An Update: Science Versus Politics in the Environmental Regulatory Process

March 6, 2000

An Update: Science Versus Politics in the Environmental Regulatory Process

John E. Heinze, Ph.D.
Technical Director
Council for LAB/LAS Environmental Research


The Council for LAB/LAS Environmental Research, CLER, is an organization of scientists and technical experts whose mission is to conduct research and to provide information on the environmental acceptability of linear alkylbenzene sulfonate, LAS. There are five member companies in CLER: CONDEA-Vista Company, Deten Química S.A., Huntsman Corporation, Petresa and Quimica Venoco, C.A.

LAS is the leading surfactant used in laundry detergents worldwide. LAS was first introduced in the 1960s in the United States and in Europe as a replacement for branched alkylbenzene sulfonate (ABS), a slowly biodegrading surfactant which caused excessive foaming in sewage treatment plants and receiving streams and rivers. Consequently, LAS may be considered the first “green” surfactant because it was the first surfactant introduced to solve an environmental problem.

This is an update of a paper presented at the 1998 World Detergents Conference (Heinze, 1999). The focus is the process by which environmental regulations are enacted and the sometimes conflicting role of politics and science in the regulatory process. A disturbing case in point is Danish Executive Order Number 823, enacted in September, 1996.

In our view, there are two fundamental defects of this environmental regulation: first, it is not based on the available science; and second, it does not use accepted procedures for environmental risk assessment. Certainly for LAS, one of the four compounds regulated by the Executive Order, there is an extensive database of scientific information available on its environmental properties (ECOSOL, 1994; Kloepper-Sams et al., 1996). Moreover, a technical guidance document has been issued by the European Commission on procedures for conducting an environmental risk assessment (European Commission, 1994). Danish Executive Order Number 823 incorporates only some of the scientific information available on LAS and does not adhere to the risk assessment procedures in the technical guidance document.

Although this Executive Order is but a single regulation in a country of 5.5 million inhabitants, such regulations can have far-reaching consequences. Regulations intended to improve public health or the environmental may be copied in other countries. Once enacted, regulations are seldom withdrawn and often lead to further regulations on the same materials. Since we live in a global economy, regulatory actions in Denmark may increase the cost of laundry detergents in Denmark and in other parts of Europe.

I think we would all agree that science should be the primary basis for regulatory decisions on human health and the environment. If the available science has not been used as a basis for a regulation and if the regulatory process is not open to discussion of the scientific basis for the regulatory decision, then the affected industry must become active in supporting the role of science in the regulatory process. Otherwise, the acquiescence of industry will be interpreted as agreement with the regulation and the regulatory process.

Further, if the regulation concerns detergent and cleaning product ingredients, as does Danish Executive Order Number 823, then the detergent industry must advocate the use of the available science in the regulatory process.

This paper will consider three aspects of the topic: first, Danish Executive Order Number 823 and its implications for detergent and cleaning product formulations; second, the regulatory process used to enact the Executive Order; and third, the detergent industry response and an update on the situation in Denmark.


The bio-solids, or sludge, from municipal sewage treatment plants have been used for many years as a low cost fertilizer and soil conditioner. The European Union Council Directive of June 12, 1986 set limits on the levels of heavy metals (cadmium, chromium, copper, lead, mercury, nickel, and zinc) in sludge that can be used for agricultural purposes (European Economic Community, 1986). Danish Executive Order Number 823 sets maximum permissible levels, or “cut off values,” on four organic compounds in sewage sludge used for agricultural purposes in Denmark (Lorenzen, 1996).

The four regulated compounds are: LAS, NPE, DEHP and Total-PAH. LAS, as previously indicated, is linear alkylbenzene sulfonate, the major surfactant used in laundry detergents and cleaning products in Denmark and worldwide.

“NPE” is defined as nonylphenol plus the one and two mole ethoxylates of nonylphenol. These are not the typical commercial materials but are primarily biodegradation intermediates of commercial nonylphenol ethoxylates. Commercial nonylphenol ethoxylates are surfactants used in industrial and institutional cleaning products and numerous other industrial applications.

