T. A. Albanis

Gas chromatographic determination of 2-hydroxy-4-methoxybenzophenone and octyldimethyl-p-aminobenzoic acid sunscreen agents in swimming pool and bathing waters by solid-phase microextraction

A method has been developed for the trace determination of two sunscreen constituents (2-hydroxy-4-methoxybenzophenone and octyldimethyl-p-aminobenzoic acid) in water samples, which are commonly used in commercial formulations. The method employs solid-phase microextraction (SPME) and gas chromatography with flame ionization and mass spectrometric detection. The technique was developed with headspace and direct sampling in order to demonstrate the applicability of these SPME extraction modes for the identification of these two UV absorbing compounds in waters. The main parameters affecting the SPME process, such as desorption time, extraction time profile, salt additives, pH, and temperature, were investigated. The poly(dimethylsiloxane) 100-microm and polyacrylate 85-microm fiber coatings were found to be the most efficient for the extraction of these compounds from aqueous matrices. Linear calibration curves in the wide range of 10-500 microg/l were obtained for both compounds yielding typical RSD values of 5-9% for both extraction modes. The recoveries were relatively high, 82-98%, with quantitation limits below 1 microg/l. A comparison between the proposed methods and the conventional multiresidue solid-phase extraction revealed that the proposed technique(s) can be reliably used for sunscreen residue measurement in water samples with satisfactory results.

Aqueous photolysis of the sunscreen agent octyl-dimethyl-p-aminobenzoic acid: Formation of disinfection byproducts in chlorinated swimming pool water

The photochemical behavior of the sunscreen agent octyl-dimethyl-p-aminobenzoic acid (ODPABA) was studied in different aqueous solutions and under different conditions. ODPABA photolysis was performed under laboratory conditions using a xenon light source and under natural sunlight conditions in sea, swimming pool as well as in distilled water. The influence of dissolved organic matter (DOM) on the degradation kinetics was also studied in the presence of various concentrations of humic acids (HA). The phototransformation was shown to proceed via pseudo-first-order reaction in all cases and the reaction rates followed the order: distilled water > swimming pool water > seawater, depending mainly on the presence of dissolved organic matter that retarded the photolysis reaction. Kinetic experiments were monitored with HPLC/UV-DAD and the half-lives (t 1/2) varied between 1.6 and 39 h in simulated solar irradiation and between 27 and 39 h in natural sunlight conditions. The product distribution during illumination was strongly dependent on the constitution of the irradiated media. Irradiation of the aqueous ODPABA solutions gave rise to several transformation products that were isolated by means of solid-phase extraction (SPE) and identified using GC-MS techniques. These were formed mainly through dealkylation and hydroxylation reactions and were detected in all aqueous solutions investigated. In the case of swimming pool water some additional byproducts were isolated and were tentatively identified as chlorinated intermediates, formed by the subsequent chlorination of the parent molecule as well as other intermediates.

Transportation of pesticides in estuaries of the Axios, Loudias and Aliakmon rivers (Thermaikos Gulf), Greece

Abstract Water and bottom sediment samples from eight stations in the wetland of the delta of the rivers Axios, Loudias and Aliakmon were collected during 1992 and 1993 and analysed for pesticide residues. Eleven herbicides, alachlor, atrazine, 2,4-D, diuron, MCPA, metolachlor, metribuzin, molinate, prometryne, simazine and triffuralin and three organochlorine compounds α-BHC, lindane and 4,4′-DDE (DDT mebolite) were detected in estuaries of the Axios, Loudias and Aliakmon rivers as well and in the Thermaikos Gulf. Highest concentrations of alachlor, atrazine, diuron, MCPA, metolachlor, metribuzin and prometryne in water samples were detected during the period of May to August. Six herbicides, alachlor, atrazine, metolachlor, molinate, simazine and trifluralin and three organochlorine compounds, α-BHC, lindane and 4,4′-DDE were found in significant amounts in estuarine sediments and in the Thermaikos Gulf. The amounts of each pesticide released were calculated using a collective model dependent on pesticide concentrations, river water flow rates and on their changes with time. Pesticides are released from the agricultural fields and transferred to the Thermaikos Gulf through the Axios, Loudias and Aliakmon rivers. The percentages of the total amount of pesticides released through the rivers to the Thermaikos gulf are estimated as 1.7 and 0.78% for alachlor, 2.5 and 1.0% for atrazine, 0.5 and 0.13% for 2,4-D, 1.1 and 0.1% for metolachlor, 7.4 and 2.5% for metribuzin, 0.8 and 0.25% for molinate, 4.5 and 4.4% for prometryne, 0.4 and 0.6% for simazine, 0.3 and 0.06% for trifluralin and 0.3 and 0.25% for lindane for the periods of 1992 and 1993, correspondingly. An estimation of the percentage of released amounts of diuron (2.3%) and MCPA (0.3%) was only possible for 1992.

Transportation of pesticides in estuaries of Louros and Arachthos rivers (Amvrakikos Gulf, N. W. Greece)

Abstract Water and sediment samples from seven stations in estuaries of the Louros and Arachthos rivers as well as in the wetlands of the Amvrakikos Gulf were collected for a period from March 1992 to February 1993. The herbicides atrazine, simazine, alachlor, metolachlor, trifluralin and diuron and the organochlorine insecticides α-BHC, lindane and 4,4′-DDE were detected in riverine estuaries and wetlands. The highest concentrations of herbicides, atrazine, simazine, alachlor, metolachlor, diuron and trifluralin in water samples were detected during the period from March to August. The same herbicides and organochlorine insecticides as well as the β-BHC and 4,4′-DDT were found in significant amounts in sediments of river estuaries and wetlands of the Amvrakikos Gulf. The percentage of total amount of detected pesticides released through the rivers into Amvrakikos Gulf are estimated as 3.1% for atrazine, 1.7% for simazine, 1.9% for diuron, 0.3% for metolachlor, 0.9% for alachlor, 0.3% for lindane and 0.6% for trifluralin.

