Registration Dossier

Administrative data

Workers - Hazard via inhalation route

Systemic effects

Acute/short term exposure
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
2.92 mg/m³
Most sensitive endpoint:
repeated dose toxicity
DNEL related information
Overall assessment factor (AF):
300
Dose descriptor:
NOAEC
Acute/short term exposure
DNEL related information

Workers - Hazard via dermal route

Systemic effects

Acute/short term exposure
DNEL related information

Workers - Hazard for the eyes

Additional information - workers

Urea Phosphate will directly dissociate into urea and phosphoric acid in aqueous environment. Based on all available data it is clear that phosphoric acid is the critical substance with regard to the toxicological profile. Therefore, the below is based on phosphoric acid.

Acute exposure

Acute short term exposure - systemic effects - dermal and inhalation:

Phosphoric acid as such is not expected to become systemically available in the body. Once absorbed, phosphoric acid is distributed widely in the body as phosphate, which is an essential element to organisms and its fate in the human body is regulated. Phosphoric acid can be locally absorbed by ingestion, inhalation and dermal contact.

Acute short term exposure – local effects - inhalation:

A DNEL for acute toxicity should be derived if an acute toxicity hazard (leading to C&L) has been identified and there is a potential for high peak exposures (REACH Guidance document R8, appendix R8 -8: Acute toxicity). The substance is not classified for acute exposure via inhalation. In addition, no peak exposure is warranted for this substance.

An European Short term Occupational exposure limit recommanded from Scientific Expert Group is available for phosphoric acid and is STEL 15 min: 2 mg/m3. This value is based on the Rushing observation on phosphorus pentoxide to the ACGIH TLV committee.

Acute short term exposure - local effects - dermal:

The concentration limit of urea phosphate is 25% (based on phosphoric acid, as reported in the CLP Regulation No 1272/2008 Annex VI Table 3.1)

The concentration range of 10 -25% is established for irritation.

Long term exposure

Long term exposure - systemic effects - dermal & inhalation DNEL in mg/kg bw/day:

Phosphoric acid as such is not expected to become systemically available in the body. Once absorbed, phosphoric acid is distributed widely in the body as phosphate, which is an essential element to organisms and its fate in the human body is regulated. Phosphoric acid can be locally absorbed by ingestion, inhalation and dermal contact.

Long term exposure - local effects - dermal DNEL in mg/cm2:

As no quantitative route-specific data are a available for phosphoric acid, no DNEL for local effects is proposed for workers and only an indication of the potency is given. As the substance is classified as corrosive to the skin category 1B, the substance is allocated to the “high hazard category”, according to the ECHA “Guidance on information requirements and chemical safety assessment Part E: Risk Characterisation Substances”.

Long term exposure – local effects - inhalation DNEL in mg/m³:

The Weinberg group (2002) reported a NOAEL value of 250 mg/kg bw/d for a repeated dose toxicity test (oral exposure) performed on rat (Combined Repeated Dose Toxicity with the Reproduction/Developmental Toxicity Screening test of diammonium phosphate in rats). Rats were exposed for 35 days. This NOAEL for oral exposure in rats should be extrapolated to a NOAEL for inhalation exposure in human (i.e. workers population). The starting point dose descriptor is calculated as following:

(250 mg/kg bw x 70 kg)/ (10 m³) = 1750 mg/m³ where 70 kg is the standard human body weight and 10 m³ is the respiration factor for the worker. In order to cover possible differences in bioavailability between routes this starting dose value should be multiplied by a factor 0.5 (assuming 100% absorption by inhalation exposure and 50% absorption by oral exposure): 1750 mg/m3 x 0.5 = 875 mg/m³.

Following assessment factors should be applied:

- allometric scale, factor 4;

- interspecies differences, factor 2.5;

- intraspecies differences, factor 5;

- exposure duration, factor 6 (sub-acute to chronic exposure duration);

-> The overall assessment factor is: 4 x 2.5 x 5 x 6 = 300

The resulting DNEL for long term inhalation, workers is (875 mg/m³)/300 = 2.92 mg/m³

An European Long term Occupational exposure limit recommanded from Scientific Expert Group is available for phosphoric acid and is 8 hour TWA: 1 mg/m3. This value is based on the Rushing observation on phosphorus pentoxide to the ACGIH TLV committee. Nevertheless as this value is more conservative it will be used in the exposure assessment and determination of the risk characterization ratio for phosphoric acid.