DEHP is di (2-ethylhexyl) phthalate, a softening agent or plasticizer used to impart flexibility and used specifically in the production of vinyl plastic.

Total-PAH is defined as the sum of nine specific polycyclic aromatic hydrocarbons [acenaphthene, benzo(a)pyrene, benzo(ghi)perylene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, phenanthrene, pyrene, and three benzofluoranthenes (b+j+k)]. These materials are byproducts of combustion or incineration.

Executive Order Number 823 sets cut off limits for the four materials in sludge used for agricultural purposes. The cut off values for LAS are 2600 and 1300 milligrams per kilogram dry weight of sludge. The first cut off limit became effective on July 1, 1997. The lower limit becomes effective July 1, 2000.

The stated purpose of the Executive Order is to “ensure elimination of concentrations of substances which over a period of time and by repeated application may have damaging effects on farm land or entail unacceptable loading on subsurface waters, crops or domestic animals and, as a result, on human beings” (Lorenzen, 1996). Notice that the justification is based on the mere possibility of environmental and human health effects. The Executive Order does not consider whether environmental concentrations are at levels that pose any actual risk.

In fact, the Executive Order is not based on an environmental risk assessment or an overall risk-to-benefit balance to society. Instead, it seems to be based on an interpretation of the Precautionary Principle. The Precautionary Principle (United Nations, 1992) states: “In order to protect the environment, the precautionary approach should be widely applied by states according to their capabilities. When there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used for postponing cost-effective measures to prevent environmental degradation.”

However, in the case of LAS, there is extensive scientific data, including environmental monitoring studies, to demonstrate that the residual levels present in sludge-amended soil rapidly biodegrade and do not accumulate (Marcomini and Giger, 1988; Berna et al., 1989; Figge & Schöberl, 1989; Holt et al., 1989; Prats et al., 1993). Furthermore, this extensive data set indicates that current LAS levels pose minimal risk to human health or the environment (Mieure et al., 1990; Holmstrup & Krogh, 1996; Kloepper-Sams et al., 1996; Severinsen et al., 1996; de Wolf and Feijtel, 1997, 1998). Consequently, the Precautionary Principle does not justify the sludge limits set in Danish Executive Order Number 823, at least for LAS.

The Executive Order has several implications, some of which we are still attempting to understand. One implication is that each municipality in Denmark which intends to provide sewage sludge for agricultural uses will be required to test its sludge for levels of the four organic compounds. Delays in the development of suitable analytical methods and in certification of testing laboratories resulted in postponement of sludge testing to July 1, 1998 (Jørgensen, 1997b). Consequently, it appears that the Executive Order was enacted without adequate laboratory capacity in Denmark to comply with the testing requirements.

Some Danish municipalities which suspect that their sludge does not meet the cut off values have indicated that they intend to pursue source reduction activities. For instance the City of Herning, Denmark, requested that The Association of Danish Cosmetics, Toiletries, Soap and Detergent Industries, SPT, provide a list of all laundry detergents which contain LAS so that the city could encourage consumers not to purchase these detergents (Herning Folkeblad, 1997). In September, 1999, the Danish Environmental Protection Agency (EPA) provided a brochure for distribution by municipalities to encourage consumers to buy laundry detergents not containing LAS (Danish EPA, 1999).

Consequently, a second implication of the Executive Order is potential consumer de-selection of specific detergent products, organized and promoted by local governments, and the national government, in Denmark. De-selection would provide no real benefit to the environment in Denmark, as is known from the extensive environmental information available on LAS and other detergent surfactants (Stalmans et al., 1995; Kloepper-Sams et al., 1996; Andree, 1997; Matthijs et al., 1997; van de Plassche et al., 1997; de Wolf and Feijtel, 1997, 1998), and would likely lead to higher prices for laundry detergents.

