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Here we describe an additional type of bacterial migration in which bacterial cells migrate vertically across a non-nutritive solid surface carried by capillary forces. Unlike standard motility experiments, these were run on a glass slide inserted into a Falcon tube, partly immersed in a nutrient medium and partly exposed to air. Observations revealed that capillary forces initiated upward cell migration when biofilm was formed at the border between liquid and air. The movement was facilitated by the production of extracellular polymeric substances (EPS). This motility differs from earlier described swarming, twitching, gliding, sliding, or surfing, although these types of movements are not excluded. We therefore propose to call it “capillary movement of biofilm”. This phenomenon may be an ecologically important mode of bacterial motility on solid surfaces.

Due to the development of resistance to antimicrobial agents, bacterium Acinetobacter baumannii is nowadays a leading cause of nosocomial outbreaks. Clinically relevant A. baumannii outside hospital settings including natural soils affected by human waste represents a public-health risk for humans and animals. The aim of this study was to investigate the potential of metal-loaded zeolites to eliminate viable A. baumannii from artificially contaminated natural soils. A. baumannii isolate was subjected to the activity of natural zeolitised tuff (NZ) and Cu-modified (CuNZ) or Ag-modified zeolite (AgNZ) in wet, slightly acidic terra rossa and slightly alkaline red palaeosol. A. baumannii survived in terra rossa and red palaeosol supplemented with 1 wt% of NZ for seven days and four months, respectively. The addition of 1 wt% of CuNZ to terra rossa and red palaeosol shortened the survival of A. baumannii to three and 14 days, respectively. The addition of 0.1 wt% of AgNZ to both soils resulted in complete removal of viable A. baumannii within 1 h of contact, while the total native heterotrophic bacterial counts remained high. Since AgNZ is prepared with a simple modification of cost-effective and environmentally friendly natural zeolite, it is a promising material for the remediation of soils contaminated with pandrug-resistant A. baumannii.

The multidrug resistant bacteria Acinetobacter baumannii cause serious hospital infections. Commercial poly(vinyl chloride) (PVC) used for endotracheal tubes was modified in order to obtain the composite with antibacterial effect towards clinical isolate of A. baumannii ST145. The composites were prepared by addition of different amounts of copper-containing zeolite tuff (CuZ) and by successive impregnation with D-Tyrosine (D-Tyr) solution. The composites which were obtained by addition of CuZ (CuZ-PVC) only did not exhibit antibacterial effect. The impregnation of the CuZ-PVC by D-Tyr resulted in an antibacterial effect which is explained by a synergistic effect of CuZ and D-Tyr. Rheological tests confirmed that the modification of PVC by CuZ does not affect its processability and reformability. [Projekat Ministarstva nauke Republike Srbije, br. 172018]

