Persistent Organic Pollutants in Livers and Hg in Feathers of Neotropic Cormorants (Phalacrocorax brasilianus) from the Trinity River Watershed (Texas, USA)
The Trinity River (Texas, USA) has been historically known as a polluted river because of its proximity to the Dallas-Fort Worth area and because of known discharges of sewage and agricultural irrigation waters to the river. Surprisingly, there are no studies regarding the presence of legacy contaminants in the river and their impacts to wildlife. The objectives of this study were to determine accumulation and potential impacts of persistent organic pollutants, such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), on Neotropic cormorants (Phalacrocorax brasilianus) nesting along the Trinity River. Adult and first-year cormorants were collected from two sites on the Trinity River Watershed during 2014 and 2015. Tissue sections from liver, spleen, kidneys, and gonads were used for histopathology analysis, and a portion of the liver was analyzed for OCPs, PCBs, and PBDEs. Breast feathers were analyzed for Hg. Surprisingly, all the contaminants were present at low concentrations, p,p′-DDE (2–724 ng/g ww), PCBs (28–851 ng/g ww), PBDEs (1–85 ng/g ww), Hg (1.9–3.4 µg/g dw), and below those that could be associated with adverse effects. Also, histological analysis of liver and kidney samples did not reveal morphologic changes consistent with acute or chronic toxicosis. The majority of the histologic changes were inflammatory and were related to parasitic infestation. Our results suggest that aquatic birds using the Trinity River watershed are not at risk for adverse effects due to the contaminants studied. These results should be useful to wildlife managers regarding concerns over contaminant impacts on wildlife of the Trinity River.
This manuscript benefitted from comments by three anonymous reviewers. This research was supported by a fellowship to C. Sandoval from the Louis Stokes Alliance for Minority Participation Program and a TAMU-CONACYT Grant to M. Mora for contaminant studies with aquatic birds.
Funding was provided by Texas A&M and NSFC: Collaborative Research Grant Program (Grant No. 230041).
- Eisler R (1987) Mercury hazards to fish, wildlife, and invertebrates: a synoptic review. Fish and Wildlife Service, US Department of the Interior, New YorkGoogle Scholar
- Eisler R, Belisle AA (1996) Planar PCB hazards to fish, wildlife, and invertebrates: a synoptic review. Patuxent Wildlife Research Center, LaurelGoogle Scholar
- U.S. EPA (1998) Method 7473 (SW-846): mercury in solids and solutions by thermal decomposition, amalgamation, and atomic absorption spectrophotometry. Washington, DCGoogle Scholar
- Friend M, Franson JC (1999) Field manual of wildlife diseases: general field procedures and diseases of birds. Information and Technology report 1999-001. U.S. Geological Survey, RestonGoogle Scholar
- Gress F, Risebrough RW, Anderson DW, Kiff LF, Jehl JR (1973) Reproductive failures of double-crested cormorants in Southern California and Baja California. Wilson Bull 85:197–208Google Scholar
- Miller A, Elliott JE, Elliott KH, Guigueno MF, Wilson LK, Lee S, Idrissi A (2015) Brominated flame retardant trends in aquatic birds from the Salish Sea region of the west coast of North America, including a mini-review of recent trends in marine and estuarine birds. Sci Total Environ 502:60–69CrossRefGoogle Scholar
- Moring JB (1997) Occurrence and distribution of organochlorine compounds in biological tissue and bed sediment from streams in the Trinity River basin, Texas, 1992–93: Geologic Survey, US Department of the InteriorGoogle Scholar
- Scudder BC, Chasar LC, Wentz DA, Bauch NJ, Brigham ME, Moran PW, Krabbenhoft DP (2010) Mercury in fish, bed sediment, and water from streams across the United States, 1998–2005. Geological Survey, US Department of the Interior, NewYorkGoogle Scholar