The contents of total P and its bioavailable forms. as well as of Fe, Al, Mn, Ca, and OM in the bottom sediments of the Solina-Myczkowce (S-E Poland) cascade of reservoirs, are presented. Notwithstanding a relatively low calcium content, it is the apatite fraction that accounts for the largest share of total phosphorus in the shallower parts of the Solina and Myczkowce Reservoirs. In turn, while contents of iron and aluminium (and manganese in the Solina Reservoir) are high, the fraction containing non-apatite inorganic phosphorus accounts for the smallest portion of the total phosphorus in the bottom sediments of both reservoirs. Bottom sediments of the Solina Reservoir are also characterised by significant correlations between total phosphorus content and aluminium content. Otherwise, significant correlations are reported for only some of the stations at each of the reservoirs.

The results of statistic estimation of measurements done within surface waters monitoring programme were described. The biogens concentrations (the years 1994-1998) and the oxygen indicators (the years 1992-1996) in the measurement point on Odra river in Krajnik Dolny constituted the date base. The time changeability of these indicators was well described by Jog-normal and gamma distributions was shown. The normalised distributions were also given.The autocorrelation and the periodicity were examined. It was stated that the considered time sequences were characterised by the strong autocorrelation and the periodicity. Using the ARIMA process the modelling of measurement series was realised. After the selection of models, the programming of examined indicators changes was accomplished. It was shown that using ARIMA models valuable results can be obtained.