicated as most common).

2) Concentrations in the paint according to PROBAS. The average concentrations in common products are shown in the next table.

The total consumption of water-based paints in Denmark is 33,000-36,300 tonnes. The estimated total consumption of in-can preservatives with paint is shown in Table 4.3. The estimate is based on the typical content of the preservatives and the consumption of the relevant types of paint. The basis for the estimate is indicated in the notes to the table. According to the industry a typical water-based paint contain either 200 ppm BIT, 30 ppm CIT/MIT or 0,1% Bronopol. The biocides may be used in combination and if so used in proportionally lower concentrations.

Table 4.3
Consumption of in-can preservatives with paint in Denmark 1998

4.1.2 In-can preservatives for inks, fountain water, sealants and adhesives

In-can preservatives are used in water-based inks, fountain water for offset printing, and water-based sealants and adhesives.

Concerning adhesives, in-can preservatives are present in most types; among others: Adhesives based on natural polymers, polymer dispersions/emulsions and adhesives based on water-soluble polymers. In sealants, preservatives are used in latex acrylic sealants that only account for a small part of the total consumption of sealants.

Producers and suppliers of inks, sealant and adhesives are organised in the trade organisation 'The Danish Paintmakers Association' ('Foreningen for Danmarks Lak- og Farveindustri'). Fountain water is usually supplied by the same business as supply the inks.

The main suppliers of inks are Akzo Nobel Inks A/S, BASF Tryksystemer A/S, Coates Lorilleux A/S, Zeller & Gmelin A/S, Resino Trykfarver A/S, Sicpa Denmark A/S, Sun Chemical Hartmann A/S.

Main suppliers of adhesives and sealant are Casco A/S, Aaffa A/S, Bostik A/S, Dana Lim A/S, Wacker-hemie Danmark, C Ljungdal A/S, Sika Danmark A/S, Dafa A/S, but there are several other actors on the market.

4.1.2.2 Biocides used in Denmark for the application area

Identified biocides used for preservation of inks, fountain water, sealants and adhesives in Denmark are shown in Table 4.4. A large number of different products are marketed and the list is probably not comprehensive. The data are based on an inventory carried out by the Danish Paintmakers Association concerning sealant and adhesives, in combination with information obtained by means of a questionnaire to suppliers of inks and fountain water. Less than half of the suppliers answered the questionnaire.

Table 4.4
Preservatives used for inks, fountain water, sealants and adhesives in Denmark

1) Typical concentration in the products. The agents are often used in combinations.

2) In some semi-manufactures for adhesives the compounds exist on hydrochloride form in acid solution as 3(2H)-Isothiazolone, 5-chloro-2methyl-, hydrochloride (CAS No. 26530-03-0) and 2-methyl-2H-isothiazol-3-one hydrochloride (CAS No. 26172-54-3).

In PROBAS, there are 29 biocides registered as preservatives in dyes, 13 in dyes, 17 in sealants and 25 in adhesives. The list of preservatives is not shown due to confidentiality.

The estimated total consumption of preservatives with these product groups is shown in Table 4.5.

According to the trade statistics from Statistics Denmark, the total consumption of inks in 1998 was 16,000 tonnes. Based on information from suppliers, it is estimated that only about 2,500 tonnes of this is water-based and contains preservatives. The consumption of fountain water containing preservatives is based on information from suppliers estimated at about 500 tonnes.

According to the trade statistics from Statistics Denmark, the total consumption of sealant and fillers in 1998 was about 34,000 tonnes. According to statistics of the trade organisation FDLP, water-based products containing preservatives only accounted for a relatively small part of this. Based on an assessment done by the organisation at the beginning of 2000 covering suppliers of sealants and fillers, it is estimated that only about 200-500 tonnes of these products should contain preservatives.

The total consumption of adhesives in 1998 was approximately 10,000 tonnes according to the trade statistics. The main part of this seems to be preserved and the assessment by the trade organisation revealed that an amount of the same magnitude was preserved with in-can preservatives.

Table 4.5
Consumption of preservatives with inks, fountain water, sealant and adhesives in Denmark 1998

4.1.3 In-can preservatives for cleaning materials

In can preservatives are added to virtually all water containing cleaning materials except cleaning materials with a very high or low pH or cleaning materials which are preserved by the content of disinfectants (see Main Group 1).

The producers of cleaning materials are organised in SPT, the Trade Organisation for Soap, Perfume and Toiletware.

The Danish main producers of food area disinfectants are Henkel-Ecolab and Novadan, and the main suppliers are Henkel-Ecolab, Diversey-Lever, Novadan, SFK a.m.b.a. and Nopa-Nordisk Parfumerivarefabrik A/S. The main suppliers of disinfectants for private areas are Reckitt Benckiser A/S, A/S Blumøller, Colgate Palmolive and Lever Fabergé Danmark A/S whereas the main suppliers of biocidal products for professional and industrial use are Henkel Ecolab A/S, Novadan A/S and Diversey Lever A/S.

There are 96 different biocides registered as preservatives in cleaning materials in PROBAS. The list of preservatives is not shown due to confidentiality.

It seems, however, only to be relatively few preservatives which account for the main part of the consumption. The main biocides used for preservation of cleaning materials according to general experience of the trade organisation SPT are shown in Table 4.6.

Table 4.6
Main biocides used for preservation of cleaning materials in Denmark

The total consumption of water-based cleaning materials in Denmark is estimated at 40,000-60,000 tonnes based on information from the trade organisation SPT.

The exact distribution between the different preservatives is not known. As the different preservatives are used in concentrations ranging from 0.02 to 0.7%, the total consumption of preservatives with the cleaning materials can only be estimated with high uncertainties (Table 4.7).

Table 4.7
Consumption of in-can preservatives with cleaning materials in Denmark 1998

4.1.4 In-can preservatives for other products

In-can preservatives are used for a large number of other product types, among others:

	Dyes and textile processing fluids
	Maintenance products (polishes, wax emulsions, car maintenance agents, etc.)
	Photographic process fluids
	Additives to concrete
	Lubricants and machine oils
	Water bed fluids
	Industrial fluids (e.g enzyme solutions)

For textile processing, biocides may be used in dyes and fluids for sizing and finishing (Laursen et al., 1997). Sizing is the protection of threads during weaving because of mechanical actions. Often the protecting agent is starch, which is degradable for microorganisms. But biocides are not necessarily used for this purpose though.

‘Other products’ covers a wide range of products, and it has not been attempted to obtain market information.

