Registration Dossier

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

medium hazard (no threshold derived)

Hazard assessment conclusion:

medium hazard (no threshold derived)

Hazard assessment conclusion:

medium hazard (no threshold derived)

Acute toxicity

ECHA Guidance R.8 (Chapter R.8.1.2.5) indicates that DNELs for acute toxicity are not required if no acute toxicity hazard leading to classification has been identified. The members of this category are not acutely toxic following oral or dermal exposure (LD₅₀>2000 mg/Kg bw) while a low vapour pressure precludes inhalation exposure indicating a low of concern for this route of exposure. No DNELs for acute toxicity are therefore necessary.

Irritation

Corrosive and irritant effects on the skin and eye are local, concentration-dependent phenomena. However, while test results indicate that members of this category are irritating to eye (but not to skin), the nature of the data is such that no conclusion can be drawn with regard to any dose-response relationship present. No DNEL for irritation can therefore be derived.

Sensitisation

The sensitisation potential of the substances included in this category is well understood and comprises results from three local lymph node assays, a guinea pig maximisation test and a guinea pig Buehler test. The results consistently show evidence of a potential to induce skin sensitisation.

Intrinsic sensitising potency

ECHA Guidance R.8, Appendix R.8-10, (ECHA, 2010) states that while skin sensitisation is generally regarded as a threshold effect it may be very difficult to derive a threshold and to set a DNEL. Thus, the general approach for sensitisers involves a qualitative approach where a DNEL is used to judge any remaining/residual risks after the implementation of appropriate risk management measures (RMM) and occupational controls (OC).

The extent of the RMM and OC required is dependent on the intrinsic sensitising potency of the substance.

For results obtained using the LLNA, intrinsic sensitising potency is based on the EC3 and defined (ECHA (2010), Appendix R.8-10) as follows:

Category	EC3 (%)
Extreme	<0.2%
Strong	>0.2 - <2
Moderate	>2

EC3 values of 0.74%, 1.9% and 5.0% were obtained for Rosin, maleated, Rosin, fumarated and Rosin, fumarated, reaction products with formaldehyde, respectively. These indicate a strong to moderate potential to cause skin sensitisation.

For results obtained using the guinea pig maximisation test, intrinsic sensitising potency is based on the (intradermal) concentration employed during the induction phase of the test together with the incidence of sensitisation following challenge (ECHA, 2010):

Induction conc (%)

Incidence of sensitisation

<0.1

Strong

(30-60%)

Extreme

(>60%)

>0.1 - <1

Moderate

(30-60%)

Strong

(>60%)

>1

Moderate

(30-60%)

Moderate

(>60%)

Results obtained from a guinea pig maximisation test on Rosin, maleated using an intradermal induction concentration of 0.003% resulted in sensitisation incidences of 79% (10% challenge concentration) and 100% (30% challenge concentration) and are therefore indicative of an extreme sensitiser.

Different criteria apply to interpretation of results obtained using the Buehler test (ECHA Guidance R.8 (Appendix R.8-10)):

Induction conc (%)

Incidence of sensitisation

<0.2

Strong

(15-60%)

Extreme

(>60%)

>0.2 - <20

Moderate

(15-60%)

Strong

(>60%)

>20

Moderate

(15-60%)

Moderate

(>60%)

Results obtained from a Buehler test on Rosin, maleated using an induction concentration of 80% gave a sensitisation incidence of 80% (5% challenge concentration) indicative of a moderate sensitiser.

Given the range of outcomes obtained (1 extreme; 2 strong; 2 moderate), it will be assumed for the purposes of risk characterisation that the members of this category have a strong potential to cause sensitisation following skin contact.

