Relationships between radionuclides, metals, and sediment properties in sediment of a bay exposed to anthropogenic pressure and mixed sediment sources (Kaštela Bay, Adriatic Sea, Croatia)

Natural and anthropogenic radionuclides, metals, organic matter, sediment grain size, mineral composition, and sediment sources were studied in marine sediment of Kaštela Bay up to a depth of 0.5 m. Deposition of man-modified material into the sea was evidenced in sediment mineral composition. Presence of pyrite and hematite in this sediment may pose an environmental concern. Metals, radionuclides, and organic matter were grouped in three groups: (i) variables under no anthropogenic influence and preferentially associated with carbonates (Ca, Sr); (ii) variables under no or weak anthropogenic influence and preferentially associated with aluminosilicates (Al, K, Ti, V, Cr, Mn, Fe, Co, Ni, Ga, Rb, Y, 40K, 232Th); (iii) variables under notable anthropogenic influence and/or natural processes of separation (Cu, Zn, Pb, As, 226Ra, 238U, 137Cs, organic matter). Predominant influencing parameters change with sediment depth for some variables. Anthropogenic influence was the most emphasised for Cu, Zn, and Pb, followed by 137Cs.

40K, 226Ra, 232Th, 238U and 137Cs relationships and behaviour in sedimentary rocks and sediments of a karstic coastal area (Kaštela Bay, Croatia) and related rocks and sediments' differentiation

Natural (⁴⁰K, ²²⁶Ra, ²³²Th, ²³⁸U) and anthropogenic (¹³⁷Cs) radionuclides in consolidated sedimentary rocks (limestones s.l. and marls) and unconsolidated sediments (stream sediments and soils) of the Kaštela Bay (Adriatic Sea, Croatia) coastal area were studied. Kaštela Bay is a typical karstic environment and it is under strong anthropogenic influence due to industrialisation and urbanisation. Relationships between radionuclides, their behaviour in different types of samples and possible influencing factors were studied. Radionuclides were also studied in relation to selected metals (Al, K, Ca, Fe, Ti, Mn, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Pb and As) and distribution in limestones s.l., marls, stream sediments and soils. Radionuclides' massic activities were determined by gamma-spectrometry and metal mass fractions were measured by EDXRF technique. Relationships were studied using statistical tools (principal component analysis, factor analysis). It was found that stream sediments were more similar to source rocks (limestones s.l. and marl) than to soils in terms of natural radionuclides' activities. ⁴⁰K and ²³²Th in consolidated rocks were preferentially bound to alumosilicates and associated with the majority of studied metals. However, this was not the case with ²²⁶Ra and ²³⁸U, which did not show any preferences regarding binding to mineral components or associating with metals. On the other hand, all four natural radionuclides presented the same behaviour in unconsolidated sediments, i.e. they were all preferentially bound to alumosilicates and associated with the majority of metals. ¹³⁷Cs did not associate with any of the metals or other radionuclides in sediments. The statistical approach applied in this study revealed differences in radionuclides' relationships and behaviour in a karstic environment and implied possible influencing processes or factors. This approach can be applied in other types of environments as well to study preferential radionuclides' binding to certain mineral components that influences radionuclides' mobility and transport to other environmental compartments.

Application of the comet assay for the evaluation of DNA damage from frozen human whole blood samples: Implications for human biomonitoring

This study proposes the application of the comet assay for the evaluation of DNA damage from frozen human whole blood samples that could be readily used in human biomonitoring and epidemiological studies. It was done on simply frozen whole blood samples collected from male volunteers (N = 60) aliquoted in small volumes and stored at -80 °C without the addition of cryopreservatives for a period of 5 years. To test the applicability of the alkaline comet assay for the evaluation of DNA damage in frozen whole blood, samples were quickly thawed at 37 °C and immediately embedded in an agarose matrix followed by an alkaline comet assay procedure. We concluded that the whole blood freezing and prolonged storage do not severely affect comet assay values, although background values were higher compared to our historical control data from the fresh whole blood. Even the influence of the variables tested, such as age, body mass index, smoking habit and alcohol consumption were in agreement with our previous data using fresh blood. The obtained results suggest that the comet assay could be applied to frozen blood samples, if properly stored, even for decades, which would certainly facilitate large-scale human biomonitoring and long-term epidemiological studies.