A third implication of the Executive Order illustrates how environmental regulations can have unintended consequences which adversely impact the environment. One of the provisions of Danish Executive Order Number 823 requires each sewage treatment plant providing fertilizer to have enclosed facilities adequate to store its entire production of sludge for seven months. This regulation follows on existing Danish regulations which allow sludge application to soil only in the spring and autumn of the year, thus requiring up to seven months storage of sludge before soil application. Traditional sludge storage practices had consisted of storage of sewage sludge, covered with straw, in open fields (Madsen, 1996). Thus this provision of the Executive Order appears to mandate improved storage of sludge that would reduce possible run-off and leaching of sludge components and reduce odors associated with storage of mounds of sewage sludge in open fields.

The capital costs of building the required sludge storage facilities exceeds the cost of alternative, but less environmentally preferred, sludge disposal methods, including construction of incinerators to combust the sludge (Jørgensen, 1997a). As a result of this provision of the Executive Order, the uncertainties that sewage sludge will meet organic compound cut-off limits, and continuing concerns by farmers regarding the safety of sewage sludge, the percentage of municipalities choosing to apply sludge to soil has been reduced from 70% in 1994, before the Executive Order was enacted, to 50% in 1997 and to an estimated 25% by the year 2000 (Jørgensen & Weitling, 1997).

The Danish EPA has publicly stated that the intention of the Executive Order was to re-assure farmers in Denmark that sewage sludge was safe for application to agricultural soil and thus to maintain this environmentally preferable option of sludge disposal (Lynghus, 1996). How did the Danish government enact an Executive Order which has had exactly the opposite impact?


This section consists of a chronology of the key events in Denmark before, during and immediately after the Executive Order was issued.

In November, 1995, scientists from CLER and our sister organization in Europe, the European Center of Studies on LAB/LAS (ECOSOL), met with an EPA official to discuss the results of a biodegradability test on LAS conducted by a consulting laboratory for the EPA (Madsen et al., 1994). During the course of this meeting, CLER and ECOSOL representatives reviewed data demonstrating that LAS is rapidly and extensively mineralized in laboratory tests for biodegradability (Schöberl, 1989). Real world data were presented demonstrating that residual levels of LAS in sewage sludge rapidly biodegrade in sludge-amended soil and do not accumulate even under conditions of repeated sludge application (Marcomini and Giger, 1988; Berna et al., 1989; Figge & Schöberl, 1989; Holt et al., 1989; Prats et al., 1993).

A representative of one of the contract laboratories used by the Danish EPA mentioned that they would be initiating a study on the biodegradation and toxicity to soil bacteria of LAS and other organic compounds in sludge-amended soils. However, no mention was made of possible sludge regulations by the EPA official or any of the EPA consultants present.

In May, 1996, officials of the Danish Ministry for Energy and the Environment announced their intention to issue an Executive Order, proposing cut-off values for LAS, NPE, DEHP and PAH in sludge. According to the announcement letter from the Danish Ministry (Lorenzen, 1996), the four organic compounds were “recognized as dangerous for the environment” and cut-off values in sludge were based on their “general policy of phasing out the presence of substances that are dangerous to natural processes.”

For LAS, cut-off value was defined on the basis of an “ecotoxicological soil quality criteria” but further details were not provided.

The Danish detergent industry association, SPT, contacted CLER, ECOSOL and the international surfactants and detergents industry for assistance in providing a response. An official written response was provided within the deadline by the European Chemical Industry Council (CEFIC) on behalf of the soap and detergent industry (Jassogne, 1996b). The industry response challenged the conclusion that LAS is dangerous for the environment, pointed out that the proposed sludge limits had not considered relevant European regulations on sludge use, and objected to the fact that the Danish EPA had “reached a conclusion on the environmental acceptability of LAS without conducting a risk assessment in an open manner and using science based procedures.”

On June 25, 1996, CLER, ECOSOL and international surfactants and detergents industry representatives met with SPT representatives and agreed to request a formal meeting with the EPA to discuss the sludge cut off values. In late August, 1996, SPT received a response from an EPA official that a meeting with industry would not be possible until October.

In early September, 1996, CLER, ECOSOL and international detergent industry scientists scheduled a meeting with an EPA scientist to discuss the proposed sludge cut off values. This meeting was canceled by the EPA representative one day prior to the meeting. Two days later EPA officials held a briefing to explain the proposed sludge cut off values to interested members of the Danish public. There was no detailed discussion of the scientific basis for the sludge limits according to the SPT representative who attended the briefing.