Wastewaters of the wood processing into groundwood are characterized by increased concentrations of organic contaminants (oils, resin acid, lignin (polymeric phenols), lignin salts (sulphonates, phenoxides), tannins, triglycerides, waxes, free long-chained fatty acids and other). Organic compounds which appear as colour come from extracted lignin, tannins and resin acids. Wood processing effluents are often resistant to degradation using biological methods, and are not removed effectively by conventional physicochemical treatment methods, such as coagulation/flocculation, sedimentation, filtration and ozonation. For processing of those effluents it is often necessary to link different methods of purification, and one of the alternative methods is sorption. In this work the removal of organic pollutants was tested from effluent of the production of mechanically milled groundwood by using sorption to clinoptilolite tuff and to samples of tuff which were modified using the solutions of cationic surfactant- hexadecyltrimethylammonium bromide (HDTMA-Br) of different concentrations. The sorption processes of hexadecyltrimethylammonium bromide were researched on the clinoptilolite tuff from Turkey (Aegean Region Turkey, Bigadic), which contains more than 70 % of clinoptilolite, and in smaller mass fraction quartz and opal-CT are present. The tested effluent has the following characteristics: chemical oxygen demand (COD): 13200 mg dm-3, total organic carbon (TOC): 3010 mg dm-3, biochemical oxygen demand (BOD5): 470 mg dm-3, colour: 681 Pt Co, turbidity: 799 NTU, pH 4.8. All testing was done without the adjustment of pH. The conventional process of pre-processing of effluent by coagulation with aluminum chloride hexahydrate (AlCl3·6H2O) was tested and the application ofHDTMA-modified clinoptilolite tuff with the intention of further decrease in organic burden of wastewater. In the Fig. 1A the results of the HDTMA uptake onto clinoptilolite tuff are shown, and in Fig. 1B the pertaining zeta potentials of the samples are shown. HDTMA cations were essentially quantitatively taken up by the clinoptilolite tuff up to loading level of L = 0.204 mmol g-1-(Fig. 1A). The results of the zeta potential measurements show that the negative surface charge changed to positive after modification with surfactant solutions (Fig. 1B). HDTMA cations form a stable organophilic coating on the clinoptilolite surface, and above surfactant loading level of 0.110 mmol g-1(isoelectric point), a second layer of HDTMA+ cations reverses the surface charge into positive. The optimal mass concentration of coagulant AlCl3·6H2O for the tested wastewater is γ = 0.8 g dm-1(Figs. 2A and 2B). Zeta potential of the solution above sediment received by coagulation with AlCl3·6H2O of mass concentration γ= 0.8 g dm-3 is ζ= -3.92 mV. The efficiency of removing the turbidity (Table 1) and COD is η = 67 % (from 799 to 263 NTU) and 54% (from 13 200 to 6 040 mg dm-3). The efficiency of removing solved organic carbon and colour is significantlylesser: 22.7% (from 3010 to 2322 mg dm-3) and η = 33.0 % (from 681 to 457 Pt Co). By processing the solutions received after coagulation with AlCl3·6H2O of mass concentration of 0.8 g dm-3, with natural tuff and organo-zeolites whose loading are: 0.074; 0.123; 0.164 and 0.204 mmol g-1 HDTMA, TOC was decreased from γ=2322 mg dm-3 to the following: γ=2042, 1976, 1945, 1907 and 1821 mg dm-3 and was sorbed: q = 28.0; 34.6; 37.7; 41.5; and 50.1 mg g-1 TOC (Fig. 3A). Using the sample of organo-zeolite with loading of 0.204 mmol g-1 HDTMA, the efficiency of removing the organic carbon was improved from η= 22.7 % to 40.0 %. The efficiency of discolouring the tested solutions also increases with the change of the surface charge of organo-zeolites from negative to positive(Fig. 3B). The efficiency of removing the colour by using the natural tuff was improved from η= 33.0 % to η = 40.0 %, and by using the organo-zeolite with loading of L = 0.204 mmol g-1 HDTMA to η= 76.3 %. In order for the biodegradation of the processes effluents to be tested, the rations of BOD5/COD are predetermined (Figs. 4A and 4B). According to literature data, the good value of biodegradation is the ratio of BOD5/COD higher than 0.5. The tested effluent was characterized as having particularly poor biodegradation. After processing the effluent with coagulation and organo-zeolite (0.204 mmol g-1 HDTMA), the biodegradation has not shown significant improvement. It could be concluded that HDTMA-modified clinoptilolite tuff can be used for discolouring and purification of the examined wastewater in one part of wastewater treatment which combines and some other physicochemical and/or biological purification methods.

Adsorptive, catalytic, and antibacterial properties of clinoptilolite-rich tuffs (ZT) are presented here. ZT transformed into Fe-containing ZT (Fe-ZT) removes various organic and inorganic anions from water. Fe-ZT, which contains selenium, is beneficial for growing Pleurotus ostreatus mushrooms. The fungi convert inorganic Se from Fe-ZT into a more useful organically bonded form. ZT and Fe-ZT as supplements retain nitrogen and potassium in sandy, silty loam and silty clay soils. ZT shows an affinity toward toxic metal cations, which are essential for cleaning contaminated water. The adsorption of atenolol, acetylsalicylic, and salicylic acid onto M-ZT (M-Cu 2+ , Mn 2+ , Ni 2+ , or Zn 2+ ) from water solutions suggests that both the natures of M and pharmaceuticals have a significant impact on the adsorption mechanism and determine the adsorption capability of the ZT. ZT is an excellent carrier for ultrafine (2-5 nm) nano oxide particles, which have been shown to have catalytic activity in different chemical processes and photodegradation reactions of organic pollutants. ZT can also be transformed into SO 4 -SnO 2 -ZT, which is catalytically active as a solid acid. M-ZT is an effective carrier of valuable bacteria. Ag-ZT possesses beneficial bactericidal activity in disinfecting water and soil remediation.

