Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
1 µg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.2 µg/L
Assessment factor:
50
Extrapolation method:
assessment factor

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
80 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
13 mg/kg sediment dw
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
2.6 mg/kg sediment dw
Assessment factor:
50
Extrapolation method:
assessment factor

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
11.9 mg/kg soil dw
Assessment factor:
10
Extrapolation method:
assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
PNEC oral
PNEC value:
10 mg/kg food
Assessment factor:
30

Additional information

PNEC aqua (freshwater)

For MCCPs, there are short-term toxicity tests with fish, invertebrates, and algae, covering three trophic levels (predators, plant-eating animals, and primary producers, respectively). In studies with various C14-17 chlorinated paraffins (40-52% chlorination), 96h LC50s of >5000 mg/L (nominal) have been reported in the brackish water (7‰ salinity) fish bleak (Linden et al. 1979; see marine section below for further details), >1 mg/L (nominal) in the freshwater crustacean Gammarus pulex (Thompson and Gore, 1999), 9 mg/L and >10,000 mg/L to the brackish water (probably 7‰ salinity) harpacticoid Nitocra spinipes (Tarkpea et al. 1981; see marine section below for further details), and a 96h EC50 of >3.2 mg/L (nominal) for the freshwater alga Selenastrum capricornutum (Thompson et al. 1997b).

 

However, Daphnia appear the most sensitive species to the acute effects of C14-17 chlorinated paraffins. In a study conducted according to OECD guideline 202, exposure of Daphnia magna to Cereclor S52 in freshwater (static system) resulted in a 48h EC50 value of 0.0077 mg/L (nominal) or 0.0059 mg/L (measured concentration), indicating that the test material is very toxic to Daphnia (Thompson et al. 1996). Similarly, in another study, the 48h EC50 in Daphnia of a C14-17 chlorinated paraffin (52% chlorinated) was less than 0.1 mg/L, as immobilisation of all Daphnia was observed at all test substance concentrations (Thompson and Gore, 1999). A 21-day NOEC of 10 µg/L (0.01 mg/L) has been determined for Daphnia (Thompson et al. 1997a - described below). The lack of feeding in the acute toxicity tests (possibly resulting in Daphnia being more susceptible to the toxic effects of MCCPs), has been put forward as an explanation for the apparent discrepancy between the results of these acute studies and those from the long term toxicity data (where feeding is carried out). As organisms in the environment will be feeding, it is considered most relevant to base the PNEC derivation on a study where feeding occurred and thus the 21-day NOEC of 10 µg/L determined for Daphnia in the Thompson et al. (1997a) study is considered the most reliable for PNEC determination. In other acute studies conducted to OECD guidelines, Daphnia were exposed to freshwater (static system) containing dilutions of a saturated solution of C14-17 chlorinated paraffins (52% chlorinated), resulting in a measured 48h EC0 of 140 µg/L and a 48h EC25 of 339-423 µg/L (Frank, 1993; Frank and Steinhauser, 1994), and a nominal 48h NOEC of <0.1 mg/L (Thompson, 2004). These animals were fed during the test.

 

There are reliable long-term toxicity tests for fish and Daphnia. No toxicity (deaths, or effects on growth or behaviour) was observed in rainbow trout (Oncorhynchus mykiss) after exposure to freshwater containing Cereclor S52 at a mean measured concentration of up to 4.5 mg/L (the maximum achievable concentration) for 60 days (Madeley et al. 1983). No deaths or effects on behaviour were seen in bleak exposed for 14 days to brackish water (7‰ salinity) containing a C14-17 chlorinated paraffin (50% chlorinated) at 125 µg/L (Bengtsson et al. 1979; see marine section below for further details). No adverse effects were seen on the mortality or development of embryos and sac-fry of Japanese medaka (freshwater fish) when fertilised eggs were exposed to either of two C14 chlorinated paraffins (48 or 55% chlorinated) for 20 days at concentrations up to 3400 µg/L (Fisk et al. 1999).

 

Thompson et al. (1997a) was a GLP study conducted according to OECD guideline 202. A significant decrease in the number of live offspring and a reduction in parental length was seen in Daphnia magna exposed in freshwater to Cereclor S52 at mean measured concentrations of 18 µg/L (considered the LOEC for these effects) and above, giving a 21-day NOEC of 10 µg/L. In other OECD guideline studies, measured 21-day NOECs of between 4 and 16 µg/L (Frank, 1993; Frank and Steinhauser, 1994; Thompson, 2004; TNO, 1993), and measured 21-day LOECs of between 18 and 32 µg/L (Frank, 1993; Frank and Steinhauser, 1994; Thompson, 2004) have been reported. The animals were fed during these tests.

