Influence of altitude and age in the accumulation of organochlorine compounds in fish from high mountain lakes.

The analysis of hexachlorobenzene, hexachlorocyclohexanes, polychlorobiphenyls, and DDTs in muscle of fish from high mountain lakes shows that a proportion of their concentration variance depends on fish age and lake altitude. Interestingly, the magnitude of this share corresponds linearly with the log-transformed vapor pressure (Vp) of the organochlorine compounds (OC). Thus, the distributions of OC with Vp < 10-2.5 Pa are mostly determined by these two variables. Altitude gradients mainly respond to temperature differences, involving concentration increases of 25−150 times between 8.7 and −2.3 °C. The age effect encompasses concentration increments of 2.4−7.8 for average lake differences between 2 and 13 yr. However, both effects are independent since no correlation between fish age and lake altitude is observed. Fish liver concentrations exhibit the same pattern, but the correlations are only significant for age, suggesting that the temperature trend is more related to long-term accumulation than episo...