It has not been possible to make a comprehensive inventory of the preservatives used in other products. Preservatives identified by direct information from suppliers are shown in Table 4.8. The preservatives are the same as used for other technical purposes.

Table 4.8
Identified in-can preservatives for other products

As shown in Table 4.1, the number of different biocides is very high, and it cannot based on the obtained information be concluded that the biocides shown in Table 4.8 are the most used for ‘other applications’. The number of different biocides registered as preservatives in PROBAS is 36 for maintenance products (wax and polish among others) and 20 for photographic processing fluids. The list of preservatives is not shown due to confidentiality.

4.1.4.3 Consumption of biocides with finished products

The consumption of preservatives with ‘other products’ has not been assessed in detail, but the total consumption may be significant compared to the application areas covered by the previous chapters. For example, the total supply of wax and polish was according to the trade statistics about 6,000 tonnes of which some may not contain preservatives.

It is roughly estimated that the consumption of preservatives with ‘other applications’ is in the order of magnitude of 10-100 tonnes.

4.2 Product-type 7: Film preservatives

Film preservatives are used for the preservation of films or coatings by the control of microbial deterioration in order to protect the initial properties of the surface of materials or objects such as paint, plastic, sealants, adhesives, paper and art works.

The product-type can be organised into three sub-types:

	Film preservatives for paints
	Film preservatives for plastics
	Film preservatives for sealants, fillers and other products

4.2.1 Film preservatives for paints

Film preservatives are used for preservation of most types of topcoat paints used for outdoor applications by the control of microbial (mainly fungal) deterioration of the paint film.

Biocides used in priming wood-care products, for which the main function is a protection of the wood agaist microbial detoriation, are included in product-type 8: 'Wood preservatives'.

The content of biocides in paints has as a part of another ongoing project supported by the Danish EPA been assessed by a panel of experts from the paint industry. The following information on film preservatives in paint is based on this work, if nothing else is mentioned.

The main suppliers of film preservatives for paint on the Danish market are Troy chemical corp. (IPBC), Bayer A/S (dichlorfluanid, tolyfluanid) and Jansen Pharmaceuticals (Propiconazol), but there a several other suppliers.

Actors on the paint market mentioned in section 4.1.1 also apply to film-preservatives in paint.

Biocides registered in PROBAS for the application is listed in Table 4.1. Except for Di-butyl-p-cresol the use of the biocides has been confirmed by the industry as actually used today.

In some linseed oil paints for outdoor use an extract of grapefruit-seed, Citricidal, is used as fungicide (Henriksen, 2000). The active component of Citricidal is a quaternary ammonium chloride (a diphenol hydroxybenzene reacted with ammonium chloride) (Nutriteam, 2000). Also zinc-sulfate (7733-22-0) may be used for linseed oil paints.

Table 4.9
Main biocides used as film preservatives for paint in Denmark 1)

1) The list includes the main biocides registered in PROBAS for the application except bis(tributyltinoxid), which is still registered, but today not allowed for this application. Except for Di-butyl-p-cresol the use of the biocides has been confirmed by the industry.

2) Concentrations according to PROBAS. The average concentrations in common products are shown in the next table.

According to the industry, different film-preservatives are typically used for different applications as shown in Table 4.10.

Table 4.10
Typical concentration of film preservatives in outdoor paints according to the industry

1) According to PROBAS; the concentration is not indicated by the industry.

The estimated total consumption of film-preservatives with paint is shown in Table 4.11.

The estimate is based on the typical content of the preservatives and the consumption of the relevant types of paint. The basis for the estimate is indicated in the notes to the table.

Table 4.11
Consumption of film-preservatives with paint in Denmark 1998

4.2.2 Film preservatives for plastics

Plastic products are in general not preserved against microbial degradation, but biocides may be added to plastics containing plasticisers to prevent microbial growth at the surface. During use of the plastic product, the plasticiser will diffuse to the surface and in moist environment, the plasticiser will be attached by microorganisms, especially fungi, which use the plasticiser as carbon source. In some flooring products, the biocide is added for antiseptic reasons to prevent growth of undesirable bacteria at the surface.

Plasticisers and other degradable additives may be added to different plastics, but soft PVC seems to account for the main part of preserved plastic.

The main application areas for soft PVC containing fungicides are roof foils, tarpaulins, bathroom curtains and tents of PVC coated fabric or reinforced PVC foil, (see section 4.4.1) and some types of PVC flooring (vinyl flooring) for bathrooms, busses and institutions.

The range of plastic products that may be preserved with fungicides appears from catalogues from producers of biocides. The catalogues from Rohm and Haas and Ackros Chemicals, some of the leading producers of preservatives for this application, mention the following application areas: Swimming pools (pool liners, accessories and furniture), boats (seat cushions, boat bumpers, canopies), geomembranes, grill covers, lawn furniture, wire insulation, wall coverings, kitchen products (cutting boards, countertops, cooking utensils, refrigerator and appliance gaskets), bathroom products (shower safety mats, toilet seats and covers, soap and lotion dispensers), automotive gaskets, shoes and cleaning products (trash cans, scrub and mop buckets, dustpans). According to suppliers of biocides, biocides seem not to be used in Denmark for production of these products, but imported products may contain biocides.

The only identified supplier of biocides for plastic in Denmark is Akcros Chemicals Nordic A/S. The only identified Danish producer of preserved PVC is Duratex A/S.

Roofing membranes and PVC flooring are imported, mainly from other Nordic countries.

It has not been possible to make a comprehensive assessment of biocides in all products within this application area, as most of the products are imported. Table 4.12 includes biocides in some of the main product groups: PVC roofing and flooring and PVC-coated fabric for tarpaulins and tents. OBPA seems to be the main biocide of choice for products produced in Northern Europe, but it has not been possible to obtain specific information on biocides in PVC produced in other parts of the world.

Table 4.12
Identified film preservatives used for plastics in Denmark

4.2.2.3 Consumption of biocides with finished products

As mentioned above it has not been possible to cover all applications of biocide preserved plastics. The estimate of the total consumption of biocides with roofing membranes is based on information from one main supplier. The estimate regarding PVC flooring and PVC coated tents and tarpaulins are based on new information from suppliers of the products. It should be noted that only a minor part of PVC flooring contains biocides.

In total, these applications correspond to a PVC consumption of 2000-3000 tonnes.