 

Overall, effects of C14-17 chlorinated paraffins have almost exclusively been observed with Daphnia from both reliable short- and long-term toxicity studies, and include mortality and effects on reproduction. Indeed, data on C10-12 chlorinated paraffins also indicate that invertebrates, and Daphnia in particular, are the most sensitive species. Therefore, it can be presumed with a high probability that the most sensitive species has been examined (i.e. a further long-term toxicity test from a different taxonomic group would not result in a NOEC lower than the 10 µg/L already available). The 21-day NOEC of 10 µg/L determined for Daphnia in the Thompson et al. (1997a) study will be used in the PNEC determination and an AF of 10 is considered to be protective of other aquatic freshwater species.

 

PNECwater (freshwater) = 10 µg/L / 10 = 1 µg/L

 

 

PNEC aqua (marine water)

In acute studies (as noted in the freshwater section above), no mortality was observed in bleak exposed for 96 h to brackish water (7‰ salinity) containing Chloroparaffin huls 40G (C15.5; 40% chlorination) or Witaclor 50 (C14-17; 50% chlorination) at up to 5000 mg/L (nominal) or with a Cereclor S52 (C14-17; 52% chlorination) at up to 10,000 mg/L (nominal). Therefore, the 96 h LC50 can be considered as greater than 5000 mg/L (Linden et al. 1979). In the harpacticoid Nitocra spinipes, 96 h LC50s of 9 mg/L and >10,000 mg/L were reported following exposure to C14-17 chlorinated paraffins (45 and 52% chlorination, respectively) in brackish water (probably 7‰ salinity) (Tarkpea et al. 1981).

 

In longer-term studies (as noted in the freshwater section above), no deaths or effects on behaviour were seen in bleaks exposed for 14 days to brackish water (7‰ salinity) containing Witaclor 350 (a C14-17 chlorinated paraffin; 50% chlorinated) at a nominal concentration of 125 µg/L (Bengtsson et al. 1979). Therefore, the 14-day NOEC can be considered as 125 µg/L (the only tested concentration) in this test system.

 

Mussels (Mytilus edulis) were exposed to a C14-17 chlorinated paraffin (52% chlorinated) at mean measured concentrations of 0.22 and 3.8 mg/L in natural sea water (salinity 34.0-35.5‰) for 60 days. No significant mortality or effects on mean shell length were seen at either concentration. Reduced filtering activity (non-quantitative visual observation) at the higher concentration could have been due to the presence of the undissolved test material (solubility limit for the substance was <3.8 mg/L) rather than a true toxic effect, but the 60-day NOEC for this study is considered as 0.22 mg/L (Madeley and Thompson, 1983).

 

According to the TGD (Chapter R.10), where at least two long-term results (e.g. NOECs) from freshwater or saltwater species representing two trophic levels and one long-term result from an additional marine taxonomic group are available, an assessment factor of 50 can be used. For MCCPs, there are reliable long-term toxicity tests for freshwater and brackish water fish and invertebrates, and an additional marine taxonomic group (molluscs), therefore an AF of 50 will be applied to the most sensitive NOEC of 10 µg/L obtained from the 21-day multigenerational study on Daphnia (Thompson et al. 1997a).

 

PNECsaltwater (marine) = 10 µg/L / 50 = 0.2 µg/L

 

 

PNEC aqua (intermittent releases)

Intermittent releases of MCCPs to water have been reported, for example from their use in metal working fluids. However, TGD (R.16) states that “Intermittent releases are defined as occurring infrequently, i.e. less than once per month and for no more than 24 hours”. It is not anticipated that such frequent releases will occur, therefore, a PNEC aqua for intermittent release has not been derived. If, however, such releases do occur in the future, the PNECs derived for continuous exposure are considered protective of intermittent releases, and can therefore be used.

