The photocatalytic disinfection of urban waste waters

In this paper we present the results of the photocatalytic disinfection of urban waste water. Two microbial groups, total coliforms and Streptococcus faecalis, have been used as indexes to test disinfection efficiencies. Different experimental parameters have been checked, such as the effect of TiO2, solar or UV-lamp light and pH. Disinfection of water samples has been achieved employing both UV-lamp and solar light in agreement with data shown by other authors. The higher disinfection rates obtained employing an UV-lamp may be explained by the stronger incident light intensity. Nevertheless no consistent differences have been found between TiO2-photocatalysis and direct solar or UV-lamp light irradiation at natural sample pH (7.8). At pH 5 the presence of TiO2 increases the relative inactivation rate compared with the absence of the catalyst. After the photocatalytic bacterial inactivation, the later bacterial reappearance was checked for total coliforms at natural pH and pH 5, with and without TiO2. Two h after the photocatalytic treatment, CFU increment was almost nill. But 24 and 48 h later an important bacterial CFU increment was observed. This CFU increment is slower after irradiation with TiO2 at pH 5 in non-air-purged samples.     

Radioactive Isotopes of Strontium, Caesium and Plutonium in Sediments of the Northern Adriatic Sea

Sediment samples of different strata (0-3 and 12-15 cm) were collected between 1990 and 1992 during seasonal cruises in the Northern Adriatic Sea. A complete mapping of the Sr-90, Cs-137, Pu-238 and Pu-239(240) concentrations was obtained for samples covering a wide area, stretching from the Gulf of Trieste towards the Ancona shoreline. Sr-90 concentrations varied between 1.5 and 6.5 Bq kg^-1 dw, Cs-137 was in the range 0.9-38.9 Bq kg^-1 dw, Pu-239(240) in the range 0.08-1.5 Bq kg^-1 dw and Pu-238 around 0.03 Bq kg^-1 dw. Special reference was also put on the comparison between the off-shore environment and data obtained from samples collected inside the Po river delta. in spite of the major accumulation of Cs-137 inside the estuarine environment, higher concentrations of strontium and plutonium isotopes were detected in the offshore environment.     

Photocatalytic degradation of formaldehyde containing wastewater from veterinarian laboratories

The photocatalytic destruction of methanol, formaline (mixture of formaldehyde, methanol and water) and formaline wastes from the preservation of vertinarian physiologic samples has been attempted by two different processes, at high concentrations of reagents and by dossification of reagents, varying pH in both. Experiment evolution has been monitored by measuring the organic matter such as TOC and formaldehyde concentrations [H2CO]. Also, methanol and methanol-formaldehyde interactions with the TiO2 surface have been analysed by FTIR spectroscopy. Results indicate that at high concentrations the catalyst surfacial alterations given by methoxy, formates or carbonates, according to the pH of the sample can profoundly affect catalyst behaviour. It has been established that reagent dossification is advantageous for enhancing photonic efficiency as it minimizes the adsorbate presence that hampers the photocatalytic process.     

Behavior of Chlorpyrifos-methyl in soil and sediment

This research was carried out with the aim of obtaining information regarding the possible environmental impact of Chlorpyrifos-methyl, an organophosphoric insecticide used in agriculture for its phytoiatric action against Hemiptera, Lepidoptera, Coleoptera, and Diptera. Studies relating to the degradation kinetics of the insecticide in two soils and one sediment have shown a rapid degradation process in all three. The prevalent form of degradation would appear to be the chemical type, because the degradation kinetics in a sterile soil have not demonstrated that micro-organisms play a significant part. The adsorption isotherms showed that the insecticide has a greater affinity for the sediment (Kf=143) as opposed to the soils (Kf=65) and that the adsorption process is practically irreversible. Moreover, hydrolysis tests in buffered solutions at pH 4, 7, and 9 revealed that the molecule is particularly unstable with a basic pH.     

