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The effects of 5 μM cadmium (Cd), a non-essential toxic element and 25 and 50 μM zinc (Zn), an essential micronutrient, were investigated in aquatic plant Lemna minor L. after 4 and 7 days of exposure to each metal alone or to their combinations. Both metals showed tendency to accumulate with time, but when present in combination, they reduced uptake of each other. Cd treatment increased the lipid peroxidation and protein oxidation indicating appearance of oxidative stress. However, Zn supplementation in either concentration reduced values of both parameters, while exposure to Zn alone resulted in elevated level of lipid peroxidation and protein oxidation but only on the 7th day. Enhanced DNA damage, which was found on the 4th day in plants treated with Cd alone or in combination with Zn, was reduced on the 7th day in combined treatments. Higher catalase activity obtained in all treated plants on the 4th day of experiment was reduced in Zn-treated plants, but remained high in plants exposed to Cd alone or in combination with Zn after 7 days. Cd exposure resulted in higher peroxidase activity, while Zn addition prominently reduced peroxidase activity in the plants subjected to Cd stress. In conclusion, Cd induced more pronounced oxidative stress and DNA damage than Zn in applied concentrations. Combined treatments showed lower values of oxidative stress parameters--lipid peroxidation, protein oxidation and peroxidase activity as well as lower DNA damage, which indicates alleviating effect of Zn on oxidative stress in Cd-treated plants.

We investigated interactions between copper (in the concentrations of 2.5 µmol L -1 and 5 µmol L -1 ) and cadmium (5 µmol L -1 ) in common duckweed (Lemna minor L.) by exposing it to either metal or to their combinations for four or seven days. Their uptake increased with time, but it was lower in plants treated with combinations of metals than in plants treated with either metal given alone. In separate treatments, either metal increased malondialdehyde (MDA) level and catalase and peroxidase activity. Both induced DNA damage, but copper did it only after 7 days of treatment. On day 4, the combination of cadmium and 5 µmol L -1 copper additionally increased MDA as well as catalase and peroxidase activity. In contrast, on day 7, MDA dropped in plants treated with combinations of metals, and especially with 2.5 µmol L -1 copper plus cadmium. In these plants, catalase activity was higher than in copper treated plants. Peroxidase activity increased after treatment with cadmium and 2.5 µmol L -1 copper but decreased in plants treated with cadmium and 5 µmol L -1 copper. Compared to copper alone, combinations of metals enhanced DNA damage after 4 days of treatment but it dropped on day 7. In conclusion, either metal given alone was toxic/ genotoxic and caused oxidative stress. On day 4 of combined treatment, the higher copper concentration was more toxic than either metal alone. In contrast, on day 7 of combined treatment, the lower copper concentration showed lower oxidative and DNA damage. These complex interactions can not be explained by simple antagonism and/or synergism. Further studies should go in that direction.

Sulfonamides, macrolides, torasemide, fumagillin, and chloramphenicol were simultaneously analyzed in surface water samples by using solid-phase extraction (SPE) and reversed-phase (RP) liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS). In the pre-concentration and clean-up process, the pH value of samples and volume of the solvent for extraction of analytes from cartridge were optimized. Extraction recoveries were high with values in the range from 62 to 115%. Limits of quantification (LoQ) were in the range from 0.02 to 0.2 μg L. Repeatability of the method was evaluated at LoQ and expressed as relative standard deviation (RSD). Calculated RSDs were low with values in the range from 2.4 to 14.5%. The method was successfully applied for analysis of surface water real samples. Samples were collected along the rivers in Croatia on four sampling sites in 2012 in Danube catchment areas, 19 sampling sites in Danube and Adriatic catchment areas in 2013, and another 19 places in 2014. Altogether, 20 target compounds were analyzed in 148 water samples and detected in 31 samples in range (0.1-5.3) μg L or in 20.1% of samples. The most frequent and highest concentrations were detected for macrolide antibiotics. This is the first attempt of such monitoring in surface waters in Croatia.

Considering the fact that water is a basic need of every living being, it is important to ensure its safety. In this work, the data on the presence of the opportunistic pathogen P. aeruginosa in drinking water (n = 4171) as well as in pool water (n = 5059) in Primorje-Gorski Kotar County in Croatia in the five-year period (2016–2020) were analysed. In addition, the national criteria were compared with those of neighboring countries and worldwide. The proportion of P. aeruginosa-positive samples was similar for drinking water (3.9%) and pool water (4.6%). The prevalence of this bacterium was most pronounced in the warmer season. P. aeruginosa-positive drinking water samples were mostly collected during building commissioning, while pool samples were from entertainment and spa/hydromassage pools. Outdoor pools showed a higher percentage of positive samples than indoor pools, as well as the pools filled with freshwater rather than seawater. The highest P. aeruginosa load was found in rehabilitation pools. Croatia, Serbia and Montenegro are countries that have included P. aeruginosa in their national regulations as an indicator of the safety of water for human consumption as well as for bottled water, while Slovenia and Bosnia and Herzegovina have limited this requirement to bottled water only. In the case of swimming pool water, this parameter is mandatory in all countries considered in this study.

