Assessment of low-level metal contamination using the Mediterranean mussel gills as the indicator tissue

Purpose  

The aim of this study was to compare the level of metal contamination in two bays in the middle part of the Eastern Adriatic coastal zone in Croatia using the gills of mussels Mytilus galloprovincialis as indicator tissue. Despite the existing sources of contamination, previous studies with caged mussels only indicated moderate metal contamination of the Kaštela Bay, contrary to the Trogir Bay in which marina and shipyard present a probable source of Cu- and Zn-contamination.     

Malondialdehyde concentrations in the intestine and gills of Vardar chub (Squalius vardarensis Karaman) as indicator of lipid peroxidation

Environmental Science and Pollution Research - A lipid peroxidation product, malondialdehyde (MDA), was studied in Vardar chub (Squalius vardarensis Karaman) as an indicator of oxidative stress,...     

Assessment of ozone variations and meteorological influences in a tourist and health resort area on the island of Mali Lošinj (Croatia)

The purpose of this study was to investigate ozone, variations, and its correlation with meteorological parameters at a remote location on the Mali Lo?inj Island, which has been a tourist and health resort area in the northern Adriatic. The measured data are discussed in relation to the EU guidelines (Directive 2002/3/EC; Directive 2008/50/EC). In order to characterize ambient air with respect to ozone vegetation injury and photochemical pollution, we calculated accumulated dose over a threshold of 40 parts per billion index and two photochemical pollution indicators. The influence of local meteorological parameters on the measured ozone volume fractions was also investigated. We used the multivariate technique principal component analysis to trace correlations between measured ozone concentration and meteorological parameters.     

Assessment of general condition of fish inhabiting a moderately contaminated aquatic environment

The assessment of general condition of fish in the moderately contaminated aquatic environment was performed on the European chub (Squalius cephalus) caught in September 2009 in the Sutla River in Croatia. Although increases of the contaminants in this river (trace and macro elements, bacteria), as well as physico-chemical changes (decreased oxygen saturation, increased conductivity), were still within the environmentally acceptable limits, their concurrent presence in the river water possibly could have induced stress in aquatic organisms. Several biometric parameters, metallothionein (MT), and total cytosolic protein concentrations in chub liver and gills were determined as indicators of chub condition. Microbiological and parasitological analyses were performed with the aim to evaluate chub predisposition for bacterial bioconcentration and parasitic infections. At upstream river sections with decreased oxygen saturation (～50 %), decreased Fulton condition indices were observed (FCI: 0.94 g?cm^?3), whereas gonadosomatic (GSI: 2.4 %), hepatosomatic (HSI: 1.31 %), and gill indices (1.3 %) were increased compared to oxygen rich downstream river sections (dissolved oxygen ～90 %; FCI: 1.02 g?cm^?3; GSI: 0.6 %; HIS: ～1.08 %; gill index: 1.0 %). Slight increase of MT concentrations in both organs at upstream (gills: 1.67 mg?g^?1; liver: 1.63 mg?g^?1) compared to downstream sites (gills: 1.56 mg?g^?1; liver: 1.23 mg?g^?1), could not be explained by induction caused by increased metal levels in the river water, but presumably by physiological changes caused by general stress due to low oxygen saturation. In addition, at the sampling site characterized by inorganic and fecal contamination, increased incidence of bacterial bioconcentration in internal organs (liver, spleen, kidney) was observed, as well as decrease of intestinal parasitic infections, which is a common finding for metal-contaminated waters. Based on our results, it could be concluded that even moderate contamination of river water by multiple contaminants could result in unfavourable living conditions and cause detectable stress for aquatic organisms.     

Influence of Meteorological Factors NO2, SO2, CO and PM10 on the Concentration of O3 in the Urban Atmosphere of Eastern Croatia

Ozone, NO₂, SO₂, CO, PM₁₀ and meteorological parameters were measured simultaneously during the summer?Cautumn season 2007 in Osijek??the eastern, flat, agricultural part of Croatia. Fourier analysis confirms the existence of variation in ozone volume fractions with periods ranging from the usual semi-daily and daily to 7 and 28 daily cycles. The relationships between O₃ and other variables were modelled in three ways: principal component analysis, multiple linear regression and principal component regression. The results of the principal component analysis detected underlying relationships among ozone concentrations and meteorological variables. An extremely simple meteorological model is suitable for the prediction of ozone levels. The meteorological factors, temperature and cloudiness played a main role in the MLR model (R ²?=?0.83). The application of the principal component regression approach confirmed that the original variables associated with the valid principal components were meteorological variables (R ²?=?0.82).     

Relevance of biotic parameters in the assessment of the spatial distribution of gastrointestinal metal and protein levels during spawning period of European chub (Squalius cephalus L.)

The present field study, conducted during the spawning period (April/May) of European chub (Squalius cephalus L.) from the Sava River in Croatia, indicates that seasonal changes of fish physiological state might cause variability in gastrointestinal metal (Cd, Cu, Fe, Mn and Zn), total cytosolic protein and metallothionein (MT) levels. During the period of fish spawning and increased metabolic activity, a significant relationship with chub hepatosomatic index was evident for Fe and Mn in gastrointestinal tissue (r?=?0.35 and 0.26, respectively) and in cytosolic fraction (r?=?0.32 and 0.41, respectively) and for Zn and Fe in the gut content (r?=?0.36 and 0.31, respectively). Total cytosolic protein and MT concentrations followed the same spatial distribution as Fe and Mn in all gastrointestinal fractions and as Zn in the sub-cellular fractions, with higher levels at upstream locations. Due to the role of essential metals in metabolic processes and gonad development, increased feeding and spawning activity in April/May resulted in higher gastrointestinal essential metal (Fe, Mn and Zn) and MT concentrations, which probably follow an increase in Zn concentrations, known as the primary MT inducer. Therefore, biotic factors should be considered as important confounding factors in metal exposure assessment, while their influence on gastrointestinal metal and protein levels should be interpreted depending on the season studied.     

Chemistry of the sternal gland secretion of the Mediterranean centipede Himantarium gabrielis (Linnaeus, 1767) (Chilopoda: Geophilomorpha: Himantariidae)

The Science of Nature - The geophilomorph centipede, Himantarium gabrielis, when disturbed, discharges a viscous and proteinaceous secretion from the sternal glands. This exudate was found by gas...