The biocide consumption with PVC and other plastics for other applications has not been assessed in detail. The order of magnitude can, however, be indicated by the amount of PVC used for these other applications. It is not known to what extent biocides are used for these applications if used at all. In the most resent assessment of the PVC consumption in Denmark from 1996, the following consumption figures were estimated:

	Fenders and other maritime equipment: 65 tonnes
	Water beds: 12 tonnes
	Shower curtains <50 tonnes
	Boots and waders: 380 tonnes
	Cars: 3,160 tonnes (including PVC for undersealing which must be expected to be without biocides)

Cars could potentially account for a significant part of the film preservatives for plastic. There is no Danish production of cars, and it has been beyond the limits of this project to gather information on biocides in imported cars.

The remaining applications are estimated to account for <1000 tonnes PVC, which is significantly less than the applications covered in Table 4.1. The total content of biocides for other applications is roughly estimated to be <2 tonnes.

Table 4.13
Consumption of film preservatives with plastic products in Denmark 1998

4.2.3 Film preservatives for sealant, fillers and other products

Film preservatives may also be used in sealant, fillers, glues and adhesives.

Fungicides are added as film preservatives to sealants and fillers for application in wet rooms. According to Danish suppliers sealants for outdoor use around windows, between concrete panels, around sheeting, etc. in general do not contain fungicides.

Film preservatives are in general not added to glues and adhesives. In some instances, however, they are added to prevent mould growth.

Producers and suppliers of sealants are organised in the Danish Adhesives and Sealants Association and the suppliers will be the same as mentioned in section 4.1.

An assessment made by the trade organisation the Danish Adhesives and Sealants Association revealed rather few film preservatives used in products on the Danish market (see Table 4.14). The list cannot be considered comprehensive, as other film preservatives may be present in products not covered by the assessment.

Table 4.14
Film preservatives used for sealants, fillers and other products in Denmark

4.2.3.3 Consumption of biocides with finished products

The total consumption of sealants and fillers was according to Statistics Denmark in 1998 about 22,000 tonnes (see section 4.1.4). According to the assessment made by the trade organisation, only a relatively small amount of oil-based fillers, solvent-based acrylic sealants, silicone sealants and ‘other’ sealants contain fungicides. In total these fillers and sealants account for about 111 tonnes. The assessment may not be comprehensive, and the total amount of sealants and fillers with fungicides is here roughly estimated to be 120-500 tonnes.

The exact distribution between the different film preservatives is not known. The estimated total consumption of fungicides, based on an average concentration of the fungicides of 0.2-0.4%, is shown in Table 4.15. The estimate on the total consumption is very uncertain, but compared to the consumption of film preservatives with paint, the consumption with sealant and fillers is certainly rather small.

Table 4.15
Consumption of film preservatives with sealants and other products in Denmark 1998

4.3 Product-type 8: Wood preservatives

The product-type includes products used for the preservation of wood or wood products by the control of wood-destroying or wood-disfiguring organisms. The product-type includes both preventive and curative products. Treatment of wood before the sawmill stage is not covered by the Biocide Directive.

The consumption of biocides with wood preservatives for control of wood-destroying organisms is registered in the Danish Pesticide Statistics (Danish EPA, 1999 A).

The product-type can be organised into two sub-types:

	Vacuum preservatives and pressure preservatives
	Preservatives for surface treatment

The first sub-type includes preservatives used in industrial processes, whereas preservatives for surface treatment are used mainly by craftsmen and private persons.

The product-type does not include biocides for preservation of paints, where the effect of the biocide is to preserve the paint itself. These are included in product-type 6 'In-can preservatives' and product-type 7 'Film preservatives'.

It should be noted that the term ‘wood preservatives’ in Danish is often used as synonym of all ‘wood-care products’. In this context, ‘wood preservatives’ only cover wood-care products for priming.

4.3.1 Vacuum and pressure preservatives

Pressure preservatives are used for wood for exterior use with a high risk of degradation, i.e. wood in contact with water or soil. A specific method is used for preservation of poles.

Vacuum preservation is mainly used for preservation of wooden doors and window frames.

Producers and suppliers of vacuum and pressure preservatives are organised in the trade organisation 'The Danish Paintmakers Association' ('Foreningen for Danmarks Lak- og Farveindustri' ).

Main Danish producers of these preservatives in 1998 were Rentokil Initial A/S, S.Dyrup & Co A/S, Sadolin Woodcare, A/S Hygæa, Tanaco Danmark A/S, and Akzo Nobel Industrial Coating A/S.

Main suppliers of these preservatives in 1998 were (apart from producers) BASF Danmark A/S, Beta DK Aps, Kai R. Spangenbergs Eftfl. I/S, and Hickson Timber Protection.

Biocidal products used for control of wood destroying organisms of wood in Denmark have to be approved by the Danish EPA and are described in the survey of approved pesticides (Danish EPA 1999 B).

The consumption of active agent in preservatives for vacuum and pressure preservation in Denmark in 1998 is listed in Table 4.16 and Table 4.17.

Of the total consumption of pesticides in Denmark in 1998, wood preservatives accounted for 7% corresponding to 297 tonnes (Danish EPA 1999 A).

Of the total production of industrial-preserved wood in Denmark in 1998, 87.1% was preserved by a pressure process, and 12.7% by a vacuum process. The last 0.2% of the production was production of poles using CKB-agents (copper, chromium, boron). In 1998, 87 plants were approved by Danish Impregnation Control. Of these plants, 64 produced vacuum-treated wood, 21 pressure-treated wood, and 2 plants produced masts and poles (Dansk Imprægneringsstatistik, 1998).

Table 4.16 Se her!
Consumption of biocides for production of pressure-preserved wood in Denmark 1998 ¹⁾

Table 4.17 Se her!
Consumption of biocides for production of vacuum-preserved wood in Denmark 1998 ¹⁾

The consumption of biocides with finished wood products in Denmark differs from the consumption for production as import and export of preserved wood alter the figures. In Table 4.18, the estimate on the consumption of active agents in preserved wood used in Denmark in 1998 is shown.

Production, import and export of chromium and creosote with preserved wood have recently been assessed by Hansen et al. (2000 a,b), and the consumption of chromium and creosote is derived from these analyses.

Figures for production of vacuum-preserved and pressure-preserved wood were found in the Danish Statistics of Preserved Wood (Dansk Imprægneringsstatistik, 1998). Statistics Denmark has figures for import and export of different wood products, but the products are not grouped to preservation method (Statistics Denmark 1999a). The statistics on import/export seem only to include a minor part of the actual import/export of preserved wood, and figures on import/export have been derived from Hansen et al. (2000 b) (see appendix 2).