Mineral Content in Honeybee Wax Combs as a Measurement of the Impact of Environmental Factors

Environmental pollution from metals needs to be constantly monitored due to their predominantly negative impacts on living organisms. As apian products stored in hives are considered useful bioindicators, the objective of this study was to: (a) investigate and compare the essential and toxic metal concentrations in freshly constructed combs (light combs, LC) and old combs (dark combs, DC) in use for two to three beekeeping seasons, and (b) compare the mineral content of beeswax combs from apiaries exposed to different levels of environmental pollution using the energy dispersive x-ray fluorescence method. Concentrations of ten elements (Cr, Pb, Cu, Ni, Fe, Zn, Mn, Sr, Rb, Ca) were determined in 18 honeybee wax comb samples from three apiaries in continental Croatia. The results showed that the influence of comb age and/or geographical origin (representing varying levels of environmental pollution exposure) on the elemental composition of beeswax was evident for the toxic elements Cr, Pb, Cu and Ni, and for the essential elements Fe, Zn, Mn and Sr, but not Rb. In addition to monitoring the environmental element content, wax combs can be used to determine contamination levels. Additionally, in-time analysis results can enable beekeepers to adjust management practices, such as moving apiaries to better positions. They can also be useful in the creation of policies on acceptable limits for toxic metal levels in particular geographical areas.

Alkaline comet assay results on fresh and one-year frozen whole blood in small volume without cryo-protection in a group of people with different health status

Using alkaline comet assay, DNA damage tail length (TL) and tail intensity (TI) parameters were compared between fresh whole blood and 1-year frozen small volume whole blood in EDTA at -80 °C without cryo-preservation. The studied group consisted of 25 volunteers with different health conditions who served as their own controls for frozen blood results. Without the purification step after thawing, the results and the usefulness of this protocol for future/retrospective (including re-analysations of putative outliers) studies were analysed. Medical surveillance and blood sampling were done at Merkur University Hospital Zagreb. No significant differences between fresh and frozen blood samples in terms of the mean TL values (mean ± SD: 29.03 ± 12.26 vs. 25.36 ± 6.97, respectively) and the mean TI values (9.19 ± 10.37 vs. 10.17 ± 8.55, respectively), and highly damaged cell percentage were determined among 25 volunteers. Median TI frozen samples values of entire group were within the allowed 10-11% (8.24). At the individual levels, no correlation between fresh and frozen whole blood samples was observed in 11 volunteers who suffered from diabetes mellitus type 2. Strong correlation between fresh/frozen samples was seen for TL (r = 0.64, p < 0.015) and TI (r = 0.71, p < 0.005) in nondiabetic subgroup. Overall, the results demonstrated the usefulness of the 1-year frozen blood without induction of heavily damaged DNA. Due to the different DNA damage behaviour connected with different health conditions, future studies should involve more volunteers, oxidative DNA damage comet assay measurements, the inclusion of a washing step after thawing and inclusion of disease/antioxidant biomarkers.

Cytokinesis-block micronucleus cytome assay parameters in peripheral blood lymphocytes of the general population: Contribution of age, sex, seasonal variations and lifestyle factors

The cytokinesis-block micronucleus cytome (CBMN Cyt) assay was used to evaluate the baseline frequency of cytogenetic damage in peripheral blood lymphocytes of the general population (average age, 38.28 ± 12.83 years) in relation to age, sex, body mass index, seasonal variations (season of sampling, period of sampling and different meteorological parameters) and lifestyle factors (smoking habit, alcohol consumption, exposure to medications and diagnostic radiation, physical activity, and family history of cancer). The background frequency of micronuclei (MNi) for the 200 subjects assayed was 5.06 ± 3.11 per 1000 binucleated cells, while the mean frequency of nucleoplasmic bridges (NPBs) was 1.21 ± 1.46 and of nuclear buds (NBUDs) 3.48 ± 2.14. The background frequency of apoptosis and necrosis was 1.58 ± 1.50 and 1.39 ± 1.56, respectively, while the mean nuclear division index (NDI) was 1.99 ± 0.14. The cut-off value, which corresponds to the 95th percentile of the distribution of 200 individual values, was 11 MNi, 4 NPBs and 7 NBUDs. The study also confirmed an association of the above mentioned parameters with age, sex and several lifestyle factors. Moreover, significant confounders based on our results are also sampling season, sampling period and different meteorological parameters that were dependent on the CBMN Cyt assay parameters. In line with the above mentioned, several factors should be taken into account when it comes to the monitoring of exposed populations using cytogenetic biomarkers. Moreover, the normal and cut-off values obtained in this study present background data for the general population, and can later serve as baseline values for further biomonitoring studies.

