Contamination and Biomarkers in the Great Blue Heron, an Indicator of the State of the St. Lawrence River

Abstract

In 1996-1997, nine breeding colonies of the great blue heron on the St. Lawrence River and its estuary (Québec, Canada) were investigated in the framework of a biomonitoring program. Fledglings from colonies in freshwater were more contaminated with mercury, PCBs and many organic contaminants than those from estuarine colonies. The level of contamination in the St. Lawrence River is generally below the levels of toxicological effects for the great blue heron. The molar ratio of retinol: retinyl palmitate in heron eggs was correlated with total PCBs (r=0.79) and Mirex (r=0.90). In plasma, all biochemical parameters were significantly different between freshwater and marine colonies. Plasma retinol concentrations at the Dickerson and Hérons colonies were significantly lower compared with those at Grande Ile (p<0.05) and Steamboat (p<0.001). Based on retinoid and beta-carotene concentrations in eggs, low plasma retinol was not associated with possible dietary deficiency. Plasma retinol was negatively correlated with many PCB congeners, total PCBs (r=-0.78), p,p'-DDE, trans-nonachlor and alpha-HCH. Similarly, the hormone T3 was correlated with many PCB congeners, total PCBs (r=-0.69) and the same organochlorine chemicals. Plasma LDH concentrations were different among freshwater colonies, Grande Ile and Hérons colonies having LDH values significantly greater than those of Steamboat (respectively, p<0.05 and p<0.01). Globally, the health status of the St. Lawrence great blue heron population was judged to be acceptable, however, several biomarkers indicated positive responses to contaminants.

Polybrominated diphenyl ethers, toxaphenes, and other halogenated organic pollutants in great blue heron eggs

“…The levels measured were below those associated with detrimental effects [3,23]. Total PCB levels showed no spatial differences as well as no significant difference compared to our previous study [9]. However, the PCB levels were notably low at Dickerson Island, which is located close to three major U.S. superfund sites known as major PCB sources in Massena, New York, USA [24].…”

Seabirds as Bioindicators of Marine Ecosystems

“…They respond more quickly to environmental changes, show their occurrence through vocalization, and are easy to detect and identify [4,34,35]. Previously, seabirds have been used as a bioindicators of pollution [36][37][38][39], oil spills [40,41], contamination in the Antarctic ecosystem [42][43][44], evaluate wetland ecosystem health [45,46], climate change [47], primary productivity [48], and environmental pollution in aquatic system [49][50][51]. This could be that, seabirds may show distinctive habitat preferences and display a variety of adaptations to exploit the marine resources and can be used to determine the marine ecosystem integrity.…”

Feathers of Little Egret (&lt;i&gt;Egretta garzetta&lt;/i&gt;) Fledglings as a Bio Monitoring Tool for Mercury, Arsenic, Cadmiumand Lead Pollution in Sri Lanka

“…As large fish eating birds, they assume the highest trophic level in aquatic ecosystems. Since they have the ability to accumulate pollutants and heavy metals that are non bio degradable [8], they can be used as biomonitors to assess the pollutant levels in aquatic systems [9][10][11][12]. Also, the changing levels of pollutants within lower tropic levels can also be mapped using these indicators [13,14].…”