Amazonian wildfires in 2019 have raised awareness about rainforest burning due to increased emissions of particulate matter and carbon. In the context of these emissions, by-products of lignin ...thermal degradation (i.e. methoxyphenols) are often neglected. Methoxyphenols entering the atmosphere may form intermediates with currently unknown reaction mechanisms and toxicity. This study for the first time provides a comprehensive insight into the impact of lignin degradation products guaiacol, catechol, and their nitrated intermediates 4-nitrocatechol, 4,6-dinitroguaiacol, 5-nitroguaiacol on zebrafish Danio rerio. Results revealed 4-nitrocatechol and catechol as the most toxic, followed by 4,6DNG > 5NG > GUA. The whole-organism bioassay integrated with molecular modeling emphasized the potential of methoxyphenols to inhibit tyrosinase, lipoxygenase, and carbonic anhydrase, consequently altering embryonic development (i.e. affected sensorial, skeletal, and physiological parameters, pigmentation formation failure, and non-hatching of larvae). The whole-organism bioassay integrated with in silico approach confirmed the harmful effects of lignin degradation products and their intermediates on aquatic organisms, emphasizing the need for their evaluation within ecotoxicity studies focused on aquatic compartments.
Chemical analysis of plasma samples of wild fish from the Sava River (Croatia) revealed the presence of 90 different pharmaceuticals/illicit drugs and their metabolites (PhACs/IDrgs). The ...concentrations of these PhACs/IDrgs in plasma were 10 to 1000 times higher than their concentrations in river water. Antibiotics, allergy/cold medications and analgesics were categories with the highest plasma concentrations. Fifty PhACs/IDrgs were identified as chemicals of concern based on the fish plasma model (FPM) effect ratios (ER) and their potential to activate evolutionary conserved biological targets. Chemicals of concern were also prioritized by calculating exposure-activity ratios (EARs) where plasma concentrations of chemicals were compared to their bioactivities in comprehensive ToxCast suite of in vitro assays. Overall, the applied prioritization methods indicated stimulants (nicotine, cotinine) and allergy/cold medications (prednisolone, dexamethasone) as having the highest potential biological impact on fish. The FPM model pointed to psychoactive substances (hallucinogens/stimulants and opioids) and psychotropic substances in the cannabinoids category (i.e. CBD and THC). EAR confirmed above and singled out additional chemicals of concern - anticholesteremic simvastatin and antiepileptic haloperidol. Present study demonstrates how the use of a combination of chemical analyses, and bio-effects based risk predictions with multiple criteria can help identify priority contaminants in freshwaters. The results reveal a widespread exposure of fish to complex mixtures of PhACs/IDrgs, which may target common molecular targets. While many of the prioritized chemicals occurred at low concentrations, their adverse effect on aquatic communities, due to continuous chronic exposure and additive effects, should not be neglected.
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•Ninety pharmaceuticals/illicit drugs and their metabolites were analyzed.•Fish plasma model and ToxCast data were used to identify chemicals of concern.•Nicotine, cotinine, prednisolone and dexamethasone: chemicals of concern.•Fish plasma model pointed psychoactive chemicals as potentially hazardous to fish.
The CompTox Chemistry Dashboard (ToxCast) contains one of the largest public databases on Zebrafish (
) developmental toxicity. The data consists of 19 toxicological endpoints on unique 1018 ...compounds measured in relatively low concentration ranges. The endpoints are related to developmental effects occurring in dechorionated zebrafish embryos for 120 hours post fertilization and monitored via gross malformations and mortality. We report the predictive capability of 209 quantitative structure-activity relationship (QSAR) models developed by machine learning methods using penalization techniques and diverse model quality metrics to cope with the imbalanced endpoints. All these QSAR models were generated to test how the imbalanced classification (toxic or non-toxic) endpoints could be predicted regardless which of three algorithms is used: logistic regression, multi-layer perceptron, or random forests. Additionally, QSAR toxicity models are developed starting from sets of classical molecular descriptors, structural fingerprints and their combinations. Only 8 out of 209 models passed the 0.20 Matthew's correlation coefficient value defined a priori as a threshold for acceptable model quality on the test sets. The best models were obtained for endpoints mortality (MORT), ActivityScore and JAW (deformation). The low predictability of the QSAR model developed from the zebrafish embryotoxicity data in the database is mainly due to a higher sensitivity of 19 measurements of endpoints carried out on dechorionated embryos at low concentrations.
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► Comparative toxicity of imidacloprid and its product 6-chloronicotinic acid. ► Higher toxicity effects of imidacloprid as commercial formulation. ► Imidacloprid and its ...transformation product influenced oxidative stress biomarkers. ► Behavioural alterations in amphipods and adverse effects on algae growth.