Derivation of a DNEL for sensitisation

ECHA Guidance R.8, Appendix R.8-10 (ECHA, 2010), indicates that the EC3 concentration from a LLNA test can be taken as a LOAEL for the induction of skin sensitisation (ECHA, 2010) after conversion into an equivalent dose per unit area of skin (µg/cm²). Assuming (i) a dose volume of 25 μL (according to the standard LLNA protocol); (ii) an estimated treatment area of 1 cm²for the mouse ear; and (iii) an assumed density of is 1, the conversion is performed as follows:

EC3 [%] * 250 [µg/cm²/%] = EC3 [μg/cm²]

Based on LLNA results for Rosin, maleated, the equivalent EC3 [μg/cm²] is therefore:

0.74% * 250 = 185 µg/cm²

EC3 [μg/cm²] values of 475 µg/cm²and 1250 µg/cm²are obtained when the calculation is repeated using results from LLNA tests run on Rosin, fumarated (EC3 = 1.9%) and Rosin, fumarated, reaction products with formaldehyde (EC3 = 5%), respectively. The EC3 of 185 µg/cm²obtained for Rosin, maleated, will be used to assess the magnitude of any remaining/residual risks after the use of RMMs and OCs recommended in the Qualitative Risk Assessment for this category. No Assessment Factors will be applied to this value since (relative to EC3 values available for other category members) it is already a conservative result, with skin penetration (and hence the capacity of the substance to induce skin sensitisation) enhanced in the LLNA test by the deliberate use of a solvent system that is not present in an occupational or consumer setting. The EC3 of 185 µg/cm²will therefore be used as a human NAEL.

Repeated dose toxicity

Information exists to characterise the repeated dose toxicity of Rosin Adducts and Rosin Adducts Salts. These are formed when rosin reacts with maleic anhydride (or maleic acid) or fumaric acid yielding a maleated rosin adduct or a fumarated rosin adduct, respectively; the rosin adduct salts are simply the rosin adducts that have been reacted with an appropriate base. The available data includes results obtained from testing Rosin, maleated and Rosin, fumarated and is summarised below.

In a key Guideline (OECD 408) sub-chronic repeated dose oral toxicity study (Envigo Research Laboratories, 2017a), the test material (Rosin, maleated; CAS# 8050-28-0) was administered by continuous dietary admixture to three groups, each composed of ten male and ten female WistarHan™:RccHan™:WIST strain rats, for ninety consecutive days, at dietary concentrations of 500, 1500 and 3000 ppm (equivalent to mean achieved dosages of 33.7, 99.5 or 195.0 mg/Kg bw/day for males and 37.1, 120.4 or 241.7 mg/Kg bw/day for females, respectively). A control group of ten males and ten females were fed basal laboratory diet.

Based on the results of this ninety-day study, the No Observed Adverse Effect Level (NOAEL) for systemic toxicity of Rosin, maleated was considered to be 1500 ppm (equivalent to a mean achieved dosage of 99.5 and 120.4 mg/Kg bw/day for males and females respectively due to reduced bodyweight gains and food consumption and adverse histopathological changes in the urinary bladder of both sexes exposed to a dietary concentration of 3000 ppm of the test material.

In another Key Guideline (OECD 408) sub-chronic repeated dose toxicity study (Envigo Research Laboratories, 2016a), the test material (Rosin, Fumarated; CAS# 65907-04-8) was administered continuously in the diet to three groups, each composed of ten male and ten female Wistar Han™:RccHan™:WIST strain rats, for ninety consecutive days, at dietary concentrations of 5000, 7500 and 10000 ppm (equivalent to mean achieved dosages of 356.3, 527.4 or 704.6 mg/Kg bw/day for males and 416.9, 593.9 or 843.4 mg/Kg bw/day for females). A control group of ten males and ten females was fed basal laboratory diet.

No mortality was observed through the study period. Oral administration of the test material to rats by continuous dietary admixture resulted in an initial reduction in body weight gain for both sexes at all exposure levels during the first week of treatment. Although overall body weight gain for females in the high exposure group was lower than control females, recovery was evident in males from all exposure levels and in females exposed to 7500 or 5000 ppm of the test item. In the absence of any toxicologically significant effects detected in the haematological or blood chemical parameters examined, organ weights measured or any histopathological changes the effect on body weight was not considered to represent an adverse effect of treatment (Lewis et al., 2002).

The No Observed Adverse Effect Level (NOAEL) for systemic toxicity for both sexes was therefore determined to be 10000 ppm (equivalent to a mean achieved dosage of 704.6 mg/Kg bw/day for males and 843.4 mg/Kg bw/day for females).

