Santicizer 2148

Endpoint summary

Description of key information

Hydrolysis

The test material Santicizer 2148 plasticizer is a mixture of five organic esters prepared from phosphoric acid. According to the Guideline EEC C7. 'Abiotic degradation: hydrolysis as a function of pH, December 1992', the test concentration should not exceed the lesser of 0.1 M or half the water solubility. For the test material (water solubility = 0.15 mg/L) that meant that the test concentration in the hydrolysis study had to be <0.08 mg/L.

The analytical method used to determine the test material concentrations in the hydrolysis study should be able to measure a decrease in concentration of at least

10% accurately. Neither High Performance Liquid Chromatography (HPLC) not Gas Chromatography (GC) were sensitive enough to measure such a low

concentration accurately. Therefore, the hydrolysis study was technically not feasible and could not be performed.

Biodegradation

Based on the poor water solubility of the test material in water (water solubility = 0.15 mg/L) and significant volatilization in water, none of the available test methods (OECD 301A - 301F) were found to be suitable for the determination of ready biodegradability.

Bioaccumulation

A key EPA OPP Guideline 165-4 dynamic 56-day study (ABC Laboratories Inc., 1993a) was conducted to evaluate the bioaccumulation of ¹⁴C-Santicizer 2148 by Bluegill Sunfish (Lepomis macrochirus). A flow-through proportional diluter system was used to maintain a mean measured water concentration of 0.097 (± 0.015) μg/L¹⁴C-Santicizer 2148 for a 35-day exposure period. Radioanalysis of fillet, whole fish, and visceral portions was performed periodically during the exposure period. In this study the fillet (body, muscle, skin, and skeleton) was considered the edible portion of the fish, while the viscera (fins, head, and internal organs) was considered the nonedible portion. Daily bioconcentration factors ranged from 22 to 210 x, 12 to 760 x, and 19 to 1300 x for fillet, whole fish, and viscera respectively. Average tissue concentrations of ¹⁴C-Santicizer 2148 during the exposure phase ranged from 2.4 to 21 ng/g for fillet, 1.4 to 74 ng/g for whole fish, and from 2.3 to 130 ng/g for viscera. The bioaccumulation of ¹⁴C-Santicizer 2148 in all tissues was consistent through day 28 uptake and by day 35 of uptake the rate slowed considerably in the fillet tissue. Since the accumulation appeared to be continuous in the whole fish and viscera tissues the uptake was terminated on day 35 and depuration was started.

 

To measure the elimination of ¹⁴C-Santicizer 2148, the test fish were placed in untreated water for 21 days. Radioanalysis at the end of the 21-day depuration period indicated 40, 64, and 73% depuration from fillet, whole fish, and viscera respectively. Fillet concentrations dropped from 20 ng/g on day 35 of exposure to 12 ng/g by day 21 of depuration. Whole fish levels decreased from 74 ng/g on day 28 of exposure to 27 ng/g by the end of depuration, while viscera concentrations dropped from 130 ng/g on day 35 of exposure to 35 ng/g by day 21 of depuration.

 

Analysis of the uptake/depuration data for whole fish was conducted using a computer modelling program. This method estimated the uptake rate constant (K1) ng/g fish perμg/L water per day of 56 ± 2, depuration rate constant (K2) day-1 of 0.064 ± 0.003, time for 50% depuration of 11 ± 0.5 days, bioconcentration factor (BCF) of 875 ± 50, and a time to reach 90% of stead state 36 ± 2 days. The BIOFAC-calculated BCF value was 115% of the observed mean whole fish bioconcentration factor of 760 x for day 35.

 

Test fish were in good health during the study and no mortality was observed in the treated and control aquaria. Therefore, the data obtained from these fish adequately defined the uptake/depuration of potential ¹⁴C-Santicizer 2148.

Adsorption

The adsorption coefficient (K_OC) in soil and on sewage sludge was estimated using HPLC (NOTOX B.V., 1999i). According to the information supplied by the sponsor, SANTICIZER 2148 PLASTICIZER is a mixture of five organic esters prepared from phosphoric acid. For the five phosphoric acid esters, the log K_OC and K_OC were given as a range of 6.1 - 7.3 and (0.13-2.0)*10⁷, respectively.