Seasonal fluctuations of organochlorine and triazines pesticides in the aquatic system of Ioannina basin (Greece)

Abstract For the period September 1984 to November 1985 water samples from the aquatic system of Ioannina basin were analyzed every second month for organochlorine and triazines pesticides. The detected compounds were found to follow a seasonal pattern, with an increment during summer followed by a decrease during winter and an increase again during late spring. This pattern was apparent for Ioannina lake as well as for the Kalamas river connected to it through the Lapsistas canal and tunnel. The results are discussed in terms of the amounts of the detected pesticides used for farming in the vicinity of the Ioannina basin and the seasonal rainfall.

Influence of Salinity and Dissolved Humic Acids on Pesticides Extraction from Water Using Solid-Phase Extraction Disks

Abstract The influence of water salinity and dissolved organic matter (DOM) on pesticide extraction recoveries using solid phase extraction disks was investigated. Eleven selected pesticides, belonging to different chemical groups were spiked at 1–5 μg/L in 500 ml distilled water containing sodium chlorine at 0, 5, 10, 15, 20, 25, 30 and 35 ‰ or humic acids at either 0, 1, 5, 10, 25, 50 and 100 mg/L dissolved organic carbon (DOC). Samples were prefiltered and their extraction was done by using C18 Empore solid phase extraction disks and filter aid glass beads. The pesticides eluted from the disks were analysed by gas chromatography with flame thermoionic detector (FTD) and mass selected detector (MSD) in the selected ion monitoring (SIM) mode. Higher recoveries of most pesticides were obtained as the water salinity increased from 0 to 35 ‰. Concentrations of DOC in humic acid had less effect on extraction efficiency, which was probably due to greater nonpolar interactions of pesticides to the charge-neutr...

Assessment of the abatement of acelsulfame K using cerium doped ZnO as photocatalyst

In the present study, we investigated the possibility to abate Acesulfame K, a persistent emerging contaminant, in aqueous media using zinc oxide based materials. For this purpose, bare and Ce-doped zinc oxide was prepared via an easy and cheap hydrothermal process using different cerium salts as precursors. Their photocatalytic performance was evaluated in different media, namely ultrapure and river water under both UV-vis and visible light. Commercial TiO2 P25 was also employed and used as a reference photocatalyst for comparison purposes. The obtained results pointed out that cerium doped zinc oxide composites exhibit higher performance than TiO2 P25, especially under visible light and in the presence of organic matter, when the activity of the latter is greatly depressed. In particular, ZnO doped with cerium (1%) was the most effective material, and could be a promising alternative to TiO2 P25, especially in the treatment of natural waters.

Movement of methyl parathion, lindane and atrazine through lysimeters in field conditions

The movement of pesticides methyl parathion, lindane and atrazine due to leaching by rainfall was studied in lysimeters containing different types of soil from the loannina area of Greece. For a period between October 1985 to June 1986 the amount of pesticides was analysed in water samples from rainfall concentrated after filtration through the soils to a depth of 100 cm. The total amounts of each pesticide transported in this way were 0.15–0.26% for methyl parathion, 0.15–0.19% for lindane and 0.54–0.66% for atrazine of the initial amounts.

The influence of fly ash on 2,4-dichlorophenoxy-acetic acid persistence in corn cultivation and soil

Abstract The influence of fly ash (raw material ignite from thermal station, pH = 11.2) in the fate of 2,4-dichlorophenoxy-acetic acid (2,4-D) was studied in an experimental corn cultivation, under environmental conditions of Ioannina region (N.W. Greece). An amount of fly ash equal to 0.15% p.w. of soil for a depth 0–10 cm was used in a sandy-clay-loam soil on the 18th of May 1988 when the sowing of the corn took place and the herbicide was applied after 21 days. Analyses of soil samples for 220 days, in a period between June 8, 1988 and January 14, 1989 showed that the addition of fly ash decreases the half-life of 2,4-D, from 25.5 to 19 days. The final results of fly ash addition showed a decrement of 2,4-D residues of about 24% in soil without corn cultivation and 41% in soil with corn after 129 days. For the 2,4-D residues in corn plants the corresponding decrements were 17.6% after 18 days and reach 37.5% after 114 days.

The influence of fly ash on hydrolysis, degradation and adsorption of methyl parathion in aqueous soil suspensions

The hydrolysis, degradation and adsorption of methyl parathion were studied in aquatic suspensions of two soils and their mixtures with small amounts (0.1–0.5%) of fly ash. For a concentration range of methyl parathion between 2–30 ppm the addition of fly ash up to 0.5% in a sandy clay loam (SCL) soil resulted in an increment of insecticide hydrolysis by 1.5% and of degradation by 8.5% on the average, and a decrease in adsorption by 1.8%. In the case of a clay (C) soil the addition of fly ash up to 0.5% resulted in an increment of insecticide hydrolysis by 1.2% and of degradation by 10.6% and a decrease in adsorption by 4.3% on the average. So the addition of fly ash in soil in fertilization levels act beneficial for their detoxification of methyl parathion residues.