In a Guideline (OECD 422) combined repeated dose, reproductive/developmental toxicity screening study (Harlan Laboratories Ltd, 2015a), the test material (Rosin, maleated; CAS# 8050-28-0) was administered daily in dietary mixtures at concentrations of 0, 1750, 3500 or 7000 ppm to male rats for 43 days and to female rats for 14 days prior to pairing, through the pairing and gestation periods until the F1 generation reached day 4 post partum.

Based on the results of this study, a NOAEL (No Observed Adverse Effect Level) for systemic toxicity was established at the dose level of 3500 ppm.

In a Guideline (OECD 422) combined repeated dose reproductive/developmental toxicity study (Inveresk Research, 2004a), Rosin fumarated was administered in the diet to rats at concentrations of 0, 1000ppm (males 72 -89 mg/Kg bw/d; females 79 -108 mg/Kg bw/d), 3000 ppm (males 221 -288 mg/Kg bw/d; females 196 -292 mg/Kg bw/d), and 10000 ppm (males 651 -889 mg/Kg bw/d; females 449 -995 mg/Kg bw/d). The males were treated for 2 weeks prior to mating, through until necropsy after 4 weeks of treatment. The females were treated for 2 weeks prior to mating, then through mating, gestation and until termination on at least Day 4 of lactation.

Under the conditions of this study, parental toxicity was exhibited at levels of 3000 and 10000 ppm, with a decrease in mean body weight at both doses and sexes, an increase in total bilirubin in both sexes at 10000 ppm and decrease in adrenal gland weight in females at 10000 ppm, but there were no clear effects of toxicity at 1000 ppm. Therefore, the parental NOEL was considered to be 1000 ppm (males 72 -97 mg/Kg bw/d; females 79 -108 mg/Kg bw/d). For reproductive parameters, the NOEL was considered to be 3000 ppm (females: 196 -268 mg/Kg bw/d).

In a key Guideline (OECD 414) pre-natal developmental toxicity study (Envigo CRS, S.A.U, 2018a), the test material (Rosin, fumarated; CAS# 65997-04-8) was administered by continuous dietary admixture to three groups of Sprague-Dawley rats, between gestation days 3 and 19 (inclusive) at dietary concentrations of 2500, 5000, and 10000 ppm (equivalent to mean achieved dosages of approximately 0, 188.2, 369.3 and 908.2 mg/Kg bw/day). An additional group of female rats was treated with basal laboratory diet to serve as a control.

Based on the results of this study, 10000 ppm was determined to be the maternal No Observed Adverse Effect Level (NOAEL) for pregnant females. Although a statistically significant effect on body weight gain between days 4 and 10 was observed at 10000 ppm, it was considered non-adverse, since it was a transient effect and no relevant differences were observed in body weight gain later during gestation, nor were there any effects on the general well-being of the dams in this group.

With respect to effects on embryofoetal development, 10000 ppm was determined to be the NOAEL. Although slight but statistically significant reduced foetal body weights were observed, this was not considered an adverse effect, due to the small magnitude of the change and because the mean value was within the Historical Control range. Despite some abnormalities in all dietary exposure groups as well as in control foetuses, there was no evidence that dietary exposure to the test material at 10000 ppm increased the occurrence of teratogenic effects. This dose was therefore considered to be the NOAEL.

In another key Guideline (OECD 414) pre-natal developmental toxicity study (Envigo Research Laboratories, 2017b), the test material (Rosin, maleated; CAS# 8050-28-0) was administered by continuous dietary admixture to three groups each composed of twenty-four time mated Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, between gestation days 3 and 19 (inclusive) at dietary concentrations of 500, 1500, and 3000 ppm equivalent to mean achieved dosages of approximately 41.2, 122.9 and 217.4 mg/Kg bw/day. A further group of twenty-four time mated females was treated with basal laboratory diet to serve as a control.

Based on the results of this study, dietary exposure to 500 ppm of the test material (equivalent to an achieved dosage of approximately 41.2 mg/Kg bw/day of the test material) was considered to be a clear No Observed Effect Level (NOEL) for the pregnant dam. The No Observed Adverse Effect Level (NOAEL) for the pregnant dam was considered to be a dietary exposure to 1500 ppm of the test item (equivalent to an achieved dosage of approximately 122.9 mg/Kg bw/day of the test material), due to effects on body weight gain and food consumption apparent at a dietary level of 3000 ppm.