The aim of this study was to find the source of Acinetobacter baumannii in the intensive care unit (ICU) after an outbreak during the coronavirus disease 2019 (COVID-19) pandemic, as there was no A. baumannii detected on usually screened susceptible surfaces. The screening of the ICU environment was done in April 2021 when eleven different samples were taken. One A. baumannii isolate was recovered from the air conditioner and was compared with four clinical A. baumannii isolates obtained from patients hospitalized in January 2021. Isolates were confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), minimum inhibitory concentrations (MICs) were determined, and the multilocus sequence typing (MLST) was performed. The molecular identification of A. baumannii isolates as ST208, the presence of the same bla OXA-23 carbapenemase gene, and the same antibiotic susceptibility profile suggest that the isolate recovered from the air conditioner is the same as the isolates recovered from hospitalized patients. The environmental isolate was recovered three months later than the clinical isolates, emphasizing the ability of A. baumannii to survive on dry abiotic surfaces. The air conditioner in the clinical environment is an important but undoubtedly neglected source of A. baumannii outbreaks, hence, frequent disinfection of hospital air conditioners with appropriate disinfectants is mandatory to mitigate the circulation of A. baumannii between patients and the hospital environment.

For a long time, the production and processing of cowhide was based on the use of chrome tanning. However, the growing problem with chromium waste and its negative impact on human health and the environment prompted the search for more environmentally friendly processes such as vegetable tanning or aldehyde tanning. In the present study, we investigated the DNA-damaging effects induced in HepG2 cells after 24 h exposure to leather samples (cut into 1 × 1 cm 2 rectangles) processed with different tanning agents. Our main objective was to determine which tanning procedure resulted in the highest DNA instability. The extent of treatment-induced DNA damage was determined using the alkaline comet assay. All tanning processes used in leather processing caused primary DNA damage in HepG2 cells compared to untreated cells. The effects measured in the exposed cells indicate that the leaching of potentially genotoxic chemicals from the same surface is variable and was highest after vegetable tanning, followed by synthetic tanning and chrome tanning. These results could be due to the complex composition of the vegetable and synthetic tanning agents. Despite all limitations, these preliminary results could be useful to gain a general insight into the genotoxic potential of the processes used in the processing of natural leather and to plan future experiments with more specific cell or tissue models.

Bacterium Acinetobacter baumannii is a leading cause of nosocomial infections. The occurrence of antibiotic-resistant A. baumannii isolates outside hospitals suggests that monitoring of this pathogen in environmental samples is needed. Survival of pandrug-resistant A. baumannii was followed on selective plates with and without carbapenems in water and soil. After a few days of starvation, A. baumannii lost the ability to be cultivated at 44°C on plates supplemented with carbapenems. Once cultivated on plates without carbapenems and/or at 36°C, A. baumannii could grow again at 44°C in the presence of carbapenems. Comparative proteomic analysis revealed that impaired membrane integrity and reduced function of efflux pumps due to elevated temperature combined with antibiotic exposure were the main reasons for this phenomenon. Loss of thermotolerance in the presence of antibiotics points to the need for temperature adjustment in long-term monitoring of A. baumannii in environmental samples, to avoid the underestimation of viable bacteria.

