P. Masclet : Contamination of Lake Water by Pesticides via Atmospheric Transport
87
Some, however, are unreactive and less soluble and, like PAHs, can be transported
over long distances and contaminate the atmosphere and all the media of our
ecosystem.
The problem is therefore the same for these two families of compounds. In
biogeochemistry, they are often used as excellent tracers, since by the monitoring
of their atmospheric concentrations, it is possible to determine the nature and the
location of the main pollution sources.
Furthermore the identification and the quantification of these compounds in the
various "nonpolluted" media of the globe can be used to evaluate the total toxic
capacity of the atmosphere. Studying the composition of the air, that of highaltitude or polar snow, sediments or marine water leads to the same result:
knowledge of the global diffusion of chemical compounds transported to a large
extent in the atmosphere, from populated areas to remote areas.
Three phases are involved in the atmospheric transport:
gaseous form, close to that in which the compounds are emitted,
particulate form (aerosols); the hydrophobic compounds have a high
affinity for carbonaceous or mineral particules, and they are especially
adsorbed on small particles « 311m),
water droplets of clouds or snow, when these compounds are sufficiently
soluble. This atmospheric transport occurs in three or four days. In the
aerosol form, PAHs and pesticides are easily transported over long
distances because of the fine aerosol association and the low reactivity
of these compounds in the particulate form. The information related to
the presence of these compounds in atmospheric particles is practically
unaltered throughout their transport and even after their wet or dry
deposition towards the soil or ice, for example.
In this study, one campaign in polluted area (Paris) and three campaigns in non
polluted areas were performed:
marine zone: the Mediterranean Sea,
mountainous zone: lakes in the French Alps,
polar zone: Greenland
Air (atmospheric particles), surface water in the mountain lakes and surface snow
of the Arctic ice sheet were sampled over the last four years (1990-93).
An account of two families of toxic or carcinogenic compounds, PAHs and
pesticides, has been established.
This study presents a quantitative account and a data set of these compounds at the
beginning of the 1990s, in these zones considered to be non-polluted. It can be
used to follow the subsequent evolution of the overall toxicity of the atmosphere
and the media, contaminated in the next years or in the next decade.
87
Some, however, are unreactive and less soluble and, like PAHs, can be transported
over long distances and contaminate the atmosphere and all the media of our
ecosystem.
The problem is therefore the same for these two families of compounds. In
biogeochemistry, they are often used as excellent tracers, since by the monitoring
of their atmospheric concentrations, it is possible to determine the nature and the
location of the main pollution sources.
Furthermore the identification and the quantification of these compounds in the
various "nonpolluted" media of the globe can be used to evaluate the total toxic
capacity of the atmosphere. Studying the composition of the air, that of highaltitude or polar snow, sediments or marine water leads to the same result:
knowledge of the global diffusion of chemical compounds transported to a large
extent in the atmosphere, from populated areas to remote areas.
Three phases are involved in the atmospheric transport:
gaseous form, close to that in which the compounds are emitted,
particulate form (aerosols); the hydrophobic compounds have a high
affinity for carbonaceous or mineral particules, and they are especially
adsorbed on small particles « 311m),
water droplets of clouds or snow, when these compounds are sufficiently
soluble. This atmospheric transport occurs in three or four days. In the
aerosol form, PAHs and pesticides are easily transported over long
distances because of the fine aerosol association and the low reactivity
of these compounds in the particulate form. The information related to
the presence of these compounds in atmospheric particles is practically
unaltered throughout their transport and even after their wet or dry
deposition towards the soil or ice, for example.
In this study, one campaign in polluted area (Paris) and three campaigns in non
polluted areas were performed:
marine zone: the Mediterranean Sea,
mountainous zone: lakes in the French Alps,
polar zone: Greenland
Air (atmospheric particles), surface water in the mountain lakes and surface snow
of the Arctic ice sheet were sampled over the last four years (1990-93).
An account of two families of toxic or carcinogenic compounds, PAHs and
pesticides, has been established.
This study presents a quantitative account and a data set of these compounds at the
beginning of the 1990s, in these zones considered to be non-polluted. It can be
used to follow the subsequent evolution of the overall toxicity of the atmosphere
and the media, contaminated in the next years or in the next decade.