Environmental risk assessment of wastewaters from printed circuit board production: A multibiomarker approach using human cells

Since the production of printed circuit boards (PCBs) generates wastewater contaminated with heavy metals and organic matter, PCB factories represent potential pollution sites. The wastewater toxicologically tested in this study contained several metals and the most abundant were copper and iron. At two exposure times tested (4 and 24 h) PCB wastewater (PCBW) proved to be cytotoxic (decreased cell viability) and genotoxic (increased comet assay tail intensity and tail moment) to human blood peripheral lymphocytes in vitro, and the oxidative stress parameter (malondialdehyde concentration) was also found to be higher. After application of combined treatment by waste base, ozone and waste sludge methods, concentrations of metals in purified PCBW were below the upper permitted levels and all tested toxicological parameters did not differ compared to the negative control. Taken together, similar methods could be implemented in PCB factories before discharging potentially toxic wastewater into the environment because purified PCBW does not represent a threat from the aspect of cytotoxicity and genotoxicity.

Variation of sedimentation rate in the semi-enclosed bay determined by 137Cs distribution in sediment (Kaštela Bay, Croatia)

Purpose of this research was to study the rate at which the semi-enclosed bay such as the Kaštela Bay reacts to the coastal processes of industrialization and urbanization, the extent of the influence of human activities on the bay, and the sediment distribution affected by anthropogenic influence. Temporal and spatial sedimentation rate variations were observed between three studied periods: 1954-2005, 1963-2005/2006, and 1986-2005/2006. Sedimentation rates were in the following ranges: 0.29-0.49 cm/yr for the 1954-2005 period, 0.58-0.95 cm/yr for the 1963-2005/2006 period, and 0.50-1.32 cm/yr for the 1986-2005/2006 period. The average total sedimentation rates for three periods were 0.41 cm/yr, 0.81 cm/yr, and 0.61 cm/yr, respectively. Sedimentation rate for the individual 1963-1986 period marked with two ¹³⁷Cs marker peaks was in the 0.65-1.30 cm/yr range, while the mean value was 1.06 cm/yr. Long-term sedimentation rate increase in the whole Kaštela Bay was observed and clearly connected to the industrialization and urbanization processes in the coastal area. These processes reflect very quickly, in terms of years, in the sedimentation rates. Intensive anthropogenic activities in the coastal area are reflected in the whole bay depending on the amount of the discharged sediment material, topography of the sea bottom, and water currents. Some localized areas of sediment accumulation may form.

Toxicological and chemical assessment of arsenic-contaminated groundwater after electrochemical and advanced oxidation treatments

Owing to its proven toxicity and mutagenicity, arsenic is regarded a principal pollutant in water used for drinking. The objective of this study was the toxicological and chemical evaluation of groundwater samples obtained from arsenic enriched drinking water wells before and after electrochemical and ozone-UV-H2O2-based advanced oxidation processes (EAOP). For this purpose, acute toxicity test with Daphnia magna and chronic toxicity test with Lemna minor L. were employed as well as in vitro bioassays using human peripheral blood lymphocytes (HPBLs). Several oxidative stress parameters were estimated in L.minor. Physicochemical analysis showed that EAOP treatment was highly efficient in arsenic but also in ammonia and organic compound removal from contaminated groundwater. Untreated groundwater caused only slight toxicity to HPBLs and D. magna in acute experiments. However, 7-day exposure of L. minor to raw groundwater elicited genotoxicity, a significant growth inhibition and oxidative stress injury. The observed genotoxicity and toxicity of raw groundwater samples was almost completely eliminated by EAOP treatment. Generally, the results obtained with L. minor were in agreement with those obtained in the chemical analysis suggesting the sensitivity of the model organism in monitoring of arsenic-contaminated groundwater. In parallel to chemical analysis, the implementation of chronic toxicity bioassays in a battery is recommended in the assessment of the toxic and genotoxic potential of such complex mixtures.

