The investigation focused on Tl, Hg, As, and Sb as the targeted contaminants in the soil surrounding a thallium mining region in southwestern China. Potential sources of toxic elements were identified using correlation analysis and principal component analysis. By interpreting the results of correlation and principal component analysis, the potential sources of Tl, Hg, As, and Sb were identified to include the mining and smelting industry. Additionally, Tl, Hg, and As are influenced by agricultural activities, while Sb is also associated with the soil parent material. Various analytical methods including the Nemerow comprehensive pollution index, Hakanson potential ecological risk index and hazard quotient assessment were employed to evaluate the sources of heavy metal pollution and associated health risks to crops. Results indicated elevated exceedance rates of Tl, Hg, and Sb in the farmland soil. Approximately 37.9% and 16.7% of the sampling locations were classified as highly and moderately polluted, respectively. Furthermore, toxic elements posed significant ecological risks to the soil, particularly with substantial contributions from Hg and Tl toward the overall risk index. Crop samples collected showed elevated levels of Tl, Hg, and As, particularly in leafy vegetables compared to cereals. Notably, the hazard quotient (HQ) values for Tl in cabbage and Lotus were 1.462 and 5.511, respectively, whereas the HQ value for Hg in Allium chinense was 1.773, posing a significant threat to human health. These findings offer valuable data and theoretical foundation for further investigations into the sources and risks associated with toxic elements in farmland near thallium mining sites.

Mining operations in Canada, including uranium mining and milling, generate by-products containing radionuclides, including radium-226 (Ra), a long-lived, bioaccumulative calcium (Ca) analog. Despite strict discharge regulations, there is limited evidence to suggest that current thresholds for Ra adequately protect aquatic organisms. Furthermore, Canada lacks a federal water quality guideline for Ra, underscoring the need for protective limits to safeguard aquatic ecosystems. Hence, this research aimed to generate data on Ra toxicity to the model aquatic invertebrate Daphnia magna. For this purpose, two 21-day chronic toxicity tests with D. magna were conducted, with survival and reproduction as the endpoints, as well as a reduced water hardness experiment, a multigenerational study, and a bioaccumulation assay. These experiments demonstrated that a high activity concentration (nominal 50 Bq/L) of Ra can significantly impact the survival of D. magna. Ra was also found to bioaccumulate in D. magna with a BAF of 72.8. Since the Canadian Metal and Diamond Mining Effluent Regulations (MDMER) monthly mean effluent limit is currently set at 0.37 Bq Ra /L, the limit for composite samples at 0.74 Bq/L Ra, and the limit for grab samples at 1.11 Bq/L Ra, it is unlikely that toxic effects to aquatic cladocerans like D. magna from Ra will be observed downstream of Canadian mines and mills.

One group of elements attracting more and more attention are so-called technology-critical elements (TCEs). In comparison with legacy pollutants, the anthropogenic impact of TCEs on the environment might still be minor, but various applications introduce them to the most remote places in the world including the marine environment. One area prone to pollution is the Baltic Sea, partly due to the lack of water exchange with the North Sea. In this study, a sediment core from the German Baltic Sea was used to analyze a total of 42 elemental mass fractions. Based on radiometric dating of Pb and Cs, results were classified in a recent (2020-2000) and a past period (< 1920), calculating background concentrations based on the Median + 2 Median Absolute Deviation (M2MAD) and the Tukey Inner Fence (TIF). Six legacy pollutants (Ni, Cu, Zn, As, Cd, Pb) and six TCEs (Ga, Ge, Nb, La, Gd, Ta) are discussed in detail. Anthropogenic impacts of both groups were assessed, and local enrichment factors were calculated showing an increase for the legacy pollutants (past period (≤ 0.8); recent period (≥ 1.2)), but also a minor increase for Ga, Ge and Nb (past period (0.9); recent period (1.1)). Values ≥ 1.5, indicating anthropogenic impact, were found for Cu, Zn, Cd and Pb, but also for Ge. Proposed background values may be considered as baseline for future studies.