On September 16, 1996, Executive Order Number 823 was officially issued by the Danish Ministry for Energy and the Environment. The cut off values for LAS and the three other organic compounds were identical to those announced the previous May.

On October 21, 1996, scientists from CLER, ECOSOL and the international surfactants and detergents industry met with EPA officials in Copenhagen to discuss the scientific and technical basis for the sludge limits on LAS. Industry representatives provided detailed comments on the sludge limits, summarized in Figure 1. These comments concluded that there was no scientific basis for the statement made by the EPA that LAS is “dangerous for the environment,” and that the cut off values for LAS in sludge were based on unrealistic assumptions, did not follow recommended European procedures for risk assessment and did not consider the environmental data on LAS.

EPA officials responded that scientific and technical comments should be discussed with the Danish consulting institutes that the EPA relies upon to develop environmental regulations and that, in any case, the EPA would only consider making the sludge limits more restrictive, not less.

In October 1996, two researchers at the Danish National Environmental Research Institute, one of the consulting institutes used by the EPA, published a paper in the science journal Environmental Toxicology and Chemistry on the effects of LAS on a common soil organism (Collembola) which plays an important role in the breakdown of plant litter and nutrient cycling in the soil (Holmstrup & Krogh, 1996). The authors conclude that negative effects from LAS on populations of

this organisms would be expected only “at concentrations 8 to 20 times higher than those likely to be found in sludge-amended soil.”

Figure 1

Scientific and Technical Comments Provided by the Soap and Detergent Industry on October 21, 1996, to the Danish Environmental Protection Agency (EPA) regarding Executive Order Number 823 (Industry Coalition on LAS in Denmark, 1996)

  • There is no scientific basis to support the statement made by the Danish EPA that LAS is “recognized as dangerous for the environment.”
  • The cut off values for LAS in sludge should be much higher than the proposed values
    1. The cut off values assume an unrealistic level of sludge use based on current Danish rules for phosphate application to agricultural lands and the phosphate content of sewage sludge.
    2. The cut off values do not consider biodegradation in sludge during the handling, storage and transportation of sludge in Denmark before application to agricultural lands.
    3. The cut off values do not consider biodegradation in soil in the mandatory waiting period before crop use. Numerous studies demonstrate that LAS undergoes rapid biodegradation in soil, with half-lives of 10 to 30 days.
    4. The cut off values do not consider biodegradation in the soil during the crop growing season as recommended by the EU Technical Guidance Document for Environmental Risk Assessment.
    5. LAS contributes to the organic nutrients in sludge, and cut-off values should not be set lower than required by soil quality criteria.

In November 1996, a second environmental consultant used by the Danish EPA, Professor Niels Nyholm of the Technical University of Denmark, and his colleagues published a paper in the science journal Chemosphere describing a regional model for conducting environmental risk assessments for Denmark (Severinsen et al., 1996). LAS was one of the reference compounds used to evaluate the model. The model calculates that the ratios of predicted environmental concentrations (PEC) to predicted no effect concentrations (PNEC) for LAS in soil, water and sediment would range from 0.02 to 0.18. These values (ratios less than 1.00) indicate that LAS poses low risk to the environment in Denmark.

In January, 1997, CEFIC received an official response from the Danish EPA to the letter submitted in June, 1996, regarding the proposed sludge limits on LAS. The EPA replied that they did not have the resources to respond to comments from outside Denmark (Hedeman, 1997).

We conclude that Danish Executive Order Number 823 was developed under a regulatory process that was not open to comment on the scientific basis of the regulation.


The detergent industry has responded to the enactment of Danish Executive Order Number 823 with two separate but complimentary activities.

The first and largest effort involves consultation with Danish environmental consulting firms. Danish EPA officials indicated that they rely on environmental consulting organizations to develop the scientific basis for proposed regulations. Consequently, industry concluded that it would be necessary to conduct environmental research on LAS under Denmark-specific conditions with Danish environmental consulting organizations used by the EPA. Although this research would, in part, replicate research which had previously been conducted in other countries in Europe, it was felt that this research would generate additional data which could be used to convince the EPA that LAS in sludge posed no risk to the environment in Denmark.