Toxicological assessment and management options for boat pressure-washing wastewater

Boats are washed periodically for maintenance in order to remove biofoulants from hulls, which results in the generation of wastewater. This study aimed at evaluating the cyto/genotoxic and mutagenic properties of wastewater produced by pressure washing of boats. The chemical characterisation of this wastewater showed that Cu, Zn, V, Cr, Fe, Pb, and select organic contaminants exceeded the maximum allowable values from 1.7 up to 96 times. The wastewater produced negative effects on human lymphocytes resulting in decreased cell viability after 4 and 24h of exposure. Chromosome aberration, micronucleus, and comet assay parameters were significantly higher after 24h of exposure. At the same time, the Salmonella typhimurium test showed negative for both TA98 and TA100 strains at all of the concentrations tested. After the treatment of wastewater using electrochemical methods/ozonation during real scale treatment plant, removal rates of colour, turbidity and heavy metals ranged from 99.4% to 99.9%, while the removal of total organic carbon (TOC) and chemical oxygen demand (COD) was above 85%. This was reflected in the removal of the wastewater's cyto/genotoxicity, which was comparable to negative controls in all of the conducted tests, suggesting that such plants could be implemented in marinas to minimise human impact on marine systems.

Toxicity assessment of the water used for human consumption from the Cameron/Tuba City abandoned uranium mining area prior/after the combined electrochemical treatment/advanced oxidation

The purpose of this work was detailed physicochemical, radiological, and toxicological characterization of the composite sample of water intended for human consumption in the Cameron/Tuba City abandoned uranium mining area before and after a combined electrochemical/advanced oxidation treatment. Toxicological characterization was conducted on human lymphocytes using a battery of bioassays. On the bases of the tested parameters, it could be concluded that water used for drinking from the tested water sources must be strictly forbidden for human and/or animal consumption since it is extremely cytogenotoxic, with high oxidative stress potential. A combined electrochemical treatment and posttreatment with ozone and UV light decreased the level of all physicochemical and radiological parameters below the regulated values. Consequently, the purified sample was neither cytotoxic nor genotoxic, indicating that the presented method could be used for the improvement of water quality from the sites highly contaminated with the mixture of heavy metals and radionuclides.

The efficiency of combined CaO/electrochemical treatment in removal of acid mine drainage induced toxicity and genotoxicity

Acid mine drainage (AMD) is a by-product of the mining industry that has a detrimental effect on aquatic plant and animal life due to high load of heavy metals and sulfates. In the present study, the toxic and genotoxic potential of AMD prior to and following combination of neutralization/electrocoagulation processes was evaluated using several bioassays and selected parameters. Regardless of pH correction of AMD prior to Daphnia bioassay, high acute toxicity was observed in Daphnia magna. The mine leachate also induced strong phyto-, cyto- and genotoxicity to Allium cepa roots. Short term exposure to AMD inhibited duckweed growth and chlorophyll a content and simultaneously promoted lipid peroxidation and DNA damage despite duckweed capability to upregulate antioxidative defense mechanisms. The results show that observed (geno)toxicity could be related to oxidative stress most probably induced by toxic metal action. However, influence of low pH as a contributing factor in the phytotoxicity of AMD cannot be excluded. The application of combined treatment eliminated genotoxicity and was highly efficient in reducing toxicity of AMD. Thus, the method seems to be suitable for treatment of AMD waters enabling their safe discharge to an aquatic environment.