Increasingly difficult treatment of multidrug-resistant (MDR) bacteria has become a global problem of the 21st century. Within a group of multiresistant bacteria, the Acinetobacter baumannii convincingly occupies the position at the top of the group designated as ESKAPE pathogens. In this study, 61 isolates of A. baumannii were recovered from different samples originating from various departments of the University Clinical Hospital Mostar during 2018. All of the isolates were identified using conventional phenotypic methods and the VITEK ® 2 Compact System, and were confirmed by MALDI-TOF mass spectrometry. The minimum inhibitory concentrations (MICs) were determined by the microbroth dilution method using MICRONAUT-S MDR MRGN-Screening and VITEK 2 Compact System. All strains were resistant to carbapenems and classified in eight different resistotypes according to their antibiotic resistance and macrorestriction pulsed-field gel electrophoresis profiles, with all belonging to IC II. One isolate displayed resistance to colistin (MIC ≥16 mg/L). The presence of bla OXA genes encoding OXA-type carbapenemases was investigated by multiplex PCR and the Eazyplex ® SuperBugAcineto system and showed 100% compatibility with the detection of acquired oxacillinases. Molecular characterization of the isolates tested in this study revealed the OXA-23- and OXA-40-like groups of acquired oxacillinases. Sequencing of two PCR products of the OXA-40-like group confirmed the presence of OXA-72. Survival assays with two selected isolates of A. baumannii encoding different mechanisms of carbapenem resistance revealed that one isolate was able to survive on a fragment of white laboratory coat during 90 days of monitoring. To the best of our knowledge, this is the first article to present the results of a comprehensive phenotypic, genotypic, and molecular analysis of A. baumannii isolates from the leading clinical hospital center in the southwestern part of Bosnia and Herzegovina, including data for the survival of this pathogen on the white laboratory coats used as compulsory medical clothing.

The order of magnitude of increased growth, multiplication rate, and decreased sporulation of Bacillus subtilis after exposure to nanotesla magnetic fields (MFs) relative to control samples were observed experimentally. Earth's total magnetic field intensity was reduced from 47.9 ± 0.4 μT to cover the range from 97.5 ± 1.7 nT to 1115 ± 158 nT in eight subsequent experiments by using three pairs of Helmholtz coils combined with Mu-metal shielding. The growth, multiplication rate, sporulation, and potassium content were measured in the probe and control containing B. subtilis cultures after 24 h of exposure to nanotesla and Earth's magnetic fields, respectively. The observed effect is discussed with regard to its possible repercussions on Earth's living species during geomagnetic reversals that occurred when the magnetic field was much weaker than the field that exists today. In addition, effects on future manned voyages into deep space, an environment with reduced magnetic field intensity, are considered.

