Laserfiche WebLink
SECTIONTHREE Technical Approach <br /> M.6 assess Toxicology of Chemicals of Concern <br /> The toxicity assessment will use toxicity values developed and/or approved by U S EPA and the State <br /> of California to characterize the potential carcinogeruc and non-carcinogenic effects of the chemicals of <br /> concern <br /> The toxicological data regarding the contaminants of concern are obtained from various data bases <br /> The hierarchy of toxicity values to be used in the assessment is as follows <br /> o Cancer potency factors(slope factors) or chronic reference doses (R#Ds) promulgated into <br /> California regulations <br /> o Slope Factors (SFs) or chronic RfDs used to develop environmental criteria promulgated <br /> into California regulations <br /> o Integrated Risk Information Data Base(IRIS, U S EPA) <br /> o The most current edition of U S EPA's Health Effects Assessment Summary Tables <br /> (FAST,U S EPA-ECAO) <br /> o Toxicity values not available through any of the aforementioned sources will be obtained <br /> through the Office of Scientific Affairs(OSA) "Helpline" <br /> This toxicity mfornnation is summarized to assess the following <br /> o Dose-response relationships with respect to site-specific exposures that may be associated <br /> with potentially harmful health effects <br /> o Species differences with regard to both dose-response and target-organ relationships <br /> o Attenuation factors which may be used to adjust estimates of contaminant absorption and <br /> Y J � <br /> uptake through the intestinal tract or across the slain <br /> o The validityof long-term animal studies to evaluate the carcino eruc potential of a <br /> g g <br /> particular chemical <br /> Other data bases, including CHEMLI E, Toxline, Chemical Abstracts, and available literature may be <br /> researched, if necessary,to evaluate toxicity of key chemicals of concern Table 3-8 provides proposed <br /> toxicity values for the potential chemicals of concern <br /> The toxicity assessment considers both carcinogenic risks and non-carcuiogemc hazards posed by the <br /> chemicals of concern The potency of potential carcinogens is quantified as a SF, that relates the dose <br /> of a chemical to the lifetime incremental excess cancer risk, expressed as a unitless probability In <br /> ® C%CALTRANWHOPIOWYRKPLNFD=7-=-9B1e7 =NALSNA 3-7 <br />