PCB levels and accumulation patterns in waterbird eggs and in their prey at Lake Kerkini, a north-eastern Mediterranean wetland of international importance.

Seven "target" PCB levels were determined and compared in waterbird eggs, in their prey, and in water at Lake Kerkini, northern Greece, to investigate PCB bioaccumulation patterns and to define the best bioindicator of target PCBs for this area. PCBs were analysed from eggs of Phalacrocorax carbo, Podiceps cristatus, Ardea cinerea, Egretta garzetta, and Nycticorax nycticorax and from prey types Alburnus alburnus, Rutilus rutilus, Lepomis gibbosus. Carassius auratus, and Rana sp. PCBs analysed were detected in all bird eggs, prey, and water but contamination patterns differed among these sample types. The lipid-corrected geometric means of the congeners analysed were significantly different among most bird species and among some prey species. PCB congeners 118, 138, 153, and 180 accounted for around 80% of the total PCB contamination in bird egg samples. Percent congener concentrations of high-chlorinated PCBs tended to increase from water through prey to most bird egg samples whereas the low chlorinated PCBs (28 and 52) decreased. Bioaccumulation factors (BAFs) also exhibited an increasing trend for higher chlorinated PCBs from prey types to bird eggs. The greatest BAFs of six of the congeners were shared between Phalacrocorax carbo and Ardea cinerea. Among prey, the BAFs of four PCBs were highest in Lepomis gibbosus. Biomagnification factors varied between 1.01 and 39.57. In contrast to low chlorinated PCBs, high chlorinated congeners biomagnified considerably through fish prey. The highest biomagnification took place in Phalacrocorax carbo. No relationship was found between the lipid content of samples and BAFs of PCBs probably due to biotransformation differences of the congeners in the biota sampled. Due to the greatest PCB concentrations especially of the higher chlorinated PCBs in the eggs of Phalacrocorax carbo and its considerable bioaccumulation tendencies, it is proposed as the best PCB biomonitor of target PCBs at Lake Kerkini. Lepomis gibbosus had the highest concentrations of most congeners and exhibited the greatest bioaccumulative properties among prey and can be used as an alternative biomonitor.

Persistent organochlorine contaminants in liver and fat of birds of prey from Greece.

The concentrations of persistent organic pollutants, such as DDT and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), cyclodienes (Cycls), and polychlorinated biphenyls (PCBs), were measured in livers and subcutaneous fat tissues of six Accipitridae and four Falconidae bird species from different areas in Greece. This is the first report of persistent organochlorine (OC) pollutants in birds of prey tissues presented for Greece and the Eastern Mediterranean region. Accumulation patterns of OCs found in birds suggested that the predominant contaminants were p,p'-dichlorodiphenyldichloro-1,1-ethylene (DDE) and PCBs, whereas Cycls and HCHs occurred at low concentrations only. Concentration values of p,p'-DDE ranged from nondetected to 19,518.72 ng/g wet wt in livers and from nondetected to 2679.19 ng/g wet wt in fat. Total PCB levels ranged from 1.01 to 7419.43 ng/g and from 3.25 to 490.10 ng/g wet weight for liver and fat samples, respectively. Higher-chlorinated PCBs such as 118, 138, 153, and 180 predominated in both the liver and subcutaneous fat samples, a pattern comparable to that observed in birds from other European countries. No significant differences in mean concentrations of OCs are detected between species. Hepatic concentrations were in general higher than the fat concentrations showing depleted fat stores in most birds. Concentration ranges were also found in lower or similar levels to those reported for birds in other regions. Variation of OCs levels in bird tissues could be due to different causes of death, with a subsequent effect on body lipid levels, and different feeding and migration habits. The liver PCB levels reported in this study are below the concentrations currently believed to exert mortality or ecotoxicological effects. On the contrary, in some cases p,p'-DDE concentrations were higher than the reported effect values for birds of the same families and could be associated with sublethal effects.

Accumulation profiles of persistent organochlorines in liver and fat tissues of various waterbird species from Greece.