For the estimate of the total import/export of biocides with wood products, it is necessary to make some assumptions regarding the content of biocides in imported/exported products. The basis for the estimates can be found in Appendix 2.

It is by Hansen et al. (2000 b) estimated that the net import of pressure-preserved wood is about 90% of the Danish production for Cr-containing wood and about 20% for Cr-free wood (see appendix 2) thereby increasing the consumption of biocides for this purpose compared to the Danish production. The main import is from the other Nordic countries.

The consumption of biocides with vacuum-preserved wood products is slightly smaller than the consumption for production of these products in Denmark due to a net export of preserved windows and doors, but there is a considerable uncertainty regarding the biocides that are actually imported/exported.

Both production and import of wood preserved with arsenic is now prohibited, but chromium and creosote are still allowed in imported wood.

Table 4.18
Consumption of biocides with vacuum-preserved and pressure-preserved wood in Denmark 1998

The range between minimum and maximum values reflects the uncertainty of the preservation method of the products covered by the different commodity numbers in the trade statistics (see appendix 2).

Organotin compounds were not permitted after October 2000.

4.3.2 Preservatives for surface treatment

Preservatives for surface treatment are used for protection of wood constructions, which are only exposed to moistness at the surface and dry easily. The biocides used and the application areas are in many ways the same as for vacuum treatment, but surface application is cheaper and more suitable for larger constructions.

The preservatives are most often used as primers and covered by one or more layers of wood grain fillers and topcoats. In-can preservatives and film preservatives in wood grain fillers and topcoats are included in product-types 6 and 7.

The methods of surface treatment can be divided into:

	Immersion of the wood products into preservative baths
	Application by machinery
	Brush painting
	Spray painting.

4.3.2.1 Actors on the market

Suppliers of approved wood preservatives are listed in (Danish EPA 1999 B).

Producers and suppliers of wood preservatives are organised in the trade organisation 'The Danish Paintmakers Association' ('Foreningen for Danmarks Lak- og Farveindustri').

Main Danish producers of these preservatives in 1998 were Rentokil Initial A/S, S. Dyrup & Co A/S, Sadolin Woodcare, A/S Hygæa, Tanaco Danmark A/S, and Akzo Nobel Industrial Coating A/S.

Main suppliers of these preservatives in 1998 were (apart from producers) BASF Danmark A/S, Beta DK Aps, Kai R. Spangenbergs Eftfl. I/S, Hickson Timber Protection. Color Dragon A/S, Profa Amba, and Borup Kemi A/S.

The consumption of active agents in biocidal products used for surface preservation is shown in Table 4.19. The figures are derived from the Danish EPA. Some of the agents may as well be used for control of wood-destroying fungi in masonry.

The biocides are a very diverse group including boron, organotin, and other organic compounds. Both waterborne preservatives and preservatives based on organic solvents are used.

Table 4.19 Se her!
Consumption of biocides for surface preservation of wood in Denmark 1998 ¹⁾

Wood preservatives that contain propiconazol (CAS No 60207-90-1), boron acid (CAS No 10043-35-3) and disodium octaborate (CAS No 12008-41-2) are also approved for control of wood-destroying fungi in masonry, and a part of the consumption may in fact be used for masonry.

4.3.2.3 Consumption of biocides with finished products

The import/export of surface preservatives with wooden products is estimated to be quite small compared to the total consumption of preservatives for surface treatment in Denmark.

The relevant wooden products are not easily identified in the trade statistics, and due to the uncertainty the net import of surface-treated wood is estimated to range between 5,000 and 13,000 tonnes. See appendix 2 for the basis for the estimate. The biocides used for imported wood is roughly estimated under the assumption that the biocide content per tonne resembles the amount typically used for this application in Denmark.

The total consumption including import/export with wood products is shown in Table 4.20.

Table 4.20
Consumption of biocides for surface treatment of wood in Denmark 1998 including net import with surface treated wood

4.4 Product-type 9: Fibre, leather, rubber and polymerised materials preservatives

The group includes products used for the preservation of fibrous or polymerised materials, such as leather, rubber, paper and textiles by the control of microbiological deterioration of the material itself.

4.4.1 Preservatives for textiles

Biocides may be used for preservation of textiles during storage, transport and use of the textiles.

Liquids used during the production of the textiles (e.g. for sizing and finishing) and inks used for textile printing may also be preserved by biocides. The purpose of the use of these biocides is, however, to preserve the processing fluids or inks and not the finished textiles, and these agents are included in product-type 6: In-can preservatives.

The main application of preservatives for textiles is for preservation of textiles for outdoor applications. Preserved textiles are used for tents, tarpaulins, awnings, sunblinds, parasols, sails, waterproof clothing, etc. Virtually all textiles used for outdoor applications except clothing seem to be preserved by biocides. For in-door applications only shower curtains and in some instances mattress ticking are preserved.

Most of the textiles are made of synthetic materials like acrylic, polyester and PVC or is coated with PVC. The boundary between this sub-type and the sub-type 'Film preservatives for plastics' in section 4.2.2 is not clear-cut. For example bathroom curtains and tarpaulins are mainly made from reinforced soft PVC, whereas the function of the biocides is to prevent microbial growth on the surface. It has been chosen to include the PVC products in section 4.2.2 together with other uses of PVC and include the remaining textile products in this section, although the primary function of the biocides on synthetic textiles is also film preservative.

It is actually only for cotton textiles that the primary function of the preservatives is to preserve the fibres itself. Today cotton seems mostly (apart form clothing) to be used for garden furniture fabric, whereas it has been replaced by synthetic fibres for other applications. According to the producers of tents, awnings, etc. one of the reasons for this substitution is that the biocides on the market today do not provide the necessary protection of the cotton fabric. Cotton fabric was formerly preserved with pentachlorophenol (PCP), which is now prohibited in Denmark, but is still used for fabric in some other EU countries, especially the UK.

Biocides are not used for protection of textiles during storage and transport in Denmark, but textiles and clothing imported from sub-tropical and tropical areas, especially from Eastern Asia, may contain small amounts of biocides applied for preservation of the textiles during transport and storage in the humid and warm climate. The biocides are applied by spraying the biocides into the containers (Eksportrådet, 1996) and can be found in trace amount in textiles. Among the biocides, PCP seems still to be used to some extent in Asia for this purpose.

