General Alkylphenols are mainly used as raw material in the production of a variety of industrial products such as surfactants, detergents, phenolic resins, polymer additives and lubricants. Private and commercial use of alkylphenols does not occur. Current world demand is estimated at approximately 400,000 tonnes/y, with nonylphenol as the most widely used compound (market share: 80- 90%). Octyl-, dibutyl-, decyl- and dodecylphenols are produced in total quantities of 60,000 tonnes/year. Nonylphenol production in Western Europe amounts to 75,000- 80,000 tonnes/year. Octylphenol production is estimated at approx. 7,000 tonnes/year. In the Netherlands, there are no production sites for alkylphenols. Nonylphenol demand in The Netherlands is estimated at 1300- 1400 tonnes/year. For the next few years, world demand will grow 1-2 % per year. Alkylphenol ethoxylates are primarily used as surfactants, detergents and emulsifiers in a wide range of applications in the industry (auxiliaries) and as commercial product (cleaning agents, wetting agents, dispersants, lubricants, etc) in many end use sectors. Current world demand is estimated at 600,000 tonnes/y, with nonylphenol (85%) and octylphenol ethoxylates (15%) as most widely used compounds. World demand growth is estimated at 2-3 %/year. In the EU, due to voluntary and regulatory initiatives, the use of these substances is to be limited in order to minimise alkylphenol emissions to the environment. In Western Europe, nonylphenol ethoxylates production is about 120,000 tonnes/year. Demand in the EU varies from 65,000 to 80,000 tonnes, while export amounts to 35,000- 45,000 tonnes/year. In the Netherlands, there is no production of alkylphenol ethoxylates. Annual nonylphenol ethoxylates demand in 1997 was estimated at approx. 1,500 tonnes, coming down from 4,900 tonnes/year in 1986. Sources and emissions Nonylphenol emissions due to use in the chemical and polymer industry in the Netherlands (<15 kg/ year) are negligible compared to emissions from nonylphenol ethoxylates degradation in municipal wastewater (14.1 tonnes/year; see table 1). Nonylphenol ethoxylates emissions to surfacewater in the Netherlands are estimated at 45 tonnes (1997). From table 1 can be seen that the first 6 use sectors are responsible for the total nonylphenol and nonylphenol ethoxylates emissions to surfacewater. On European scale, emissions of nonylphenol and nonylphenol ethoxylates amount to 1065 and 3400 tonnes/year. Environmental characteristics and toxicity in aquatic systems Environmental characteristics Alkylphenols are characterised by low solubility in water (< 15 mg/l) and low vapour pressures (< 10 Pa). Log Kow values vary from 4.1 for octylphenol to 4.5 for nonylphenol. Octyl- and nonylphenol will be non-volatile and will adsorb strongly onto solids. Alkylphenol ethoxylates with many ethoxylate groups (n>10), are very soluble in water, making these compounds potentially mobile. However, once released in water, they are easily hydrolysed to compounds with few ethoxylate groups (n<3), which behave more or less the same as the core alkylphenol compounds (strong adsorption to solids). Environmental data for nonylphenol indicate that this compound is strongly concentrated in freshwater algae and fish. (BCF = 6000- 7000 and 200- 600 l/kg respectively). Nonylphenol was not found to bio-accumulate in the food chain. BCF values for short chained nonylphenol ethoxylates (n<3) show the same tendency to accumulate in aquatic biota, but BCF values are somewhat lower (1000- 5000 l/kg for algae and 80- 150 l/kg for fish). Half-life for excretion from fish is short (< 1 day). BCF data in marine biota were found to be in the same range as for freshwater organisms. Nonylphenol is resistant to hydrolysis but is susceptible to photolysis in water. Nonylphenol ethoxylates (n>10) are easily hydrolysed to short chained ethoxylate compounds (n<3), which show significant resistance to photolysis in water. In atmosphere, however, all selected compounds have a short photochemical half- life (< 1 day). Primary biodegradation of nonylphenol in fresh water occurs at half-life values of 15- 20 days. Half life in sea water is 50- 70 days. In both cases, adaptation (20-30 days) is required. Mineralisation occurs solely on the nonyl chain. Primary degradation of nonylphenol ethoxylates (n=9) in fresh water had an half-life of < 4 days. Mineralisation half-live for the major degradation product (NP2EO) in river water is 20- 30 days. In sewage sludge, nonylphenol ethoxylates degradation is fast (half-life < 6 days). In both river water and sewage sludge, degradation of the phenolic ring is observed. Half-lives for primary nonylphenol ethoxylates degradation in brackish and salt water were 3-4 days and 14-35 days respectively and depends strongly on the water temperature. Major degradation product, NP2EO, was found to mineralise slowly, but without substantial formation of nonylphenol. Nonylphenol mineralisation in soil is fast (half-life of 10-15 days) after adaptation of 15-20 days. Mineralisation occurs solely on the nonyl chain. Half-life for mineralisation of nonylphenol ethoxylates in sludge-amended soils was 5- 10 days and 50 days in non-amended soils. Nonylphenol, produced from nonylphenol ethoxylate mineralisation, is fully degraded. Toxicity in aquatic systems Octyl- and nonylphenol are capable of binding to the estrogen receptor thus disturbing the endocrine system. The order