The aim of this study is to determine the quality of drinking water in the city of Pogradec, Albania. Daily samples were taken from six fixed points in the city. They were analyzed based on the standard methods for the following parameters: taste, odor, temperature, pH, conductivity (EC), turbidity, NO-3, NO-2, NH+4, chloride, and microbial load. The assessment of water quality was made using the water quality index (WQI) of the Canadian Council of Ministries of the Environment (CCME). The calculated value of CCME WQI by 87.81 indicates that the drinking water quality in the city of Pogradec is “good,” and that turbidity is the main problem in quality.
From a data set of observations of Suspended Particulate Matter (SPM) concentration, Turbidity in Formazin Turbidity Unit (FTU) and fluorescence-derived chlorophyll-a at a mooring station in Liverpool Bay, in the Irish Sea, we investigate the seasonal variation of the SPM: Turbidity ratio. This ratio changes from a value of around 1 in winter (minimum in January— February) to 2 in summer (maximum in May—June). This seasonal change can be understood in terms of the cycle of turbulence and of the phytoplankton population that affects the nature, shape and size of the particles responsible for the Turbidity. The data suggest a direct effect of phytoplankton on the SPM:Turbidity ratio during the spring bloom occurring in April and May and a delayed effect, likely due to aggregation of particles, in July and August. Based on the hypothesis that only SPM concentration varies, but not the mass-specific backscattering coefficient of particles bbp *, semi-analytical algorithms aiming at retrieving SPM from satellite radiance ignore the seasonal variability of bbp * which is likely to be inversely correlated to the SPM:Turbidity ratio. A simple sinusoidal modulation of the relationship between Turbidity and SPM with time helps to correct this effect at the location of the mooring. Without applying a seasonal modulation to bbp *, there is an underestimation of SPM in summer by the Ifremer semi-analytical algorithm (Gohin et al., 2015) we tested. SPM derived from this algorithm, as expected from any semi-analytical algorithm, appears to be more related to in situ Turbidity than to in situ SPM throughout the year.
Coagulation/flocculation of a suspension of silica SiO2 was carried out with the use of macromlecular organic polymers which supported the action of two inorganic coagulants – PACl and Al₂(SO₄)₃. The results indicate the exceptional effectiveness of cationic and anionic flocculants in coagulation with Al₂(SO₄)₃ and an anionic polymer P 2540 in combination with PACl. They also show the correlation between the degree of purification of the liquid phase with 20 mg Al dm⁻³ from Al₂(SO₄)₃, supported by flocculants and the fractal dimension D of the aggregates obtained with Al₂(SO₄)₃ and organic polymers. An increase in coagulation of the liquid phase corresponds to an increase in the fractal dimension D = 1.52–1.97.
Eleven PCB congeners were determined in phytoplankton samples collected from the Odra Estuary at 9 stations in 2001–2002. The PCB concentrations were related to the temperature, turbidity, salinity, oxygen and redox potential of the water as well as to the pigment content in the samples. The results indicate that phytoplankton and the detritus derived from it play a crucial role in the distribution of PCBs, their transfer from the water column to sediments and from the Estuary to the sea. The species composition of the phytoplankton occurring in this area could also be very important as regards the sorption of PCBs.
A method is described for determining the state of health of a river basin in order to monitor any actual or predictive changes that may occur as a result of perturbations in certain key catchment variables. The mean annual baseflow and mean annual baseflow turbidity at chosen sites on the Latrobe River Basin are obtained by using a simple filter on the discharge and turbidity data in a time series. Six variables are used to calculate the factors influencing baseflow turbidity within the sub-catchments and mutiple regression is carried out on a matrix of the data. The resulting calculated turbidity contributions for each sub-catchment is compared to the observed values in order to determine the closeness of correlation. Suggestions for improving the model are provided.
In lakes, chaoborids can be a food resource and also act as competitors for planktivorous fish. Usually their density varies reciprocally with the density of planktivorous fish, which forage on chaoborids. Results from Lake Hiidenvesi show, however, that in deep clay-turbid lakes chaoborids may be the main regulators of herbivorous zooplankton although the density of planktivorous fish is high. This is because turbidity reduces the feeding efficiency of fish while the feeding of chaoborids is not affected by the high turbidity levels.
The large and shallow lowland lakes constitute a distinctive type of lake ecosystem, because of their polymixis, frequent resuspension of bottom sediments and internal nutrient loading, high turbidity and usually high productivity and eutrophication rate. Lake Peipsi is one of the largest lake in Europe, its area is 3555 km² and mean depth is 7.1 m. The study results for the vegetation seasons (May-October) obtained for the decade 1997–2008 allow to evaluate the long-term changes in the functioning of its ecosystem in terms of dynamics of phyto- and zooplankton and nutrient content in a lake. Lake Peipsi consists of three different parts: the northern, the largest and deepest one is eutrophic L. Peipsi s.s. (sensu stricto), the southernmost part is hypertrophic L. Pihkva, connected with L. Peipsi s.s. by the river-like L. Lämmijärv. The decrease in nutrient loading to L. Peipsi observed in the early 1990s was brought about by social changes (collapse of Soviet type agriculture) rather than by the purification of point-pollution sources. In the northern part, Lake Peipsi s.s., the content of both nitrogen and phosphorus was stabilized, while the increase in phosphorus in the water of L. Pihkva was evident. The resistance of the three lake parts to external nutrient loading is different. It seems that the ecosystem of the southern lake part (L. Pihkva) is losing its resilience. The disturbance of the ecosystem is most likely caused by the fact that the slight trend of re-oligotrophication beginning in the early 1990s was reversed in the mid-1990s due to increasing P loading. The share of cyanobacteria in phytoplankton biomass increased from 20% to 60% in L. Peipsi s.s., and from 30% to 90% in the southern parts of the lake in the summer months. The lake was characterized by massive cyanobacterial blooms. Potentially toxic genera (Microcystis, Aphanizomenon, Anabaena, Gloeotrichia) dominated, and the quantity of microcystins in the lake was relatively large. The biomass of phytoplankton increased whereas that of all zooplankton groups – cladocerans, copepods and rotifers – decreased. The most essential decline affected rotifers: their abundance was about 60% lower in 2001–2008 than in the 1990s. The biomass of copepods decreased almost 50% and that of cladocerans 34%. In parallel with changes in plankton, the fish composition of L. Peipsi was characterized by sharp decline of planktivorous smelt (Osmerus eperlanus eperlanus m. spirinchus Pallas) and vendace (Coregonus albula (L). The most likely causes of the changes seem to be mainly the anthropogenic P input, decreasing N:P ratio, cyanobacterial toxins, and changes in ichthyocoenosis. Our data from last decade demonstrate a kind of disturbance in the ecosystem of the lake as compared to the second half of last century. The disturbance of the ecosystem is most likely caused by the fact that the slight trend of re-oligotrophication beginning in the early 1990s was reversed in the mid-1990s due to increasing P loading from southern part of lake watershed.