Lipids Water

Cwater GILL UPTAKE GILL ELIMINATION Fish-Water Two Compartment Model dC F / dt = k 1.C W – k 2.C F C F : Concentration in Fish C W : Concentration in Water k 1 : Uptake clearance rate k 2 : Elimination rate constant C F = C W (k 1 /k 2 ).(1 - exp(- k 2.t))

Slope = - k 2

Bioconcentration : Equilibrium Partitioning f biota  f water

Woodwell, (1967) Sci Amer.

Biomagnification : f biota  f water f predator  f prey

Criteria for Bioaccumulation * Parameter Value Bioaccumulation FactorBAF > 5,000 Bioconcentration FactorBCF > 5,000 Octanol - Water Partition log K OW > 5 Coefficient * - BAF is better than BCF is better than K OW

Calves are born in June and weaned after 130 days Grazing: Lichen Diet (C. rangiferina, and C. nivalis)

Female wolves gives birth in may (litter of 2 to 7 pups, 0.5 kg each) Pups are weaned after 70 days 100% caribou diet (G D ) =1.5 kg/day: 5 calves, 2 yearlings and 16 adults)

Field Study Results: Spatial distribution of PCB 153 InuvikCambridg e Bay Bathurst Inlet Lichen Caribo u Wolf

Observed biomagnification in Bathurst Inlet food-chain logK OW Chemica l

BMF - K OW relationshipBMF - K OA relationship

L G Diet (m ol d -1 ) Growth Lactation (mol d -1 ) Metabolism (k M ) Fecal Excretion (mol d -1 ) Urine (mol d -1 ) GI T Air (m ol d -1 )

Canada’s Domestic Substance List

PCBs (PNVs)(NPNVs) (PVs)(NPVs)

United Nations LRTAP POPs Protocol (1998) Targets chemicals that are: P ersistent B ioaccumulative T oxic

Canadian Environmental Protection Act: Framework for Evaluating DSL Chemicals Inherently Toxic Persistent or Bioaccumulative Screening Assessment List of Toxic Substances No Further Action at this Time Substances on the DSL and No Yes PHASE 1: Categorization PHASE 2: Screening level risk assessment Outcomes Priority Substances List no further action under this program

Bioconcentration Factor: BCF = C F / C W Biota-Sediment Accumulation Factor : BSAF = C F / C S Bioaccumulation Factor : BAF = C F / C W Measures of Bioaccumulation Octanol-Water Partition Coefficient: Kow = C O / C W Biomagnification Factor: BMF = C F / C Diet

BCF or BAF = C Fish / C Water C Fish = g substance/ kg wet weight organism C Water = g substance / L water BCF WW = L/kg wet weight C Fish = g substance/ kg lipid C Water = g substance / L BCF L = L/kg lipid Units of Bioaccumulation BCF WW = L.BCF L BCF WW : Wet weight based BCF BCF L : Lipid weight based BCF L : Lipid content organism (kg lipid/kg wet weight organism)

BSAF = C Biota / C Sediment C Biota = g substance / kg wet weight biota C Sediment = g substance / kg dry sediment BSAF = kg dry sediment/kg wet weight biota C Fish = g substance / kg lipid C Sediment = g substance / kg organic carbon BSAF L = kg organic carbon L/kg lipid Units of Bioaccumulation

BSAF WW = (L/  OC ).BSAF L BSAF WW : Wet weight based BSAF (kg dry sediment/kg wet weight biota) BSAF L : Lipid & Organic carbon normalized BSAF (kg organic carbon/ kg lipid) L : Lipid content biota (kg lipid/kg wet weight biota)  OC : Organic carbon content sediment (kg organic carbon/kg dry weight sediment)

BMF = C F / C D C F = g / kg wet weight C W = g / L BCF W = L/kg wet weight C F = g / kg lipid C W = g / L BCF L = L/kg lipid Units of Bioaccumulation BCF W = L.BCF L BCF W : Wet weight based BCF BCF L : Lipid weight based BCF L : Lipid content organism (kg lipid/kg wet weight organism)

Read Environ. Sci. Technol. 16: (1982)

Read: Environ. Sci. Technol. 22: (1988)

Trophic Dilution

Criteria for Bioaccumulation UNEP & CEPA * Parameter Value Bioaccumulation FactorBAF > 5,000 Bioconcentration FactorBCF > 5,000 Octanol - Water Partition log K OW > 5 Coefficient * - BAF is better than BCF is better than K OW

Aquatic organismsAir-breathing animals GIT Lipid-Air partitioningLipid-Water partitioning (K OW ) GIT (K OA ) may better assess bioaccumulation potential in air- breathing animals

Food-Chain Biomagnification is observed for chemicals with a log Kow as low as 3.8. Koa is a better predictor of bioaccumulation in terrestrial food-chains than Kow Current bioaccumulation protocols in CEPA & UNEP do not identify low Kow- high Koa substances that have a biomagnification potential in terrestrial food-chains Preliminary data and models indicate that in absence of metabolism, chemicals with log Koa > 4 biomagnify in terrestrial food-chains. Conclusions

Chemicals on the DSL

Algae Suspended Sediments Bottom Sediments C water C sediment

Chemical Equilibrium K d = C A /C W f A = f W f : Fugacity (Pa) C : Concentration (mol/m3) Z : Fugacity Capacity (mol/Pa.m3) C = f.Z

Algae Suspended Sediments Bottom Sediments f WATER f ALGAE f SUSP-SED f SEDIMENT = = =

K d = C A /C W K d = C SS /C W K d = C BS /C W

f = C/Z Z water = 1/H Z algae = OC.0.41.K ow.d a /H Z ssed = OC.0.41.K ow.d ss /H Z bsed = OC.0.41.K ow.d bs /H

Lake Ontario

Lake Erie

Lake Superior

Lake St. Clair

Observations: 1. There is no equilibrium 2. f BS > f SS > f A > f W 3. f BS /f w, f SS /f W, f A /f W increase when Kow decreases

26% 4% 1.5% Mineralization OCZf

fafa f bs f ss f W3 f W2 f W1 DpDp DsDs D bs D wp D pw D sw D bsw D wbs D ws

fafa f bs f ss f W3 f W2 f W1 DpDp DsDs D bs D wp D pw D sw D bsw D wbs D ws f a / f w = D pw / (D pw + D p ) f ss / f a = G p. Z p / G s. Z s f bs / f s = G ss. Z ss / G bs. Z bs

fafa f ss f W2 DpDp DsDs D sw D ws f ss / f a = (D p + D sw ) / (D s + D sw ) f ss / f a = D p / D s = G p. Z p / G s. Z s

f bs f ss f W3 DsDs D bs f bs / f s = (D s + D ssw ) / (D ss + D ssw ) f bs / f s = D s / D ss = G s. Z s / G ss. Z ss

Log Kow =4Log Kow =7

DISEQUILIBRIUM Between sediment, suspended sediments & water Fugacity pump Increases when Kow decreases Organic carbon mineralization Affects the degree to which the sediments & water and diet & water contribute to body burdens Affects BAFs & BSAFs