Ole Martin Eklo

Bioaccumulation of organochlorine pollutants in the fish community in Lake Årungen, Norway.

Organochlorine pollutants in the major fish species (pike Esox lucius, perch Perca fluviatilis, and roach Rutilus rutilus) of Lake Arungen, Norway, were investigated after an extensive removal of large pike in 2004. The organochlorine pollutants detected in fish liver samples in 2005 were dichlorodiphenyltrichloroethane (DDTs), polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and heptachlor epoxide (HCE). DDTs were the dominant among all analyzed OCs. Sigma PCB and HCB, detected in fish from two clearly distinct trophic levels (prey and predators), give an indication of biomagnification. All OC concentrations in female pike were significantly lower compared to males, which might be due to the removal of high concentrations of pollutants in roe during spawning.

Pesticides in precipitation in Norway

Abstract Contamination of rainwater by pesticides has been investigated by analyzing samples from three locations in Norway: Lista,A˚s, and Tromso. The samples were taken weekly, when possible, during the periods June–September in 1992 and May–September in 1993. The samples were analyzed for nine pesticides, including the five herbicides MCPA, dichlorprop, atrazine, simazine, and ioxynil (1992), the fungicide propiconazole, and the insecticides lindane (γ-HCH), dimethoate, and cypermethrin (1992). Residues were found in the samples from Lista andA˚s. The samples from Tromso, however, showed no residues of any pesticide. A total of 520 analyses for Lista andA˚s were performed, and every tenth sample showed measurable residues. The highest concentrations (ng/l) measured for MCPA, dichlorprop, atrazine, and lindane were 320, 250, 86, and 84, respectively. The level of pesticides stated in the EEC-directive 80/778 for the quality of water intended for human consuption is 100 ng/l. This level was exceeded twice for the herbicides MCPA and dichlorprop. On average, total deposition of the pesticides in 1992–1993 was 2.4 times higher atA˚s than at Lista. Atrazine and lindane were often found in precipitation when the wind was blowing from the east. As these chemicals were taken off the market before this investigation began, it seems reasonable to conclude that long-distance transport is the probable cause.

Groundwater Pollution and Quality Monitoring Approaches at the European Level

The authors investigate the sources and processes of groundwater contamination and their assessment within the Drivers-Pressures-State-Impact-Response (DPSIR) framework. Naturally occurring substances, trace elements, radionuclides, nutrients, and salt (sodium chloride) are reviewed with emphasis on the assessment of the natural background load. Some synthetic substances are also considered, these being petroleum hydrocarbons, chlorinated aliphatics, pesticides and organic-waste contaminants. Newly emerging contaminants cannot be described within the DPSIR; therefore monitoring approaches and indicators of contamination are discussed in order to propose improved monitoring plans that combine physical, chemical and biological indicators and combine science with policy.

An integrated approach for assessing influence of agricultural activities on pesticides in a shallow aquifer in south-eastern Norway.

The study examines the influence of agricultural activities on pesticides in groundwater in an area with fluvial deposits of sand with a top layer of sandy silt and silt, intensive cultivation of potatoes and cereals, and drinking water supplies of households from local groundwater wells. Information about local agricultural practice and washing sites for pesticide spraying equipment, properties of soils and deeper deposits, hydrogeology and groundwater flow, simulations of pesticide leaching, and contents of pesticides and nitrate in groundwater samples from drinking water wells was used to explore extension and reasons of pesticide contamination of groundwater. Pesticides were found in a majority of the sampled wells. Eight different pesticides and metabolites were detected in groundwater samples. The results demonstrate that on fluvial deposits diffuse pollution from spraying of fields with pesticides can result in groundwater contamination in Nordic climate. Higher concentrations of pesticides in some wells can be explained by point source contamination from washing sites. The occurrence of pesticides in drinking water wells touches up the question whether pesticides should be given general approvals, or approvals should include restrictions or recommendations regarding use on areas with high risk of groundwater contamination. Combination of washing sites for pesticide spraying equipment and groundwater wells for drinking water requires attention, proper equipment and practice, and knowledge about pesticides, soil and water to avoid contamination. Samples from wells adjacent to washing sites for pesticide equipment might overestimate average pesticide concentrations in groundwater bodies. In Nordic areas attention should be given to pesticide pollution of shallow groundwater in fluvial deposits. To provide basis for interpretation of results and planning of mitigation measures against pesticide contamination, an integrated approach using information about agronomical practice and point sources, soil properties, hydrogeology and simulations of pesticide leaching is recommended for future surveys and monitoring of pesticides in groundwater.

