title: A new method for setting guidelines to protect human health from agricultural exposure by using chlorpyrifos as an example.
abstract: OBJECTIVE
  Guidelines set by various agencies for the control and management of chlorpyrifos cover a wide range of values reflecting difficulties in the procedures for their development. To overcome these difficulties a new method to set guidelines would be developed. Published data derived from epidemiological investigations on human populations would be used to develop a dose-response relationship for chlorpyrifos allowing the calculation of threshold values which can be used as guidelines.
  
  
  METHODS
  Data from the scientific literature on human populations were collected to evaluate the adverse response doses for a range of health effects. The Cumulative Frequency Distribution (CFD) for the minimum levels of adverse effects measured in terms of the Lifetime Average Daily Dose (LADD(D)) and the Absorbed Daily Dose for neurological (ADD(DN)) and non-neurological effects were used.
  
  
  RESULTS
  Linear regression equations were fitted to the CFD plots giving R 2 values of 0.93 and 0.86 indicating a normal distribution of the data. Using these CFD plots, the chronic and acute threshold values were calculated at the 5% cumulative frequency level for chlorpyrifos exposure giving values at 0.5 µg/kg/d and 3 µg/kg/d respectively.
  
  
  CONCLUSIONS
  Guidelines set using this technique at the values at 0.5 µg/kg/d and 3 µg/kg/d for chronic and acute exposure respectively provide an alternative to the currently used biological endpoint and safety factor method.
authors.affiliation: Centre for Environment and Population Health, Griffith School of the Environment, Griffith University, Nathan, Australia.
authors.forename: Dung Tri
authors.initials: DT
authors.lastname: Phung
authors.affiliation: Griffith School of Environment, Griffith University, Nathan, Australia.
authors.forename: Des
authors.initials: D
authors.lastname: Connell
authors.affiliation: Centre for Environment and Population Health, Griffith School of the Environment, Griffith University, Nathan, Australia.
authors.forename: Cordia
authors.initials: C
authors.lastname: Chu
mesh_terms: D000383:Agriculture; D000826:Animal Testing Alternatives / Q000379:methods*; D004390:Chlorpyrifos / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D017408:Guidelines as Topic; D006801:Humans; D007306:Insecticides / Q000633:toxicity*; D016273:Occupational Exposure; D018570:Risk Assessment
chemical_list: D007306:Insecticides; D004390:Chlorpyrifos