Consultation with Danish environmental research organizations began with the formation of an industry coalition on LAS in Denmark. This coalition consists of seven companies or organizations, of which CLER participates as one of the organizations. Coalition activities are administered by CEFIC.

The research sponsored by the industry coalition on LAS in Denmark is summarized in Figure 2.

The studies were conducted by three Danish consulting organizations: the Water Quality Institute (VKI), the National Environmental Research Institute (NERI), and the Danish Institute of Agricultural Sciences (DIAS). The VKI

Figure 2

Research Studies and Budget of Danish Consulting Organizations

Sponsored by the Industry Coalition on LAS in Denmark

Water Quality Institute (VKI)

Focus: LAS fate in sludge and soil

    1. Testing and modeling of transport in Danish soil
    2. Degradation during sludge storage

A) Danish conditions

B) During sludge composting

    1. Final report

National Environmental Research Institute (NERI)

Focus: LAS effects on soil organisms

1. Review of scientific literature

    1. Identification of soil organisms for testing
    2. Toxicity to selected soil organisms

A) Invertebrates (five species)

B) Microorganisms (five species)

C) Influence of soil type

D) Influence of calcium and magnesium

E) Influence of sludge aging

    1. Statistical derivation of Predicted No Effect Concentration and final report

Danish Institute of Agricultural Sciences (DIAS)

Focus: Long-term effects on soil

  1. Microbiological parameters

Total Research Budget $410,000

studies focused on the biodegradation of LAS during sludge storage and composting and on possible LAS migration in soil. The NERI and DIAS studies focused on measuring a predicted no effect concentration (PNEC) of LAS for soil organisms. For these studies NERI examined a number of soil invertebrates and microorganisms, and various factors that may influence the soil PNEC. DIAS, which worked under subcontract to NERI, measured long term effects of LAS on microbiological parameters in soil. The total budget for this research was over four hundred thousand dollars.

This research was completed in early 1999 and presented in a science workshop sponsored by SPT in coordination with the Danish EPA (SPT, 1999). In this workshop, Danish EPA-sponsored research on LAS was also presented and the full set of results were discussed openly.

The SPT workshop report concludes that:

“Even at a concentration of LAS in sludge equal to the highest observed in Denmark, LAS is not predicted to cause a problem when half-lives are less than 25 days, provided that less than 8 tons of sludge is applied per hectare per year.”

Since legal restrictions in Denmark limit the amount of sludge applied to soil to less than 8 tons per hectare per year (Madsen, 1996) and since LAS rapidly biodegrades in soil, with half-lives less than 25 days (Marcomini and Giger, 1988; Berna et al., 1989; Figge and Schöberl, 1989; Holt et al., 1989; Prats et al., 1993), even the highest concentration of LAS observed in sludge in Denmark poses no risk to the soil.

Although the workshop found no scientific basis for restrictions on LAS levels in sludge used as fertilizer in Denmark, Danish authorities have apparently not changed their approach towards regulating LAS. This approach was clearly demonstrated by the “Avoid LAS” brochure prepared by the EPA and distributed to municipalities in September, 1999, to encourage consumers to buy laundry detergents that do not contain LAS (Danish EPA, 1999). This brochure contained factual errors and misrepresented the science on LAS (CLER, 1999).

The second, smaller activity, supported by the industry coalition on LAS in Denmark, focused on efforts to communicate the science on LAS to interested parties in Denmark.

These efforts began in response to the February, 1996, publication of a major report on LAS in an influential Danish weekly publication, Ingeniøren(The Engineer) (Breinholt, 1996). The front page and following articles in this publication reported the results of unpublished VKI studies which concluded that LAS levels in treated wastewater may pose a risk to salt water organisms.

The articles also quoted the results of two unpublished Danish EPA studies which concluded that LAS was the man-made substance found in the largest amounts in treated wastewater and sewage sludge.

