Logarithmic Relationship of DDE Residues to Eggshell Thinning

DDT, Chlordane, Toxaphene and PCB Residues in Newport Bay and Watershed: Assessment of Hazard to Wildlife and Human Health

“…15 Relationship of DDE in eggs and eggshell thinning in brown pelicans. Figure 1 in Blus et al ( 1972a ) reproduced with permission from the author and from Nature pelican eggs by gulls whenever nests were unattended. The source of DDE was attributed to the Los Angeles outfall.…”

“…Eggs from two colonies in South Carolina had DDE residues ranging from 3.3 to 10.6 ppm. Blus et al ( 1972a ) reported that eggshell thinning of 15-20% had been associated with declining populations of several species of birds. The doseresponse of DDE residue in eggs and eggshell thinning in brown pelicans was log-linear (Fig.…”

“…White et al ( 1984 ) reported that 35% of black skimmer eggs collected in 1978-1981 along the Texas coast contained DDE levels of 10 ppm or more (levels of DDE ranged as high as 51 ppm), but no signifi cant correlation was found between residue levels and fl edgling success. The authors state that: "Some degree of eggshell thinning was detected in most colonies (9/10), ranging from 4% to 12%, but thinning was below that (15-20%) believed to cause population declines in other avian species (Anderson and Hickey 1972 ;Blus et al 1972a ;Longcore and Stendell 1977 )." King and Krynitsky ( 1986 ) assessed DDT residues, shell thinning and reproductive success in black skimmers along the Texas coast in 1980-1982.…”

“…The paper by Blus et al ( 1972a ) was accompanied by a letter from William Hazeltine challenging the assertion that the DDE eggshell thinning dose-response was log-linear. Moreover, Hazeltine questioned whether DDE caused eggshell thinning.…”

Retrospective: Adjusting Contaminant Concentrations in Bird Eggs to Account for Moisture and Lipid Loss During Their Incubation

“…Conservationists and natural resource managers were attempting to resolve whether pesticide exposure and accumulated residues were related to population declines in several species of predatory and scavenging birds (e.g., bald eagle Haliaeetus leucocephalus, peregrine falcon Falco peregrinus, brown pelican Pelecanus occidentalis and osprey Pandion haliaetus). The avian egg was a favored sampling matrix even before the realization that eggshell thinning was linked to population declines (Ratcliffe 1967;Hickey and Anderson 1968) and that the concentration of p,p'-DDE in an egg was associated with the shell thinning phenomenon (e.g., Blus et al 1972;Wiemeyer et al 1988). The necessity for making wet-weight concentration adjustments to account for natural moisture loss during incubation of viable eggs was realized.…”