Toxicological characterization of the landfill leachate prior/after chemical and electrochemical treatment: a study on human and plant cells

In this research, toxicological safety of two newly developed methods for the treatment of landfill leachate from the Piškornica (Croatia) sanitary landfill was investigated. Chemical treatment procedure combined chemical precipitation with CaO followed by coagulation with ferric chloride and final adsorption by clinoptilolite. Electrochemical treatment approach included pretreatment with ozone followed by electrooxidation/electrocoagulation and final polishing by microwave irradiation. Cell viability of untreated/treated landfill leachate was examined using fluorescence microscopy. Cytotoxic effect of the original leachate was obtained for both exposure periods (4 and 24 h) while treated samples showed no cytotoxic effect even after prolonged exposure time. The potential DNA damage of the untreated/treated landfill leachate was evaluated by the comet assay and cytokinesis-block micronucleus (CBMN) assay using either human or plant cells. The original leachate exhibited significantly higher comet assay parameters compared to negative control after 24 h exposure. On the contrary, there was no significant difference between negative control and chemically/electrochemically treated leachate for any of the parameters tested. There was also no significant increase in either CBMN assay parameter compared to the negative control following the exposure of the lymphocytes to the chemically or electrochemically treated landfill leachate for both exposure periods while the original sample showed significantly higher number of micronuclei, nucleoplasmic bridges and nuclear buds for both exposure times. Results suggest that both methods are suitable for the treatment of such complex waste effluent due to high removal efficiency of all measured parameters and toxicological safety of the treated effluent.

Assessment of surface water in the vicinity of fertilizer factory using fish and plants

The genotoxic and toxic potential of polluted surface water exposed to a fertilizer factory effluent was evaluated using assays with fish (Cyprinus carpio) and plant (Lemna minor) model organisms. Beside classical physicochemical parameters, the contents of fluorides, some heavy metals and polycyclic aromatic hydrocarbons were analyzed as well. Surface water caused inhibition of plant growth and decrease of photosynthetic pigment content. Regarding DNA damage and oxidative stress parameters, both fish and plants showed similar response to the surface water. In confirmation to biochemical markers, histopathological analysis of gill and liver tissues revealed a higher incidence of lesions in fish exposed to polluted surface water. Generally, results obtained by biological monitoring were mostly in agreement with chemical analysis of the surface water, although several discrepancies were observed which might be due to difference in sensitivity of model organisms or in experimental conditions (laboratory and field exposure). The results imply that conventional chemical analysis should be extended to genotoxicity/toxicity assays as measured biological effects and the potential health hazard cannot be predicted based on the physicochemical characteristics of water samples alone.

Cytogenetic status of healthy children assessed with the alkaline comet assay and the cytokinesis-block micronucleus cytome assay

In the present study the alkaline comet assay and the cytokinesis-block micronucleus cytome (CBMN Cyt) assay were used to evaluate the baseline frequency of cytogenetic damage in peripheral blood lymphocytes (PBLs) of 50 healthy children from the general population in Croatia (age, 11.62±1.81 years). Mean values of tail length, tail intensity and tail moment, as comet assay parameters, were 12.92±0.10, 0.73±0.06 and 0.08±0.01, respectively. The mean frequency of micronuclei (MN) for all subjects was 2.32±0.28 per 1000 bi-nucleated cells, while the mean frequency of nucleoplasmic bridges (NPBs) was 1.72±0.24 and of nuclear buds (NBUDs) 1.44±0.19. The mean nuclear division index (NDI) was 1.70±0.05. When comet-assay parameters were considered, higher mean values for all three were found for the female population. According to the Mann-Whitney U test applied on the results of the comet assay, the only statistically significant difference between the male and female populations was found for tail length. Similar to the results obtained by the comet assay, girls showed higher mean values of all three measured parameters of the CBMN Cyt assay. This difference was statistically significant for total number of NPBs only. In the case of the NDI, a higher mean value was also obtained in girls, but this difference was not statistically significant. The results obtained present background data that could be considered as normal values for healthy children living in urban areas, and can later on serve as baseline values for further toxicological monitoring. Additionally, the usefulness of both techniques in measuring cytogenetic damage during bio-monitoring of children is confirmed.

