California Code of Regulations › Title 27 - Environmental Protection › Division 4 - Office of Environmental Health Hazard Assessment › Chapter 1 - Safe Drinking Water and Toxic Enforcement Act of 1986 › Article 8 - NO Observable Effect Levels › Section 25803 - Assessment

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) A
				  quantitative risk assessment which conforms to this section shall be deemed to
				  determine the level of exposure to a listed chemical which will have no
				  observable effect, assuming exposure at one thousand times the level in
				  question. The assessment shall be based on evidence and standards of comparable
				  scientific validity to the evidence and standards which form the scientific
				  basis for listing the chemical as known to the state to cause reproductive
				  toxicity. In the absence of principles or assumptions scientifically more
				  appropriate, based upon the available data, the following default principles
				  and assumptions shall apply in any such assessment:
(1) Only studies producing the reproductive
				  effect which provides the basis for the determination that a chemical is known
				  to the state to cause reproductive toxicity shall be utilized for the
				  determination of the NOEL.
(2)
				  Where multiple reproductive effects provide the basis for the determination
				  that a chemical is known to the state to cause reproductive toxicity, the
				  reproductive effect for which studies produce the lowest NOEL shall be utilized
				  for the determination of the NOEL. The NOEL shall be the highest exposure level
				  which results in no observable reproductive effect, expressed in milligrams of
				  chemical per kilogram of bodyweight per day. This may be the no observed effect
				  level in a scientific study or, alternatively, may be calculated by means of a
				  generally accepted scientific methodology such as the benchmark dose
				  methodology. Where a study (e.g., epidemiological publication) reports a range
				  of exposure levels associated with no observed effect, the NOEL may be selected
				  from within the range or calculated by benchmark dose or other accepted
				  scientific methodology.
(3) The
				  quality and suitability of available epidemiologic data shall be appraised
				  according to generally accepted scientific principles to determine whether the
				  study is appropriate as the basis for an assessment. Factors for consideration
				  in this appraisal include but are not limited to: the identification and
				  selection of study subjects (e.g. cases, controls, exposed, unexposed),
				  validity and reliability of the ascertainment of exposure, completeness of
				  follow-up, assessment of outcomes, and appropriateness of the statistical
				  analysis and power of the study to detect an effect. Biases and confounding
				  factors shall be identified, quantified, or otherwise considered, as
				  appropriate.
(4) Animal bioassay
				  studies for assessment shall meet generally accepted scientific principles,
				  including the thoroughness of experimental protocol, the degree to which dosing
				  resembles the expected manner of human exposure, the temporal exposure pattern,
				  the duration of study, the purity of test material, the number and size of
				  exposed groups, and the route of exposure and the extent of occurrence of
				  effects.
(5) The NOEL shall be
				  based on the most sensitive study deemed to be of sufficient quality.
(6) The results obtained for the most
				  sensitive study deemed to be of sufficient quality shall be applicable to all
				  routes of exposure for which the results are relevant.
(7) When available data are of such quality
				  that anatomic, physiologic, pharmacokinetic and metabolic considerations can be
				  taken into account with confidence, they may be used in the
				  assessment.
(8) When data do not
				  allow the determination of a NOEL, the lowest observed effect level shall be
				  divided by 10 to establish a NOEL for purposes of
				  assessment.