In a supporting dose range-finding toxicity study, the test material (Rosin, Maleated, CAS # 8050-28-0) was administered to four groups of 3 males and 3 female rats at dose levels of 0, 5000, 10000 and 20000 ppm.

The results of the study show a dose-dependent reduction in food consumption resulting in effects on body weights and body weight gain. Water consumption was also slightly reduced in all dose-groups. At the high dose levels, adverse effects on food consumption and body weight gain were observed in both genders. Body weight loss was recorded in both sexes from treatment start until termination of this group. In addition, ruffled fur was observed in males and females at high-dose level. Due to these observations males and females were terminated for ethical reasons prior to schedule. In group 3, animals recovered in food consumption followed by a slight reduction at the end of the treatment.

Reduction of food consumption was accompanied by body weight loss in both sexes. In group 2, reduction in food consumption was less pronounced and reversible, although also in this group values remained slightly lower than control values until the end of the study. Reduced body weight gain and reduced body weights were recorded in males and females during the entire study period with slight body weight loss at the beginning of the treatment. These values recovered partially during the study, although remained lower than control values until the end of the study.

Based on the results of the study, the dose level selected for the OECD 422 screening study to be conducted on the test material Rosin maleated are 0, 1750, 3500 and 7000 ppm.

Genetic Toxicity

Adequate information exists to characterise the mutagenicity of Rosin adducts and rosin adducts salts. Results of bacterial mutation assays demonstrate that Rosin, fumarated; Rosin, maleated; and Rosin, fumarated, reaction product with formaldehyde were not mutagenic in four strains of Salmonella typhimurium and strain WP2 of Escherichia coli when tested in the absence or presence of exogenous metabolic activation. When tested using mammalian cells in vitro, in the absence and in the presence of S9 fraction, Rosin, fumarated was inactive in a gene mutation assay (L5178Y mouse lymphoma cells) and in a mammalian chromosome aberration test (Chinese Hamster Ovary (CHO) cells).

Reproductive / Developmental Toxicity

Reproductive Toxicity

Information exists to characterise the reproductive toxicity of Rosin Adducts and Rosin Adducts Salts. These are formed when rosin reacts with maleic anhydride (or maleic acid) or fumaric acid yielding a maleated rosin adduct or a fumarated rosin adduct, respectively; the rosin adduct salts are simply the rosin adducts that have been reacted with an appropriate base. The available data includes results obtained from testing Rosin, fumarated; and Rosin, maleated along with supporting data for Rosin (the precursor of all substances included in this category) and Resin acids and rosin acids, esters with pentaerythritol (a Rosin reaction product). This information is summarised below.

In a key Guideline (OECD 422) combined repeated dose, reproductive/developmental toxicity screening study (Harlan Laboratories Ltd., 2015a), the test material (Rosin, maleated; CAS# 8050-28-0) was administered daily in dietary mixtures at concentrations of 0, 1750, 3500 or 7000 ppm to male rats for 43 days and to female rats for 14 days prior to pairing, through the pairing and gestation periods until the F1 generation reached day 4 post partum.

Based on the results of this study, a NOAEL (No Observed Adverse Effect Level) for systemic toxicity was established at the dose level of 3500 ppm.

The NOAEL and NOEL (No Observed Effect Level) for reproduction were set at the dose level of 3500 ppm whereas the NOEL and NOAEL for developmental toxicity was established at the dose level of 1750 ppm due to the reduced body weights and body weight gain in pups at the dose level of 3500 ppm.

In another key Guideline (OECD 422) combined repeated dose, reproductive/developmental toxicity study (Inveresk Research 2004a), the test material (Rosin, fumarated; CAS# 65997-04-8) was administered in the diet to rats at concentrations of 0, 1000 ppm (males 72-89 mg/Kg bw/d; females 79-108 mg/Kg bw/d), 3000 ppm (males 221-288 mg/Kg bw/d; females 196-292 mg/Kg bw/d), and 10,000 ppm (males 651-889 mg/Kg bw/d; females 449-995 mg/Kg bw/d). The males were treated for 2 weeks prior to mating, through until necropsy after 4 weeks of treatment. The females were treated for 2 weeks prior to mating, then through mating, gestation and until termination on at least Day 4 of lactation.

