Trophic Magnification of Legacy (PCB, DDT and Hg) and Emerging Pollutants (PFAS) in the Fish Community of a Small Protected Southern Alpine Lake (Lake Mergozzo, Northern Italy)

Anthropogenic pollution may enhance natural transformation in water, favouring the spread of antibiotic resistance genes

Aquatic ecosystems are crucial in the antimicrobial resistance cycle. While intracellular DNA has been extensively studied to understand human activity's impact on antimicrobial resistance gene (ARG) dissemination, extracellular DNA is frequently overlooked. This study examines the effect of anthropogenic water pollution on microbial community diversity, the resistome, and ARG dissemination. We analyzed intracellular and extracellular DNA from wastewater treatment plant effluents and lake surface water by shotgun sequencing. We also conducted experiments to evaluate anthropogenic pollution's effect on transforming extracellular DNA (using Gfp-plasmids carrying ARGs) within a natural microbial community. Chemical analysis showed treated wastewater had higher anthropogenic pollution-related parameters than lake water. The richness of microbial community, antimicrobial resistome, and high-risk ARGs was greater in treated wastewaters than in lake waters both for intracellular and extracellular DNA. Except for the high-risk ARGs, richness was significantly higher in intracellular than in extracellular DNA. Several ARGs were associated with mobile genetic elements and located on plasmids. Furthermore, Gfp-plasmid transformation within a natural microbial community was enhanced by anthropogenic pollution levels. Our findings underscore anthropogenic pollution's pivotal role in shaping microbial communities and their antimicrobial resistome. Additionally, it may facilitate ARG dissemination through extracellular DNA plasmid uptake.

Occurrence and risk characterization of per- and polyfluoroalkyl substances in seafood from the Persian Gulf

Potential exposure to 14 per- and polyfluoroalkyl substances (PFAS) through seafood consumption was investigated in widely consumed seafood (Platycephalus indicus, Lethrinus nebulosus, and Penaeus semisulcatus) from the Persian Gulf. A total of 61 samples of fish and prawns were purchased from local fishers at Bushehr port (Persian Gulf, South-West of Iran) and were analyzed for PFAS compounds. In addition, potential factors influencing factor of PFAS bioaccumulation in fish and invertebrates such as age, sex, and habitat, were investigated. ƩPFAS concentrations were in the range of 2.3- 6.1 ng/g-d.w (mean = 3.9 ± 1.9) in studied species which are equal to 0.46-1.2 ng/g-w.w according to their conversion factor. Perfluorooctane sulfonic acid (PFOS) was the most abundant perfluorinated compound in studied organisms and tissues. The results of correlation analysis showed that the bioaccumulation of PFAS in aquatic organisms is significantly correlated to the length of the compound's carbon chain, the identity of anionic group, and organism's age, sex, and habitant. The risk assessment using hazard index calculation and Monte-Carlo simulation indicated that weekly consumption of prawn and fish fillets does not pose a health risk to adults but might threaten children's health. However, the risk posed by PFAS exposure via entire fish or fish liver intake is an important issue for wild marine mammals (i.e., dolphins). So, accurate and routine monitoring of PFAS in aquatic environments seems mandatory to preserve wildlife and human health in the Persian Gulf.

The biological invasion of an apex predator (Silurus glanis) amplifies PCB transfer in a large lake food web