 

 

PNEC STP (sewage treatment plant)

Toxicity data available for the effects of C14-17 chlorinated paraffins (41 and 52% chlorinated) on bacteria, suggest that MCCPs are of low toxicity to microorganisms. The respiration of microorganisms in activated sludge from a municipal sewage treatment plant over three hours was unaffected by the presence of a C14-17 chlorinated paraffin (52% chlorinated) at concentrations of up to 2000 mg/L (considered the 3 h NOEC for this study) (Hoescht, 1985). The harmful threshold (24 h) of a C14-17 chlorinated paraffin (41% chlorinated) to anaerobic bacteria from a domestic waste water treatment plant using the ETAD fermentation method was reported as 800 mg/L (considered the NOEC/LOEC for this study). This is the lowest threshold concentration reported to cause effects, and therefore considered the most sensitive test system available. The TGD suggests that an assessment factor of 10 can be applied to the NOEC from a test using mixed bacterial populations.

 

PNECmicroorganisms= 800 mg/L / 10 = 80 mg/L

 

PNEC sediment (freshwater)

Three prolonged toxicity studies, based on OECD Guideline 218, have been performed with freshwater amphipods, oligochaete worms and midges exposed to artificial sediment spiked with Cereclor S52 for 28 days. Mortality and a range of sub-lethal endpoints such as reproduction, growth and emergence were assessed, and these are regarded as the most relevant. For Chironomus riparius, a 28-day NOEC of 3800 mg/kg sediment dry wt was determined based on the number of emerged adult midges (Thompson et al. 2001b). However, a lower 28-day NOEC of 130 mg/kg sediment dry wt has been reported based on the reduced growth seen in female amphipods (Hyalella azteca) and effects on mortality/reproduction in the oligochaete worm (Lumbriculus variegates) (Thompson et al. 2001a, 2002). Therefore, the lowest NOEC from these three reliable prolonged toxicity tests is 130 mg/kg sediment dry wt for both the freshwater amphipod and oligochaete worm.

The TGD suggests that an assessment factor of 10 can be applied to the lowest NOEC from three long-term sediment tests with species representing different living and feeding conditions (which is the case with these amphipods, worms and midges).

PNECsediment (freshwater): 130 mg/kg sediment dry wt / 10 = 13 mg/kg dry wt. Based on the default sediment wet:dry ratio of 2.6, this equates to 5 mg/kg wet wt.

In addition, the PNECsediment should also be calculated from the PNECwater using the equilibrium-partitioning method as follows:

PNECsediment =Ksusp-water × PNECwater × 1000= 12.8 mg/kg wet wt

                                                  RHOsusp

Where,

Ksusp-water = suspended matter – water partition coefficient = 14,721 m3/m3

RHOsusp = bulk density of suspended matter = 1150 kg/m3

PNECwater = 1 µg/L

Overall, the PNECsediment(freshwater) of 5 mg/kg wet wt, derived from the available experimental data, will be considered in the risk characterisation.

 

PNEC sediment (marine water)

No toxicity data are available for sediment-dwelling organisms in the marine environment. As described above, three reliable prolonged toxicity studies, based on OECD Guideline 218, have been performed with freshwater amphipods (Thompson et al. 2002), oligochaete worms (Thompson et al. 2001a) and midges (Thompson et al. 2001b) exposed to artificial sediment spiked with Cereclor S52 for 28 days. These studies assessed mortality and a range of sub-lethal endpoints such as reproduction, growth and emergence. The lowest NOEC from these studies was 130 mg/kg sediment dry wt for both a freshwater amphipod and oligochaete worm.

The TGD suggests that an assessment factor of 50 can be applied to the lowest NOEC from three long-term sediment tests with species representing different living and feeding conditions (which is the case with these amphipods, worms and midges).

PNECsediment (marine water): 130 mg/kg sediment dry wt / 50 = 2.6 mg/kg dry wt. Based on the default sediment wet: dry ratio of 2.6, this equates to a value of 1 mg/kg wet wt.

In addition, the PNECsediment should also be calculated from the PNECsaltwater using the equilibrium-partitioning method as follows:

PNECsediment = Ksusp-water × PNECsaltwater × 1000 = 2.6 mg/kg wet wt

                                                   RHOsusp

Where,

Ksusp-water = suspended matter – water partition coefficient = 14,721 m3/m3

RHOsusp = bulk density of suspended matter = 1150 kg/m3

PNECsaltwater = 0.2 µg/L

Overall, the PNECsediment (marine water) 1 mg/kg wet wt, derived from the available experimental data on three freshwater species, will be considered in the risk characterisation.

PNEC soil (terrestrial)

There are prolonged toxicity tests with plants [see note below], microorganisms and earthworms, covering primary producers, decomposers and consumers respectively.

