Characterizing the Movement of Per- and Polyfluoroalkyl Substances in an Avian Aquatic–Terrestrial Food Web

The movement of per- and polyfluoroalkyl substances (PFAS) through linked aquatic–terrestrial food webs is not well understood. Tree swallows (Tachycineta bicolor) in such systems may be exposed to PFAS from multiple abiotic and/or biotic compartments. We show from fatty acid signatures and carbon stable isotopes that tree swallow nestlings in southwestern Ontario fed on both terrestrial and aquatic macroinvertebrates. The PFAS profiles of air, terrestrial invertebrates, and swallows were dominated by perfluorooctanesulfonic acid (PFOS). Short-chain perfluoroalkyl acids (PFAAs) were largely restricted to air, surface water, and sediment, and long-chain PFAAs were mainly found in aquatic invertebrates and tree swallows. PFOS, multiple long-chain perfluorocarboxylic acids [perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorotridecanoic acid (PFTrDA)] and perfluorooctane sulfonamide precursors were estimated to bioaccumulate from air to tree swallows. PFOS bioaccumulated from air to terrestrial invertebrates, and PFOS, PFDA, and perfluorooctane sulfonamidoacetic acids (FOSAAs) bioaccumulated from water to aquatic invertebrates. PFOS showed biomagnification from both terrestrial and aquatic invertebrates to tree swallows, and PFDA and FOSAAs were also biomagnified from aquatic invertebrates to tree swallows. The movement of PFAS through aquatic–terrestrial food webs appears congener- and compartment-specific, challenging the understanding of PFAS exposure routes for multiple species involved in these food webs

Occurrence of Triclocarban and Triclosan in an Agro-ecosystem Following Application of Biosolids

Triclocarban (TCC) and triclosan (TCS), two of the most commonly used antimicrobial compounds, can be introduced into ecosystems by applying wastewater treatment plant biosolids to agricultural fields. Concentrations of TCC and TCS were measured in different trophic levels within a terrestrial food web encompassing land-applied biosolids, soil, earthworms (<i>Lumbricus</i>), deer mice (<i>Peromyscus maniculatus</i>), and eggs of European starlings (<i>Sturnus vulgaris</i>) and American kestrels (<i>Falco sparverius</i>) at an experimental site amended with biosolids for the previous 7 years. The samples from this site were compared to the same types of samples from a reference (biosolids-free) agricultural site. Inter-site comparisons showed that concentrations of both antimicrobials were higher on the experimental site in the soil, earthworms, mice (livers), and European starling eggs, but not American kestrel eggs, compared to the control site. Inter-species comparisons on the experimental site indicated significantly higher TCC concentrations in mice (TCC: 12.6–33.3 ng/g) and in starling eggs (TCC: 15.4–31.4 ng/g) than in kestrel eggs (TCC: 3.6 ng/g). Nesting success of kestrels only was significantly lower on the experimental site compared to the reference site due to nest abandonment. This study demonstrates that biosolids-derived TCC and TCS are present throughout the terrestrial food web, including secondary (e.g., starlings) and tertiary (i.e., kestrels) consumers, after repeated, long-term biosolids application

The Flame Retardant β‑1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane: Fate, Fertility, and Reproductive Success in American Kestrels (<i>Falco sparverius</i>)

Captive American kestrels (<i>Falco sparverius</i>) were exposed via diet during reproduction to an environmentally relevant concentration of β-1,2-dibromo-4-(1,2-dibromoethyl)­cyclohexane (β-TBECH). The β-TBECH isomer was injected into the food source at a daily dosing concentration of 0.239 ng/g kestrel/day (22 pairs); control birds were exposed via diet to the safflower oil vehicle only (24 pairs). Eight pairs in each group were exposed for four weeks and sacrificed for tissue analysis; the remaining pairs completed their breeding cycle, with exposure ceasing at the end of incubation (82 days). α- and β-TBECH appeared to be rapidly metabolized and/or eliminated from fat, liver, and plasma; both isomers and potential hydroxylated metabolites of β-TBECH (plasma) were undetected. Notwithstanding, compared to controls, pairs exposed to β-TBECH laid fewer eggs (<i>p</i> = 0.019) and laid lighter eggs (successful eggs: <i>p</i> = 0.009). Exposed pairs also demonstrated poorer egg fertility (<i>p</i> = 0.035) although testis mass and histology were similar among males. Reductions in egg production and fertility resulted in decreased hatchling success (<i>p</i> = 0.023). The β-TBECH-exposed pairs also produced fewer males overall (<i>p</i> = 0.009), which occurred concurrently with increased estradiols maternally deposited in eggs (<i>p</i> = 0.039). These findings demonstrate that β-TBECH may be detrimental for breeding in wild birds receiving similar exposure levels