Waterbirds are particularly subject to accumulation of persistent organic pollutants (POPs) that have been shown to constitute a major hazard for this group of birds. Liver and fat tissue from ten species belonging to the orders Ciconiformes (Ardeidae, Ciconiidae, Phoenicopteridae) and Pelicaniformes (Pelecanidae, Phalacrocoracidae) were used as bioindicators in order to assess environmental pollution by POPs (HCHs, DDTs, cyclodienes, PCBs) in Greek wetlands. To our knowledge, this is the first study on POPs in livers of water birds in Greece and Eastern Mediterranean area. The DDTs consisted mainly of p,p'-DDE with percentages over 60% in the great majority of the samples. The highest summation SigmaDDT concentrations were measured in the liver and subcutaneous fat of Phoenicopterus rubber and in Ardea purpurea liver (15565, 24706 and 10406 ng g(-1) wet weight, respectively). Low concentrations of cyclodienes (Cycls) and HCHs were detected occasionally and the contamination pattern of OCPs in most species of waterbirds followed the order summation SigmaDDTs> summation SigmaCycls> summation SigmaHCHs. Individual values of total PCBs reached the levels of 4468 and 3252 ng g(-1) wet weight, for Nycticorax nycticorax and Egretta garzetta samples respectively. Some of the recorded differences in organochlorine concentrations could be due to different causes of death, with a subsequent effect on body lipid levels. Organochlorine pesticides and PCBs residues were lower than those commonly associated with mortality and reduced reproductive success in most species. However, low level exposure to these contaminants may constitute one of the many stressors that in combination could adversely affect bird populations.

Photocatalytic degradation of selected s-triazine herbicides and organophosphorus insecticides over aqueous TiO2 suspensions.

The photocatalytic degradation of selected s-triazine herbicides and organophosphorus insecticides was carried out in aqueous TiO2 suspensions under simulated solar light. The tested herbicides from the s-triazines group were atrazine, propazine, cyanazine, prometryne, and irgarol. The tested insecticides from the organophosphorus group were ethyl parathion, methyl parathion, ethyl bromophos, methyl bromophos, and diclofenthion. Degradation kinetics followed first-order reaction and has been monitored through gas chromatography. The degradation was fast with half-lives varying from 10.2 to 38.3 min depending on the nature and the structure of compounds. The generated transformation products (TPs) were formed via oxidation, dealkylation, and dechlorination for s-triazines and via oxidation and photohydrolysis for organophosphates. The TPs of irgarol, bromophos, and dichlofenthion were identified using solid-phase extraction (SDB-disks) and GC-MS techniques, and possible degradation routes were proposed showing similar degradation pathways as for other triazines and organophosporus pesticides. This work points out to the necessity of extended knowledge of the successive steps in a solar-assisted detoxification process.

Monitoring of pesticide residues and their metabolites in surface and underground waters of Imathia (N. Greece) by means of solid-phase extraction disks and gas chromatography.

Seasonal variations of pesticide residues in surface waters and ground waters of the Imathia area of Central Mecedonia (N. Greece) were determined for the period from May 1996 to April 1997. The sampling cruises included eight sites in rivers Aliakmon, Loudias, Tripotamos, Arapitsa and Canal-66, seven water springs in the mountain Vermion, seven rainfall water collection stations and one hundred underground points. Solid-phase extraction disks followed by gas chromatographic techniques with flame thermionic detection, electron capture detection and mass-selective detection were used for the monitoring of various pesticides their transformation products in environmental waters. The most commonly encountered pesticides in underground waters, were alachlor, atrazine, desethylatrazine (DEA), metolachlor, molinate, propanil, simazine, carbofuran, diazinon and parathion methyl. The above compounds including propazine, trifluralin, malathion, parathion ethyl, lindane, alpha-benzene hexachloride (alpha-BHC), beta-BHC, 4,4'-DDE and heptachlor were determined in river waters. The higher concentrations in underground waters were measured during the period from May to August, 1996, following seasonal application and diminished significantly during the autumn and winter. Water pollution by triazine and chloroacetanilides was highest in the estuarine areas; showing that many of these compounds are transported significant distances from their application sites. The major inputs of atrazine, alachlor, simazine and metolachlor occurred in May and June just after their application. Atrazine, DEA, diazinon and metolachlor were also detected in spring waters at concentration levels below 0.006 microgram/l. Finally, atrazine, DEA, carbofuran, simazine, diazinon, parathion ethyl and parathion methyl were detected in rainfall water samples collected in the agricultural area of Imathia (central part of the plain).