In GLP studies conducted according to OECD Guideline 208, no significant effects were seen on seedling emergence at 14 days and growth up to 28 days in wheat (Triticum aestivum), oilseed rape (Brassica napus) and mungbean (Phaseolus aureus) exposed to soil containing Cereclor S52 at up to nominal concentrations of 5000 mg/kg dry wt soil (the highest tested concentration; considered the NOEC for these studies) (Thompson et al. 2001d). [Please note, studies conducted according to the updated OECD Guideline 208 are designed to assess the potential effects of substances on seedling emergence and growth. Therefore, it is specific to a part of the plant's life-cycle and does not cover chronic effects or effects on reproduction. However, it is assumed to cover a sensitive stage in the life-cycle of a plant and therefore data obtained from this study can be used to estimate chronic toxicity.]

In a GLP study conducted according to OECD Guideline 216, the effect of Cereclor S52 at up to 400 mg/kg dry wt soil (nominal concentration) on the transformation by soil microorganisms of an organic nitrogen source (lucerne) to nitrate over a period of 28 days has been assessed. No statistically significant decrease in nitrate formation was seen at any concentration, giving a NOEC of 400 mg/kg dry wt of soil (Thompson, 2002).

In a GLP study conducted according to OECD Guideline 216 (draft 2000 version), exposure of earthworms (Eisenia fetida) to Cereclor S52 resulted in adverse effects on survival, growth and reproduction at measured concentrations of 9300, 2800 and 900 mg/kg dry wt soil, respectively (Thompson et al. 2001c). Therefore, the overall lowest NOEC from these three studies was 280 mg/kg dry wt soil for effects on reproduction of earthworms (equivalent to about 248 mg/kg wet wt). As the majority of MCCP exposure to worms occurs via the pore water, this value has been converted to a standard soil, which is defined in the TGD as a soil with an organic matter content of 3.4% and organic carbon of 2% (the organic carbon content of the soil used in the worm study was 4.7%). Therefore, the normalised NOEC is calculated as follows:

NOECstandard = NOECexp x Fomsoil(standard) = 119 mg/kg dry wt

                                                         Fomsoil(exp)

Where,

NOECexp = experimental NOEC = 280 mg/kg dry wt soil

NOECstandard = NOEC in standard soil

Fomsoil(standard) = fraction organic carbon in standard soil = 0.02

Fomsoil(exp) = fraction organic carbon in experimental soil = 0.047

Based on the default soil wet/dry ratio of 1.13, this equates to a value of 119 / 1.13 = 105 mg/kg wet wt.

The TGD suggests that an assessment factor of 10 can be applied to the lowest NOEC from three long-term tests with species representing three trophic levels (which is the case here).

PNECsoil: 105 mg/kg wet wt / 10 = 10.5 mg/kg wet wt

 

PNEC oral (secondary poisoning; birds/mammals)

Regarding avian toxicity, no deaths or other significant adverse effects were seen in mallard ducks and pheasants following acute (single gavage at up to 24 g/kg bw) or repeated (in the diet for 5 days at up to 24 g/kg feed) exposure to Cereclor S52 (Madeley and Birtley, 1980). The TGD suggests that an assessment factor of 3000 could be applied to the LC50 from a 5-day avian study. However, results from long-term studies are strongly preferred, therefore, the PNECoral will be derived from the available mammalian data.

 

A NOAEL of 300 mg/kg food (about 23 mg/kg bw/day) was reported in a good-quality study (Elcombe, 2005b) in which kidney effects were seen at higher doses in rats administered Cereclor S52 for 90 days in the diet. According to the TGD an AF of 90 is appropriate for extrapolation from a 90-d study. However, the results of several long-term reproduction studies (and lifetime cancer bioassays on C10-12 chlorinated paraffins) are also available, and these give higher NOAELs than that from the 90-day study. On this basis, it can be argued that an AF of lower than 90 would be sufficiently protective as the need for a higher value for the subchronic to the chronic extrapolation is not warranted. Therefore, an AF of 30 will be used which takes into account both species variation and lab-to-field extrapolation.

 

PNECoral(mammal): 300 mg/kg diet / 30 = 10 mg/kg food

 

Atmospheric compartment

No data are available on possible effects of MCCPs on the atmosphere. However, given their low volatility, neither biotic nor abiotic effects (e.g. global warming, ozone depleting, acidification) are likely.

 

 

 

 

Conclusion on classification

Based on the available data (48 h EC50 < 1 mg/L and a BCF>500), MCCPs should be classified as as H410 (Very toxic to aquatic life with long lasting effects) according to the EU CLP.