Infant's dioxin exposure

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Question

How to measure infant's dioxin exposure due to fetal period and breast feeding?

Answer

Mother's exposure at level 100 pg /d (fairly typical amount) will lead to child's TEQ concentration of 44 pg /g fat (logTEQ 3.8).

+ Show code- Hide code # This is code Op_en7797/ on page [[Infant's dioxin exposure]] library(OpasnetUtils) objects.latest("Op_en7797", code_name="initiate") exposure <- Ovariable("exposure", data = data.frame(Exposure_agent = "TEQ", Result = 100)) dx.expo.child <- EvalOutput(dx.expo.child) oprint(summary(dx.expo.child))

Rationale

Inputs

Parametres(-)

Obs	Parametre	Value	Description
1	TEQ half-life	2737.5	t0.5: 7.5 * 365, Dioxin half-life in adults (d)
2	TEQ fraction absorbed	0.8	f_ing: 0.80, Fraction of dioxin ingested that is actually absorbed (-)
3	TEQ fraction to child	0.1 - 0.25	f_mtoc: 0.25, Fraction of mother's dioxin burden that enters the child during breast-feeding in 6 mo. Alaluusua et Vartiainen (-)
4	Body fat in infant	1580	BF: 0.2 * (7.692+8.141) / 2, body fat amount in the infant at six months of age (g) [[:op_en:Body weight of 0-24 months old Finnish children]].

Calculations

• Ovariables initiated 19.5.2017 [1]
• Updated 30.5.2017 [2]

+ Show code- Hide code # This is code Op_en7797/initiate on page [[Infant's dioxin exposure]] library(OpasnetUtils) ################## CREATE a separate ovarible about children's exposure: expo.child # Convert mother's dioxin intake (pg/d) into child's dioxin concentration (pg/g) in fat after 6 months of breast-feeding. # For details, see [[ERF of dioxin#Dental defects]] a <- opbase.data("Op_en7797", subset = "Parametres") # [[Infant's dioxin exposure]] t0.5 <- Ovariable("t0.5", data = a[a$Parametre == "TEQ half-life" , ][-(1:2)]) f_ing <- Ovariable("f_ing", data = a[a$Parametre == "TEQ fraction absorbed" , ][-(1:2)]) f_mtoc <- Ovariable("f_mtoc", data = a[a$Parametre == "TEQ fraction to child" , ][-(1:2)]) BF <- Ovariable("BF", data = a[a$Parametre == "Body fat in infant" , ][-(1:2)]) dx.expo.child <- Ovariable( "dx.expo.child", dependencies = data.frame( Name = c( "expoRaw", # Mother's exposure to dioxin (pg/d) "t0.5", # Half-life of dioxin in mother (d) "f_ing", # Fraction of dioxin ingested by mother that is actually absorbed "f_mtoc", # Fraction of mother's dioxin body burden that enters the child during 6 mo breast feeding. "BF" # Body fat amount (g) in the infant at 6 mo of age ) ), formula = function(...) { out <- expoRaw * f_ing * t0.5 / log(2) # Body burden in mother after long constant exposure out <- out * f_mtoc / BF # Dioxin concentration in child out <- log(out + 0.1) # Convert to logarithm for ERF compatibility (avoid log(0)) # Technical conversion out <- out[out$Exposure_agent == "TEQ" , ] out$Exposure_agent <- "logTEQ" return(out) } ) objects.store(t0.5, f_ing, f_mtoc, BF, dx.expo.child) cat("Ovariables t0.5, f_ing, f_toc, BF, dx.expo.child stored.\n")

See also

• Human PBPK model for dioxin