Neonicotinoids are widely applied pesticides due to their higher affinity for insect nicotinic acetylcholine receptors. These compounds are extensively applied to control pest insects in different agricultural crops; however they can also affect non-target invertebrates. Little is known about the toxicity effects of their transformation products on aquatic non-target organisms. Oxidative stress responses and behavioural changes in the crustacean amphipod Gammarus fossarum were investigated as well as the growth rate in freshwater algae Desmodesmus subspicatus after 96h exposure to imidacloprid, its commercial formulation Confidor 200SL and its transformation product 6-chloronicotinic acid. Algal growth has shown significant sensitivity to Confidor 200SL and 6-chloronicotinic acid when compared to imidacloprid. In the case of amphipods, low doses of imidacloprid (102.2μgL−1) were sufficient to induce lipid peroxidation, while Confidor 200SL induced increased catalase activity (511.3μgL−1) and lipid peroxidation (255.6μgL−1). 6-Chloronicotinic acid altered significantly only antioxidant mechanisms (catalase activity) without changing lipid peroxidation levels. These different biochemical responses are helpful to understand the mechanism of imidacloprid and 6-chloronicotinic acid-induced oxidative stress. In addition, obtained data demonstrate potential harmful effects of neonicotinoid-based pesticides on non-target aquatic organisms.
Maternal nutrition and lifestyle in pregnancy are important modifiable factors for both maternal and offspring's health. Although the Mediterranean diet has beneficial effects on health, recent ...studies have shown low adherence in Europe. This study aimed to assess the Mediterranean diet adherence in 266 pregnant women from Dalmatia, Croatia and to investigate their lifestyle habits and regional differences. Adherence to the Mediterranean diet was assessed through two Mediterranean diet scores. Differences in maternal characteristics (diet, education, income, parity, smoking, pre-pregnancy body mass index (BMI), physical activity, contraception) with regards to location and dietary habits were analyzed using the non-parametric Mann-Whitney U test. The machine learning approach was used to reveal other potential non-linear relationships. The results showed that adherence to the Mediterranean diet was low to moderate among the pregnant women in this study, with no significant mainland-island differences. The highest adherence was observed among wealthier women with generally healthier lifestyle choices. The most significant mainland-island differences were observed for lifestyle and socioeconomic factors (income, education, physical activity). The machine learning approach confirmed the findings of the conventional statistical method. We can conclude that adverse socioeconomic and lifestyle conditions were more pronounced in the island population, which, together with the observed non-Mediterranean dietary pattern, calls for more effective intervention strategies.
Integrative taxonomic studies of macrofungal diversity in the Brijuni National Park (Istria County, Croatia) led to the discovery of a second species of Inocybe (Agaricales, Inocybaceae) new to ...science. Inocybe istriaca sp. nov. is described on the basis of morphological, ecological, and multigene phylogenetic analyses, and its placement within the family Inocybaceae is discussed. The combination of most important morphological characters that distinguish I. istriaca from the other similar Inocybe species are smooth, (sub)amygdaliform, (sub)phaseoliform, or ellipsoid basidiospores (ca. 8.5–12 × 5–7 μm), large basidia (36–45 × 9–15 μm), mostly (sub)fusiform and weakly thick-walled (up to 1.5 μm) metuloid pleurocystidia, and lamellar edge and stipe apex partially covered by a dark resinous substance. The species was collected on the edge of grassland and Mediterranean evergreen holm oak (Quercus ilex) forest. In this study, a total of 14 DNA sequences from four Inocybe species were generated. Two-gene (ITS, LSU) and four-gene (ITS, LSU, rpb2, tef1) phylogenetic analyses confirmed the status of I. istriaca as an independent species.
Olive mill wastewater (OMW) as a by-product of olive oil extraction process has significant polluting properties mainly related to high organic load, increased COD/BOD ratio, high phenolic content ...and relatively acidic pH. Raw OMW from Slovenian Istria olive oil mill and its polar fraction were investigated in this study. Chemical characterization of OMW polar fraction identified tyrosol as the most abundant phenolic product, followed by catechol. Lethal and sub-lethal effects of OMW matrix and its polar fraction were tested using a battery of bioassays with model organisms: bacteria Vibrio fischeri, algae Chlorella vulgaris, water fleas Daphnia magna, zebrafish Danio rerio embryos, clover Trifolium repens and wheat Triticum aestivum. Raw OMW sample was the most toxic to V. fischeri (EC50 = 0.24% of OMW sample final concentration), followed by D. magna (EC50 = 1.43%), C. vulgaris (EC50 = 5.20%), D. rerio (EC50 = 7.05%), seeds T. repens (EC50 = 8.68%) and T. aestivum (EC50 = 11.58%). Similar toxicity trend was observed during exposure to OMW polar fraction, showing EC50 values 2.75–4.11 times lower comparing to raw OMW. Tested samples induced also sub-acute effects to clover and wheat (decreased roots, sprouts elongation); and to zebrafish embryos (increased mortality, higher abnormality rate, decreased hatching and pigmentation formation rate). A comprehensive approach using a battery of bioassays, like those used in this study should be applied during ecotoxicity monitoring of untreated and treated OMW.
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•Raw OMW and polar fraction exhibited the highest toxicity on the photobacterium Vibrio fischeri.•Tyrosol was the most common phenolic compound in the tested OMW.•Multi-biomarker approach showed as a good indicator of OMW toxic potential.
