Purpose
The levels of metal(loid)s at the beginning of the coastal pelagic food web, providing an insight into accumulation in the suspended particulate matter (SPM) and size-fractionated plankton, ...were studied in the shallow coastal marine environment of the Gulf of Trieste (northern Adriatic Sea) affected by the metal polluted Isonzo/Soča River as a result of historical Hg, and Pb and Zn mining activities in the hinterland.
Materials and methods
Levels of metal(loid)s were investigated in suspended particulate matter (0.45–20 µm) and fractionated plankton (20–50 µm, 50–200 µm, > 200 µm) collected monthly at the Marine Biology Station oceanographic buoy Vida in the southern part of the Gulf of Trieste.
Results and discussion
Concentrations of meta(loid)s showed the following order Al,Fe > Zn,Mn > Ni > Cu,Cr > As,Pb,V > Co > Se > Cd > U > Hg and were similar to those of dissolved metal(loid)s of the gulf waters (Al,Fe > Zn > Cu > V > Mn > As > Ni,Se > U,Cr > Cd > Hg) where Hg, Cu, Cr and Se were significantly associated with colloidal organic matter (< 0.2 µm, > 5 kDa). The partition of metal(loid)s between their particulate phase and free ion and inorganic complexes in the water (K
pd
) confirmed a strong binding of Hg, Al, Mn, Fe, Cr and Pb onto seawater particles. In general, the metal(loid) data for SPM and plankton showed high levels in the 50–200 µm microplankton fraction. Larger plankton fractions, especially > 200 µm, contain a lower amount of metal(loid)s associated with mineral particles originating from sedimentary pelite resuspension and riverine inflows. Variations of metal(loid)s levels in SPM and plankton fractions were related to their biomass (ash free dry weight—AFDW) and organic matter, and mineral (inorganic) content, which is difficult to separate from biogenic particles including organisms, and to the taxonomic composition and feeding behaviour of organisms in various fractions.
Conclusions
The Redfield's stoichiometric concept including metal(loid)s in the coastal marine plankton (SPM and mesozooplankton) appears unreliable. The bioconcentration factors (log BCFs) of the studied metal(loid)s, ranging between 4 and 6 for Hg, Fe, Mn, Cr, Pb, Co, Zn, Ni, As, Cu and V and lower for Se and U both in micro- and mesoplankton, can possibly be used in micro- and especially in mesoplankton fraction less impacted by mineral metal(loid)s. This should be considered when establishing the metal(loid)s levels at the base of the coastal and estuarine food webs, at the onset of marine bioaccumulation, to provide information for marine organisms consumed by humans.
Purpose
Hypersaline environments are extremely vulnerable and important ecological niches. Because much knowledge has focused on the distribution of heavy metals in these areas, the detailed behavior ...of key major elements in hypersaline environments has not been elucidated in detail.
This research aims to define the distribution, translocation pathways, and mobility patterns of the major elements in hypersaline sediments and halophytes.
Materials and methods
Samples of
Sarcocornia fruticosa
plants were collected from evaporation (ES) and crystallization (CA) sites in the Sečovlje Salina area (Republic of Slovenia). The major element contents were measured by digestion in HNO
3
then aqua regia and analyzed by ICP-MS for ultra-low detection limits. Rhizo-sediments from EA and CA were processed using sequential extraction analysis to determine the precise fractionation of Al, Ca, Fe, K, Mg, Mn, and Na. To determine the translocation patterns of individual major elements in
S. fruticosa
, two indices were calculated: bioconcentration (BCF) and translocation factor (TF). Differences and similarities between samples and elements were highlighted using Statistica VII and Grapher 8 statistical software and Ward’s method, respectively.
Results and discussion
The obtained results confirmed that halophyte plants take up large amounts of the essential micronutrient Na due to high salinity, and that macronutrients (Ca, Mg, P, and S) are intensively translocated from the roots to the upper parts of the plant. The overall trend in translocation signature for major elements, distinguished by BCF and TF factor calculations, emphasizes that root tissues accumulate a significant amount of major elements and that accumulation depends on individual major elements. It also showed that the major elements Ca, Mg, Na, P, and S are highly translocated within plants, while the mobility of Al, Fe, and K is limited.
Conclusions
Our results suggest that the major elements are vital macronutrients for halophytes, but their accumulation in the roots and further translocation within the plant depend on individual elements and their dynamics. The translocation pattern of the major elements can be justified as follows: Ca is an essential element for plant growth, maintenance, and membrane integrity; Mg is a specific component of chlorophyll; Na is present because of the hypersaline environment; P is a key component of plant metabolic processes; S represents an important component of enzymes and other key proteins; Al and Fe are preferentially accumulated in roots; and plant leaves are generally undersupplied with K. The presented results are of great importance for the general knowledge and use/application of halophytes in agriculture and biotechnology.