Aquatic systems are impacted by temperature fluctuations which can alter the toxicity of pesticides. Increased temperatures related to climate change have elevated pest activity, resulting in an escalation of pesticide use. One such pesticide class, pyrethroids, has replaced the use of several banned pesticides due to its low mammalian toxicity. The impacts of increased temperatures on the toxicity of a pyrethroid, permethrin, to fish is not yet known. In the current study, juvenile inland silversides (Menidia beryllina) were exposed to permethrin at three temperatures: 10 °C, 20 °C, and 30 °C. Inland silversides were chosen for this study because they are a species used in standardized USEPA whole effluent toxicity testing. Permethrin toxicity showed an inverse relationship with temperature. As temperatures fluctuate, fishes experience a change in respiration, biotransformation, and elimination rates, which can drive the noted difference in toxicity. Based on these findings, toxicity can be temperature-dependent and should be considered when assessing risk of exposure to pesticides in aquatic systems.

Environmental risk assessments of very hydrophobic organic compounds (VHOCs) in soils are often difficult because multiple processes (e.g., sorption, volatilization, biodegradation) can complicate the interpretation of results. A standardized soil dosing and aging procedure is presented for assessing bioavailability of VHOCs in a synthetic soil, which was used to evaluate the phytotoxicity of VHOCs. The soil preparation protocol resulted in relatively stable freely dissolved concentrations of test substance compared to bulk soil concentrations with some losses likely due to volatility and biodegradation. This dosing method was used in a chronic terrestrial plant toxicity bioassay to evaluate the potential toxicity of VHOCs on complex reproductive endpoints like inflorescence and seed bud formation. Testing included representative hydrocarbons and three very hydrophobic lubricant substances (logKow > 10). The toxicity data were used to evaluate existing predicted no-effect concentrations (PNECs) that had originally been derived with the target lipid model, which did not have these higher order chronic plant endpoints. The initial exposure concentrations were set at the PNECs to provide an independent validation of the PNEC. This evaluation was performed to expand the domain of applicability of the PNEC to VHOCs and for the chronic terrestrial plant endpoints. No effects were observed on plant biomass or inflorescence production at these low exposure concentrations, demonstrating that the established PNEC is protective of long-term plant health. The results of the present study confirm that the new dosing method is fit for purpose, and that the existing PNEC framework can be extended to chronic plant endpoints for VHOCs.

Concerning the entrance of oil into the Persian Gulf due to the presence of oil fields in this ecosystem, a wide investigation was carried out in 2017 to evaluate the hydrocarbons source identification and chemical fingerprinting. To this end, surface sediments were collected from the Persian Gulf. In the laboratory, compounds (n-alkanes, PAHs, hopane and sterane) were then extracted with a Soxhlet system and two steps of chromatographic columns and analyzed using a GC-MS instrument. The results showed that the concentrations of the n-alkanes and Σ30 PAHs increased with a reduction in distance from hot spots. This suggests that high concentrations of hydrocarbons in the locations near the hot spots might be due to oil leakage, transportation of and exploration for oil, pipeline fractures and industrial activities. A positive relation between total organic matter (TOM) and hydrocarbons was observed. A common petrogenic hydrocarbon source was strongly implied in most places by the presence of unresolved compounds resolved (UCM), lower molecular weight/higher molecular weight (LMW/HMW) and carbon preference index (CPI) ratios < 1. Typical profiles of petrogenic PAHs with predominant alkyl substituted naphthalene and phenanthrene, various PAH ratios and multivariate analysis showed that PAHs were mainly derived from petrogenic sources. Simultaneous use of n-alkanes and PAHs in source identification can be effective to precisely specify the hydrocarbon sources in complicated mixture ecosystems. Furthermore, using multivariate analysis and chemical fingerprinting of n-alkanes, PAHs, hopanes and sterane confirmed that Hendijan crude oil may be the source of the sediment pollution in the study area.