Both CLER and ECOSOL submitted letters to Ingeniøren pointing out that real world studies have demonstrated that LAS levels in the environment are below the lowest adverse effect levels reported by VKI or other researchers, and that numerous studies have concluded that LAS poses little risk to aquatic or terrestrial environments. These letters were published in April, 1996 (Heinze, 1996; Jassogne, 1996a).

In 1997, communications activities continued with the preparation of a white paper on LAS (Industry Coalition on LAS in Denmark, 1997). This white paper reviewed, in non-technical language, industry comments on the sludge limits and the scientific data indicating that LAS in sewage sludge poses little risk to the environment from the use of sludge as fertilizer.

When the first phase of the sludge limits became effective in July, 1997, the white paper was distributed to Danish municipalities and associations of municipalities which are directly affected by the Executive Order. This white paper was also distributed to Danish civil engineering firms who provide advice to municipalities on the most cost-effective methods for fulfilling the sludge regulations. The white paper also proved useful to SPT in responding to grocery chains and individual stores which inquired about LAS levels in laundry detergent after being approached by local municipalities.

Copies of the white paper were also distributed to various Danish politicians, including members of the Parliamentary Committee on Environment and Planning, which has oversight responsibility for the Ministry for Energy and the Environment. Members of the Committee then posed questions to the head of the Ministry for Energy and the Environment regarding the sludge regulations. After these questions were raised in the Danish Parliament, members of the industry coalition on LAS met for a second time with Danish EPA representatives. At this meeting, held in December, 1997, EPA officials indicated, for the first time, a willingness to consider the results of the industry sponsored research on LAS under Danish sludge and soil conditions.

Regrettably, the Danish authorities have ignored the results of this research and continue to take actions, such as distribution of the “Avoid LAS” brochure, based on policy rather than science. These actions have consumed public resources without providing any demonstrated benefit to the environment.


To summarize our experience to date in Denmark, CLER would like to emphasize one final point:

It is surprisingly easy to enact regulations which impact ingredients and thus dictate detergent and cleaning product composition. In the case of Danish Executive Order No. 823, which sets cut-off limits on organic compounds in sewage sludge, this has been done by:

1) the use of selected data, thus ignoring the extensive scientific information available;

2) assumptions in the calculations of the cut-off limits which are not based on accepted procedures for environmental risk assessment; and

3) a regulatory process which minimized or precluded stakeholder involvement and thus was not open to comment on the scientific basis of the regulation.

The lesson for all of us from Danish Executive Order No. 823 is that science can easily be outweighed by politics and expediency in the environmental regulatory process. The legal rulemaking procedure — “due process” as we would call it — may have been followed in Denmark. However, the absence of an analogous process for input and discussion of the available scientific information and approved procedures for environmental risk assessment has given rise to a regulation that reflects a policy rather than science. The result may well be a significant and diverse economic impact with no real environmental gain.


Andree, H., 1997, Conclusions from the Colloquium of the Hauptausschuß Detergentien “The State of the Debate on the Ecological Risk Assessment of Surfactants” on 24th April 1997 in Frankfurt, Tenside Surf. Det. 34:224.

Berna, J.L., F. Ferrer, A. Moreno, D. Prats and F.R. Bevia, 1989, The Fate of LAS in the Environment, Tenside Surf. Det. 32:101-107.

Breinholt, T., 1996, Sænestof Rykker ved Ökosystemer (Soap Suds Dislocate the

Ecosystem), Ingeniøren, February 2, 1996, page 1, and related articles, pages 16-18.

CLER, 1999, “CLER’s Response to the Danish EPA Brochure ‘Avoid LAS,'” under “Denmark” at the Internet web site.

Danish EPA, 1999, Undgå LAS (Avoid LAS), Environmental Protection Agency, Copenhagen, Denmark, September, 1999.

de Wolf, W. and T. Feijtel, 1997, Terrestrial Risk Assessment for Linear Alkylbenzene Sulfonate (LAS) in Sludge-amended Soils: A Literature Review, Specialty Conference “Management and Fate of Toxic Organics in Sludge Applied to Land,” April 30 – May 2, 1997, Copenhagen, Denmark, The Procter & Gamble Company, European Technical Center, Strombeek-Bever, Belgium.

de Wolf, W. and T. Feijtel, 1998, Terrestrial Risk Assessment for Linear Alkyl Benzene Sulfonate (LAS) in Sludge-amended Soils,Chemosphere 36:1319-1343.