Clothing, especially for sport, may be preserved with biocides to prevent odour producing microbial growth on the sweat. One example is the use of tributyltin in some t-shirts. No examples have been found as regards the use of biocides for clothing for outdoor applications. It has within this project not been possible to assess these application areas further.

Table 4.21
Biocides used for textile products produced in Denmark ¹⁾

1) Most of the fabrics are produced abroad, but are used for production of tents and other products in Denmark

Imported tents, awnings, etc. are predominantly produced in Asia. It has been difficult to receive information on the biocides used for preservation of the fabric.

The total consumption of biocides with textile products can only be estimated with very high uncertainty. The total consumption of cotton textiles for outdoor use has by 1983 been estimated at 500-600 tonnes, which were all preserved with pentachlorophenol (Tørslev, 1985). The total supply of tents, tarpaulins, awnings and sails in 1988 can based on the trade statistics be estimated at 5,000-7,000 tonnes (inclusive non-textile parts of the products). Only a part of this is the fabric and only a part of the fabric is preserved. The tarpaulins are virtually all produced of PVC and are included in section 4.2.2.

Based on the present information it is estimated that approximately 600-1,400 tonnes preserved textile is annually used in Denmark. Cotton seems only to be used for garden furniture, whereas the rest of the textiles are made of polyester, acrylic and other synthetic materials.

The estimated total consumption of biocides with textiles is shown in Table 4.22.

Table 4.22
Consumption of biocides with textile products in Denmark 1998

4.4.2 Preservatives for leather

Biocides are applied to leather during the tanning process for life-time preservation of the leather.

The only large Danish producer of leather is Swewi Svendborg A/S, but tanning also takes place in small scale at Mønsters Garveri. The biocides for tanning are directly imported by the users from suppliers abroad. Leather and leather products are imported by a large number of companies.

Biocides used for tanning in Denmark are shown in Table 4.23. Some of the other chemicals used for tanning may also have a biocidal effect, although the primary function of the chemicals in the tanning process is another.

Table 4.23
Biocides used for tanning in Denmark

Leather and leather products used in Denmark are, however, mainly imported, and the Danish production only accounts for a small percentage of the consumption with finished products. The main biocides that can be expected to be present in imported leather products are listed in Table 4.24 (Frendrup, 2000).

Table 4.24 Se her!
Main biocides in imported leather and leather products ¹⁾

Chromium salts are widely used for tanning of leather. In 1998, about 80% of leather tanned worldwide was tanned with chromium salts (USGS, 1999). Chromium is not used any more for tanning in Denmark. The chromium salts may have a biocidal effect, but the main function of the chromium in the tanning process is not as a biocide, and chromium salts are consequently not included as biocide in this assessment. To give an impression of the magnitude of the chromium consumption with leather products, the consumption of chromium with leather products in Stockholm, Sweden, in 1995 has been estimated at about 6 tonnes (Lohm et al., 1997). Upscaled to the Danish population, it corresponds to some 20-30 tonnes chromium.

The total consumption of biocides for tanning in Denmark is considered confidential.

No assessment of the content of biocides in imported leather products is available. The average concentration of the biocides in the leather is estimated to be 200-300 ppm (Frendrup, 2000), but will vary by agent. The expected most common biocides in imported leather are indicated in Table 4.24.

The main application areas for leather are furniture, clothing, bags, shoes and riding gear. The total consumption of leather products cannot be estimated exactly from the trade statistics; e.g. leather furniture is not registered under specific commodity numbers, and the production of leather products is not registered in terms of weight. The total consumption of leather products in Denmark in 1998 is roughly estimated at 3,000-8,000 tonnes.

Table 4.25
Consumption of biocides with leather in Denmark 1998

4.4.3 Preservatives for rubber and other polymerised materials

Preservatives may be used for rubber products for two reasons:

	Preservation of liquid latex raw materials
	Preservation of the finished rubber products

Liquid latex is preserved for control of microbial growth in the liquid before polymerisation of the latex. The preservatives used for this application may instead be considered ‘In-can preservatives’.

Rubber products are in general not explicitly preserved against microbial degradation, but many of the chemicals used for manufacturing of rubber products may, however, have a biocidal effect as well. Product catalogues from leading suppliers of chemicals for the rubber industry includes in general no preservatives, but a few biocides are marketed for use in latex products (natural rubbers).

The only identified application where biocides are explicitly added to control microbial deterioration of the rubber is applications where the rubber is in permanent contact with soil, e.g. rubber in seal rings for tubes in soil. However, no specific information on the biocides in such products has been obtained.

Other polymerised materials include linoleum made from linseed oil. Linoleum has an inherent capability of preventing microbial degradation and growth at the surface due to some components of the linseed oil and is in general not added preservatives.

Polymerised materials like plastics, paints and fillers are added preservatives that are included in the product-types ‘In-can preservatives’ and ‘Film preservatives’. It has not been possible to identify applications where the preservatives are added to protect the polymers itself.

Enquiries to the main producers of rubber products in Denmark did not reveal any use of biocides for production of rubber products in Denmark.

To stabilise liquid latex and prevent coagulation, ammonia (CAS no. 7664-41-7) is added to the latex at concentrations of about 0.2-0.6%. The ammonia may as well have a biocidal effect by increasing the pH and is included in the 'List of biocidal substances' of July 1999 from the European Chemical Bureau. It will, however, not be considered a biocide in this report. Liquid latex, e.g. used for rubber under sides of carpets, was formerly preserved with formaldehyde, but this is no longer used in Danish produced carpets. According to a leading Danish producer of carpets and a supplier of latex, the same is presumed to be true for most imported carpets. In cannot, however, be excluded that some imported carpets or other products made from liquid latex may contain preservatives in the rubber.

As mentioned above, many of the chemicals used for manufacturing of rubber products may as well have a biocidal effect. The following list includes chemicals placed on the global market by some of the leading suppliers of chemicals for the rubber industry (the list may not be complete). The listed chemicals are all included in the 'List of biocidal substances' of July 1999 from the European Chemical Bureau, but is used in the processing of rubber as accelerators, antioxidants, vulcanising agents etc.

