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A survey of atrazine residues in Serbian soils

M. Mojasevic¹, D. Kovacevic¹, N. Protic², S. LJ. Vitorovic¹, and I. Elezovic^1
1 Faculty of Agriculture, University of Belgrade, Nemanjina 6, Zemun

² Institute of Soil Science, Teodora Drajzera 11, Belgrade, Serbia & Montenegro

Atrazine has attracted much attention recently because of its frequent detection in surface and ground water and the potential problem it may present. As a result, its usage has been severely restricted and is currently being reassessed with the possibility of it being banned in EU countries. In Serbia, atrazine is still widely used, especially for maize production and the maximum residue concentrations in agricultural soils are regulated for rotational crops.

With a view of providing more information on this controversial issue, a summary of atrazine residues in soils was obtained from the study “The control of soil fertility and the presence of harmful and hazardous materials in the soils of Serbia”. The study was first designed for the Province of Vojvodina and completed in 1991-1993. There some 926 surface soil samples (0-30 cm) collected from predefined locations were analyzed. The survey was extended to cover other regions of Serbia in 1993, but due to financial constrains the project was held in abeyance until 2002. The data indicated that atrazine was present (>0.01 ppm) in 23% of the 878 samples analyzed in 1993-1997 and in 28% of the 223 samples collected in 2002. The percentage of samples with residues > 0.06 ppm, which is considered to be the threshold value for most sensitive rotational crops, was found in both batches of soils samples to be quite small (< 1.5%).
Based on these data , the question if detected atrazine concentrations have no other significance but to pose a low risk to rotational crops, might be further elaborated.

Com. 21
UNEP /GEF REGIONALLY BASED ASSESSMENTOF PERSISTENT TOXIC SUBSTANCES IN MEDITERRANEAN REGION: Case of Pesticides
J.F Narbonne
Biochemical Toxicology, LPTC UMR 5472 CNRS, University Bordeaux 1
SOURCE CHARACTERISATION and TRANSPORT

The main sources, vectors and reservoirs of PTS pesticides are summarised in Table 1.

Compound type	Air sources	Soil sources	Freshwater sources	Seawater sources
Pesticides	Agriculture use, sprying/land application	Stockpiles, production waste DDT, dicofol production	Runoff from agriculture use.DDT, dicofol production.	Major rivers and coastal runoff

For PTS pesticides, including lindane, the sources are multiple and diffuse. Although, these compounds have a tendency to disappear as a result of the implementation of the PIC procedure and the associated conventions, there is a worrisome lack of control regarding the existing stockpiles in the countries of the Mediterranean region. The use of lindane is severely restricted in the Region, but in countries like France and Spain the estimated atmospheric emissions are quite large. DDT is still being used in the Region as precursor of dicofol, information about the amounts being used is uncertain. In the case of toxaphene and other pesticides, the dumping of obsolete stocks in the southern countries of the region is deemed to have created potential hot spots.

Due to climatic and physiographic characteristics of the Mediterranean region long range transport of air pollutants may occur during all seasons, with the warm period of the year being the most effective. Transcontinental scale transport between Europe, Asia and Africa is evident based on meteorological modelling, the Europe to Africa direction prevailing over the others.

Modelling of long range transport of PTS developed by the MSC-East Center, from EMEP data, and the issued deposition estimates are rather comprehensive for northern and central Europe but much less reliable for the southern part. More emission data and environmental measurements of known quality are needed for an accurate assessment of sources and receptors in the region and the transport pathways. The long-range transport of PTS have several implications in the Mediterranean Region. Air masses from Europe should reach the mid-tropospheric layers of the Equatorial Zone within a time period of a few days (4-6).

Localised inputs or "hot spots" of PTS have been identified near sewage outfalls from highly industrialised and populated cities such as Marseille, Barcelona, Naples, and Nice. And from the major rivers (e.g. Rhône, Po, Ebro, Seine, etc). However, 80% of the terrestrial sediments are trapped on the continental shelf and only currents to deep-sea sediments transport the finest particles. Therefore, it appears that these discharges have limited significance regarding the transport of PTS at regional scale.