Oxytetracycline (OTC) and Florfenicol (FF) are prevalent antibiotics choices in both fish production and livestock farming. A comprehensive understanding of their effects is paramount for effective control of their use and for elucidating their physiological and pharmacological implications. In our investigation, zebrafish larvae were subjected to varying concentrations of OTC, FF or a combination of OTC + FF during 96 h. We observed behavioral alterations in the group exposed to OTC + FF. These fish displayed increased mobility, spent more time in the central zone, exhibited reduced turn angles, and experienced an impaired optomotor response. Coincidentally, our data provided evidence of reduced anxiety-like behavior in zebrafish larvae treated with OTC and FF, while also demonstrating the adverse effects of antibiotics on the optomotor response. Anxiety-like behavior plays an important role in species survival, acting as a key mechanism for adaptation and protection. The absence of such behavior can increase organism vulnerability in the environment. Thus, this study showed the behavioral consequences of OTC and FF exposure in zebrafish larvae, highlighting the impact of the combined toxicity of these antibiotics.

Metallic elements in excess may cause adverse biological effects. Flamingos, with a lifespan of up to 50 years, are therefore likely to accumulate metals from the highly saline waters where they feed and breed. The concentrations of accumulated metals would be reflected in organs, feathers, and eggs. There are no data available on metals in flamingo egg contents. Concentrations of 24 elements in egg content and eggshells from Lesser Flamingo Pheoniconaias minor breeding at Kamfers Dam South Africa suggest metal pollution, but with considerable variation between eggs, reflecting their nonbreeding, nomadic movements. Strontium in eggshells exceeded toxic reference values. Copper in egg contents suggests reproductive stress. Lower than-expected metal concentrations (especially mercury) in egg contents we attributed to several excretory pathways prior to oogenesis and embryogenesis, thereby protecting the embryo. Molar concentrations of selenium and mercury were not correlated. However, the mean molar ratio of 8.2 suggests a highly protective effect afforded by selenium. Relative compositional differences show that eggshells are not a proxy for egg contents. We highlight previously unrecognised routes of post-hatching pollutant uptake via consumption of eggshells and parental crop milk. The post-hatching development of flamingo chicks may therefore be more susceptible to pollutant disruption compared with embryonic development. We conclude that P. minor eggs are not good indicators of environmental metal pollution, nor does it reflect post-hatching risks. This first report on metal concentrations in egg contents of any flamingo species shows that a more nuanced approach is needed to protect Phoenicopteridae from pollution.

Fertilization with animal manure and sewage sludge, and the use of sewage water for irrigation, can lead to high antimicrobial concentrations in agricultural soils. Once in soil, antimicrobials can exert direct and indirect toxic effects on plants by misbalancing plant-microbe symbiotic relationships. We performed germination tests to determine the optimum germination conditions of 24 plant species (10 crop and 14 wild species). Subsequently, we analyzed the differences in oxytetracycline and sulfamethazine phytotoxicity in 19 plant species for which optimum germination conditions could be established. The root elongation of the majority of wild species was inhibited in the presence of oxytetracycline and sulfamethazine, whereas crops were mainly affected by oxytetracycline. There were no differences in sensitivity to oxytetracycline between crop and wild plant species, whereas wild plants were significantly more susceptible to sulfamethazine than crop species. Thus, to cover both productivity and biodiversity protection goals, we recommend pharmaceuticals' predicted no-effect concentration (PNEC) values based on crop and wild plant species phytotoxicity data.

