The role of zooplankton in DDT biomagnification in a pelagic food web of Lake Maggiore (Northern Italy).
BACKGROUND
In the present study, we report the analytical results of pp'DDT, pp'DDE and pp'DDD determination in lake water, plankton and zooplanktivorous fish of Lake Maggiore (Northern Italy), rather recently polluted by DDT of industrial origin, in order to understand the bottom-up pollution transfer among the abiotic and biotic components of the lake ecosystem.


METHODS
Fourteen water sampling campaigns were carried out from March 2003 to January 2009 in the water column of the deepest point (Ghiffa) of Lake Maggiore. Suspended and dissolved pollutants were determined separately. Three sampling campaigns were carried out from July 2008 to January 2009 for zooplankton and pelagic fish, and DDT residues were analysed by HRGC coupled with ECD and MS. Moreover, food items were detected in fish stomachs.


CONCLUSIONS
Starting from 2007, the DDT contamination along the water column became rather homogeneous, probably because no flooding or other relevant hydrological events occurred; although steady-state condition should be expected, lipid normalised concentrations of pp'DDE and pp'DDD in zooplankton exceeded the levels of the same compounds in zooplanktivorous fishes.


CONCLUSIONS
As this finding represents a thermodynamic paradox since bioaccumulative pollutant concentrations are expected to increase along the trophic chain, it was supposed that the abiotic and biotic lake components were not in a steady-state condition in Lake Maggiore.
Bettinetti
Roberta
R
Department of Chemical and Environmental Sciences, University of Insubria, 22100 Como, Italy. roberta.bettinetti@uninsubria.it
Galassi
Silvana
S
Guzzella
Licia
L
Quadroni
Silvia
S
Volta
Pietro
P
D000818:Animals; D003634:DDT / Q000032:analysis / Q000378:metabolism*; D003633:Dichlorodiphenyl Dichloroethylene / Q000032:analysis / Q000378:metabolism; D003632:Dichlorodiphenyldichloroethane / Q000032:analysis / Q000378:metabolism; D004784:Environmental Monitoring; D005399:Fishes / Q000378:metabolism; D020387:Food Chain; D005618:Fresh Water / Q000737:chemistry; D010573:Pesticide Residues / Q000378:metabolism; D010575:Pesticides / Q000032:analysis / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*; D015048:Zooplankton / Q000378:metabolism*
D010573:Pesticide Residues; D010575:Pesticides; D014874:Water Pollutants, Chemical; D003633:Dichlorodiphenyl Dichloroethylene; D003634:DDT; D003632:Dichlorodiphenyldichloroethane