Effects of chrysotile asbestos on coho salmon and green sunfish: evidence of behavioral and pathological stress

Our plain-English summary of Effects of chrysotile asbestos on coho salmon and green sunfish: evidence of behavioral and pathological stress, by S.E. Belanger, K. Schurr, D.J. Allen, et al (Environmental Research, 1986).

The study

• Authors: S.E. Belanger, K. Schurr, D.J. Allen, A.F. Gohara
• Journal: Environmental Research
• Published: 1986;39(1):74-85
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The effects of chrysotile asbestos on larval coho salmon (Oncorhynchus kisutch) and juvenile green sunfish (Lepomis cyanellus) were investigated at levels approximating those reported in the Great Lakes basin (10(6) fibers/liter). Behavioral stress effects, such as loss of rheotaxic position and balance, were observed in salmon exposed at 3.0 X 10(6) fibers/liter and in sunfish exposed at 1.5 and 3.0 X 10(6) fibers/liter. Coho larvae at 1.5 X 10(6) fibers/liter were significantly more susceptible to an anesthetic stress test, becoming ataxic and losing equilibrium faster than control cohorts (P less than 0.001). Two of 106 larvae exposed at 3.0 X 10(6) fibers/liter developed tumorous swellings and three additional fish developed coelomic distentions. Cytological examination of ventral epidermal tissue revealed cellular histolysis, and evidence by transmission electron microscopy confirmed the presence of asbestos in the salmon larvae. Distortion of the lateral line region in asbestos-treated coho salmon was linked to behavioral and orientational aberrations. Differential mortality was not observed between control and treated groups of either test species.

In plain English

The authors exposed young fish in laboratory tanks to chrysotile asbestos at 1.5 or 3.0 million fibers per liter, near levels reported in the Great Lakes basin. Of 53 coho salmon set apart at the eyed-egg stage, some were exposed at 1.5 million from hatching for 86 days and the rest were not. Of another 212, 106 were exposed at 3.0 million for 40 days. Green sunfish were kept in groups of 20, unexposed or at either level. Among the 106 higher-level coho, 2 developed tumorous swellings in the gill region and 3 others developed swollen bellies and died. The authors called the changes consistent with, but not confirmatory of, a neoplasm (tumor). By Day 20 nearly all these coho lay on their sides, and the three examined microscopically had distorted lateral line organs. Electron microscopy of three higher-level and three control coho confirmed asbestos fibers in exposed fish, none in controls. Lower-level coho lost balance faster than controls in an anesthetic test. Sunfish at both levels swam abnormally. At the higher level, scale and skin loss ended their exposure early. Deaths did not appear related to exposure in either species.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory animal experiment (fish exposed to asbestos in tank water, compared with unexposed control fish)
• Who was studied: Coho salmon (Oncorhynchus kisutch) from eggs obtained from a Michigan hatchery in fall 1980. The fish were separated into two groups at the eyed-egg stage. Group I had 53 fish, divided into control and exposed. Group II had 212 fish, of which 106 were exposed. Juvenile green sunfish (Lepomis cyanellus) came from a pond near Bowling Green, Ohio, in spring 1981. They were kept in six groups of 20 fish: two control groups and two groups at each exposure level.
• Exposure: Mined chrysotile asbestos, milled and sonicated into water. Group I coho were exposed at 1.5 x 10^6 fibers/liter beginning at hatching, for 86 days. Group II coho were exposed at 3.0 x 10^6 fibers/liter from Day 75 after spawning, for 40 days. Sunfish were exposed at 1.5 x 10^6 fibers/liter for 67 days or at 3.0 x 10^6 fibers/liter for 52 days.
• Main results:
  • Among the 106 coho exposed at 3.0 x 10^6 fibers/liter, 2 developed tumorous swellings in the gill region.
  • Three additional coho at 3.0 x 10^6 fibers/liter developed belly distention, became less active and died. Similar injury was absent in controls.
  • The authors judged the tissue changes in exposed coho to be consistent with, but not confirmatory of, a neoplasm.
  • Among coho at 3.0 x 10^6 fibers/liter, many lay on their sides on the tank bottom by Day 13, and nearly all did by Day 20.
  • Histology of the lateral line in 3 coho exposed at 3.0 x 10^6 fibers/liter showed distorted lateral line regions. The 3 control fish examined were normal.
  • Electron microscopy was done on 3 coho exposed at 3.0 x 10^6 fibers/liter and 3 control coho. It confirmed asbestos fibers in the asbestos-treated fish; the article does not report results fish by fish. No fibers were found in control or blank samples.
  • In the anesthetic (TMS) stress test, coho exposed at 1.5 x 10^6 fibers/liter (n=23) lost equilibrium and became ataxic significantly faster than controls (n=24), with p less than 0.001. Average time to loss of equilibrium was 73.6 seconds (SD 26.0) in exposed fish versus 114.7 seconds (SD 30.2) in controls.
  • Both groups of asbestos-exposed green sunfish showed abnormal swimming similar to the salmon.
  • Exposed green sunfish lost scales and skin surface tissue. The higher-dose (3.0 x 10^6 fibers/liter) sunfish tanks were ended early because of this scale loss and skin erosion.
  • Coho deaths occurred in all groups and did not appear related to dose or length of exposure. Sunfish mortality did not differ between treatments.
• The authors' conclusion: The authors concluded that aberrant behavior, cell pathology and developmental injury were documented in asbestos-exposed fish, but that fish mortality was not affected at the levels used. They suggested that damage to the lateral line is the likely source of the erratic swimming, and they called for further study in natural waters.
• Limitations the authors state:
  • Total body burdens of asbestos were not calculated because the fish were not weighed.
  • Abnormal swimming in sunfish was not quantified as it was in the salmon.
  • Inactivity in coho was not quantified until Day 13 of exposure.
  • The higher-dose sunfish groups were ended early because scale loss and skin erosion contaminated their tanks.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Chrysotile, Fluorescence In Situ Hybridization (FISH), Transmission Electron Microscopy (TEM).

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