Based on the results observed, the NOAEL for reproductive parameters was considered to be 10,000 ppm (males 651-889 mg/Kg bw/d; females 449-995 mg/Kg bw/d).

Results from two supporting screening studies are presented below:

In a Guideline (OECD 421) reproductive/developmental toxicity screening study (Inveresk Research, 2003a), 10 rats/sex/group were exposed to the test material (Gum Rosin; CAS# 8050-09-7) at dietary concentrations of 0, 1000, 3000, or 10000 ppm for 41-45 days (females) or 30 days (males) in the diet.

Based on the results of the study, the NOAEL for reproductive/developmental toxicity in Sprague-Dawley rats was considered to be 3000 ppm for males (equivalent to 248 mg/Kg bw/d) and females (equivalent to 309 mg/Kg bw/d) and the NOAEL for subchronic toxicity was considered to be 1000 ppm in males (equivalent to 84 mg/Kg bw/d) and 3000 ppm in females (equivalent to 309 mg/Kg bw/d) based upon reduced feed consumption and lower weight gain in animals consuming higher dietary concentrations of the test material.

In another Guideline (OECD 421) reproductive/developmental toxicity screening study (Inveresk Research, 2004b), 10 rats/sex/group were exposed ad libitum in the diet to the test material (Resin acids and rosin acids, esters with pentaerythritol; CAS# 8050-26-8) at dietary concentrations of 0, 1000, 5000, or 20000 ppm for 57-60 days (females) or 28 days (males). There were no test substance-related effects on reproductive performance of the parental females or on survival and development of the F1 pups. All findings occurred in a non dose-dependent manner, were spurious in nature, or were biologically irrelevant and were not considered related to rosin pentaerythritol ester consumption. The no-observed-adverse-effect-level (NOAEL) for reproductive/developmental toxicity in Sprague-Dawley rats was considered to be 20000 ppm for males and females, equivalent to received doses of 1864 mg/Kg bw/d and 1757 -2054 mg/Kg bw/d, respectively.

Developmental Toxicity

Information exists to characterise the developmental toxicity of Rosin Adducts and Rosin Adducts Salts. These are formed when rosin reacts with maleic anhydride (or maleic acid) or fumaric acid yielding a maleated rosin adduct or a fumarated rosin adduct, respectively; the rosin adduct salts are simply the rosin adducts that have been reacted with an appropriate base. The available data includes results obtained from testing Rosin, fumarated; and Rosin, maleated and is summarised below.

In a key Guideline (OECD 414) pre-natal developmental toxicity study (Envigo CRS, S.A.U, 2018a), the test material (Rosin, fumarated; CAS# 65997-04-8) was administered by continuous dietary admixture to three groups of Sprague-Dawley rats, between gestation days 3 and 19 (inclusive) at dietary concentrations of 2500, 5000, and 10000 ppm (equivalent to mean achieved dosages of approximately 0, 188.2, 369.3 and 908.2 mg/Kg bw/day). An additional group of female rats was treated with basal laboratory diet to serve as a control.

Based on the results of this study, 10000 ppm was determined to be the maternal No Observed Adverse Effect Level (NOAEL) for pregnant females. Although a statistically significant effect on body weight gain between days 4 and 10 was observed at 10000 ppm, it was considered non-adverse, since it was a transient effect and no relevant differences were observed in body weight gain later during gestation, nor were there any effects on the general well-being of the dams in this group.

With respect to effects on embryofoetal development, 10000 ppm was determined to be the NOAEL. Although slight but statistically significant reduced foetal body weights were observed, this was not considered an adverse effect, due to the small magnitude of the change and because the mean value was within the Historical Control range. Despite some abnormalities in all dietary exposure groups as well as in control foetuses, there was no evidence that dietary exposure to the test material at 10000 ppm increased the occurrence of teratogenic effects. This dose was therefore considered to be the NOAEL.