Formaldehyde (CAS No. 50-00-0)
Thioperoxydicarbonic diamide (CAS No. 97-77-8)
Carbamodithioic acid, dimethyl-, sodium salt (CAS No. 128-04-1)
Tetramethyl thiuramidisulfide (CAS No. 137-26-8)
Thioperoxydicarbonic diamide ([(H2N)C(S)]2S2), tetramethyl- (CAS No. 137-26-8)
Zinc, bis(dimethylcarbamodithioato-S,S')- (T-4)- (CAS No. 137-30-4)
2-Mercaptobenzothiazole, zinc salt (CAS No.155-04-4)
2(3H)-benzothiazolethione (CAS No. 149-30-4)
Zinc oxide (CAS No. 1314-13-2)
2(3H)-benzothiazolethione, sodium salt (CAS No. 2492-26-4)

Most of these chemicals can be expected to be present in products produced in or imported to Denmark.

It has not been possible to identify any use of biocides for production of synthetic rubbers. Product catalogues from suppliers of chemicals for the rubber industry (globally) contain in some instances biocides for use for preservation of latex and natural rubber products. It has not been possible within the boundaries of this project to try obtaining specific information of biocides in imported rubber products and in this way confirm the presence of these chemicals in products marketed in Denmark. The list, which may not be comprehensive, is shown in Table 4.1.

Table 4.26
Biocides that may be present in imported latex products ¹⁾

1) The list may not be comprehensive. The chemicals are in March 2000 marketed at the Internet as preservatives for latex.

4.4.3.3 Consumption of biocides with finished products

Due to lack of data it has not been possible to estimate the consumption of biocides with finished products of rubber and other polymeric materials.

4.4.4 Preservatives for insulating materials of organic fibres

Insulating materials of organic fibre materials like paper, cellulose, wool and flax (Linum) contain preservatives for control of microbial degradation of the fibres during use.

The preservatives are mixed up with the fibre materials before the insulation material is blown into the walls of the houses or placed above the ceiling. The used agents have both a biocidal effect and a flame retarding effect.

Insulation materials of organic fibres are produced in Denmark by Isodan Danmark A/S and Miljøisolering Aps.

The main suppliers of insulation materials of organic fibres are Miljøisolering Aps, Isodan Danmark A/S, Borry Henriksen ApS and Holbæk Byggemateriale Compagni A/S.

The main biocides used for this application area are boric acid and borax, which are used in insulation materials made of paper, cellulose fibres and wool. The boron compounds also have a flame retarding effect. Beside the boron compounds, the insulation materials may also contain aluminium hydroxide. The main function of the aluminium hydroxide is flame retardancy, but the compound may also have a biocidal effect by increasing the alkalinity of the material. Aluminium hydroxide will, however, not be considered a biocide in this context.

In flax, the main preservative seems to be ammonium sulphate, but ammonium phosphate may be used as well.

Table 4.27
Biocides used for preservation of insulation materials of organic fibres in Denmark

1) In the list of biocidal substances from the EU, ‘Borax’ is used as chemical name for CAS no. 12267-73-1, tetraboron disodium heptaoxide, hydrate.

2) The totals of borax and boric acid vary from 5-25%.

Insulating materials of paper account for the main part of the consumption of insulating materials of organic fibres (Table 4.28). The total content of boric acid and borax vary between 5% and 25% of the products dependent on whether the products are added other flame retardants (e.g. aluminium hydroxide). Based on information from suppliers, it is roughly estimated that the paper insulation on average contains 6-9% borax and boron acid with a 1:2 ratio between the two compounds. The consumption of insulation materials of wool is very close to 0 tonnes.

One of the main insulation materials of flax contains about 8% ammonium sulphate, and it is roughly estimated that the products on average contain 6-10% ammonium sulphate or ammonium phosphate.

Table 4.28
Consumption of preservatives for insulation materials of organic fibres in Denmark 1999

4.4.5 Preservatives for paper and other materials

‘Paper and other materials’ include:

	Paper and cardboard (other than insulating materials)
	Art and archaeological artefacts

Biocides used for prevention of slime formation during production of paper and cardboards are included in product-type 12: 'Slimicides'. Besides these preservatives may be used during the production process to control microbial growth in the wet paper, if it is stored before drying. According to the Danish paper factories, preservatives are not used for this purpose in Denmark.

Paper for applications where the paper can be exposed to moisture may be preserved. One example of use of preservatives for paper is preservation of library books that have been stored under moist conditions. No use of preservatives for this application in Denmark has been identified.

According to information from two museums in Denmark, biocides are not used for preservation of art, archaeological artefacts or other items in these two museums, but insecticides (included in section 5.5) are used for control of insects in the stores.

It has not been possible to identify any use of preservatives in Denmark for this application area.

4.5 Product-type 10: Masonry preservatives

Masonry preservatives are products used for preservation and remedial treatment of masonry or construction materials other than wood by the control of microbiological and algal attack.

The product-type does not include biocides for preservation of insulation materials, which are included in product-type 9.

Some of the wood preservatives are also approved for use on masonry. By attack of wood destroying fungi both wood and masonry may be preserved to control the fungi. These preservatives are included in section 4.3: 'Wood preservatives’. Apart from this, the only masonry preservatives identified are agents for treatment of algal attack on masonry.

Mortar, which is moist when stored, is not added preservatives, as the high pH prevents microbial growth during storage.

Producers and suppliers of products for cleaning of masonry are organised in the Danish Paintmakers Association (FDLF) and/or the trade organisation Soap, Perfume and Toiletware (SPT).

Suppliers of products containing masonry preservatives are S. Dyrup & Co. A/S, BN Skaderenovering I/S, Sadolin Farver A/S, Superfos A/S and Profa amba among others.

Biocides for prevention of algal attack (algicides) are to be approved by the Danish EPA. According to the ‘Survey of Approved Pesticides’ no algicides were approved in 1998. In 1999, only one product containing quinoclamine in horticulture was approved for use.

For use as masonry preservatives, two products containing fatty acids (C8-C18, main fraction: decanoic acid) were according to the Danish EPA approved in 1998 and 1999, but the products are not included in the ‘Survey of Approved Pesticides’.

A few years ago a number of products were approved for use as algicide (20 products in 1994). The most common active agents in the approved algicides were benzalkonium chloride and sodium hypochlorite. These agents are today not approved as algicides, but are allowed in cleaning materials. As a consequence, algae are today removed, and algal attack is prevented by use of ‘masonry cleaners’ instead of algicides.

Information on masonry cleaners from six of the main suppliers of formerly approved algicides has been obtained. The masonry cleaners from these all contain benzalkonium chloride or sodium hypochlorite, and the products in general have the same trade names as the formerly approved algicides.

Biocides used in products for cleaning of masonry is listed in Table 4.29.

