title: An experimental design to probe the interactions of dissolved organic matter and xenobiotics: bioavailability of pyrene and 2,2',5,5'-tetrachlorobiphenyl to Daphnia magna.
abstract: Experiments were conducted to probe the interactions between natural dissolved organic matter (DOM) and two xenobiotics, and to determine how DOM influences their bioavailability. The experimental set-up, using dialysis bags, was designed to expose test organisms to the same constant concentration of free dissolved chemical, while increasing the concentration of the bound-to-DOM fraction. Daphnia magna S. were exposed to pyrene or 2,2',5,5'-tetrachlorobiphenyl in the presence of 0, 1, 2, 5, 10 or 20 mg L(-1) of a reference riverine humic acid (Suwannee River Humic Acid). The physico-chemical parameters were well constrained in the microcosm, demonstrating its potential usefulness. However bioaccumulation by D. magna showed important variability between replicate treatments, sufficient to mask any trends as a function of DOM concentration. The organic-carbon-normalised partition coefficients (K(OC)) ranged from 52000 to 92000 L kg(-1) for pyrene and from 8200 to 89000 L kg(-1) for 2,2',5,5'-tetrachlorobiphenyl, with a marked "concentration effect" for the latter compound.
authors.affiliation: Université du Québec, INRS-Eau, Sainte-Foy, Canada.
authors.forename: L K
authors.initials: LK
authors.lastname: Granier
authors.forename: P
authors.initials: P
authors.lastname: Lafrance
authors.forename: P G
authors.initials: PG
authors.lastname: Campbell
mesh_terms: D000818:Animals; D001682:Biological Availability; D002273:Carcinogens / Q000737:chemistry / Q000493:pharmacokinetics*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003621:Daphnia / Q000737:chemistry / Q000378:metabolism*; D006812:Humic Substances / Q000494:pharmacology; D011078:Polychlorinated Biphenyls / Q000737:chemistry / Q000493:pharmacokinetics*; D011721:Pyrenes / Q000737:chemistry / Q000493:pharmacokinetics*; D012107:Research Design; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000493:pharmacokinetics*; D015262:Xenobiotics / Q000737:chemistry / Q000493:pharmacokinetics*
chemical_list: D002273:Carcinogens; D006812:Humic Substances; D011721:Pyrenes; D014874:Water Pollutants, Chemical; D015262:Xenobiotics; C009407:2,5,2',5'-tetrachlorobiphenyl; D011078:Polychlorinated Biphenyls