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Metals have a variety of negative outcomes on plants, essential components of any ecosystem. The effects of CdCl 2 (5 µmol L -1 ), ZnCl 2 (25 or 50 µmol L -1 ), and CuCl 2 (2.5 or 5 µmol L -1 ) and combinations of CdCl 2 with either ZnCl 2 or CuCl 2 on the growth, photosynthetic pigments, and photosystem II (PSII) efficiency of duckweed (Lemna minor L.) were investigated. All of the treatments caused growth inhibition and remarkable metal accumulation in plant tissue after 4 and 7 days. In the combined treatments, the accumulation of each metal applied was lesser in comparison to treatments with single metals. After 4 days, all of the treatments generally diminished chlorophyll a content and decreased the maximum quantum yield (F v /F m ) and effective quantum yield (ΔF/F' m ) of PSII. However, after 7 days of exposure to a combination of Cd and Zn, pigment content and PSII activity recovered to control levels. A higher concentration of Cu (5 µmol L -1 ) as well as Cd in combination with Cu had a prolonged inhibitory effect on photosynthetic features. Our results suggest that growth inhibition was due to the toxic effect of absolute metal quantity in plant tissue. Zn counteracted Cd uptake, as seen from the recovery of pigment content and PSII efficiency in plants exposed for 7 days to the Cd and Zn combination. Cu-induced oxidative stress led to a prolonged inhibitory effect in plants treated both with a higher concentration of Cu (5 µmol L -1) and simultaneously with Cd and Cu. Our findings could contribute to general knowledge on anthropogenic and environmental contaminants that endanger plant communities and significantly disrupt the sensitive balance of an ecosystem by influencing photosynthetic mechanisms. KEY WORDS: chlorophyll fluorescence; duckweed; metal uptake; photosynthetic pigments; PSII efficiencyVidaković-Cifrek Ž, et al. Growth and photosynthetic responses of Lemna minor L. exposed to Cd in combination with Zn or Cu Arh Hig Rada Toksikol 2015;66:141-152 Excess amounts of heavy metals are present in the environment due to natural conditions or industry, mining, and agricultural and other human activities. They influence not only plant growth and reproduction but also human health (1). The impact of heavy metals on plant growth and metabolism has been studied extensively; however, the effect of plant exposure to a single heavy metal has received much more attention than the simultaneous effects of multiple metals, although contaminated terrestrial and aquatic environments usually contain a mixture of substances.Cadmium (Cd) is a non-essential toxic heavy metal. Its salts are dangerous due to their high water solubility and relatively high soil mobility. It is easily taken up by plants and introduced into the food chain, which is why it can have adverse effect not only on plants, but also on animal and human health (2-4). Apart from growth inhibition, leaf chlorosis, and a disturbed uptake and distribution of water and essential elements, Cd has also been reported to bind to functional groups (...

The Croatian National Health Care Act defines the areas of activities of the public health institute, including the activities of the epidemiology of infectious diseases and chronic non-communicable diseases, public health, health promotion, environmental health, microbiology, school and adolescent medicine, mental health and addiction prevention at Zagreb City level. This paper reviews the highly variable activities in the Andrija Štampar Teaching Institute of Public Health with the aim of promoting a comprehensive approach to the COVID-19 pandemic. Human and analytical resources in the Institute, activities and rapid implementation of innovations testify to the high capacities for adaptation to emerging risks. In the Institute, it is possible to carry out a whole range of tests and to monitor the environmental factors with predominant impact on human health and safety of the Zagreb environment. The supply of safe water for human consumption in the Republic of Croatia during the current COVID-19 crisis has been uninterrupted and in accordance with applicable legislation. Also, our laboratories have been developing and introducing a method for wastewater testing for SARS-CoV-2 presence. The sludge from wastewater treatment plants is used in agriculture, and potential risks associated with the COVID-19 outbreak should be assessed prior to each application on the soil. Increased use of disinfectants during the epidemic may present a higher risk to the aquatic environment. Air quality monitoring indicates a positive impact on air quality as result of isolation measures.