The association between prenatal exposure to polycyclic aromatic hydrocarbons and childhood intelligence: a systematic review of observational studies

Environmental Science and Pollution Research - Exposure to polycyclic aromatic hydrocarbons (PAHs) during pregnancy has been associated with many adverse child health. However, the evidence on such...     

Combining TiO2-photocatalysis and wetland reactors for the efficient treatment of pesticides

In the present work the photocatalytic and biological degradation of two commercial mixtures of pesticides (Folimat and Ronstar) and two fungicides (pyrimethanil and triadimenol) has been studied. The evolution of some components of these commercial products (dicofol, tetradifon and oxadiazon) and that of the two fungicides has been monitored by means of HPLC, GC-MS, TOC and toxicity (Lemna minor toxicity test) measurements. The photocatalytic method was able to degrade dicofol, tetradifon, pyrimethanil, triadimenol and the components of Ronstar with the exception of oxadiazon. In addition to this, the photocatalytic method eliminated pyrimethanil toxicity and reduced that of triadimenol by a 90%, Ronstar by a 78% and Folimat by an 87%. Nevertheless, the wetland reactors alone could reduce the toxicity of only the former. Finally, the proper dosage of the water containing the pesticides to a photocatalytic reactor followed by a wetland reactor resulted to be the most successful strategy for the detoxification of the studied compounds and their mixtures.     

(238)U, (234)U, (226)Ra, (210)Po concentrations of bottled mineral waters in Italy and their dose contribution

Due to the importance of bottled mineral water in human diet with special regard to children in lactation period, a monitoring of natural radioactivity in some bottled mineral waters produced in Italy was performed. Gross alpha and beta activities and (226)Ra, (238)U, (234)U, and (210)Po concentrations were measured. Gross alpha and beta activities were determined by standards ISO 9696 and ISO 9697; for (226)Ra determination liquid scintillation was used. The (238)U and (234)U concentrations were determined by alpha spectrometry after their separation from matrix by extraction chromatography and electroplating. (210)Po was measured by alpha spectrometry. The results revealed that the concentrations (mBqL(-1)) of (226)Ra, (238)U, (234)U, and (210)Po ranged from <10.00 to 52.50, from <0.17 to 89.00, from <0.17 to 79.00, and from <0.04 to 21.01, respectively. Uranium and radium concentrations do not reach the relevant recommended derived activity concentration (DWC). For polonium concentration, none of the samples reaches the relevant DWC in the case of adults and children, but one sample exceeds this value for infants. The dose contribution for different classes of age was calculated using the dose coefficient factors reported by EC Directive 96/29 EURATOM and certain annual intake. For children and adult age class, the calculated doses are quite similar and lower than 0.1mSvy(-1); for infants (<1y) in three cases the calculated dose ranges from 0.11 to 0.17mSvy(-1).     

Natural and artificial radioactivity determination of some medicinal plants

Several medicinal plants used in Italy were analysed to determine natural and artificial radioactivity in those parts (leaves, fruits, seeds, roots, peduncles, flowers, barks, berries, thallus) used generally as remedies. The radionuclides were determined by alpha (²³⁸U, ²¹⁰Po) and gamma (²¹⁴Pb-Bi, ²¹⁰Pb, ⁴⁰K and ¹³⁷Cs) spectrometry. ²³⁸U ranged between <0.1 and 7.32 Bq kg_dry⁻¹; ²¹⁰Po between <0.1 and 30.3 Bq kg_dry⁻¹; ²¹⁴Pb-²¹⁴Bi between <0.3 and 16.6 Bq kg_dry⁻¹; ²¹⁰Pb between <3 and 58.3 Bq kg_dry⁻¹; ⁴⁰K between 66.2 and 3582.0 Bq kg_dry⁻¹; ¹³⁷Cs between <0.3 and 10.7 Bq kg_dry⁻¹. The percentage of ²¹⁰Po extraction in infusion and decoction was also determined; the arithmetical mean value of percentage of ²¹⁰Po extraction resulted 20.7 ± 7.5.