of estrogenic potency is octylphenol > nonylphenol > nonylphenol ethoxylate. Octylphenol and nonylphenol ethoxylates are metabolized to octyl- and nonylphenol. Numerous ecotoxicity data are available on nonylphenol. There are no data on the ecotoxicity of octylphenol ethoxylates. From the available data on octylphenol is appears that octylphenol is extremely toxic to aquatic organisms but seems to be less toxic to algae and bacteria. Nonylphenol is also very toxic to most aquatic organisms. Nonylphenol ethoxylate is moderately to very toxic to aquatic organisms. The iMPCs are derived for octylphenol (0.122 ?g/l and 16.08 ?g/kg ds), nonylphenol (0.35 ?g/l and 1186 ?g/kg ds) and nonylphenol ethoxylate (0.044 ? g/l and 5.67 - 11.31 ?g/kg ds). Comparing the iMPC with the actual measured concentrations the iMPCs for nonylphenol and nonylphenol ethoxylate are exceeded in the Netherlands. The iMPCs for octylphenol is not exceeded in the Netherlands but concentrations in other countries in Europe do exceed the iMPC. Occurrence and behaviour in aquatic systems Significantly increased levels of alkylphenols and alkylphenol ethoxylates are found in sediments near wastewater treatment plants and specific user sites, with highest levels for nonylphenol and its ethoxylates. Levels in water are significantly lower. In the middle and late 1980s, sediment/water concentration ratios for nonylphenol ranged from 300- 5,000, at concentrations of 500- 15,000 ?g/kg (dw) in sediment and 1- 10 ?g/l in water. Concentrations for short chained nonylphenol ethoxylates (NP1EO and NP2EO) varied from 3,000- 12,000 ?g/kg (dw) in sediment and 10- 100 ?g/l in water. Comparison of 1984 and 1996 nonylphenol concentrations in Swiss river waters revealed that levels in water have decreased by roughly a factor 10. Similar data for comparison of sediment concentrations were not available. In the Netherlands, 1997 values for nonylphenol in fresh waters were below detection (< 0.07 ?g/l), whereas concentrations of nonylphenol ethoxylates were only a little higher (0.14 ?g/l). Nonylphenol levels in fresh water sediments (1,500- 1,700 ?g/kg dw) were lower than for nonylphenol ethoxylates (3,000- 8,000 ? g/kg dw). Concentrations of nonylphenol and nonylphenol ethoxylates were < 0.07 ?g/l in Dutch estuarine surfacewaters. For both nonylphenol and nonylphenol ethoxylates, levels in Dutch estuarine sediments were approximately 2-3 times lower than in fresh water sediments. Policy In several countries policy has been made on octylphenol and nonylphenol ethoxylates. Virtually all domestic uses of nonylphenol ethoxylates as cleaning agents have been phased out. In the Netherlands the use of nonylphenol ethoxylates as cleaning agents for industrial uses is reported as terminated. Prognosis Further to voluntary industry initiatives to minimise the use of nonylphenol ethoxylates as much as possible, the nonylphenol ethoxylates demand in the EU is expected to decline in the coming years. Quantitative data for future reduction targets are not available, however. Within the framework of PARCOM, national authorities in various Western European countries will shortly review the progress of current voluntary initiatives, in order to assess the necessity of further regulatory use restrictions. Conclusions and recommendations From the study results can be assessed that due to wide spread use of nonylphenol ethoxylates in industrial and non-industrial applications, selected compounds are abundantly present in fresh water environments, mainly due to biodegradation of nonylphenol ethoxylates in municipal wastewater. Major emissions to surfacewater are coming from end-use applications where used products are integrally discharged with wastewater. Physico-chemical data of selected compounds indicate that, due to sorption onto sediments, mobility in aquatic environments will be low. Environmental data for release verification and distribution in marine sediments and biota are however scarce. In the Netherlands, due to restricted use in non-industrial applications, many nonylphenol ethoxylates have been replaced in the last decade and their use has decreased by approx. 70%. National data for historical evaluation of emissions are not available, but from foreign figures it is expected that lower use will have lead to lower nonylphenol and nonylphenol ethoxylates levels in environments. Further it is assessed that alkylphenols are moderately to very toxic to aquatic organisms. Alkylphenols also exert endocrine disrupting effects and are widely observed in the environment at concentrations exceeding the derived iMPCs. Although degradation in the environment occurs (inherently biodegradable) the substances present a considerable risk to the environment. Based on the fact that alkylphenols are carcinogenic and exert endocrine disrupting effects, it is recommended to derive an ADI or TDI in order to facilitate a comparison between human exposure and the concentrations in the environment. From comparison of iMPC values with concentrations in the environment it follows that the iMPC are exceeded in most cases. It is therefore advised to derive an official MPC. There are for the moment no data available on octylphenol ethoxylate. Although octylphenol ethoxylate use is minor and their occurrence is scarcely monitored in the environment, it is recommended to gather more information on these substances because it is closely related to nonylphenol ethoxylates.