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Description
After nearing extinction in the 1980s, California condor populations have risen to over 400 individuals, but the species remains critically endangered. Eggshell thinning continues to threaten the reproductive success of condors, particularly those living in coastal environments. Coastal condors, unlike their inland-dwelling counterparts, partially rely on marine mammals for their diet. When scavenging marine mammals, these condors are exposed to halogenated organic compounds (HOCs), which are lipophilic and can act as endocrine disruptors. Our study classifies the HOC profiles of the coastal and inland condors to identify compounds that may be causing these reproductive health effects. Condor profiles were also compared with previously identified HOC profiles of marine mammals from the Southern California Bight (SBC) to investigate the link between marine mammal consumption and HOC exposure. HOCs were identified in the plasma of the condors through non-targeted chemical analysis using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS). Results showed that the coastal condors (pooled, n=7) contain 13-45 HOCs (avg. = 31 ± 5), while inland condors (pooled, n=10) have 1-16 HOCs (avg. = 8 ± 2). In both groups, DDT-related compounds and PCBs exhibited the highest average abundance. Average relative response of DDT-related compounds in coastal condors was 7x higher than inland condors, and PCBs were 40x higher in coastal than inland condors. Seven HOC structural classes were absent from the inland condors, including 4’,4’,4’’-tris(chlorophenyl)methane (TCPM) and the halogenated natural products heptachlorinated 1 methyl 10,2-bipyrrole (MBP Cl7) and 1,10- dimethyltetrabromo- dichloro-2,20-bipyrrole (DMBP Br4Cl2). This highlights the greater exposure of coastal condors to HOCs than their inland counterparts. All but two of the HOCs identified in the coastal condors were detected in marine mammals from the SBC, and trends of biomagnification of several compounds was observed. These results indicate HOC levels are significantly elevated in coastal condors due to their consumption of marine mammal carcasses, and these exposures may be responsible for adverse developmental and reproductive health effects.