In another key Guideline (OECD 414), pre-natal developmental toxicity study (Envigo Research Laboratories, 2017b), the test material (Rosin, maleated; CAS# 8050-28-0) was administered by continuous dietary admixture to three groups each composed of twenty-four time mated Sprague-Dawley Crl:CD® (SD) IGS BR strain rats, between gestation days 3 and 19 (inclusive) at dietary concentrations of 500, 1500, and 3000 ppm equivalent to mean achieved dosages of approximately 41.2, 122.9 and 217.4 mg/kg bw/day. A further group of twenty-four time mated females was treated with basal laboratory diet to serve as a control.

Based on the results of this study, dietary exposure to 500 ppm of the test material (equivalent to an achieved dosage of approximately 41.2 mg/kg bw/day of the test material) was considered to be a clear No Observed Effect Level (NOEL) for the pregnant dam. The No Observed Adverse Effect Level (NOAEL) for the pregnant dam was considered to be a dietary exposure to 1500 ppm of the test item (equivalent to an achieved dosage of approximately 122.9 mg/kg bw/day of the test material), due to effects on body weight gain and food consumption apparent at a dietary level of 3000 ppm.

The NOEL for the developing conceptus was considered to be a maternal dietary exposure to 500 ppm of the test item. The NOAEL for developmental toxicity was also considered to be at least 500 ppm of the test material, due to effects on foetal and placental weights and numerous skeletal findings indicating incomplete ossification or no ossification for many regions of the skeleton at the 1500 ppm level.

In a key Guideline (OECD 422), reproductive/developmental toxicity study (Harlan Laboratories Ltd, 2015a), the test material (Rosin, Maleated; CAS# 8050-28-0) was administered daily in dietary mixtures at concentrations of 0, 1750, 3500 or 7000 ppm to male rats for 43 days and to female rats for 14 days prior to pairing, through the pairing and gestation periods until the F1 generation reached day 4 post partum.

Based on the results of this study, a NOAEL (No Observed Adverse Effect Level) for general toxicity was established at the dose level of 3500 ppm. The NOAEL and NOEL (No Observed Effect Level) for reproduction were set at the dose level of 3500 ppm whereas the NOEL and NOAEL for development was established at the dose level of 1750 ppm due to the reduced body weights and body weight gain in pups at the dose level of 3500 ppm.

In another Guideline (OECD 422), reproductive/developmental toxicity study (Inveresk Research, 2004a), the test material (Rosin, fumarated; CAS# 65997-04-8) was administered in the diet to female rats at concentrations of 0, 1000 ppm (79-108 mg/Kg bw/d), 3000 ppm (196-292 mg/Kg bw/d), and 10,000 ppm (449-995 mg/Kg bw/d) throughout pregnancy until termination on Day 4 of lactation. Food consumption and mean body weights were decreased at 10,000 ppm and 3000 ppm, with high dose animals also showing an increase in total bilirubin and decreased adrenal weight. The lower of these two values will be used as the maternal (systemic) NOAEL. This is considered scientifically defensible since, apart from poor palatability and associated body weight reduction following exposure to 10000 ppm test substance, no clearly adverse effects were apparent. With regard to litter parameters, there was a slight decrease in the mean number of implant sites per pregnancy and a consequent slight reduction in litter size at birth in the high dose group. A slight reduction in litter size between Day1-4 of lactation at 3000 ppm was due to the loss of most pups in one litter. As there were no effects of treatment on litter survival at 10,000 ppm the findings at 3000 ppm are considered to be incidental. Based on these results, the NOAEL for developmental effects was considered to be 10,000 ppm (449-995 mg/Kg bw/d).

Endpoint for risk characterisation

Experimental results indicating a potential to cause sensitisation by skin contact, with associated classification under Regulation (EC) No. 1272/2008, indicate that members of this category may present a risk to workers during normal handling and use. Qualitative risk characterisation (ECHA, 2010) will therefore be conducted on this endpoint.

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Explanation for the modification of the dose descriptor starting point:

This substance is not classified for acute toxicity or has any observed acute toxicity, DNELs are therefore not appropriate.