Invasive species can affect food web structure possibly modifying the transfer of pollutants in ecosystems but this facet of biological invasion remains largely unexplored. We examined how trophic and ontogenetic characteristics of the invasive European catfish could differ from its native counterpart, the Northern pike, possibly resulting in the amplification of PCB transfer to the higher trophic levels in a large lake food web. The PCB contents of catfish and pike were on average low (Ʃ7 PCBi 42.4 ± 38.6 ng g-1 ww and 37.9 ± 49.4 ng g-1 ww respectively) and dominated by PCB153 (~35 % of the PCB contamination). Only the largest pike (126 cm) slightly exceeded the European sanitary threshold of 125 ng g-1 ww Ʃ6 PCBi-NDL. Both species increased in trophic position with body size while catfish had clearly higher littoral reliance than pike indicating they exploited complementary trophic niches. PCB biomagnification was identified only for catfish (PCB153, Ʃ7 PCBi) leading to trophic magnification factor of ~5. PCB ontogenetic bioaccumulation was pervasive for catfish (PCB101, PCB118, PCB153, PCB138 and Ʃ7 PCBi) and identified for pike only regarding PCB101. The derived size accumulation factors (~1.02) indicated a size-doubling PCB contamination of ~40 cm for catfish. This finding suggested that catfish would exceed the European sanitary threshold at body size larger than 168 cm possibly constraining their commercial exploitation. Our results highlighted that the invasive catfish was a littoral-oriented apex predator occupying an alternative trophic niche as compared to pike thereby modifying the lake food web structure that resulted in an enhancement of PCB transfer to higher trophic levels. The biomagnification and ontogenetic bioaccumulation of catfish underlined the impact of this biological invasion on the fate of PCB in the ecosystem. Finally, the remarkable inter-individual PCB contamination suggested variable inter-individual PCB exposure likely associated to localized hotspots of PCB contamination in the lake.

Research Priorities for the Environmental Risk Assessment of Per- and Polyfluorinated Substances

Per- and polyfluorinated substances (PFAS) are a group of thousands of ubiquitously applied persistent industrial chemicals. The field of PFAS environmental research is developing rapidly, but suffers from substantial biases toward specific compounds, environmental compartments, and organisms. The aim of our study was therefore to highlight current developments and to identify knowledge gaps and subsequent research needs that would contribute to a comprehensive environmental risk assessment for PFAS. To this end, we consulted the open literature and databases and found that knowledge of the environmental fate of PFAS is based on the analysis of <1% of the compounds categorized as PFAS. Moreover, soils and suspended particulate matter remain largely understudied. The bioavailability, bioaccumulation, and food web transfer studies of PFAS also focus on a very limited number of compounds and are biased toward aquatic biota, predominantly fish, and less frequently aquatic invertebrates and macrophytes. The available ecotoxicity data revealed that only a few PFAS have been well studied for their environmental hazards, and that PFAS ecotoxicity data are also strongly biased toward aquatic organisms. Ecotoxicity studies in the terrestrial environment are needed, as well as chronic, multigenerational, and community ecotoxicity research, in light of the persistency and bioaccumulation of PFAS. Finally, we identified an urgent need to unravel the relationships among sorption, bioaccumulation, and ecotoxicity on the one hand and molecular descriptors of PFAS chemical structures and physicochemical properties on the other, to allow predictions of exposure, bioaccumulation, and toxicity. Environ Toxicol Chem 2023;42:2302-2316. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Developing Methods for Assessing Trophic Magnification of Perfluoroalkyl Substances within an Urban Terrestrial Avian Food Web

We investigated the trophic magnification potential of perfluoroalkyl substances (PFAS) in a terrestrial food web by using a chemical activity-based approach, which involved normalizing concentrations of PFAS in biota to their relative biochemical composition in order to provide a thermodynamically accurate basis for comparing concentrations of PFAS in biota. Samples of hawk eggs, songbird tissues, and invertebrates were collected and analyzed for concentrations of 18 perfluoroalkyl acids (PFAAs) and for polar lipid, neutral lipid, total protein, albumin, and water content. Estimated mass fractions of PFCA C8-C11 and PFSA C4-C8 predominantly occurred in albumin within biota samples from the food web with smaller estimated fractions in polar lipids > structural proteins > neutral lipids and insignificant amounts in water. Estimated mass fractions of longer-chained PFAS (i.e., C12-C16) mainly occurred in polar lipids with smaller estimated fractions in albumin > structural proteins > neutral lipids > and water. Chemical activity-based TMFs indicated that PFNA, PFDA, PFUdA, PFDoA, PFTrDA, PFTeDA, PFOS, and PFDS biomagnified in the food web; PFOA, PFHxDA, and PFHxS did not appear to biomagnify; and PFBS biodiluted. Chemical activity-based TMFs for PFCA C8-C11 and PFSA C4-C8 were in good agreement with corresponding TMFs derived with concentrations normalized to only total protein in biota, suggesting that concentrations normalized to total protein may be appropriate proxies of chemical activity-based TMFs for PFAS, which predominantly partition to albumin. Similarly, TMFs derived with concentrations normalized to albumin may be suitable proxies of chemical activity-based TMFs for longer-chained PFAS, which predominantly partition to polar lipids.

