Maria C. Vagi

Organochlorine pesticides in the surface waters of Northern Greece

A survey undertaken in Northern Greece has shown that organochlorine pesticides are present in the surface waters. Surface water samples have been collected seasonally from four rivers and five lakes for a period of two years. Solid-phase extraction followed by gas chromatographic techniques with electron capture detection was used for the determination of the compounds. The most commonly encountered organochlorine pesticides in surface waters were the isomers of hexachlorocyclohexane, aldrin, dieldrin and endosulfan sulfate. In some cases the concentrations detected were higher than the qualitative target levels set by the European Union, especially for hexachlorocyclohexane and aldrin. The occurrence of these compounds in Greek surface waters can be attributed to intense agricultural activity as well as to transboundary pollution.

Adsorption and desorption processes of the organophosphorus pesticides, dimethoate and fenthion, onto three Greek agricultural soils

Laboratory studies were conducted to determine the sorption and desorption behaviour of two commonly used organophosphorus pesticides dimethoate and fenthion, which are widely used in the studied area to treat the olivetrees. Three Greek soils from the region of Mytilene island (denoted M, KT and P) which differed with respect to pH (pH 5.45–6.90), clay content (6–26%), organic matter content (1.0–4.2%), cation exchange capacity (4.8–24.4 meq/100 g) and specific surface (10.79–109.22 m2 g−1) were selected for the experimental section that was conducted using the batch equilibrium technique. The sorption isotherms could be described by Freundlich and Langmuir equations for both compounds with correlation regression coefficients for fit of the isotherms to that models R 2 ≥ 0.9666 and R 2 ≥ 0.8117, respectively. Freundlich sorption coefficients Kf were normalised to soil organic matter content and KOM estimated values for M, KT and P soils respectively were 60.19, 163.58 and 663.43 for dimethoate and 1365.84, 820.73 and 2902.52 for fenthion. Desorption studies revealed that dimethoate was adsorbed very weakly on soils tested and easily desorbed with water, while on the contrary fenthion was adsorbed very strongly on studied matrices with acetone extractable amounts.

Monitoring priority substances of directives 76/464/EEC and 2000/60/EC in Greek water bodies.

The priority substances of List I, 76/464/EEC Directive, some of which belong to the new Water Framework Directive 2000/60/EC, have been monitored in the surface waters of Greece through the developed network of 53 sampling stations. The analytical methods used for the determination of these substances included Purge and Trap-Gas chromatography-Mass spectrometry for volatile and semivolatile organic compounds, Gas Chromatography-Electron Capture Detection for organochlorine insecticides, High Performance Liquid Chromatography for pentachlorophenol and Atomic Absorption Spectrometry for metals. The results have shown the presence of several priority substances in Greek surface waters, in most cases at concentrations well below the regulatory limits. However, non-compliance was observed for a limited number of compounds. The monitoring network and the analytical determinations have to be expanded to more water bodies and more priority substances, in order to safeguard the quality of Greek surface waters.

Determination of the priority substances regulated by 2000/60/EC and 2008/105/EC Directives in the surface waters supplying water treatment plants of Athens, Greece

ABSTRACT An investigation into the occurrence of priority substances regulated by 2000/60/EC Water Framework Directive and 2008/105/EC Directive was conducted for a period of one year in the surface water sources supplying the water treatment plants (WTPs) of Athens and in the raw water of WTPs. Samples from four reservoirs and four water treatment plants of Athens were taken seasonally. The substances are divided into seven specific groups, including eight volatile organic compounds (VOCs), diethylhexylphthalate, four organochlorine pesticides (OCPs), three organophosphorus/organonitrogen pesticides (OPPs/ONPs), four triazines and phenylurea herbicides, pentachlorophenol, and four metals. The aforementioned substances belong to different chemical categories, and different analytical methods were performed for their determination. The results showed that the surface waters that feed the WTPs of Athens are not burdened with significant levels of toxic substances identified as European Union (EU) priority substances. Atrazine, hexachlorocyclohexane, endosulfan, trifluralin, anthracene and 4-nonylphenol were occasionally observed at very low concentrations. Their presence in a limited number of cases could be attributed to waste disposal, agricultural activities, and to a limited industrial activity in the area nearby the water bodies.

Effects on the Photosynthetic Activity of Algae after Exposure to Various Organic and Inorganic Pollutants: Review

Algal studies remain necessary for risk assessment and their utility in ecotoxicology is the evaluation of lethal and sub-lethal toxic effects of potential toxicants on inhabitants of several ecosystems. Effects on algal photosynthetic apparatus caused by various chemi‐ cal species have been extensively studied. The present chapter summarizes the pub‐ lished data concerning the toxicity of various organic and inorganic pollutants such as oils, pesticides, antifoulants and metals on photosynthesis of aquatic primary producers. Biochemical mode of action resulting in the disruption of photosynthesis depends on the chemical’s nature and the characteristics of the exposed microorganism. Observed differ‐ ences in response and sensitivity by different species to the same toxicant were attributed to several algal characteristics including photosynthetic capacity, pigment type, cellular lipid and protein content, and cell size. Single species bioassays either for one chemical alone or in mixture have been well reported and tolerance of both marine and freshwater water-column phytoplaktonic species has been examined. Adequate published informa‐ tion on multispecies tests (communities) in laboratory and field studies exists. However, risk assessment on photosynthesis of microbenthic periphyton is inadequate, though it is essential especially for hydrophobic organic molecules. Further studies are required to evaluate the adverse effects of metabolites on aquatic microalgae.