Animal studies show that long time exposure to hexachlorobenzene can harm the liver, immune system, kidneys, and blood and it can produce eruptions and pigmentations of the skin. Higher levels of hexachlorobenzene can lead to cancer of the liver and thyroid.
When interpreting the background data for hexachlorobenzene, no significant differences between the seabird species were found. This contrasts with the results reported in several published papers. We believe that this can be attributed to differences in the way the data has been collected. The highest mean liver levels of hexachlorobenzene were found in herring gull, great black-backed gull and glaucous gull.
No regional difference or differences between years was found for hexachlorobenzene. The data distribution is however not even, and the data is therefore not well suited for trend analyses.