Registration Dossier

Environmental fate & pathways

Bioaccumulation: aquatic / sediment

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The key parameter is a calculated value. However, additional measured data for analogs from a biomagnification study support the use of the of the calculated value to characterize the BCF of DTDP, and suggest that DTDP has a low bioaccumulative potential, not expected to accumulate through food chains in the aquatic environment.

Key value for chemical safety assessment

Additional information

The results of a study to assess the bioaccumulative potential of high molecular weight phthalate diesters, di-C8 PEs to di-C10 PEs, in an aquatic food-web that included 18 marine species, showed that high molecular weight phthalate esters did not biomagnify, but rather decreased in tissue concentration in organisms of increasing trophic position. Decreasing concentrations also referred to as biodilution, can be quantified by food-web magnification factors (FWMFs). A FWMF that is greater than 1.0 is an indication of chemical biomagnification within a food-web, whereas a value of less than 1.0 indicates biodilution ordecreasing concentrationsfrom lower to higher trophic levels. Study results showed that lipid equivalent concentrations of the high molecular weight phthalate diesters significantly declined with increasing trophic level and that the FWMFfor di-isodecyl phthalate was 0.44. Similar results would be expected with DTDP, an analog of DIDP(Mackintoshet al., 2004).

The finding above is consistent with a laboratory fish bioaccumulation study in which rainbow trout were fed a DTDP spiked diet for 9 days(ExxonMobil, 2007). The low water solubility and high Kowof DTDP prevent conducting an aqueous exposure BCF (bioconcentration factor) study. At the end of the exposure period, fish were sampled after different depuration times (0, 1, 3 days). Results demonstrated a low potential for bioaccumulation with a lipid normalized biomagnification factor (BMF, concentration ratio in tissue to that in diet) of <0.1 and rapid subsequent depuration with a tissue elimination half-life of <1 day. The half-life of <1 day was used to calculate a BCF in fish of approximately <1 L/kg for DINP.

A low bioconcentration factor (BCF) value, 3.2 (log BCF = 0.5), is estimated for DTDP using theU.S. Environmental Protection Agency model, EPI SuiteTM(USEPA, 2000).