Table 4.29
Biocides used for preservation and remedial treatment of masonry in Denmark 1998 ¹⁾

1) Wood preservatives containing propiconazol (CAS No 12008-41-2), boron acid (CAS No 12008-41-2) and disodium octaborate (CAS No 60207-90-1) are also approved for control of wood-destroying fungi in masonry.

2) ‘Benzalkonium chloride’ is also used as trivial name for CAS no. 8001-54-5 and CAS no. 959-55-7.

According to the Pesticide Statistics, the consumption of approved algicides in 1998 was 0 tonnes.

As mentioned above algicides are not used for prevention of algal attack on masonry anymore. As the same products are used today, the former use of algicides is assumed to give a good indication of the consumption of the active agents with 'masonry cleaners' today. The consumption trend from 1992 to 1996 is shown in Table 4.1.

Table 4.30
Consumption of active agents with algicides 1992-1996

1) Benzalkonium chloride was also active agent in some wood preservatives, which explains that the total consumption of the two agents is larger than the consumption of algicides.

Beside the consumption of sodium hypochlorite in approved algicides there has presumably in addition been some consumption of sodium hypochlorite in all-round cleaning materials applied for cleaning of masonry. Consequently the amount of sodium hypochlorite in approved products will somewhat underestimate the actual consumption.

The annual consumption will vary with higher consumption after mild winters. Based on information from suppliers the consumption has more likely increased than decreased since the mid-nineties.

Based on this information, the total consumption of biocides with 'masonry cleaners' in 1998 is estimated at 11-25 tonnes (Table 4.2). Some of the products may also be used as algicides indoors, but it is presumed to be a minor part of the total consumption.

Table 4.31
Consumption of biocides with products for preservation and remedial treatment of masonry in Denmark 1998 ¹⁾

4.6 Product-type 11: Preservatives for liquid-cooling and processing systems

Products of this product-type are used for the preservation of water or other liquids used in cooling, heating or processing systems by the control of harmful organisms such as microbes, algae and mussels. District heating systems are neither liquid-cooling systems nor processing systems, but are included here, as they do not fit into any other product-type.

The product-type does not include slimicides (product-type 12) and products used for the disinfection of drinking water (product-type 5), drinking water drainwork (product-type 4), preservation of metalworking-fluids (product-type 13) and moisteners used in the printing process (product-type 6, section 4.1.4).

Biocides are applied to the systems either to preserve the liquids (control of microorganisms) or to disinfect the systems (kill the microorganisms) (Dokkum et al., 1998).

Biocides used for preservation of the liquid cooling system or air-conditioning systems are included here although the biocides in semi-open systems may serve as both preservatives and disinfectants. Microbial growth in the systems leads to biofilm mediated corrosion, and the formation of biofilms increases the heat exchange resistance of the systems.

The liquid systems can be organised into three types (Dokkum et al., 1998):

	Once-through cooling systems
	Open recirculation systems
	Closed recirculation systems

Once-through systems can be used when plenty of cheap cool water is available and adequate facilities for disposal of warm waterare available. Once-through cooling systems may be used for power plants and industrial installations. No use of biocides has specifically been identified for these systems, but biocides may be used in the systems.

Open recirculation systems are mainly used for cooling water in the food-processing and pharmaceutical industry and in large air-conditioning systems. The water in these systems is cooled down in open cooling towers. In these systems, the biocides are applied by shock dosage at a frequency of usually once or twice a week. To prevent development of resistant bacteria usually two biocides are used alternately. The water in the semi-open systems is changed continuously, and the average residence time of the water may be down to a few hours.

Closed systems include first of all district heating systems, but also liquid systems of air-conditioning systems. The biocides are added continuously. The control of microbial growth in district heating systems has thoroughly been described by Smidt et al. 1998.

Open processing systems are used for pressure founding and wash of semi-manufactures and tolls. Microbial growth may as well be a problem in these systems, but the use of biocides for control of the growth in these systems is not as widespread as in the food-processing and pharmaceutical industry.

In air-conditioning systems with open recirculating cooling water, the biocides may as well be applied for control of pathogenic bacteria; especially some species of Legionella. Some of the applied biocides are particularly efficient in the control of these organisms and are often used in air-conditioning systems of hospitals. The bacteria in the cooling water may be released with aerosols from the cooling towers and expose patients via e.g. windows. The content of Legionella in the cooling water is not a hospital specific phenomenon, but patients may be more liable to infection than the main population.

Main suppliers of biocidal products for preservation of water used in cooling, heating or processing systems are Hydro-X A/S, Ashland Denmark A/S and Aqua-Sur A/S.

Biocides used in Denmark for the application area are shown in Table 4.32.

The main biocides of choice for district heating system are quaternary ammonium compounds. According to a study on microbial corrosion in district heating systems, four groups of biocides are proposed by suppliers for use in district heating systems: Hydrogen peroxide, glutaraldehyde, quaternary ammonium compounds and isothiazolones, but only the use of quaternary ammonium compounds and isothiazolones is evident (Schmidt & Frølund, 1998). According to a survey from 1994, about 8% of the district heating stations used biocides.

For cooling water in air-conditioning systems and for the food processing and pharmaceutical industry, a number of biocides is used.

Table 4.32
Biocides used for preservation of water for cooling, heating and processing systems in Denmark

1) Particularly applied for control of pathogenic bacteria in air-conditioning systems.

The total consumption of biocides for this application area is estimated on the basis of a questionnaire estimated to cover more than 80% of the market (see Table 4.33).

The market for biocides for cooling water and processing water is increasing, as it becomes more evident that corrosion and other operational problems of the systems are microbially mediated.

Table 4.33
Consumption of preservatives for cooling, heating and processing systems in Denmark 1999

4.7 Product-type 12: Slimicides

Slimicides are used for the prevention or control of slime growth on materials, equipment and structures used in industrial processes.

The product-type can be organised into two sub-types:

	Slimicides for wood and paper pulp
	Slimicides used by oil extraction and fuel storage

4.7.1 Slimicides for wood and paper pulp

Slimicides are added to paper pulp to prevent the formation of slime during the pulping process by biocidal control of bacteria in the pulp. The slime formation may also be controlled by other agents as enzymes, and there seems to be a trend toward the use of these other agents.

Suppliers of approved slimicides (1999) are Flemming Zwicky Aps., Chr. Krogh A/S and BetzDearborn AB (Sweden).

The main Danish producers of paper and paper products are Dalum Papir A/S, Skjern Papirfabrik A/S, Grenaa Papir A/S, Drewsen Silkeborg Papirfabrik A/S and Brødrene Hartmann A/S. Paper pulp is used in small scale by a few additional users.