General Population - Hazard via inhalation route

Systemic effects

Acute/short term exposure
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.73 mg/m³
Most sensitive endpoint:
repeated dose toxicity
DNEL related information
Overall assessment factor (AF):
600
Dose descriptor:
NOAEC
Acute/short term exposure
DNEL related information

General Population - Hazard via dermal route

Systemic effects

Acute/short term exposure
DNEL related information

General Population - Hazard via oral route

Systemic effects

Acute/short term exposure
DNEL related information

General Population - Hazard for the eyes

Additional information - General Population

Urea Phosphate will directly dissociate into urea and phosphoric acid in aqueous environment. Based on all available data it is clear that phosphoric acid is the critical substance with regard to the toxicological profile. Therefore, the below is based on phosphoric acid.

Acute exposure

Acute short term exposure - systemic effects - dermal and inhalation:

Phosphoric acid as such is not expected to become systemically available in the body. Once absorbed, phosphoric acid is distributed widely in the body as phosphate, which is an essential element to organisms and its fate in the human body is regulated. Phosphoric acid can be locally absorbed by ingestion, inhalation and dermal contact.

Acute short term exposure – local effects - inhalation:

A DNEL for acute toxicity should be derived if an acute toxicity hazard (leading to C&L) has been identified and there is a potential for high peak exposures (REACH Guidance document R8, appendix R8 -8: Acute toxicity). The substance is not classified for acute exposure via inhalation. In addition, no peak exposure is warranted for this substance.

Acute short term exposure – local effects - dermal:

The concentration limit of urea phosphate is 25% (based on phosphoric acid, as reported in the CLP Regulation No 1272/2008 Annex VI Table 3.1)

The concentration range of 10 -25% is established for irritation.

Long term exposure

Long term exposure - systemic effects - oral / dermal / inhalation DNEL :

Phosphoric acid as such is not expected to become systemically available in the body. Once absorbed, phosphoric acid is distributed widely in the body as phosphate, which is an essential element to organisms and its fate in the human body is regulated. Phosphoric acid can be locally absorbed by ingestion, inhalation and dermal contact.

Long term exposure - local effects - dermal DNEL in mg/cm2:

As no quantitative route-specific data are a available for phosphoric acid, no DNEL for local effects is proposed for the general population and only an indication of the potency is given. As the substance is classified as corrosive to the skin category 1B, the substance is allocated to the “high hazard category”, according to the ECHA “Guidance on information requirements and chemical safety assessment Part E: Risk Characterisation Substances”.

Long term exposure general population – local effects - inhalation DNEL in mg/m³:

The DNEL for inhalation exposure can be derived from the oral NOAEL. This NOAEL for oral exposure in rats should be extrapolated to a NOAEL for inhalation exposure in human (i.e. general population). The starting point dose descriptor is calculated as following:

(250 mg/kg bw x 70 kg)/ (20 m³) = 875 mg/m3 where 70 kg is the standard human body weight and 20 m3 is the respiration factor for the general population. In order to cover possible differences in bioavailability between routes this starting dose value should be multiplied by a factor 0.5 (assuming 100% absorption by inhalation exposure and 50% absorption by oral exposure): 875 mg/m³ x 0.5 = 437.5 mg/m³.

Following assessment factors should be applied:

- allometric scale, factor 4;

- interspecies differences, factor 2.5;

- intraspecies differences, factor 10;

- exposure duration, factor 6 (sub-acute to chronic exposure duration);

-> The overall assessment factor is: 4 x 2.5 x 10 x 6 = 600

The resulting DNEL for long-term exposure - local effects - inhalation, general population is (437.5 mg/m³)/600 = 0.73 mg/m³