Chapter 22
Chemometric Applications to Seawater Analysis
M.e. Gennaro . S. Angelino
22.1
Introduction
22.1.1
The Sea: A Very Complex Ecosystem
Seas and oceans have been defined as "water bodies acting as natural reactors" in which
matter is constantly imported, exported and transformed. The main boundaries are
the land, the atmosphere and the sediments; the inlet and the outlet pathways are rivers, channels and the air-water and water-sediment interfaces. Since a large number
of physical, chemical, geochemical and biological processes are there taking place, the
marine system is a very complex one. The chemical species undergo adsorption, desorption, solubilization, precipitation, oxido-reduction and settling processes which also
govern speciation competitive equilibria; organisms give rise to mechanisms of production, uptake, excretion, decomposition and accumulation; sediments, particulate
and colloids are involved in aggregation, fragmentation and desegregation phenomena, etc. Each of these processes can be individually described, but its role in the environment can be correctly evaluated only considering its connection with all the others simultaneously taking place.
The equilibria and natural cycles of biochemical transformation of the marine ecosystem are threatened by human impact and pollution, and oceans too often become
the ultimate sink for many pollutants. Pollutants, when in the marine environment,
can assume different forms and undergo different fates, due to the taking place of processes as adsorption onto suspended particles and sediments, scavenging by inorganic
and organic particles, assumption by living organisms, mobilisation during regeneration and diagenesis, etc. Pollutant transport is strongly influenced by the behaviour
of sediments and suspended matter, in turn driven by water dynamics and organic
matter production and diagenesis; pollutants can be adsorbed and cumulate in sediments, be mixed by the physical action of waves and by the benthic organisms activity, be transported downward into the sediment or resuspended or solubilized in water. Suspended matter can be therefore considered as a sort of link among the different components of the system and it can be said that particles control a large part of
the aquatic environmental chemistry.
The natural composition of water depends on many factors, such as time (variations within day, month, season, year), depth, tide and conditions of the main components of the ecosystem (water, sediments, organisms). This compositional variability
must be distinguished from pollution induced variations (domestic and industrial
sewage, leaching processes from agricultural activities, atmospheric precipitation, etc.).
Chemometric Applications to Seawater Analysis
M.e. Gennaro . S. Angelino
22.1
Introduction
22.1.1
The Sea: A Very Complex Ecosystem
Seas and oceans have been defined as "water bodies acting as natural reactors" in which
matter is constantly imported, exported and transformed. The main boundaries are
the land, the atmosphere and the sediments; the inlet and the outlet pathways are rivers, channels and the air-water and water-sediment interfaces. Since a large number
of physical, chemical, geochemical and biological processes are there taking place, the
marine system is a very complex one. The chemical species undergo adsorption, desorption, solubilization, precipitation, oxido-reduction and settling processes which also
govern speciation competitive equilibria; organisms give rise to mechanisms of production, uptake, excretion, decomposition and accumulation; sediments, particulate
and colloids are involved in aggregation, fragmentation and desegregation phenomena, etc. Each of these processes can be individually described, but its role in the environment can be correctly evaluated only considering its connection with all the others simultaneously taking place.
The equilibria and natural cycles of biochemical transformation of the marine ecosystem are threatened by human impact and pollution, and oceans too often become
the ultimate sink for many pollutants. Pollutants, when in the marine environment,
can assume different forms and undergo different fates, due to the taking place of processes as adsorption onto suspended particles and sediments, scavenging by inorganic
and organic particles, assumption by living organisms, mobilisation during regeneration and diagenesis, etc. Pollutant transport is strongly influenced by the behaviour
of sediments and suspended matter, in turn driven by water dynamics and organic
matter production and diagenesis; pollutants can be adsorbed and cumulate in sediments, be mixed by the physical action of waves and by the benthic organisms activity, be transported downward into the sediment or resuspended or solubilized in water. Suspended matter can be therefore considered as a sort of link among the different components of the system and it can be said that particles control a large part of
the aquatic environmental chemistry.
The natural composition of water depends on many factors, such as time (variations within day, month, season, year), depth, tide and conditions of the main components of the ecosystem (water, sediments, organisms). This compositional variability
must be distinguished from pollution induced variations (domestic and industrial
sewage, leaching processes from agricultural activities, atmospheric precipitation, etc.).