Toxic effects of herbicide atrazine (ATR) have been evaluated in various aquatic organisms, but our understanding of its potential impacts in reptile species remains limited. In this study, the functional performances, and gut microbiota and liver metabolite alterations of ATR-exposed Mauremys sinensis juveniles were measured to evaluate its potential toxic effects in turtles. ATR exposure had no impact on the growth rate, but would allow turtles to right themselves more quickly. Despite having no difference in gut microbial diversity, the microbial composition was slightly changed after ATR exposure. For example, a few bacterial genera were shown to increase in exposed turtles (e.g., Turicibacter), or only observed in higher-concentration groups (e.g., Dialister, Alistipes, Delftia). Similarly, only a few identified liver metabolites were found to change significantly (e.g., decreased levels of arginine and N-acetylneuraminate; increased levels of glutathione and isomaltose in low-concentration exposure group) after ATR exposure. Overall, minor alterations in gut microbial composition and liver metabolite indicated that ATR exposure at environmentally-relevant concentrations only produced limited impacts in turtle species, although these alterations might have potentially adverse consequences on the long-term health of exposed turtles.

This study investigated the accumulation (deposition) of 13 potentially toxic elements (PTEs) in moss tissue (dominated by Hypnum cupressiforme at 64% and Pseudoscleropodium purum at 13.4%) collected from 33 rural sites of Tuscany (Central Italy). In addition, the magnetic susceptibility of moss was measured to provide insight into the accumulation of anthropogenic particles. Prior to the analysis, moss samples were washed, and the rinse waters were also analyzed for PTEs. Exploratory spatial analysis and source identification of airborne PTEs were carried out; the results suggest that the main anthropogenic airborne pollutants in the region were Cd and Zn from long-range transport with the mean concentrations of 0.12 mg/kg and 18.2 mg/kg, respectively. Wet deposition was the dominant source for these elements, which were however accumulated by moss in modest amounts. Soil also emerged as an important source for several elements i.e., Al, Fe, Cr and Ni, but its contribution was largely unpredictable, as indicated by the lack of correlation between moss tissue and rinse water concentrations. Further, sample washing of a few seconds was not effective in fully removing soil particles. The sensitivity analysis suggested that the results of the study are reliable and did not depend on the methodology used for data analysis. This is the first comprehensive regional-scale study in rural areas of Tuscany using moss biomonitoring, and as such, it provides important baseline data for future research.

Oil spills and tarballs are significant pollutants in marine environments, and identifying their sources is crucial for mitigating environmental impacts. This study aims to determine the primary sources of petroleum spills and tarballs along the shores of Genaveh (northwest of the Persian Gulf) by employing chemical fingerprinting techniques and biomarkers. Specifically, petroleum hydrocarbons were analyzed in 19 tarball samples, 13 surface sediment samples from the Genaveh coast, and reference oil samples from 21 offshore oil platforms located in the Bahregan, Khark, Lavan, Siri, and Hendurabi regions. Samples were extracted using the Soxhlet extraction method, followed by two-step column chromatography, and the compositions of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes were determined using gas chromatography-mass spectrometry (GC-MS). The concentration of PAHs in coastal sediment samples from Genaveh ranged from 345 (S841) to 27,374 ng/g-dw (S852), indicating moderate to very high pollution levels. The total concentration of aliphatic hydrocarbons in coastal sediment samples from Genaveh ranged from 8,694 (S842) to 27,374 µg/g-dw (S851), significantly exceeding n-alkane concentrations reported in surface sediments from many other regions worldwide, suggesting considerable pollution levels. For the 19 collected tarball samples, PAH concentrations varied from 597.5 to 10,173 ng/g-dw, while n-alkane concentrations ranged from 27,136 to 66,341 µg/g-dw, which may indicate differences in age or freshness. Diagnostic indicators, such as undifferentiated complex mixtures (UCM), a carbon preference index (CPI) close to 1 for n-alkanes, diagnostic ratios of PAHs, and ratios of hopanes and steranes, pointed to a predominantly petrogenic origin of hydrocarbons in the coastal sediments of Genaveh. The principal component analysis (PCA) results revealed a distinction between oil samples from the Lavan, Hendurabi, and Siri platforms, indicating oil leakage from the Khark oilfield pipelines (Doroud and Forouzan) and Bahregan oilfields (Bahregansar and Soroosh) as a major pollution source. This implies that both oil spills, observed in the coastal sediments of Genaveh, and episodic spills, represented by tarballs, originate from a similar, homogeneous source. Only sediment samples from stations S841 and S812 were not influenced by tarballs, suggesting pollution from a different source compared to other sediment samples.

