Ecotoxicological assessment of industrial effluent using duckweed (Lemna minor L.) as a test organism.

This study aimed at assessing the toxic effects of industrial effluents using duckweed (Lemna minor L.) plants as a test system. Growth inhibition test according to standardized protocol (ISO 20079) was performed. The suitability of the Comet assay (indicates DNA damage) and certain parameters such as peroxidase activity and lipid peroxidation level, as biomarkers for environmental monitoring was evaluated. The water samples were collected monthly over a 3-month period from the stream near the industrial estate of Savski Marof, Croatia. All samples caused inhibition of growth rates based on frond number and biomass as well as decrease of chlorophylls content. In contrast, peroxidase activity, malondialdehyde content and tail extent moment (measure of DNA strand breaks) markedly increased. Obtained data demonstrate the relevance of duckweed as sensitive indicators of water quality as well as the significance of selected biological parameters in the reliable assessment of phyto- and genotoxic potential of complex wastewaters.

The evaluation of surface and wastewater genotoxicity using the Allium cepa test.

Screening for mutagens in complex environmental mixtures, such as surface water or industrial wastewater, is gradually being accepted as a routine method in environmental monitoring programs. In the present work, the simplified Alliumcepa root assay was utilized to evaluate the possible cyto- and genotoxic effects of surface and wastewaters collected near the Sava River (Croatia) over a three-month monitoring period. Physicochemical characterization of the water samples included measurements of conductivity, chemical and biological oxygen demand, levels of suspended matter and salts, nitrate, nitrite, ammonium, total nitrogen and total phosphorus. Morphological modifications of the A. cepa roots, inhibition of root growth, cell division and induction of mitotic and chromosomal aberrations were observed. The most highly polluted water samples (industrial effluents) caused an inhibition of root growth of over 50%, a decrease in the mitotic index of over 40%, and a considerable increase in chromosomal aberrations compared to the control. The measured biological effects of some water samples appeared related to the physicochemical characteristics. Therefore, mutagenicity/genotoxicity assays should be included, along with conventional chemical analysis, in water quality monitoring programs. Their use would allow the quantification of mutagenic hazards in surface and wastewaters.

[Drinking water safety from private wells in Zagreb]. / Zdravstvena ispravnost pitke vode iz privatnih zdenaca u Zagrebu.

Bacterial quality of water from private wells was examined seasonally during the year 2003 in 3 districts of Zagreb-Pescenica, Trnje and Tresnjevka. The aim of the study was to estimate the quality of water consumed by 5% of citizens who are not connected to the public water supply system. Total coliforms, fecal coliforms and Enterococcer were determined by the multiple tube (most probable number) method, and the heterotrophic plate count by enumerating culturable microoorganisms. Samples taken from Trnje had the best water quality, and the worst were from Tregnjevka. 21 out of 34 examined samples were sanitarily unsatisfactory (61.8%). Only one private well had no bacterial contamination and was satisfactory in all four seasons. Total coliforms were detected in 24 samples and values were from 2 to >240/100 ml, and 16 samples had values above maximal allowed concentration (MAC). Fecal coliforms were detected in 17 samples and values were from 2 to >240/100 ml. Two samples contaminated by Enterococcus were taken from Tregnjevka (autumn) and Trnje (spring). Heterotrophic plate count (colony count) was present in all samples, values being from 1 to 1920/ml, but were above MAC in 8 samples.