Novel hyper-resistant bacteria were isolated from the Crven Dol mine (Allchar, North Macedonia), arsenic-rich extreme environment. Bacteria were recovered from a secondary mineral mixture, an alteration of hydrothermal realgar rich in arsenates (pharmacolite, hornesite, and talmessite). The sample was recovered from the dark part of the mine at 28 m depth. Three bacterial strains and a bacterial consortium were isolated for their capacity to survive exposure to 32 g/L (209 mM) of arsenite, and 176 g/L (564 mM) of arsenate. The 16S rRNA gene analysis identified bacterial isolates as Stenotrophomonas sp. and two Microbacterium spp. This analysis also revealed that bacterial consortium comprise two Bacteriodetes exhibiting similarity to Olivibacter ginsengisoli and to uncultured bacterium, and one γ-proteobacteria with similarity to Luteimonas sp. Among all isolates Stenotrophomonas sp. exhibited the highest tolerance to As compound as well as the capacity to accumulate As inside the cells. Analysis of genes involved in As-resistance showed that recovered isolates possess the genes encoding the ArsB, Acr3(1) and Acr3(2) proteins, indicating that at least a part of their resistance could be ascribed to As-efflux systems described in isolates obtained from human-polluted environments., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A mercury-resistant bacterial strain has been isolated from a rock of the Idrija mercury mine in Slovenia. The rock had 19 g carbon and 2952 mg mercury (Hg) per kg. Mass spectrometry and DNA sequencing showed that the bacterium belongs to the Pseudomonas genus. It is called Pseudomonas idrijaensis. This bacterial strain is sensitive to methylmercury (MeHg) like the reference P. aeruginosa strain PAO1, and is resistant to divalent mercury (Hg(II)) in contrast to PAO1. This difference could be attributed to the presence of the mer operon yet deprived of the merB gene encoding the organomercurial lyase, on the basis of whole genome sequencing. The P. idrijaensis mer operon displays the RTPCADE organization and is contained in the Tn5041 transposon. This transposon identified here occurs in other Gram-negative Hg-resistant strains isolated from mercury ores, aquatic systems and soils, including Pseudomonas strains from 15,000 to 40,000 years old Siberian permafrost. When P. idrijaensis was exposed to mercury chloride, two intracellular Hg species were identified by high energy-resolution XANES spectroscopy, a dithiolate Hg(SR) 2 and a tetrathiolate Hg(SR) 4 complex. P. idrijaensis had a much higher [Hg(SR) 2 ]/[Hg(SR) 4 ] molar ratio than bacteria lacking the mer operon when exposed to 4 μg Hg 2+ /L - resulting in an intracellular accumulation of 4.3 μg Hg/g dw. A higher amount of the Hg(SR) 2 complex provides a chemical signature for the expression of the dicysteinate Mer proteins in response to mercury toxicity., Competing Interests: Declaration of competing interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In the previous studies OXA-23-like and OXA-24-like β-lactamase were reported among Acinetobacter baumannii in both hospitals and long-term care facilities (LTCF) in Croatia. The aim of this study was to analyze clinical and sewage A. baumannii isolates from two nursing homes in Zagreb, with regard to antibiotic susceptibility and resistance mechanisms, to determine the route of spread of carbapenem-resistant isolates. Nine clinical isolates were collected from February to May 2017 whereas in April 2017, ten A. baumannii isolates were collected from sewage of two nursing homes in Zagreb. Antibiotics susceptibility was determined by broth microdilution method. The presence of carbapenemase and extended spectrum β-lactamases (ESBL) encoding genes was explored by PCR. Conjugation and transformation experiments were performed as previously described. Genotyping was performed by SG determination, PFGE and MLST. Seven clinical isolates were positive for bla OXA24-like whereas two clinical and environmental carbapenem-resistant isolates, respectively, were found to possess bla OXA-23-like genes. Attempts to transfer imipenem resistance were unsuccessful indicating chromosomal location of bla OXA-23 gene. All carbapenem-resistant isolates belonged to SG- 1 (IC-2) whereas the rest of the isolates susceptible to carbapenems were allocated to SG- 2 (IC-1). PFGE analysis revealed low degree of genetic variability within both IC- I and IC- II. MLST corroborated that two environmental OXA-23 isolates belong to the ST-195. This study showed dissemination of OXA-23 producing A. baumannii from the nursing home into the urban sewage. Disinfection of nursing home sewage should be recommended in order to prevent the spread of resistance genes into the community sewage.

Acinetobacter baumannii is an opportunistic pathogen causing infections in immunocompromised patients. Recent studies recorded its persistence in a variety of abiotic conditions, but data regarding the biotic interactions with other microorganisms are limited. The aim was to assess the interaction of clinically relevant A. baumannii with common faecal bacteria Escherichia coli and Enterococcus faecium. Additionally, the interaction with a bdelloid rotifer Adineta vaga as a potential agent for biological control of A. baumannii was examined. Experiments were conducted in nutrient-poor spring water (SW) and nutrient-rich diluted nutrient broth (DNB) at 22 °C. A. baumannii coexisted with E. coli and E. faecium in both media, suggesting the absence of inter-bacterial competition in long-term survival. No difference in the survival of pandrug-resistant, extensively drug-resistant or antibiotic sensitive isolates of A. baumannii was observed. Rotifers contributed to the removal of all tested bacteria, particularly in SW. Rotifers were able to remove 5.5 ± 1.3 log CFU/mL of A. baumannii in SW and 3.5 ± 1.7 log CFU/mL in DNB. Additionally, no intracellular growth of A. baumannii inside A. vaga was detected. In wastewater treatment plants and drinking water facilities, grazing by rotifers might be useful for the removal of emerging human pathogens such as A. baumannii from water.