In this research, sediments from the Sečovlje Salina (northern Adriatic, Slovenia) were geochemically investigated in order to decode the mobility of metal(oid)s in the hypersaline environment. The ...results demonstrated that the concentrations of As, Co, Cu, Mo, Ni, Pb, Sb, Sn and Zn were comparable to those detected in various similar coastal background areas, as well as in the Sečovlje salt marsh core sample. The estimated mobility potential of metal(oid)s in sediment decreases in the following order: Mo > As > Cu > Sb > Sn > Co > Pb > Ni > Zn. Since the hypersaline sediment (e.g. healing mud) is used as a healing factor (it can be applied directly on human skin), the study of metal(oid) bioavailability in an interaction between the hypersaline sediments and the artificial sweat was also performed. It is significant that the metal(oid) contents are leached in very low concentrations and are treated as nontoxic for humans according to international norms for cosmetic products. The study provides information in order to assess the role of metal mobility on the potential health impact of the application of natural healing mud.
Display omitted
•The transfer of metal(oid)s in a hypersaline environment was investigated.•Availability of metal(oid)s from a health risk perspective was conducted.•Sediment-water physical and geochemical properties induced limited mobility dynamics.•Extraction testing in artificial sweat indicate low mobility of metal(oid)s.
Microbial mats are commonly observed in estuaries and in salt marshes but they only rarely represent a significant surface involved in salt production. In the Sečovlje salt works in Northern ...Adriatic, a microbial mat known as the “petola” covers the bottom of salt crystallising pans, highly influencing salt composition and salt production processes. Throughout the year the petola is subjected to numerous co-varying factors that drive changes in its structure and the microbial community. Seasonal modifications were investigated via various methods (cryo-HRSEM, XRD, elemental analysis, carbohydrate content, bacterial community structure). This study provides knowledge on microbial mat compositional characteristics and functional roles in response to seasonal variation in environmental conditions. The in situ characterisation (close-to its natural hydrated state) of the three-dimensional microstructure provides precise information about dominating filamentous cyanobacterium Coleofasciculus chthonoplastes and extracellular polymer secretion (EPS) organisation. This is the first study to address how microbial mat composition and structure, especially 3D EPS network (and microbial diversity), affects the salt production processes within a hypersaline environment.
Display omitted
•Role of a microbial mat called “petola” in traditional Slovenian salt production.•Combination of microscopic, mineralogical, geochemical and biomolecular analyses.•High resolution cryo-scanning electron microscopy.•Petola's 3D organic microtexture impacts salt formation and production.•Magnesium sequestration by cyanobacterial sheaths favours salt purity.
Environmental education represents an important factor in solving environmental issues and teachers have an important role in developing the environmental literacy of future generations. The aim of ...the present research was to assess and compare preservice preschool and primary school teachers’ environmental awareness, attitudes, and behaviour, as well as their opinions about environmental education. The research was carried out with 152 Slovenian preservice teachers of the Faculty of Education, University of Primorska. The data were collected using a questionnaire. Results showed that students have a relatively high level of environmental awareness and mostly demonstrated a positive attitude towards nature and its protection. Students highlighted the importance of environmental education in early childhood. The research showed no significant differences in the responses of students of both programmes in general, which indicates that the course contents have a less significant influence on students’ awareness, behaviour, and attitudes. According to the findings, there is a need for an improved course within the teacher training programme, especially with the implementation of more innovative teaching methods and activities to increase students’ environmental literacy.
Among the various exometabolitic effects of marine microorganisms, massive mucilage events in the coastal zones of temperate and tropical seas are the most spectacular and environmentally important. ...Abundant mucilage material in the form of aggregates appears in late spring/early summer in the water column of the Adriatic Sea. These macroaggregate biopolymers originate mainly from plankton exometabolites, with both autochthonous and allochthonous components, and strongly impact the tourism, fisheries, and economy of coastal countries. In contrast to extensive studies on the structural and chemical nature of macroaggregates performed over past decades, the full elemental composition of these substances remains poorly known, which does not allow for a complete understanding of their origin, evolution, and necessary remediation measures. Here, we report the results of comprehensive analyses of 55 major and trace elements in the composition of macro aggregates collected at the surface and in the water column during massive mucilage events. Through normalization of the elemental chemical composition of the upper earth crust (UCC), river suspended material (RSM), mean oceanic plankton, and mean oceanic particulate suspended material, we demonstrate that the water column macroaggregates reflect a superposition of the signal from plankton and marine particulate matter. The surface macroaggregates were preferentially enriched in lithogenic component, and carried the signature of planktonic material. The rare earth element (REE) signal was strongly dominated by plankton and, to a lesser degree, by oceanic particulate matter, while at the same time being strongly (>80 times) impoverished compared with UCC and RSM. Taken together, the elemental composition of macroaggregates allows for distinguishing the lithogenic and biogenic impacts on the occurrence of these unique large-scale mucilage events, linked to the exometabolism of marine plankton combined with the input of allochthonous inorganic material.
