Polychlorinated biphenyls in eggs and chorioallantoic membranes of American alligators (Alligator mississippiensis) from coastal South Carolina

Abstract

Abstract-Assessing chemical exposure in threatened or endangered wildlife species presents unique analytical problems. Chorioallantoic membranes (CAMs) have been proposed as surrogate tissues for evaluation of polychlorinated biphenyl (PCB) exposure in oviparous species. Research was undertaken to determine the extent of PCB accumulation in alligators (Alligator mississippiensis) at sites along the coast of South Carolina and to evaluate the utility of CAMs as surrogate tissues for determining PCB concentrations in whole alligator eggs. Polychlorinated biphenyls were found in eggs and CAMs of alligators from both sites examined. Concentrations of PCBs were higher in CAMs (p ϭ 0.02) and eggs (p ϭ 0.001) from sites known to contain chlorinated hydrocarbons than from more pristine sites. Total PCBs partitioned predictably (r 2 Ͼ 0.59; p Ͻ 0.02) between egg and CAM tissues indicating the utility of CAMs to serve as surrogate tissues when comparing total PCB concentrations in whole eggs. Tetrachloro through octachloro biphenyl homologues and total PCBs in CAMs from reference areas were correlated with concentrations of these homologues in eggs. At contaminated sites, total PCB concentrations in CAMs were correlated with total PCB concentrations in eggs.

Maternal transfer of selenium in Alligator mississippiensis nesting downstream from a coal‐burning power plant

“…Chorioallantoic membranes appear to have potential as indicators of Se exposure in embryos of A. mississippiensis, a finding in agreement with other investigations suggesting CAMs as useful, nondestructive indices of exposure to some organic contaminants for crocodilian embryos [4,5]. Alternatives to lethal sampling techniques are valuable when assessing contaminant exposure in rare wildlife, and conservation-oriented exposure assessments are particularly appropriate for crocodilian species, one third of which are endangered [12].…”

“…Maternal transfer can be a significant source of exposure to potentially toxic substances for crocodilian embryos and hatchlings. Most studies of maternal transfer of environmental pollutants in crocodilians have focused on organic contaminants and mercury [1–8], but nothing is known about maternal transfer of selenium (Se) in crocodilians inhabiting Se‐con‐taminated sites despite evidence that Se is embryotoxic to other oviparous organisms [9,10]. Selenium contamination in aquatic habitats is a growing concern worldwide as a consequence of mining, industrial, and agricultural discharges and runoff; oil procurement, transport, refining, and utilization; and the disposal of fly ash from electric power‐generation facilities [11–13].…”

Functional relationships among selenium concentrations in the diet, target tissues, and nondestructive tissue samples of two species of snakes

“…Chorioallantoic membranes are highly vascularized extra-embryonic membranes that typically are discarded with the eggshell in oviparous vertebrates. Total polychlorinated biphenyls in CAMs from American alligators (Alligator mississippiensis) nesting in a contaminated area in South Carolina, USA, correlated positively with egg contents [21]. Similarly, concentrations of polychlorinated biphenyls in CAMs were used to estimate concentrations in eggs of loggerhead sea turtles (Caretta caretta) [22].…”

Inorganic elements in green sea turtles (Chelonia mydas): Relationships among external and internal tissues

“…Such techniques have been established for many other vertebrate species; notable examples are assessments of a wide variety of chemicals in fingernails and hair from humans and eggs and feathers from birds . Among reptilian species, chorioallantoic membranes have been used to provide estimates of polychlorinated biphenyl exposure in alligators and loggerhead sea turtles ( Caretta caretta ) , caudal scutes and eggs were indicators of mercury exposure among crocodiles , and eggs have been used to assess exposure to organochlorine pesticides among Morelet's crocodiles . Tail clippings have also been reported to be useful indicators of contaminant exposure among snakes .…”