Removing lowermost dams can reestablish fish passage on Great Lakes tributaries. This can increase the transfer of contaminants from anadromous fish to piscivorous wildlife upstream; however, concentrations of bioaccumulative contaminants in Great Lakes fish have decreased over the last several decades. We analyzed concentrations of PCBs and the toxic equivalence (TEQs) calculated from PCBs, DDTs, other organochlorine pesticides, and PBDEs in the plasma of bald eagle nestlings above and below lowermost dams on five river systems in Michigan from 1999 to 2013. We examined relationships between contaminants and metrics of reproductive success from 1997 to 2018, including the effects of year and location relative to the lowermost dam. ΣPCB and p,p'-DDE were important in characterizing differences in contaminant mixtures above and below dams. Concentrations of contaminants were generally greater below dams than above. There were generally greater nest success and more nestlings per nest below dams, but nest location explained little variability (R values = 0.03-0.15). Neither ΣPCB nor p,p'-DDE was a significant predictor of 5-year productivity means by river reach despite concentrations exceeding previously established effects thresholds for healthy bald eagle populations in the Great Lakes (≥ 1 nestling/nest). Our study indicates that dams may continue to reduce the upstream movement of contaminants to bald eagles, but at the measured concentrations, contaminants did not impair productivity and reproductive success as indicated by nestlings per nest. Additional information about population dynamics could clarify population-level effects of contaminants on bald eagles and to what degree these populations are self-sustaining throughout the Great Lakes.

Understanding the relationship between the aerobic transformation of organic matter (OM) and the bioavailability of lead to plants may allow the safe application of organic fertilizers (OF) in agriculture. The present study aimed to elucidate the relationship of different OM structures with Pb, revealing the action of OF (poultry litter) on Pb dynamics, presenting the effects of OM transformations on bioavailability and transfer to vegetables produced in tropical mountain agroecosystems (TMA). The association of Pb with hydrophilic structures (CAlk-O and CAlk-di-O) during the aerobic transformation of poultry litter (PL) contributes to the increase in the water-soluble form of this metal (3.17-15.30%). The structural changes promoted by the transformation of OM, in addition to reducing the adsorption capacity of Pb in PL (Kd reduction from 1135.50 to 87.49), favor the formation of outer-sphere complexes. PL that have a more labile structure, i.e., those that are less humified, have greater affinity for Pb. The greater affinity of Pb for labile structures that are preserved in PL during OM transformations contributed to its increase and transport to edible plant parts. Considering the edible parts of vegetables grown in TMA and fertilized with fresh PL, 100% of broccoli, 91.78% of cabbage, 80.00% of tomato, 65.96% of parsley, 49.19% of lettuce, and 32.88% of cauliflower showed Pb contamination that exceeded the permitted level. Therefore, OF contributes to lead contamination of food produced in TMA, representing a risk to human health. Studies are needed to propose additional treatments for this residue before its use.

In order to investigate the distributions and possible dispersion mechanism(s) of naturally occurring radioactive materials (NORMs: Ra, Th, and K) from coal-based brick kilns, a systematic set (n = 60) of coal, ash, surface-soil, and subsurface soil samples were analyzed. High-quality analytical data of U, Th and K obtained from HPGe detector and TRIGA Mark-II research reactor-based neutron activation analysis were converted to the corresponding radioactivities. Average (n = 10) radioactivities of Ra, Th, and  K in coal samples were 15.6, 16.7, and 145.5 Bq.kg, respectively, where only  K surpassed the corresponding global mean value. Average (n = 10) radioactivities of Ra, Th, and  K in ash samples were 62.7, 88.5, and 521 Bq.kg, respectively, where only Ra was within the established limit. In soil samples, average (n = 40) activities of Ra, Th, and  K were 62.7, 95.1, and 641 Bq.kg, respectively, which have surpassed the corresponding worldwide mean values. The observed differences in activity levels between soil samples collected near and far from the kilns, as well as between topsoil and subsoil samples, suggest the presence of distinct transport mechanisms for NORMs within the pedosphere. Dispersions of NORMs from the brick kilns to the ambient pedosphere are largely governed by aerodynamic convection and hydrodynamic leaching. These mechanisms are also influenced by geochemical mobility and relative solubility of NORMs, as well as factors such as rainfall patterns and wind-flow direction. Radiological indices invoke long-term carcinogenic-risks, whereas aerodynamic convection of finer particles (coal fly ash) from chimneys can cause significant health hazards to the nearby dwellers. Scientific processes as well as public awareness are essential to mitigate the risks.