Chemical composition and genotoxicity assessment of sanitary landfill leachate from Rovinj, Croatia

Chemical analysis and an in vitro approach were performed to assess elemental composition and genotoxic effects of the samples of landfill leachate taken from Lokva Vidotto sanitary landfill the official landfill for Rovinj town, Croatia. Two samples of landfill leachate were collected and analyzed in order to evaluate macro, micro and trace elements by atomic absorption spectroscopy, energy dispersive X-ray spectrometry and colorimetry. Genotoxicity of sanitary landfill leachate was evaluated in human lymphocytes by the use of the micronucleus test and comet assay. Samples were characterized with relatively low concentrations of heavy metals while organic component level exceeded upper permissible limit up to 39 times. Observed genotoxic effects should be connected with high concentrations of ammonia nitrogen, which exceeded permissible limit up to 180 times. Leachate samples of both sanitary landfills increased the frequency of micronuclei, nucleoplasmic bridges and nuclear buds. Increase of DNA damage in human lymphocytes was also detected by virtue of measuring comet assay parameters. All parameters showed statistically significant difference compared to negative control. Increased micronucleus and comet assay parameters indicate that both samples of sanitary landfill leachate are genotoxic and could pose environmental and human health risk if discharged to an aquatic environment.

Chemical and toxicological characterization of the bricks produced from clay/sewage sludge mixture

The present study aimed to characterize chemical properties of clay bricks containing 20 % of sewage sludge. After detection of potentially hazardous metals, we simulated precipitation exposure of such material to determine the amount of heavy metals that could leach out of the bricks. Metals, such as copper, zinc, nickel, cobalt, chromium, etc., were detected in leachate in low concentrations. Moreover, human peripheral blood lymphocytes were exposed to brick leachate for 24 h in order to evaluate its possible negative impact on human cells and genome in vitro. Cytotoxicity tests showed no effect on human peripheral blood lymphocytes viability after exposure to brick's leachate. On the contrary, the alkaline comet assay showed slight but significant increase in DNA damage with all three parameters tested. As we might predict, interactions of several heavy metals in low concentrations could be responsible for DNA damaging effect. In that manner, our findings suggest that leachates from sewage sludge-produced bricks may lead to adverse effects on the exposed human population, and that more stabile bricks should be developed to minimize leaching of heavy metals into the environment. Bricks with lower percentage of the sludge may be one of the solutions to reduce the toxic effect of the final product.

Chemical and radiological characterization of fly and bottom ash landfill of the former sulfate pulp factory Plaški and its surroundings

The subject of this study was chemical and radiological characterization of the fly and bottom ash, by-product of the combustion of coal used as an energy source in the former sulfate pulp factory in Plaški. The research involves determination of the concentration of macro, micro and trace elements and activities of the radionuclides in: (i) ash from different positions of the landfill; (ii) soil samples in the zone of the influence of the landfill; (iii) control soil samples and (iv) sediment sample from the river Dretulja. Besides, in situ measurement of an effective dose rate above ash/soil was also determined. In relation with the control soil the average increase of the concentrations of the elements Ca, Cd, Hg, Ni, Se, Sr, Th and U in the samples taken from the fly and bottom ash landfill as well as soil samples within the radius of 300 m from the landfill was 38.3, 6.7, 9.9, 8.5, 9.4, 7.2, 3.6 and 5.7 times, respectively. In these samples, the concentrations of the above mentioned elements were in the following ranges: calcium from 7.94 to 19.7 %; cadmium from 0.33 to 1.66 mg/kg; mercury from 0.18 to 0.49 mg/kg; nickel from 260 to 1500 mg/kg; selenium from 2.7 to 21 mg/kg; strontium from 176 to 542 mg/kg; thorium from 8 to 55 mg/kg and uranium from 5.6 to 19.7 mg/kg. Compared to the world's average soil concentration, uranium and thorium values increased 3.7 and 1.7 times, respectively. The mean value of the total effective dose rate measured in the air at the height of 1 m for all samples of ash and soil under the influence of the landfill was 1.60 mSv/yr. Compared to the Croatian average (0.7015 mSv/yr), the determined mean value for the Plaški landfill is two times higher. However, compared to the local background (0.14 mSv/yr), the mean value of the total effective dose rate measured above the Plaški landfill is 11.4 times higher. In the samples of ash and contaminated soil regardless of the sampling location the activity concentrations of the radionuclides in Bq/kg vary in the following ranges: (226)Ra from 82.10 to 314.90 (mean value 145.99), (232)Th from 32.50 to 223.60 (mean value 76.76) and (238)U from 69.10 to 243.20 (mean value 134.38). Compared to the mean values found in the background soil (226)Ra and (238)U mean activity concentrations increased from 1.6 to 6.4 times and (232)Th from 1.4 to 4.3 times. In order to reduce total effective dose rate to the local "background" values and to prevent redistribution of the radionuclides and heavy metals from the deposited material into the environment fly and bottom ash landfill must be sealed with 10 cm thick layer of the material with low permeability.

