Contaminants of Emerging Concern in Bats from the Northeastern United States.

We analyzed bat carcasses (Myotis lucifugus, M. sodalis, M. septentrionalis, and Eptesicus fuscus) from the northeastern United States for contaminants of emerging concern (CECs) such as polybrominated diphenyl ethers (PBDEs), and pharmaceuticals and personal care products. The CECs detected most frequently in samples were PBDEs (100 %), salicylic acid (81 %), thiabendazole (50 %), and caffeine (23 %). Other compounds detected in at least 15 % of bat samples were digoxigenin, ibuprofen, warfarin, penicillin V, testosterone, and N,N-diethyl-meta-toluamide (DEET). The CECs present at the highest geometric mean wet weight concentrations in bat carcasses were bisphenol A (397 ng/g), ΣPDBE congeners 28, 47, 99, 100, 153, and 154 (83.5 ng/g), triclosan (71.3 n/g), caffeine (68.3 ng/g), salicylic acid (66.4 ng/g), warfarin (57.6 ng/g), sulfathiazole (55.8 ng/g), tris(1-chloro-2-propyl) phosphate (53.8 ng/g), and DEET (37.2 ng/g). Bats frequently forage in aquatic and terrestrial habitats that may be subjected to discharges from wastewater-treatment plants, agricultural operations, and other point and nonpoint sources of contaminants. This study shows that some CECs are accumulating in the tissue of bats. We propose that CECs detected in bats have the potential to affect a number of physiological systems in bats including hibernation, immune function, and response to white-nose syndrome, a fungal disease causing population-level impacts to bats.

Bioenergetics-based modeling of individual PCB congeners in nestling tree swallows from two contaminated sites on the upper Hudson River, New York.

A bioenergetics-based model was used to simulate the accumulation of total PCBs and 20 PCB congeners by nestling tree swallows at two contaminated sites on the Upper Hudson River, New York. PCB concentrations in birds were calculated as the sum of inherited residues and those acquired through consumption of contaminated insects. Close agreement between simulations and measured residues in 5-, 10-, and 15-day-old nestlings was obtained when PCB concentrations in the diet were set equal to those in food boli taken from adult birds. These simulations were further optimized by fitting the value of a dietary assimilation efficiency constant. Fitted constants for both sites were similar and averaged about 0.7. An evaluation of model performance for individual congeners provided no evidence of metabolic biotransformation. The results of this study are consistent with a companion effort in which principal components analysis was used to compare PCB congener patterns in insects and in tree swallow eggs, nestlings, and adults. Together, these studies establish a quantitative linkage between nestling tree swallows and the insects that they consume and provide strong support for the use of nestling swallows as a biomonitoring species for exposure assessment.

Accumulation of PCB congeners in nestling tree swallows (Tachycineta bicolor) on the Hudson River, New York.

Tree swallows (Tachycineta bicolor) were used as a sentinel species to monitor the contamination and bioavailability of polychlorinated biphenyls (PCBs) in the Hudson River watershed. Several tree swallow nest box colonies around and downstream from Hudson Falls, NY, were studied. Tree swallow eggs, adults, and 5-, 10-, and 15-day-old nestlings were collected and analyzed for 103 PCB congeners. Emergent insects collected by net (primarily Odonata) or as a food bolus (primarily Diptera) taken from the mouths of adult tree swallows returning to the nest were analyzed in the same manner. Total PCB concentrations (wet weight) in eggs from two contaminated sites ranged from 9000 to 25,000 ng/g and accumulated to 32,000 and 96,000 ng/g in 15-day-old nestling at two contaminated sites. The congener patterns of PCBs in eggs, nestlings, and adults were compared to those found in emergent insects (Odonata and Diptera) using principal components analysis. The PCB patterns of the biota differed from that of Aroclor technical mixtures. PCB patterns in adult tree swallows were similar to those in eggs, while the patterns in dietary insects were similar to nestling tree swallows. Uptake rate constants were determined for tree swallow nestlings and compared between the two contaminated sites. The estimated PCB congener uptake rate constants were 0.008-0.02 d(-1) based on uptake in nestlings until day 15 post-hatch. The rate constants were comparable between the two study areas and may be used to predict nestling contamination at other locations. Our studies confirm the utility of nestling tree swallows to evaluate localized PCB contamination.

Health of tree swallow (Tachycineta bicolor) nestlings exposed to chlorinated hydrocarbons in the St. Lawrence River Basin. Part II. Basal and stress plasma corticosterone concentrations.

Sixteen-day-old tree swallows (Tachycineta bicolor) were collected in 1999 and 2000 from nine sites within the vicinity of the St. Lawrence River in Canada and the United States to determine if organochlorine contaminant concentrations correlated with corticosterone levels. Basal plasma corticosterone levels were determined in chicks reared in nest boxes, and stress plasma corticosterone levels were determined in chicks after exposure to a 10-min standardized stress test. Mean basal plasma corticosterone concentrations ranged from 4 to 37 ng/ml in 1999, and from 5 to 20 ng/ml in 2000. Mean poststress plasma corticosterone levels ranged from 26 to 67 ng/ml in 1999, and from 26 to 109 ng/ml in 2000. In 1999 and 2000, basal corticosterone was negatively correlated with polychlorinated dibenzofuran (PCDF). Total PCDFs ranged from 4.8 to 120.5 ng/kg wet weight in chicks in 1999 and 2000 among sites. These results indicate that current levels of organochlorine contaminants in the St. Lawrence River and surrounding tributaries may be interfering with the glucocorticoid endocrine axis of tree swallows.

Health of tree swallow (Tachycineta bicolor) nestlings exposed to chlorinated hydrocarbons in the St Lawrence River basin. Part I. Renal and hepatic vitamin A concentrations.

Sixteen-day-old tree swallows (Tachycineta bicolor), near fledging, were collected in 1999 and 2000 from nine sites representing a gradient of dioxin concentrations, within the vicinity of the St. Lawrence River in Canada and the United States, to determine if organochlorine contaminants correlated with vitamin A levels measured as retinol and retinyl palmitate. Mean concentrations of hepatic retinol ranged from 3 mg /kg to 13 mg /kg, and from 0.35 mg /kg to 1.5 mg /kg for renal retinol. Mean concentrations of hepatic retinyl palmitate ranged from 18 mg /kg to 146 mg /kg, and 1mg /kg to 6 mg/kg for renal retinyl palmitate. In 1999, molar ratio of renal retinol: retinyl palmitate was significantly and positively correlated with total polychlorinated dibenzodioxin (PCDD) concentration. Among sites, total PCDDs ranged from 5.4 ng /kg wet weight to 79.5 ng /kg wet weight in tree swallows. These results suggest that current levels of organochlorine contaminants in the St. Lawrence River and surrounding tributaries may be interacting with the vitamin A pathway. Lower circulating levels and higher tissue concentrations of retinoids may result in compromised immune function and reduced reproductive success in adult birds.

Botany on a plate. Pleasure and the power of pictures in promoting early nineteenth-century scientific knowledge.

In early nineteenth-century Britain the use of pictures in introducing novices to the study of science was contentious, leading to debates over the ways in which words and images constituted knowledge and over the role of pleasure in intellectual pursuits. While recent studies have stressed visual representation as a critical element of science and considered its relation to the written word in conveying information, this essay explores the nineteenth-century preoccupation with the mind and mental faculties in relation to corporeal responses to explain concerns over the role of images and the process of recognition. By considering illustration in this way, it argues that popular botany was defined by many expert naturalists as the means by which private individuals could best be encouraged to extend their aesthetic appreciation and love of plants to an active and participatory pursuit of science.