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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TARGET ORGANS AND TISSUES

Human Data

  • DEHP is lipophilic and migrates to adipose deposits. Clearance from these deposits is slow, therefore fat tissues provide best test for previous exposure.
  • Research has been conducted but has yielded prevalence data only, and no information regarding DEHP exposure history can be gleaned. Two research studies conducted in the United States have contributed to this knowledge.
    • Mes et al. 1974- Analysis of human abdominal adipose tissues from accident victims indicates that DEHP was present in these tissues at a concentration of 0.3-1.0 ppm. XLIII
    • Human Adipose Tissue Survey measured DEHP in 48% of the specimens sampled from the cadavers in a1982 study. XLIV

Animal Data

    • Indicates that the organ most consistently targeted by DEHP is the liver. The result appears to be an increase in liver peroxisomes. XXI
    • The effect of DEHP appears to vary across species.
    • Extrapolation from the animal data suggests that Lipfuscin deposits in the liver may be an indication of prolonged DEHP exposure.
    • Evidence of such an effect in humans is weak.
    • Hemodialysis patients have been studied, and liver biopsy studies have resulted in inconclusive findings.
    • Liver biopsy of hemodialysis patients is not indicated at this time because the risk of the procedure outweighs the benefit of the acquired information.

Reproductive Targets

    • Some studies in rats did not demonstrate deleterious effects on fertility or mating performance. L
    • Other research indicates that DEHP does in fact have adverse effect on reproduction in rats and mice. XXI
    • Animal studies exhibit the most severe effects during male reproductive organ development, but the effects do appear to be reversible until puberty. L
    • Sertoli cells are the main target and MEHP is the toxicant. LII
      Data on female reproductive targets is not as extensive.
    • Data on reproductive effects in humans is not available.