Cytogenotoxicity of sewage sludge leachate before and after calcium oxide-based solidification in human lymphocytes

Present study aimed to establish the chemical composition of sewage sludge leachate before/after calcium oxide-based solidification using energy dispersive X-ray fluorescence (EDXRF). The other aim was to determine leachate effects on human lymphocyte and DNA integrity in vitro using a battery of bioassays (DNA diffusion assay, micronucleus test and comet assay) to determine effects of those complex mixtures of elements on cell and DNA integrity. EDXRF showed that nickel concentration in the leachate of untreated sludge was 18.5 times higher than the upper permissible limit for inert waste landfills. Other elements were kept below the permissible values. After sludge solidification, leachate concentrations of Cr, Mn, Fe, Ni, Cu, Zn, and Pb dropped 1.6, 2.7, 37, 5.9, 3.2, 7.8, and 2.6 times, respectively. Untreated sludge leachate was cytogenotoxic to lymphocytes, and may lead to adverse effects on the exposed human populations, but calcium oxide-based solidification reduced these effects in significant manner.

Correlation between folate and vitamin B₁₂ and markers of DNA stability in healthy men: preliminary results

The aim of this study was to find correlations between folate and vitamin B₁₂ on baseline damage in white blood cells and their association with smoking, alcohol consumption and ageing. Thirty-six healthy vitamin non-deficient male subjects were selected in a randomized study. Comet assay (SCGE) and micronucleus (MN) assay were used as biomarkers of DNA damage. The amount of DNA damage was correlated with vitamin B₁₂ and folic acid concentration. Positive, but non-significant correlation (canonical R = 0.61; χ²=28.97; P=0.253) was found between micronucleus (MN) frequency or comet assay parameters (SCGE) and five covariates (age, smoking, alcohol consumption, vitamin B₁₂ and folate blood serum concentration). The highest MN frequency was observed in the group with the lowest vitamin B₁₂ concentration (F=3.59; P=0.024). The SCGE assay failed to show significant correlation with vitamin B₁₂ or folic acid concentration. Concentration of vitamin B₁₂ was significantly correlated with incidence of micronuclei. Our results present background data that could be valuable for future genotoxicological monitoring.

Correlation between folate and vitamin B₁₂ and markers of DNA stability in healthy men: preliminary results

The aim of this study was to find correlations between folate and vitamin B₁₂ on baseline damage in white blood cells and their association with smoking, alcohol consumption and ageing. Thirty-six healthy vitamin non-deficient male subjects were selected in a randomized study. Comet assay (SCGE) and micronucleus (MN) assay were used as biomarkers of DNA damage. The amount of DNA damage was correlated with vitamin B₁₂ and folic acid concentration. Positive, but non-significant correlation (canonical R = 0.61; χ²=28.97; P=0.253) was found between micronucleus (MN) frequency or comet assay parameters (SCGE) and five covariates (age, smoking, alcohol consumption, vitamin B₁₂ and folate blood serum concentration). The highest MN frequency was observed in the group with the lowest vitamin B₁₂ concentration (F=3.59; P=0.024). The SCGE assay failed to show significant correlation with vitamin B₁₂ or folic acid concentration. Concentration of vitamin B₁₂ was significantly correlated with incidence of micronuclei. Our results present background data that could be valuable for future genotoxicological monitoring.