LEVELS and EFFECTS

Contamination levels and trends in biotic and abiotic compartments: A large number of determinations of OC pesticides in abiotic compartments were performed in the 80’s. These historical data were difficult to assess due to changes in analytical methodology and results expression. In the Northern Mediterranean long-term temporal trend monitoring in fish, mussels and seabird eggs indicate a general decline of DDTs has been reported for marine biota between 1960s and 1990s, A similar trend was observed in the Ebro River for all DDT and HCB for the period from 1980 to 1990; and for all DDT and HCHs in the French monitoring network of coastal pollution during the period 1979-1998.

Based on a few dated sediment core studies levels DDTs, HCHs, HCB and chlordane compounds in the coastal lagoon of Manzala (Egypt) increased rapidly from early 60’s to a maximum recorded in the 80’s. However, HCHs were still increasing till 1993. A similar trend was observed in the Nile River except for HCB which exhibits a steady increasing trend. Comparison between Western and Eastern Mediterranean basins has been approached using the Audouin’s Gull (Larus audouinii) eggs. Levels are significantly and consistently (less variable) higher in the Western than in the Eastern basin. Total DDT medians are significantly higher in the Mediterranean than in the North Atlantic or the Arctic. The results obtained confirm that in Mediterranean dolphins the accumulation of contaminants is higher than in similar species living in the Atlantic.

Ecotoxicology effects. Many laboratory experiments have investigated the acute toxicity of persistent pesticides to invertebrates (mainly marine organisms). Subacute effects refer to growth, endocrine disruption, CYP and drug metabolism induction, biochemical parameters and genotoxicity. Bioaccumulation in fish is the main element in biomagnification and trophic transfer of PTS from the aquatic reservoir to humans. Redistribution of OCs from maternal tissues to the developing eggs, represent the important route to exposure for critical early life stages.

A number of reports illustrated the development of the ecotoxicology studies in the region::. However specific effects of pesticides are generally part of the global response of living organisms to exposure of a mixture of contaminants and natural stressors. Protocols including specific biomarkers are able is some situations to discriminate pesticide effects.

Different approaches have been proposed for risk assessment: PEC / PENEC, Hazard Quality ratio (HQs), biomarker scales. Most of them have been developed in northern countries and there is a need for their adaptation and testing also in the southern countries.

Contamination levels and effects in humans

Because of the variety of biologic mechanisms (uptake, transport, metabolism, bioaccumulation) which makes the external exposure to OCs different from their concentration in tissues, the assessment of their levels in the human body ("internal dose") is the most accurate procedure to correlate PTS dose and the related adverse effects.

For many OCs toxicological effects are stillnot fully clarified, specially for low-dose, subtle and long-term effects. Number of studies indeed suggests that OCs can cause biological effects at levels far below of deemed safe doses, specially for developing organisms, in utero and via breast feeding, may result in subtle effects with respect to highly sensitive endpoints (i.e. neurodevelopmental, endocrine).

Temporal trends

Decreasing trends have generally been observed for organochlorine insecticides in surface streams during the 80s and 90s. Temporal trends of chlorinated pesticides have also been assessed using dated sediment cores collected in the mouths of the rivers (e.g. Ebro, Nile, etc.), showing increasing discharges until mid 80’s and further decrease, although HCHs are still increasing at present times in the Nile. The French monitoring network of coastal pollution using bivalves as sentinel organisms indicated that during the period 1979-1998 the decreasing trends were found in more than 60% of the sites. In human tissues Ocs levels generally decreased except for certain countries (Egypt, Jordan).

Com. 22
Formation and analysis of bound pesticide residues in fruits
W. Schwack
Institute of Food Chemistry, University of Hohenheim (170),