Isocyanates are used as raw materials for polyurethane foams, paints, and building materials. The isocyanates can cause acute adverse health effects such as irritation of the respiratory tract, skin, and eyes, and induce asthma and sick house syndrome. However, investigations into the potential sources and risk assessments of indoor isocyanates are limited. Thus, this study aimed to determine the sources and exposure routes of isocyanates and to assess their risk in indoor environments. The results showed that household products, such as infant chairs, mattresses, and polyurethane foam spray, used in indoor environments are potential sources of atmospheric isocyanic acids (ICA). Toluene diisocyanate and methyl isocyanate pose relatively high risks to indoor environments. Total concentrations of isocyanates ranged from 38.2 to 1570 ng g in infant chairs, mattresses, and spray polyurethane foams. The indoor products can be indoor sources of ICA because emission rates of ICA from household products were observed in all products (0.0536-1.37 ng g d). Field observations showed that isocyanate concentrations in house-dust samples ranged from 0.194±0.126 (ethyl isocyanate) to 70.1±67.8 (ICA) ng g. Atmospheric isocyanate concentrations ranged from 0.0030±0.020 (propyl isocyanate) to 26.0±14.3 (ICA) ng m. An estimation of human exposure demonstrated that air inhalation was the major route of isocyanate exposure. The minimum margin of exposure values of methyl isocyanate and toluene diisocyanate were 523 and 655, respectively, for children, indicating that they may pose a relatively high risk.

This study focuses on the "El Lavadero" tailings deposit, a mining environmental liability (MEL) located near the town of San Felipe de Jesús, Sonora, in northwest Mexico. The objective was to determine the total arsenic (As) content, its granulometric and geochemical distribution, as well as its mobilization capacity and bioavailability. The results from oxidized and unoxidized tailings showed low potential of hydrogen (pH) values (2.4-5.7) and high concentrations of total arsenic (8235-36,004 mg kg), predominantly in the finer granulometric fractions (< 0.05 mm). Arsenic also prevails in the finest fraction of agricultural soil (> 2 mm). These fine particles could present adverse environmental effects due to their potential to be transported by leaching and water suspension. In contrast, arsenic in the effluent sediments is primarily found in the coarser fraction (> 2 mm). A significant proportion of arsenic in the tailings (5-40%) was found in the non-residual geochemical fractions (I + II + III) (1106-7675 mg kg), indicating potential for mobilization and bioavailability. Depending on environmental conditions (redox potential and pH), arsenic can redissolve and exhibit high mobility in abiotic media, which may ultimately impact the environment and human health. Therefore, it is crucial to rehabilitate the "El Lavadero" MEL to prevent further environmental damage. This study provides useful information to understand some phenomena in other global mining environmental liabilities, such as mobilization and bioavailability of arsenic and its possible impact on the surrounding environment and biota, contributing to the worldwide research of ecosystems polluted by mining activity, especially in arid and semi-arid climates.

