Phthalates

Introduction

Characteristic of the Agent

Fate and Transport

Environmental Impacts

Environmental Monitoring

Exposure Pathway

Routes of Exposure

Methods for Measuring Human Exposure

Strategies for Preventing or Controlling Exposures



Harmful Effects

Dose Response

Absorption, Distribution and Metabolism

Biomarkers

Target Organs and Tissues

Mechanisms of Toxicity

Risk Assessment and Risk Management

References

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DOSE-RESPONSE

Measuring human exposures by looking at the urinary metabolite levels can gauge human exposures, rather than just measuring the chemicals in the environment. However, at what level of exposure causes illness in humans is still unknown. XXXIV

Research predicted daily intake of phthalates by an adult averaged 0.8 mg/person/day (0.013 mg/kg body weight/day) up to 1.6 mg/person/day (0.027 mg/kg body weight/day) for someone with a diet high in phthalate-containing products. XIII

The dose-response data is shown below with the corresponding animal model. Specific studies with dose-response data was given in the “Harmful effects of agent” section above. Tables show calculated exposures levels for various sources:

FIGURE 2: Levels of Significant ORAL Exposure to Di-(2-ethylhexyl)phthalate Chronic >365 days XXI. ATSDR.


Figure 3- Levels of Significant Inhalation Exposure to Di-(2-ethylhexyl)phthalate XXI
ATSDR, pg 27.


Source: XXXIV Wolfgang Huber et al., "Hepatocarcinogenic Potential of Di(2-ethylhexyl)phthalate in Rodents and its Implications on Human Risk," Critical Reviews in Toxicology, vol. 26, issue 4 (June 1996), pp. 370, 438.

The above tables demonstrate that few humans, if any, are exposed to phthalate doses shown to cause minor harm in chronic animal testing, when administered over a lifetime. With the exception of short-term, life saving medical procedures, safety margins for typical human exposures are over 1000. XII With the differences between humans and rodents, it is hard to extrapolate what the dose response for humans would look like and even if humans would have similar responses for disease/symptoms