ECOSOL, 1994, EUCLID Data Sheet: Benzenesulfonic acid, C10-13-alkyl derivs., Sodium salts, CAS-No.: 68411-30-3, European Center of Studies on LAB/LAS, Brussels, Belgium.

European Commission, 1994, Risk Assessment of Existing Substances, Technical Guidance Document, Report XI/919/94-EN, Directorate-General, Environment, Nuclear Safety and Civil Protection, Brussels, Belgium.

European Economic Community, 1986, Council Directive of 12 June 1986 on the Protection of the Environment, and in Particular of the Soil, When Sewage Sludge Is Used in Agriculture (86/278/EEC), Off. J. Eur.Com. Number L 181, July 4, 1986, pages 6-12.

Figge, K. and P. Schöberl, 1989, LAS and the Applications of Sewage Sludge in Agriculture, Tenside Surf. Det. 26:122-128.

Hedeman, H., 1997, Re: Statutory Order on the Utilization of Waste Products for Agricultural Purposes (letter), Ministry of Energy and the Environment, Danish Environmental Protection Agency, January 17, 1997, available from the European Chemical Industry Council, Brussels, Belgium.

Heinze, J.E., 1996, Ingen Risiko ved Brug af LAS (No Risk in Connection with Using LAS), Ingeniøren, May 3, 1996, page 8.

Heinze, J.E., 1999, Science Versus Politics in the Environmental Regulatory Process, Proceedings of the 4th World Conference on Detergents: Strategies for the 21st Century, (A. Cahn, Ed.), AOCS Press, Champaign, Illinois, pages 83-88.

Herning Folkeblad, 1997, “Herning Slås Med-sæbefabrikanter” (Herning Fights Soap Producers), October 9, 1997, translated by Mannov Consult, Rodovre, Denmark.

Holmstrup, M. and P.H. Krogh, 1996, Effects of an Anionic Surfactant, LAS, on Survival, Reproduction and Growth of the Soil-living Collembolan Folsomia fimetariaEnv. Toxicol. Chem. 15:1745-1748.

Holt, M.S., E. Matthijs and J. Waters, 1989, The Concentration and Fate of Linear Alkyl Benzene Sulfonate in Sludge Amended Soils, Wat. Res. 23:749-759.

Industry Coalition on LAS in Denmark, 1996, Technical Comments from Industry on Revision of Executive Order No. 730 from the Danish Ministry of Energy and the Environment Regarding the Utilization of Sludge in Agriculture, October 21, 1996, European Council of Studies of LAB/LAS, European Chemical Industry Council, Brussels, Belgium.

Industry Coalition on LAS in Denmark, 1997, Industrial Comments on “The Sludge Regulation,” July, 1997, written and edited by Mannov Consult, Rodovre, Denmark.

Jassogne, C.B., 1996a, Miljøsikkerheden for LAS Veldokumenteret (Environmental Safety of LAS is Well Documented), Ingeniøren, May 3, 1996, page 8.

Jassogne, C.B., 1996b, Re: Draft for a Revision of Executive Order No 730 Dated 5/9/95 from the Ministry of Environment Regarding the Utilization of Waste Products for Agricultural Purposes (letter to Mrs. I.- M. Lorenzen, Danish Ministry for Energy and the Environment, Copenhagen, Denmark), European Chemical Industry Council (CEFIC), Brussels, Belgium, 12 June 1996.

Jørgensen, L., 1997a, Hård Konkurrence mellem Gylle og Slam (Hard Competition between Liquid Manure (Slurry) and Sludge),Ingeniøren, January 3, 1997, translated by Mannov Consult, Rodovre, Denmark.

Jørgensen, L., 1997b, Laboratorier Dumper til Slameksamen (Labs Fail Sludge Exam), Ingeniøren, August 15, 1997, translated by Mannov Consult, Rodovre, Denmark.