Pesticides have posed health risks to consumers and the ecosystems in different parts of the world, including Ethiopia, and researchers recommend continual assessments of pesticide residues in food items and ecosystems to know the level of risks. This study aimed to quantify the pesticide residues in samples of cabbage and fish and their risks to humans and the ecosystems. The cabbage samples were collected from April to May 2023 from 3 market centers, and the fish samples were collected in June 2023 from two fish ponds of Fogera District of Ethiopia using appropriate sampling procedures, extracted using the modified QuEChERS methods, and analyzed using a triple quadrupole GC/MS technique to quantify the pesticide residues and level the risks to humans and the ecosystems. The findings of the present study confirmed that all the samples of cabbage and fish were contaminated with pesticide residues. More than 44% and 37% of pesticide residues detected in both cabbage and fish samples were organochlorine and organophosphate pesticides, respectively. Furthermore, 92.86% of the pesticide residues and 96.43% of the maximum pesticide residues in cabbage exceeded the MRL and the TQ set by the Codex Alimentarius Commission. The sum total hazard indices of the pesticide residues in the cabbage (22.320) and fish (43.071) were much higher than the threshold value. Though Fogera District is a potential area for fish production in ponds, agricultural pesticides are a threat to the sector. Establishing an efficient system of monitoring for the pesticide supply chain and application procedures, choosing the appropriate pesticide types, timing in spraying, and establishing pesticide-free buffer zones are crucial steps in mitigating the negative effects of pesticides in the area.

In general, mercury (Hg) undergoes biomagnification in aquatic systems. The absence of Hg biomagnification in a certain aquatic environment constitutes an exceptional finding and this seems to be the case for Sepetiba Bay, in Rio de Janeiro state (RJ), Brazil. There are three distinct ecological populations of Guiana dolphins in the Sepetiba Bay (SB)-Ilha Grande Bay (IGB) Complex, inhabiting: (1) the inner part of SB; (2) SB entrance; and (3) IGB. In addition, there are two other delphinid species, rough-toothed dolphin and Atlantic spotted dolphin, that feed on the SB-IGB Complex. Considering the widely employed use of cetaceans as sentinels of environmental contamination by bioaccumulative toxicants, we have biopsy sampled individuals of the abovementioned ecological populations/species for measuring skin Hg concentrations. Two Bryde's whales and one humpback whale were biopsied in the SB-IGB Complex as well. Skin Hg concentrations [μg g dry weight (dw)] of Guiana dolphins were the highest in IGB, followed by SB entrance and the inner part of SB (0.99-5.47; 0.09-6.00; 0.08-2.22). Considering all species investigated in the present study, skin Hg concentrations were found in the following order: humpback whale < Bryde's whale < Guiana dolphins from SB inner part < Guiana dolphins from SB entrance < Guiana dolphins IGB = Atlantic spotted dolphins < rough-toothed dolphins. The skin Hg concentrations found in Guiana dolphins from the inner part of Sepetiba Bay (0.08-2.22) and rough-toothed dolphins from the SB-IGB Complex (1.26-20.0) are among the lowest and highest ever reported for dolphins worldwide, respectively.

Historical changes of sediment characteristics and levels of inorganic and organic contaminants were studied in dated sediment cores from the Visovac Lake, situated in the Krka National Park, Croatia, to identify the main sources of anthropogenic pressures on this highly protected system. Depth distributions of lithogenic elements showed a steady decrease of terrigenous inputs due to the reduction in agricultural activities in the area, which was particularly pronounced during the 1991-1995 war in Croatia. Vertical and longitudinal distributions of Cd and Zn indicated that they are predominately of anthropogenic origin. The historical profiles of these toxic metals coincide well with the recorded production of metal industry in the upper reach of the Krka River with a sharp decrease reflecting the interruption by the war and slow recovery afterwards. By contrast, the recovery of the tourist industry in Krka NP after the war was accompanied by increasing contamination by elements characteristic of boat and car traffic (Sn, Cu, Pb) as well as oil pollution. The contamination with polycyclic aromatic hydrocarbons and polychlorinated biphenyls was only moderate. Although levels of metallic and organic contamination can be considered relatively low, the observed shift from industrial to tourism-related sources indicated that touristic activities should also be regarded as a possible threat for this vulnerable karst aquatic ecosystem.