Integrative taxonomic studies of macrofungal diversity in the Brijuni National Park (Istria County, Croatia) led to the discovery of a second species of Inocybe (Agaricales, Inocybaceae) new to ...science. Inocybe istriaca sp. nov. is described on the basis of morphological, ecological, and multigene phylogenetic analyses, and its placement within the family Inocybaceae is discussed. The combination of most important morphological characters that distinguish I. istriaca from the other similar Inocybe species are smooth, (sub)amygdaliform, (sub)phaseoliform, or ellipsoid basidiospores (ca. 8.5–12 × 5–7 μm), large basidia (36–45 × 9–15 μm), mostly (sub)fusiform and weakly thick-walled (up to 1.5 μm) metuloid pleurocystidia, and lamellar edge and stipe apex partially covered by a dark resinous substance. The species was collected on the edge of grassland and Mediterranean evergreen holm oak (Quercus ilex) forest. In this study, a total of 14 DNA sequences from four Inocybe species were generated. Two-gene (ITS, LSU) and four-gene (ITS, LSU, rpb2, tef1) phylogenetic analyses confirmed the status of I. istriaca as an independent species.
Quantitative chemical analyses of 428 organic contaminants (OCs) indicated the presence of 313 OCs in the sediment extracts from Sava River, Croatia. Pharmaceuticals were present in higher ...concentrations than pesticides thus confirming their increasing threat to freshwater ecosystems. Toxicity evaluation of the sediment extracts from four locations (Jesenice, Rugvica, Galdovo and Lukavec) using zebrafish embryotoxicity test (ZET) accompanied with semi-quantitative histopathological analyses exhibited correlation with cumulative number and concentrations of OCs at the investigated sites (10.05, 15.22, 1.25, and 9.13 μg/g respectively). Toxicity of sediment extracts and sediment was predicted using toxic unit (TU) approach and persistence, bioaccumulation and toxicity (PBT) ranking. Additionally, influential OCs and genes were identified by graph mining of the prior knowledge informed, site-specific chemical-gene interaction models. Predicted toxicity of sediment extracts (TUext) was similar to the results obtained by ZET and associated histopathology with Rugvica sediment being the most toxic, followed by Jesenice, Lukavec and Galdovo. Sediment TU (TUsed) favoured OCs with low octanol-water partition coefficients like herbicide glyphosate and antibiotics ciprofloxacin and sulfamethazine thus indicating locations containing higher concentrations of these OCs (Galdovo and Rugvica) as the most toxic. Results suggest that comprehensive in silico sediment toxicity predictions advocate providing equal attention to organic contaminants with either very low or very high log Kow.
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•Pharmaceuticals are a major component of river sediment pollution.•ZET and histopathological analysis are good indicators of sediment toxic potential.•In silico sediment toxicity predictions should include OCs with low or high log Kow.
•Untreated and FeCl3 treated sewage sludge enhanced plant growth in both soils.•FeCl3 treated sewage sludge increased PTE bio-availability when added to the acid soil.•FeCl3 treated sewage sludge ...reduced PTE bio-availability when added to the neutral soil.
Land application of sewage sludge (SS) is a convenient way of disposal compared to incineration or landfill, but can result in accumulation of potentially toxic elements (PTE) in agricultural soils. The environmental risk associated with PTE accumulation in soils that received several SS applications depends mainly on soil pH and SS treatments. We studied the effects of addition to soil of SS treated and untreated with FeCl3 on the biological availability of Zn, Ni, Cd and Cu to oilseed rape (Brassica napus). The plants were grown on an acid and a neutral soil in a greenhouse incubation experiment. The following treatments were carried out: (i) unamended control soil, (ii) sewage sludge amended soils kept bare throughout the experiment and (iii) sewage sludge amended soil planted with oilseed rape. Amended soils received either untreated SS or FeCl3 treated SS at a rate equivalent to 75td.w.ha−1y−1.
Plant growth was enhanced by addition of both untreated SS and FeCl3 treated SS, but the latter produced a lower shoot dry matter than untreated SS, particularly in the acid soil. Evaluation of biological availability of PTE was performed by three different methods: plant shoot analysis, single DTPA-extraction, and sequential fractionation procedure (SEP) in soil. After 50 days, accumulation of PTE was considerably larger in plant shoots grown on the acid soil and amended with FeCl3 treated sludge. Conversely, the FeCl3 treated SS reduced Cd, Ni and Zn accumulation in shoots in the neutral soil in comparison to untreated SS. Copper was generally unaffected by SS treatment in both soils. Plants significantly decreased the DTPA-extractability of Cd, Ni and Zn in both soils that received FeCl3 treated SS, but they did not change it in soils that received untreated SS.
These different behaviors may be explained by the different mechanism involved in metals stabilization in the two soils: adsorption on Fe and Mn oxides in the neutral soil, precipitation and organic complexation in the acid soil.
The chemical flocculation treatment of waste water with FeCl3 and addition to soils reduces PTE availability in neutral soils amended with SS, but markedly increases their solubility and bio-availability in acid soils. Therefore, the application of SS obtained from flocculation with FeCl3 should be restricted to neutral or calcareous soils.
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