Jørgensen, L. and H. Weitling, 1997, Efterbehandling Nødvendig (Final Treatment Necessary), Ingeniøren, January 3, 1997, translated by Mannov Consult, Rodovre, Denmark.

Kloepper-Sams, P., F. Torfs, T. Feijtel and J. Gooch, 1996, Effects Assessments for Surfactants in Sludge-amended Soils: A Literature Review and Perspectives for Terrestrial Risk Assessment, Sci. Total Env. 185:171-185.

Lorenzen, I.-M., Re: Draft for a New Executive Order on the Utilization of Waste Products for Agricultural Purposes (letter with appendix and tables of cut-off values), Danish Ministry for Energy and the Environment, June 1, 1996, translated by E. Madsen and S. Bjørkholt, The Association of Danish Cosmetics, Toiletries, Soap and Detergent Industries, Copenhagen, Denmark.

Lynghus, J., 1996, New Draft on Limit Values for LAS Released; Denmark Faces Toughest Sludge-legislation in the World, Summary of Danish Press Reports, Mannov Consult, Rodovre, Denmark, May 6, 1996.

Madsen, T., A. Damborg, H.B. Rasmussen and C. Seierø, 1994, Evaluation of

Methods for Screening Surfactants, Ultimate Aerobic and Anaerobic Biodegradability, Environmental Protection Agency Working Report

Nr. 38, Environmental Protection Agency, Ministry of Energy and the Environment, Copenhagen, Denmark, 1994, English version published 1995.

Madsen, C.S., 1996, Utilization of Sludge on Farmland in Denmark, The Association of Danish Cosmetics, Toiletries, Soap and Detergent Industries (SPT), translated by SPT, September 18, 1996.

Marcomini, A. and W. Giger, 1988, Behavior of LAS in Sewage Treatment, Tenside Surf. Det. 25:226-229.

Matthijs, E., M.S. Holt, A. Kiewiet and G.B.J. Rijs, 1997, Fate of Surfactants in Activated Sludge Wastewater Treatment Plants, Tenside Surf. Det. 34:238-241.

Mieure, J.P., J. Waters, M.S. Holt and E. Matthijs, 1990, Terrestrial Safety Assessment of Linear Alkyl Benzene Sulfonate, Chemosphere 21:251-262.

Prats, D., F. Ruiz, B. Váquez, D. Zarzo, J.L. Berna and A. Moreno, 1993, LAS Homologue Distribution Shift during Wastewater Treatment and Composting: Ecological Implications,” Env. Toxicol. Chem. 12:1599-1608.

Severinsen, M., M.B. Andersen, F. Chen and N. Nyholm, 1996, A Regional Chemical Fate and Exposure Model Suitable for Denmark and Its Coastal Sea, Chemosphere 32:2159-2175.

Schöberl, P., 1989, Basic Principles of LAS Biodegradation,” Tenside Surf. Det. 26:86-94.

SPT, 1999, Report from SPT Workshop in Coordination with the Danish EPA, 19 – 20 April 1999, Eigtveds Pakhus, Copenhagen, Chairman: Prof. Finn Bro-Rasmussen, Danish Technical University, Lyngby, Denmark, Rapporteur: John Solbé, Unilever, Port Sunlight, UK, The Association of Danish Cosmetics, Toiletries, Soap and Detergent Industries (SPT), Copenhagen, Denmark. The report, together with the VKI and NERI summaries of their research, is available in The CLER Review, volume 5, number 1, December, 1999.

Stalmans, M., H. Berenbold, J.L. Berna, L. Cavalli, A. Dillarstone and others, 1995, European Life-cycle Inventory for Detergent Surfactants Production, Tenside Surf. Det. 32:84-109.

United Nations, 1992, Principle 15 (The Precautionary Principle), Agenda 21: The United Nations Program of Action from Rio, New York, New York.

van de Plassche, E., J. de Bruijn, T. Feijtel, 1997, Risk Assessment of Four Major Surfactant Groups in the Netherlands,” Tenside Surf. Det. 34:242-249