Occurrence of per- and polyfluoroalkyl substances in aquatic environments and their removal by advanced oxidation processes

Per- and polyfluoroalkyl substances (PFAS), one of the main categories of emerging contaminants, are a family of fluorinated organic compounds of anthropogenic origin. PFAS can endanger the environment and human health because of their wide application in industries, long-term persistence, unique properties, and bioaccumulation potential. This study sought to explain the accumulation of different PFAS in water bodies. In aquatic environments, PFAS concentrations range extensively from <0.03 (groundwater; Melbourne, Australia) to 51,000 ng/L (Groundwater, Sweden). Additionally, bioaccumulation of PFAS in fish and water biota has been stated to range from 0.2 (Burbot, Lake Vättern, Sweden) to 13,900 ng/g (Bluegill samples, U.S.). Recently, studies have focused on PFAS removal from aqueous solutions; one promising technique is advanced oxidation processes (AOPs), including microwaves, ultrasound, ozonation, photocatalysis, UV, electrochemical oxidation, the Fenton process, and hydrogen peroxide-based and sulfate radical-based systems. The removal efficiency of PFAS ranges from 3% (for MW) to 100% for UV/sulfate radical as a hybrid reactor. Therefore, a hybrid reactor can be used to efficiently degrade and remove PFAS. Developing novel, efficient, cost-effective, and sustainable AOPs for PFAS degradation in water treatment systems is a critical area of research.

Multicompartmental monitoring of legacy and currently used pesticides in a subtropical lake used as a drinking water source (Laguna del Cisne, Uruguay)

A pilot annual monitoring survey (April 2018-March 2019) was conducted to investigate the presence of pesticides in superficial water and fish in Laguna del Cisne, one of the most critical drinking water sources in Uruguay. A total of 25 pesticide residues were detected in superficial water (89.3 % of the samples). Pesticide's temporal distribution was associated with crops and livestock practices, with higher occurrences in spring and summer than in autumn and winter. The most frequent compounds in superficial water were the insecticide chlorantraniliprole, and the herbicides glyphosate (including its metabolite AMPA) and metolachlor. The levels of Organochlorine pesticide, p,p'-DDT, was in some cases two order of magnitude above the international water quality guidelines for Ambient Water Criteria. In fishes, eight different pesticides were detected, at concentrations from 1000 to 453,000 ng·kg^-1. The most frequent pesticides found were propiconazole, chlorpyrifos, and p,p'-DDE. The widespread occurrence of pesticides in fish suggests potential exposure effects on fish populations and the aquatic ecosystem. The sampling approach of this work allowed monitoring the continuous concentrations of several pesticides in surface waters and fishes to establish the influence from past and current agriculture practices in Laguna del Cisne basin. For safety measures, continuous monitoring programs must be performed in this system to prevent toxicity impacts on aquatic organisms and human health.

Seasonal and plurennial changes of POPs repository in freshwater zooplankton: A 10-year study in the large deep subalpine Lake Maggiore (Italy)

Determining the concentration of POPs (Persistent Organic Pollutants) such as total dichlorodiphenyltrichloroethane (DDT_tot) and polychlorinated biphenyls (PCBs) in the zooplankton is essential for evaluating the level of toxicity in the environment and the risk to ecosystem health. The extent to which POPs persist in the environment and affect human health depends on accumulation in the different components of the zooplankton community such as particle feeders and/or predators and their subsequent consumption by fish, which varies seasonally. We analyzed ten-years (2011-2020) of seasonal data on POPs in the crustacean zooplankton community of Lake Maggiore (Italy). The concentration of total DDTs, as sum of all congeners ranged between 23.5 and 156.9 ng/g dry weight, while sumPCB₁₄ ranged from 24.4 and 133.6 ng/g dry weight. We traced particle feeders' vs predatory taxa within the zooplankton community using carbon and nitrogen stable isotopic values. POPs concentration was significantly related to the nitrogen isotopic values. The zooplankton biomass increase in Spring was important, both through this being a period of increased metabolism and activity of planktivorous fish and also as it was the period when the zooplankton repository of POPs was at a maximum. DDT_tot stocked in zooplankton ≥450 μm was up to 275 ng/m², while sumPCB₁₄ was 285 ng/m² in 2013. A decrease of DDT_tot stocked in the zooplankton repository characterized the last five years examined, when mean annual values (14.8-56.9 ng/m²) were less than half those of the previous period (50.7-128.6 ng/m²).