Hazard assessment conclusion:

medium hazard (no threshold derived)

Hazard assessment conclusion:

medium hazard (no threshold derived)

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

no hazard identified

Hazard assessment conclusion:

medium hazard (no threshold derived)

Acute toxicity

ECHA Guidance R.8 (Chapter R.8.1.2.5) indicates that DNELs for acute toxicity are not required if no acute toxicity hazard leading to classification has been identified. The members of this category are not acutely toxic following oral or dermal exposure (LD₅₀>2000 mg/Kg bw) while a low vapour pressureprecludes inhalation exposure indicating a low of concern for this route of exposure. No DNELs for acute toxicity are therefore necessary.

Irritation

Corrosive and irritant effects on the skin and eye are local, concentration-dependent phenomena. However, while test results indicate that members of this category are irritating to eye (but not to skin), the nature of the data is such that no conclusion can be drawn with regard to any dose-response relationship present. No DNEL for irritation can therefore be derived.

Sensitisation

The sensitisation potential of the substances included in this category is well understood and comprises results from three local lymph node assays, a guinea pig maximisation test and a guinea pig Buehler test. The results consistently show evidence of a potential to induce skin sensitisation.

Intrinsic sensitising potency

ECHA Guidance R.8, Appendix R.8-10, (ECHA, 2010) states that while skin sensitisation is generally regarded as a threshold effect it may be very difficult to derive a threshold and to set a DNEL. Thus, the general approach for sensitisers involves a qualitative approach where a DNEL is used to judge any remaining/residual risks after the implementation of appropriate risk management measures (RMM) and occupational controls (OC).

The extent of the RMM and OC required is dependent on the intrinsic sensitising potency of the substance.

For results obtained using the LLNA, intrinsic sensitising potency is based on the EC3 and defined (ECHA (2010), Appendix R.8-10) as follows:

Category	EC3 (%)
Extreme	<0.2%
Strong	>0.2 - <2
Moderate	>2

EC3 values of 0.74%, 1.9% and 5.0% were obtained for Rosin, maleated, Rosin, fumarated and Rosin, fumarated, reaction products with formaldehyde, respectively. These indicate a strong to moderate potential to cause skin sensitisation.

For results obtained using the guinea pig maximisation test, intrinsic sensitising potency is based on the (intradermal) concentration employed during the induction phase of the test together with the incidence of sensitisation following challenge (ECHA, 2010):

Induction conc (%)

Incidence of sensitisation

<0.1

Strong

(30-60%)

Extreme

(>60%)

>0.1 - <1

Moderate

(30-60%)

Strong

(>60%)

>1

Moderate

(30-60%)

Moderate

(>60%)

Results obtained from a guinea pig maximisation test on Rosin, maleated using an intradermal induction concentration of 0.003% resulted in sensitisation incidences of 79% (10% challenge concentration) and 100% (30% challenge concentration) and are therefore indicative of an extreme sensitiser.

Different criteria apply to interpretation of results obtained using the Buehler test (ECHA Guidance R.8 (Appendix R.8-10)):

Induction conc (%)

Incidence of sensitisation

<0.2

Strong

(15-60%)

Extreme

(>60%)

>0.2 - <20

Moderate

(15-60%)

Strong

(>60%)

>20

Moderate

(15-60%)

Moderate

(>60%)

Results obtained from a Buehler test on Rosin, maleated using an induction concentration of 80% gave a sensitisation incidence of 80% (5% challenge concentration) indicative of a moderate sensitiser.

Given the range of outcomes obtained (1 extreme; 2 strong; 2 moderate), it will be assumed for the purposes of risk characterisation that the members of this category have a strong potential to cause sensitisation following skin contact.

Derivation of a DNEL for sensitisation

ECHA Guidance R.8, Appendix R.8-10 (ECHA, 2010), indicates that the EC3 concentration from a LLNA test can be taken as a LOAEL for the induction of skin sensitisation (ECHA, 2010) after conversion into an equivalent dose per unit area of skin (µg/cm²). Assuming (i) a dose volume of 25 μL (according tothe standard LLNA protocol); (ii) an estimated treatment area of 1 cm²for the mouse ear; and (iii) an assumed density of is 1, the conversion is performed as follows: