Wastewaters contaminated by xenobioties of oil-bearing origin, generated by various sources and subsequently discharged into the natural environment create a major ecological problem throughout the world because of the persistence and accumulation of these compounds.The main goal of this research is to investigate the effectiveness of a removal process composed of several treatments including physical, chemical and biological phases. Considered watewater are wash-waters originated from the cleaning of ships' fuel tanks (slopes). Beside the presence of refractory compounds, these waters show extremely high salinity levels (up to 25,000 p.p.m.), that limit the possibility of discharge to sewers and address the disposal to the sea. This severely lowers the concentrations limits for most of the "sensible" parameters, such both COD and xenobiotic hydrocarbons, thus requiring a higher level treatment. The research has also led to a proper characterization of the specific wastewater typologies as available scientific data are incomplete or too scattered.The main objective of this work was to investigate the feasibility of treating slop wastewater by sedimentation and chemical coagulation followed by granular activated carbon (GAC) filtration and offline bioregeneration of exhaust carbons. Previous research is far from provide a complete understanding of process design, operation, and performance of GAS bioregeneration systems treating mixtures of biodegradable and nonbiodegradable SOCs such slops are. Experiments on bioregeneration are still in progress and results are thus incomplete and only methods are here presented.

Algal bioassays and pesticide analysis were joined in Tuscany regional monitoring of surface and ground waters. Results were compared. Waters affected algal growth in any of the following ways: stimulation, inhibition, stimulation at low concentrations and inhibition at higher concentrations. Most of ground waters inhibited algal growth whereas only a little percentage were contaminated with pesticide. Most of surface waters stimulated algal growth and a higher percentage were contaminated with pesticides. In waters with inhibitory effect toxicological parameters (EC50, EC25, EC10 and NOEC) were measured and compared; EC25 values were very close to NOEC values. Hazard to aquatic primary productivity for each pesticide found during chemical monitoring was evaluated; for this aim the margin of safety (MOS) was calculated by using algal toxicity and the pesticide concentration measured.

Textile wastewaters, which contain numerous chemicals such as dyes, surfactants, solvents, organic and inorganic salts, can cause severe pollution problems for the receiving freshwaters. The ecotoxicity of wastewaters in Prato, where there are about 14,000 textile and related factories, was investigated from 1996-1999 by means of bioassays. 147 samples of reclaimed wastewater were collected at the outlets of 4 centralized wastewater treatment plants. The acute and chronic toxicity of the effluents was measured with bioassays using three different target organisms: green algae (Pseudokirchneriella subcapitata), crustaceans (Daphnia magna) and bioluminescent bacteria (Vibrio fischeri). Toxicity was expressed as Effective Concentration 50 (EC50) and Toxic Units (TU). The results indicated that the effluents did not have significant acute toxicity: only 2.74% (EC50<100%, TU>1) of the 146 samples tested with crustaceans and 6.52% (EC50<50%, TU>2) of the 78 tested with bioluminescent bacteria showed toxic effects. With algae, slight chronic toxicity was found in 49.33% (mean EC50 value=86.56%, mean TU=1.16) of the 140 samples tested. The highest relative response was found with the algal assay using Pseudokirchneriella subcapitata: 49.33% of 140 samples showed chronic toxicity at 96 hours (EC50<100%).

The occurrence of actinomycetes, cyanobacteria and microalgae in surface water of the Arno River, used for water supplies in Florence, was investigated in this study on taste and odour compounds (such as geosmin and 2-methylisoborneol (MIB)). Throughout the 12-month monitoring period, raw water samples were collected and analysed for the number and genera of actinomycetes, cyanobacteria and microalgae.The research has shown that actinomycetes (Streptomyces, Nocardia, Micromonospora) are numerous in autumn and winter and decrease in spring and summer; in contrast, diatoms (Melosira, Navicula), green algae (Chlorella, Pediastrum) and cyanobacteria (Anabaena, Oscillatoria, Nostoc) present a completely opposite trend and are numerous in spring and summer and reduced in autumn and winter The monitoring of the two odour-causing metabolites gives rise to a trend that is more similar in time to that of cyanobacteria than that of actinomycetes. The constant occurrence geosmin may be a sign of a synergy between microalgae, cyanobacteria and actinomycetes, while MIB could derive from the activity of cyanobacteria or other species of actinomycetes present in a low concentration.