Bacterium Acinetobacter baumannii is an emerging human pathogen whose presence in the aquatic environment raises the issue of public health risk. Fish colonization represents the potential route of pathogen transmission to humans. The aim was to examine the colonization of A. baumannii to freshwater fish Poecilia reticulata. An extensively drug-resistant A. baumannii was tested at three concentrations in natural spring water. Additionally, 70 fish from the Sava River (Croatia) were screened for the presence of A. baumannii, which was not found in gill swabs or analysed gut. The colonization potential of A. baumannii in freshwater fish is dependent upon its concentration in surrounding water. The low concentration of A. baumannii in natural waters represents low colonization potential of freshwater fish. The risk for public health exists in closed water bodies where there is constant inflow of water polluted by A. baumannii in concentrations above 3 log CFU mL -1 .

The aim of this study was to determine the susceptibility of hospital and environmental Acinetobacter baumannii isolate biofilms on ceramics and glass to common disinfectants benzalkonium chloride and chlorhexidine. For this purpose we developed a new method for biofilm cultivation and quantification on ceramics. The biofilm bacteria were more resistant to disinfectants than the planktonic populations, as more than 50 % of the biofilm population and none of the planktonic population survived 5-minute exposure. Furthermore, biofilm populations on ceramic tiles were significantly more resistant than those on glass coverslips, even though the amount of biofilm was practically the same on ceramics and glass. The reason for reduced susceptibility of A. baumannii biofilms on ceramics may be related to surface/disinfection interactions. Our findings suggest that biofilms on ceramic surfaces can be an important source of A. baumannii infection in hospital environments.

Background: Acinetobacter baumannii is one of the most prevalent causes of severe hospital-acquired infections and is responsible for the dramatic increase in carbapenem resistance in Croatia in the last 5 years. Such data have encouraged multicenter research focused on the organism's ability to form biofilm, susceptibility to antibiotics, and particular genotype lineage., Methods: Biofilm formation in 109 unrelated clinical isolates of A. baumannii recovered in six cities of Southern Croatia was investigated. Genotyping was performed by pulsed-field gel electrophoresis and antibiotic profile was tested by applying the disc diffusion method and confirmed by determining the minimum inhibitory concentrations. The ability to form biofilm in vitro was determined from overnight cultures of the collected isolates on microtiter plates, after staining with crystal violet, and quantified at 570 nm after solubilization with ethanol. The statistical relevance was calculated in an appropriate program with level of statistical confidence., Results: There was no significant difference in biofilm formation due to the genotype lineage. Isolates collected from intensive care units (ICUs) and isolated from respiratory samples were more likely to create a biofilm compared with isolates from other departments and other samples. There was a significant difference in the ability to produce biofilm in relation to antibiotic resistance pattern. A large proportion of A. baumannii isolates that were resistant to ampicillin/sulbactam, carbapenems, and amikacin were found to be biofilm-negative. In contrast, isolates susceptible and intermediately susceptible to ampicillin/sulbactam, carbapenems, and amikacin were biofilm producers., Conclusion: Clinical isolates of A. baumannii from respiratory samples in ICUs with a particular susceptibility pattern are more prone to form biofilm.

Wood fly ash is an industrial by-product of the combustion of different wood materials and is mostly disposed of as waste on landfills. In our preliminary experiments, wood ash exhibited antibacterial activity against urban wastewater bacteria and we focused on wood fly ash as a potential substrate for wastewater disinfection. The addition of ash at a concentration of 10 g L⁻¹ (1%) caused an instant increase of pH in urban wastewater and landfill leachate. High pH (10.1-12.7) inactivated bacterial populations in the wastewater and the removal of faecal coliforms and intestinal enterococci after 6 h of contact was 100% (below the detection limit; <1 CFU per mL) with the most efficient ash sample (ash from combustion of beech) both in urban wastewater and landfill leachate. Properly chosen wood fly ash, i.e. one that tends to increase the pH to the greatest extent, proved to be a very effective disinfection substrate. Considering that water treated with wood ash has a high pH and needs to be neutralised before discharge, ash would be suitable for disinfection of leachates when smaller volumes are treated.