Biocides for control of slime in paper pulp have to be approved by the Danish EPA and aredescribed in the survey of approved pesticides (Danish EPA 1999 B).

The consumption of slimicides in Denmark in 1998 is listed in Table 4.34.

Table 4.34
Consumption of slimicides for pulp and paper in Denmark 1998 ¹⁾

1) Consumption according to the Danish Pesticide Statistics 1998 (Danish EPA 1999 A).

2) According to the Danish survey of approved pesticides 1998 (Danish EPA 1999 B). Includes only the number of products for this application.

3) Was not permitted after December 31, 1998.

4) Used for prevention of microbial growth in paper-pulp (not paper manufacturing). Not approved as slimicide.

According to two paper producers, the content of the biocides in the finished paper is expected to be insignificant, but no analysis is available (Hoed, 2000; Tang, 2000). The biocides are water-soluble and are expected to follow the process water to the wastewater treatment system. The trace amounts following the fibre fraction are expected to be decomposed during the subsequent paper production processes.

A British report regarding pentachlorophenol (PCP) in paper and cardboard indicates that PCP may be present in paper and cardboard in trace amounts (MAFF, 1997). PCP has previously been widely used as slimicide in paper pulp and may still be in use in some countries out of Europe. In 36 out of 403 samples, PCP was found in concentrations above 0.008 ppm, with 0.7 ppm as the highest value. PCP is, however, a relatively stable compound.

On this basis, the content of biocides in the finished paper is assumed to be low, and no attempt has been done to estimate the content of biocides in the finished paper.

Paper pulp with copper sulphate is mixed with other raw materials and ends up in finished building materials.

4.7.2 Slimicides and other biocides used at oil extraction and fuel storage

Biocides are used at oil extraction for three purposes:

	Control of slime forming microorganisms in water-based drilling mud during storage (when necessary)
	Control of hydrogen sulphide formation by sulphate reducing bacteria by oil extraction
	Control of microbial growth and hydrogen sulphide formation in oil pipelines

Actually only biocides used for control of slime formation by preserving the drilling mud should be included in the product-type 'Slimicides', but for the sake of the clearness all biocides used by oil extraction and storage of oil are included here.

The biocides are added to flows pumped into the reservoir (drilling processes, injection and reinjection water) and to the transportation flow of produced oil and gas before transportation by either pipeline or tanker to shore.

The biocides are generally used in the offshore industry in very large quantities and are therefore supplied to the rig/platform in bulk containers. Chemicals from bulk containers are usually added to the drilling mud, the water injection or production flows through closed systems.

When the used drilling mud reappears at the surface, cuttings are separated from the mud in a shaker system, and the drilling mud is discharged to the sea.

Based on information from one Danish refinery, it is estimated that biocides are not added to the crude oil or oil products at the refineries. Microbial growth is prevented by avoidance of water in the tanks with crude oil and oil products.

During storage of fuels, especially diesel and fuel oil, slime formation by microorganisms may take place if water finds it ways into the tanks. The phenomenon is in Denmark known as 'diesel plaque' (in Danish: 'diesel pest'). The biocides are not preventively added to the fuel, but preventive addition of biocides is to some extent done by the owners of fuel tanks; for example on ferries. Biocides are most commonly only used when an infected tank is to be disinfected. Diesel plaque was formerly a more widespread phenomenon, but is today reduced by avoidance of water in the tanks.

Beside this, biocides may be used in antifouling paint for oilrigs, but according to the reports from the contractors to the Danish EPA, antifouling paints are not used for this purpose in the Danish oilfields.

Suppliers of biocides for offshore activities have not been surveyed.

All emissions from offshore activities in the Danish part of the North Sea are reported by the operators to the Danish EPA. For this assessment, the Danish EPA has asked for more specific information on the used biocides in 1998. The results are shown in Table 4.35 and Table 4.36.

Isothiazolones are used for disinfection and preventive control of microorganisms in fuel tanks. The compounds used, CIT an MIT, are also used as in-can preservatives for paint, fillers and other products.

Table 4.35
Biocides used for control of microbial growth by oil extraction and fuel storage in Denmark

4.7.2.3 Consumption of biocides with finished products

The consumption of biocides by oil extraction and fuel storage is shown in Table 4.36. Due to confidentiality, only the total consumption of slimicides in drilling mud and biocides for other offshore activities respectively, is given.

Table 4.36
Consumption of biocides for control of microbial growth by oil extraction and fuel storage in Denmark 1988

4.8 Product-type 13: Metalworking-fluid preservatives

Metalworking-fluid preservatives are used for control of microbial deterioration of metalworking fluids.

Metalworking fluids are a very diverse group of products. An assessment of metalworking fluids marketed in Denmark 1987 includes more than 300 different products of which 133 products contain preservatives (Brandorf & Fries, 1987).

The main objectives of metalworking fluids are reduction of friction, removal of heat and flushing away chips. The fluids are nearly always used in closed or semi-open systems where the fluids are recirculated and filtered to remove chips.

Biocides are added as preservatives to metalworking fluids based on emulsions, synthetic or semi-synthetic fluids and fluids based on pure vegetable oils. Metalworking fluids based on pure mineral oils and solvent-based liquids contain in general no biocides.

Besides the use as preservatives, biocides are also used for thorough disinfection of the systems by maintenance of the systems and changing of the fluids. The biocides are for this application strictly speaking not used as preservatives but as disinfectants, but will nevertheless be included here.

The main Danish producer of metalworking-fluids is Castrol A/S. The main suppliers of metalworking-fluids are Castrol A/S, Fuchs & Sidal A/S, Rocol Scandinavia A/S, A/S Dansk Shell and Houghton Danmark A/S, but there is a large number of minor suppliers.

Biocides identified as used for metalworking fluids in Denmark are listed in Table 4.37.

Table 4.37
Identified biocides used for metalworking-fluid in Denmark

There are 30 biocides registered as preservatives in metalworking fluids in PROBAS. The list of preservatives is not shown due to confidentiality.

4.8.1.3 Consumption of biocides with finished products

The consumption of biocides with metalworking fluids in Denmark is estimated from information from suppliers covering approximately 70% of the market. The biocides have been organised into three groups: Quaternary ammonium compounds, isothiazolones and 'Other' (Table 4.38).

Table 4.38
Consumption of biocides for preservation of metalworking fluids in Denmark 1999

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