Effects of Picoxystrobin and 4-n-Nonylphenol on Soil Microbial Community Structure and Respiration Activity

There is widespread use of chemical amendments to meet the demands for increased productivity in agriculture. Potentially toxic compounds, single or in mixtures, are added to the soil medium on a regular basis, while the ecotoxicological risk assessment procedures mainly follow a chemical by chemical approach. Picoxystrobin is a fungicide that has caused concern due to studies showing potentially detrimental effects to soil fauna (earthworms), while negative effects on soil microbial activities (nitrification, respiration) are shown to be transient. Potential mixture situations with nonylphenol, a chemical frequently occurring as a contaminant in sewage sludge used for land application, infer a need to explore whether these chemicals in mixture could alter the potential effects of picoxystrobin on the soil microflora. The main objective of this study was to assess the effects of picoxystrobin and nonylphenol, as single chemicals and mixtures, on soil microbial community structure and respiration activity in an agricultural sandy loam. Effects of the chemicals were assessed through measurements of soil microbial respiration activity and soil bacterial and fungal community structure fingerprints, together with a degradation study of the chemicals, through a 70 d incubation period. Picoxystrobin caused a decrease in the respiration activity, while 4-n-nonylphenol caused an increase in respiration activity concurring with a rapid degradation of the substance. Community structure fingerprints were also affected, but these results could not be directly interpreted in terms of positive or negative effects, and were indicated to be transient. Treatment with the chemicals in mixture caused less evident changes and indicated antagonistic effects between the chemicals in soil. In conclusion, the results imply that the application of the fungicide picoxystrobin and nonylphenol from sewage sludge application to agricultural soil in environmentally relevant concentrations, as single chemicals or in mixture, will not cause irreversible effects on soil microbial respiration and community structure.

Degradation and Dissipation Studies of Isoproturon in a Silty Clay Loam from Norway

Degradation and dissipation studies in laboratory and field were performed with isoproturon (IPU) to produce data for modelling the fate of an autumn applied pesticide in a Gleyic Podzoluvisol in Norway. Transformation rate studies of IPU in the laboratory during 8 weeks displayed a DT 50 of 13 days in topsoil (0-20 cm) and 21 days in subsoil (20-40 cm) at 20°C. In topsoil, a decline in the content of the metabolite monodesmethyl-isoproturon (MMU) was observed along with an initial production of didesmethyl-isoproturon (MU) after 4 weeks. In subsoil, the content of MMU was stabilized and no decrease was observed during the experiment. Only trace amounts of MU were found in the subsoil. Field dissipation of IPU was investigated in a silty clay loam following post-emergence application to winter wheat (September 1999). A bromide tracer was used to monitor the water flow in the soil profile. Soil was sampled from the 0-20, 20-40, 40-60 and 60-80 cm layers after 1, 2, 4, 13, 62, 232 and 371 days. 13 days after herbicide application, the waterfront had reached a depth of 80 cm and as a result an amount of 7 mg IPU m m 3 could be recovered from this depth, representing 2% of the initial amount of herbicide applied. Less than 9% of the herbicide applied could be seen to penetrate below 20 cm soil depth. After 62 days, only 18% of the initial IPU amount applied could be recovered from the profile. Using the results from the laboratory degradation study, a theoretical DT 50 of IPU in the field was estimated to 18-25 days ( Q 10 = 2.2). The theoretical DT 50 corresponded well with the actual dissipation of IPU observed in the field. This indicated that degradation of IPU was the primary contribution to the fast dissipation of IPU in the field, and that the risk of runoff of IPU was negligible. Appearance of the major degradation product MMU in the field was monitored during the entire experimental period, at most representing 11% of the initial herbicide concentration. Field studies showed that MMU was more easily transported below the plough layer than isoproturon. Traces of IPU and MMU could be found in soil one year after application. A second degradation product, MU, could not be recovered in quantifiable amounts in the soil samples.