Intense industrial development has been accompanied by the production of wastewaters of very complex content, which pose a serious hazard to the environment, put at risk sustainable development, and call for new treatment technologies that would more effectively address the issue. One particular challenge in terms of science and technology is how to biodegrade xenobiotics such as azo dyes, which practically do not degrade under natural environmental conditions. These compounds tend to bioaccumulate in the environment, and have allergenic, carcinogenic, mutagenic, and teratogenic properties for humans. Removal of azo dyes from effluents is mostly based on physical-chemical methods. These methods are often very costly and limited, as they accumulate concentrated sludge, which also poses a significant secondary disposal problem, or produce toxic end-products. Biotechnological approach may offer alternative, lowcost biological treatment systems that can completely biodegrade and detoxify even the hard-to-biodegrade azo dyes.

Surfactants are a diverse group of chemicals that are best known for their wide use in detergents and other cleaning products. After use, residual surfactants are discharged into sewage systems or directly into surface waters, and most of them end up dispersed in different environmental compartments such as soil, water or sediment. The toxic effects of surfactants on various aquatic organisms are well known. In general, surfactants are present in the environment at levels below toxicity and in Croatia below the national limit. Most surfactants are readily biodegradable and their amount is greatly reduced with secondary treatment in wastewater treatment plants. The highest concern is the release of untreated wastewater or wastewater that has undergone primary treatment alone. The discharge of wastewater polluted with massive quantities of surfactants could have serious effects on the ecosystem. Future studies of surfactant toxicities and biodegradation are necessary to withdraw highly toxic and non-biodegradable compounds from commercial use and replace them with more environmentally friendly ones.

In a cross-sectional study of growth, 5,260 healthy children of both sexes from Zagreb (Croatia) aged 2 to 18 years were measured. Six transversal body dimensions were studied: biacromial, transverse chest, antero-posterior chest, biiliocristal, bicondylar humerus and bicondylar femur diamters. A significant increase in body diameters has been observed until the age of 14 to 15 in girls and until the age of 16 in boys, showing that girls have a 1 to 2 years shorter period of growth. Compared to boys of the same age, they achieved larger amounts of final transversal bone size throughout the whole growth period. The most pronounced example was the knee diameter that in girls attained 95% of adult size as early as the age of 10. In both genders, the adult size is achieved earlier in widths of the extremities than in those of the trunk. The studied transversal body segments showed different growth dynamics, which is gender-specific. While sexual dimorphism in pelvic and shoulder diameters emerged with pubertal spurt, gender differences in chest and extremities' diameters started early in life. In all ages, boys had larger chest, elbow and knee diameters. In pubertal age boys gained a significantly larger biacromial diameter (from the age of 13 onwards), while girls exceeded them in biiliocristal diameter (from 10 to 14 years). The findings of gender differences were compared to those reported for other European populations and their growth patters were discussed comparing viewpoints.

In a cross-sectional study of growth, 5,155 children (2,591 females, 2,564 males) from the town of Zagreb (Croatia) were measured. Four traits of linear dimensionality (stature, sitting height, arm and leg lengths) were studied in the age span of 3 to 18 years. A significant average annual increase of all four anthropometric parameters were observed up to 14 and 15 years of age in girls and 16 years of age in boys, showing that girls had a shorter growing period. In the prepubertal period until 9 years of age, gender differences were negligible. At the age of 10, boys were overgrown by girls in all parameters due to the earlier onset of puberty in girls. The growth gains for girls, when compared with those for boys, show a different pattern across variables. The female growth advantage remained in a two years period for the limbs length, but in a three year period for stature and the longest, for 4 years, for sitting height. The male predominance in size had an onset at the age of 13 for the limbs and in the age of 14 for stature and sitting height. The patterns of sexual dimorphism in stature and sitting height during growing years are similar to those observed in other populations of Europe. Growth of Croatian children and youth is very similar to that of the tallest European populations.