Hypersaline environments are among the most vulnerable coastal ecosystems and are extremely noteworthy for a variety of ecological reasons. Comprehensive assessment of metal(oid) contamination in ...hypersaline sediments from Sečovlje (Northern Adriatic, Slovenia) was addressed by introducing the detrital and diagenetic mineralogy and geochemical properties within the solid sediment material. Close associations between Fe/Mn oxides and oxyhydroxides with As, Cr, Ni, Pb and Zn, and between organic matter with Cu, Pb and Zn were confirmed using X-ray powder diffraction, SEM-EDS and ICP emission spectrometry analysis. Possible incorporation or adsorption on the crystal lattices of clay minerals (As, Cr, Pb, Sn and Zn), halite (As) and aragonite/calcite (Cd, Cu, Pb, Sr and Zn) were also detected. All presented correlations were highlighted by various statistical analyses. The enrichment factor (EF) values showed a low degree of anthropogenic burden for As, Bi, Hg and Zn, while Cd, Cr, Cu, Ni, Pb, Sn and Sr originated from the geological background. These results emphasise that a detailed mineralogical and geochemical characterisation of solid (especially detrital and diagenetic) sediment particles is crucial in further understanding the metal(oid) translocation within the hypersaline ecosystems.
With a rich spa and wellness heritage, Slovenia now boasts fifteen registered natural health resorts and spas. Certain locations feature the traditional use of the Sečovlje Salina mud, or “fango.” ...This study represents the first investigation of the mineralogical, geochemical and thermophysical characteristics of this mud. The healing saline mud samples were characterized by very fine, sandy, medium silt in which the mud fraction greatly dominated over the sand fraction. The mineral fraction was predominantly composed of an amorphous phase, followed by quartz, calcite, illite/muscovite, gypsum and halite, albite, and clinochlore and pyrite. The results of XRD analysis with oriented preparation identified smectite, chlorite, interstratified layers of smectite/illite, and kaolinite mineral components. The contents of the major and trace elements of saline muds were comparable to their mean concentrations in surface sediment from the Central Adriatic Sea. The samples had a high cation exchange capacity, yet low total organic carbon, total nitrogen, and total sulphur content. The concentrations of select trace metals were in the range of that found in other healing saline muds. Additionally, the physical properties of the mud (i.e., density, specific heat, thermal conductivity, and viscosity) were measured. This study contributes new knowledge about natural peloid characteristics and their quality criteria related to wellness and therapeutic purposes.
•Saline (salt-pan) mud from the Sečovlje Salina is commonly used for therapeutic treatment.•Mineralogical, geochemical and thermophysical properties of healing saline mud were determined.•Saline muds from Sečovlje Salina are suitable for therapeutic purposes in form of wraps or poultices.•Quality criteria for peloids are necessary for user safety and standardization.
► Periphyton in Idrijca river was assessed as a bioindicator of Hg in the food chain. ► Mercury concentrations in the periphyton do not reflect Hg in water or sediments. ► Hg methylation takes place ...in the periphyton. ► Periphyton is a complex system of limited use as a sensor of increased Hg pollution.
Mercury presents a potential risk to the environment and humans, especially in its methylated form. It is among the highest priority environmental pollutants. River Idrijca (Slovenia) is highly contaminated with mercury due to past mercury mining. The aim of this work was to investigate whether the periphyton community in rivers such as Idrijca is a suitable indicator of Hg pollution and of changes in mercury methylation and could serve as an early warning system of increased input of MeHg in the food chain. Periphyton is the only site of primary production in temperate torrential rivers such as Idrijca and is therefore an important link in the food chain. It is also a potential site of Hg accumulation and its introduction to higher trophic levels. Our aim was to assess the response of the periphyton to seasonal and spatial variations in mercury levels and to evaluate its potential as an early warning system of changes in mercury reactivity and mobilization The results indicate that periphyton in a torrential river is too complex and unpredictable to be used as a sole indicator of mercury concentrations and changes in the river. Nevertheless, it can complement environmental measurements due to its importance in the riverine food web.
In our research the concentrations of major and minor elements were determined in natural sea salts from the Se~ovlje salina (Piran salts, Slovenia) and compared to those of selected samples of ...commercially available unrefined salts with different geographical origins (Croatia, Austria, Italy, Portugal, India, and Pakistan). In the case of major element contents such as sodium (Na), iron (Fe), aluminum (Al), manganese (Mn), and titanium (Ti) many similarities were observed among the analysed salt samples. On the other hand, Piran salts are characterized by lower silicon (Si) values. Among the salts from the Sečovlje salina, the salt with the trade name Piran salt has a higher Mg content while Flower of salt has a lower concentration of calcium (Ca). In Slovenian samples the majority of trace element values were lower than 0.5 µg g-1, which was comparable to the results from commercially available unrefined salts. The salt composition differences observed indicate area-specific signatures related to geographic origin and diverse salt production processes. The quality of the studied salt samples is in accordance with standards established by the Codex Alimentarius Commission and the Piran salts are also suitable regarding issues of national food control.
PDF
