Intestinal Polycyclic Aromatic Hydrocarbon-DNA adducts in a Population of Beluga Whales with High Levels of Gastrointestinal Cancers.

Funding Source

World Wildlife Fund, National Cancer Institute

Grant Number

Z01 BC 005177


Department of Chemistry

Document Type


Publication Date



Carcinogenic polycyclic aromatic hydrocarbons (PAHs) were disposed directly into the Saguenay River of the St. Lawrence Estuary (SLE) by local aluminum smelters (Quebec, Canada) for 50 years (1926–1976). PAHs in the river sediments are likely etiologically related to gastrointestinal epithelial cancers observed in 7% of 156 mature (>19-year old) adult beluga found dead along the shorelines. Because DNA adduct formation provides a critical link between exposure and cancer induction, and because PAH–DNA adducts are chemically stable, we hypothesized that SLE beluga intestine would contain PAH–DNA adducts. Using an antiserum specific for DNA modified with several carcinogenic PAHs, we stained sections of paraffin-embedded intestine from 51 SLE beluga (0–63 years), 4 Cook Inlet (CI) Alaska beluga (0–26 years), and 20 beluga (0–46 years) living in Arctic areas (Eastern Beaufort Sea, Eastern Chukchi Sea, Point Lay Alaska) and aquaria, all with low PAH contamination. Stained sections showed nuclear light-to-dark pink color indicating the presence of PAH–DNA adducts concentrated in intestinal crypt epithelial lining cells. Scoring of whole tissue sections revealed higher values for the 51 SLE beluga, compared with the 20 Arctic and aquarium beluga (P = 0.003). The H-scoring system, applied to coded individual photomicrographs, confirmed that SLE beluga and CI beluga had levels of intestinal PAH–DNA adducts significantly higher than Arctic and aquarium beluga (P = 0.003 and 0.02, respectively). Furthermore, high levels of intestinal PAH–DNA adducts in four SLE beluga with gastrointestinal cancers, considered as a group, support a link of causality between PAH exposure and intestinal cancer in SLE beluga. Environ. Mol. Mutagen. 60:29–41, 2019.


DOI: 10.1002/em.22251

PubMed ID: 30307653

Grant sponsor: Intramural Research Program of the Center for Cancer Research, National Cancer Institute; Grant number: Z01 BC 005177. Grant sponsor: John H. Prescott Marine Mammal Rescue Assistance Grant; Grant number: NA12NMF4390162. Grant sponsor: NOAA Fisheries Alaska Regional Office; Grant number: 932-1905/MA-009526-00. Grant sponsor: National Marine Fisheries Services; Grant number: 16305. Grant sponsor: Department of Fisheries and Oceans Canada, Parks Canada, Canadian Wildlife Health Cooperative, World Wildlife Fund, the Fonds Aquasantédu Saint-Laurent, and Les Industries Filmar. Grant sponsor: Public Health Agency of Canada. Grant sponsor: Coastal Impact Assistance Program USFWS US DOI; Grant number: F12AF01265.