The influence of size distribution on the particle concentration effect and trace metal partitioning in rivers

摘要: The particle concentration effect (p.c.e.) is an unexpected decline in partition coefficients (Kd) as suspended particulate matter (SPM) increases. This anomaly has been attributed to a variety of causes, but most often the existence colloidal forms adsorbate, which are included, error, dissolved fraction when calculating Kd. To test this hypothesis we have directly measured colloidal, macroparticulate, and truly metals (Cd, Cu, Pb, Zn, Fe, Al, Mn, Ag) monthly for one year (6/96–7/97) four Connecticut rivers having range ancillary biogeochemical characteristics. These include factors that all likely influence partitioning between solid phases, such DOC, pH, competing cations. p.c.e. clearly evident these rivers, explicit consideration eliminates or reduces nearly cases. Furthermore, substantial portion occurs fraction, amount increases with SPM. Both conditions necessary model explain p.c.e.. Important differences observed among metals, some cases systematic decreases Kd continue even taken into account. additional decrease can be eliminated by excluding large particles negligible surface complexation sites. When corrections applied both colloids particles, values become constant.