In this study, the authors evaluated exposure to airborne polycyclic aromatic hydrocarbons (PAHs) in workers exposed to exhaust gas from cars, and they assessed the efficiency of urinary 1-hydroxypyrene as an indicator of exposure to pyrene and PAHs. The authors selected 2 groups of police who worked in 2 areas in the city of Florence: 1 group was highly exposed to high-density traffic emissions during the winter and summer of 1997, and the 2nd group experienced low exposure to traffic emissions during the same period. Ambient monitoring was achieved with personal sampling of airborne PAHs during each workshift. Eight hydrocarbons were used as indicators of pollution caused by PAHs (e.g., pyrene, benzo[a]pyrene, benzo[a]anthracene, dibenzo[a,h]anthracene). Biological monitoring was performed through dosing of 1-hydroxypyrene (pyrene metabolite) in urine samples taken at the end of each workshift. The ambient monitoring revealed that PAH concentrations were influenced by both season of sampling and varying intensities of traffic in the different areas. The median concentration of benzo[a]pyrene in winter was twice as high in the high-density traffic area as in the low-density traffic area (i.e., 4.1 ng/m(3) versus 1.8 ng/m(3)). In summer, the high-density traffic area experienced benzo[a]pyrene concentrations that were 6 times higher than in the low-density traffic area (i.e., 1.2 ng/m(3) versus 0.2 ng/m(3)). Benzo[a]pyrene was also correlated highly (r(s) = .92, p < .0001) with the mixture of total PAHs analyzed, thus confirming its function as a good indicator of exposure to PAHs in an urban environment. Levels of urinary 1-hydroxypyrene appeared to be generally influenced by the intensity of traffic, especially during the winter (i.e., median value in winter was 199.2 ng/gm creatinine in the high-density traffic area and 120.5 ng/gm creatinine in the low-density traffic area). An analysis of the general data revealed that 1-hydroxypyrene was, to some degree, related to pyrene, benzo[a]pyrene, and airborne total PAHs, whereas analysis of separate data for the area and the season revealed an emergence of a closer correlation during the winter in the high-traffic area. Therefore, 1-hydroxypyrene can be considered a good biological indicator of exposure to airborne PAHs in the urban environment, especially in winter and in high-density traffic areas.

Samples of Quercus ilex leaves and of the inhalable fraction of atmospheric particulate (PM10) were collected along a busy road and in a park in Florence (Italy). Quantitative comparisons and correlations of element concentrations in PM10 collected by air samplers at two sites showed that Ba, Cu, Fe, Mn, Pb and Zn were the main metal pollutants emitted by vehicles in Florence. Very similar results were obtained by the analysis of Q. ilex leaves which were found to accumulate airborne metals as a function of the exposure time (i.e. their age). One-year-old leaves showed the highest rate of metal accumulation. Our results show that the progressive phasing-out of leaded petrol in Italy has resulted in a decrease of about 20% per year in the Pb concentrations in PM10. Both PM10 and Q. ilex analysis singled out Ba and Zn as valid tracers of automotive traffic instead of Pb. (C) 2000 Elsevier Science Ltd. All rights reserved.

The occurrence of algae was investigated in surface water of the Arno river and in a drinking-water treatment utility serving the city of Florence. Throughout the 12 months monitoring period, raw water and treated water samples were collected and analysed for the number and species of microalgae and cyanobacteria; settled and filtered water samples were only examined for counts of organisms, Chlorophyll concentrations, temperature, pH, turbidity, flow rate and other indicators of surface water pollution were measured in raw water samples. Microalgae, mainly diatoms (46.1%, with a predominance of the genus Melosira) and green algae (35.1%. non flagellate 30.7%, green flagellate 4.4%) were constantly found in river water samples. Cyanobacteria were rarely detected except in summer, mainly of genera Oscillatoria and Anabaena. In treated water only depigmented and inactive algal cells, mainly of green algae, were detected for which the treatment procedure was found to be less effective. The average algal removal by drinking-water treatment resulted in 97.4% for all samples and in 98.3% when significant algal concentrations were present in raw water. The combination of chlorine dioxide and coagulants resulted in a removal of 90.1%.

Vibrio spp. of clinical interest from the Arno River basin (Tuscany, Italy) were investigated in this study. Vibrios were isolated from 70% of water samples. Vibrio cholerae non-O1 was the most prevalent species (82% of isolates), followed by Vibrio mimicus (10%) and Vibrio metschnikovii (8%). Recovery of vibrios was correlated with temperature, pH, and various indicators of municipal pollution. None of the 150 Vibrio isolates carried ctx-related genomic sequences, whereas 18 (14.6%) of the 123 V. cholerae non-O1 isolates and 1 (6.7%) of the 15 V. mimicus isolates carried sto alleles. These findings indicate that considerable circulation of sto-positive vibrios may occur in temperate-climate freshwater environments.