A worldwide evaluation of trophic magnification of per- and polyfluoroalkyl substances in aquatic ecosystems

A review of the published literature on the trophic magnification factor (TMF) for per- and polyfluoroalkyl substances (PFAS) was conducted to assess how biomagnification varies across aquatic systems worldwide. Although the TMF has been recognized as the most reliable tool for assessing the biomagnification of organic contaminants, peer-reviewed studies reporting TMFs for PFAS are few and with limited geographical distribution. We found 25 published studies of the biomagnification of 35 specific PFAS, for which the TMF was generated through linear regression of individual log-PFAS concentration and the δ¹⁵ N-based trophic position of each organism in the food webs. Studies were concentrated mainly in China, North America, and Europe, and the most investigated compound was perfluorooctane sulfonate (PFOS), which was frequently shown to be biomagnified in the food web (TMFs ranging from 0.8 to 20). Other long-chain carboxylates displayed substantial variation in trophic magnification. Observed differences in the TMF were associated with length of the food web, geographic location, sampling methodologies, tissue analyzed, and distance from known direct PFAS inputs. In addition to biomagnification of legacy PFAS, precursor substances were observed to bioaccumulate in the food web, which suggests they may biotransform to more persistent PFAS compounds in upper trophic levels. This review discusses the variability of environmental characteristics driving PFAS biomagnification in natural ecosystems and highlights the different approaches used by each study, which can make comparisons among studies challenging. Suggestions on how to standardize TMFs for PFAS are also provided in this review. Integr Environ Assess Manag 2022;18:1500-1512. © 2022 SETAC.

Bioaccumulation and trophic transfer of perfluorinated alkyl substances (PFAS) in marine biota from the Belgian North Sea: Distribution and human health risk implications

Per- and polyfluorinated alkyl substances (PFAS) are highly persistent chemicals, which pose a potential risk for aquatic wildlife due to their bioaccumulative behaviour and toxicological effects. Although the distribution of PFAS in marine environments has been studied worldwide, little is known on the contamination of PFAS in the southern North Sea. In the present study, the bioaccumulation and trophic transfer of Perfluoroalkyl acids (PFAAs) was studied in liver and muscle tissue of seven fish species and in whole-body tissue of two crustacean species, collected at 10 sites in the Belgian North Sea. Furthermore, the human and ecological health risks were examined. Overall, perfluorooctane sulfonate (PFOS) was predominant in all matrices and other long-chain PFAS were frequently detected. Mean PFOS concentrations ranged from <LOQ to 107 ng/g (ww) in fish liver, from <LOQ to 24 ng/g ww in fish muscle and from 0.29 to 5.6 ng/g ww in crustaceans. Elevated perfluorotridecanoic acid (PFTrDA) concentrations were detected in fish liver from the estuarine and coastal region (<LOQ-116 ng/g ww), indicating a specific point source of this compound. Based on stable isotope analysis, no distinctive trophic transfer patterns of PFAS could be identified which implies that the bioconcentration of PFAS from the surrounding abiotic environment is most likely dominating over the biomagnification in the studied biota. The consumption of commercially important species such as the brown shrimp (Crangon crangon), plaice (Pleuronecta platessa), sole (Solea solea) and whiting (Merlangus merlangus) might pose potential health risks if it exceeds 17 g/day, 18 g/day, 26 g/day and 43 g/day respectively. Most PFOS measurements did not exceed the QS_biota,hh of 9.1 ng/g ww, however, the benchmark of 33 ng/g ww targeting the protection of wildlife from secondary poisoning was exceeded for 43% and 28% of the samples in plaice and sole.

Organohalogenated Substances and Polycyclic Aromatic Hydrocarbons in Fish from Mediterranean Sea and North Italian Lakes: Related Risk for the Italian Consumers

The primary source of persistent organic pollutant (POP) exposure is food, especially fish. European seabass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) are among the most eaten sea fish in Italy. Fish from lakes in Northern Italy, such as agone (Alosa agone), represent niche consumption for most people, but possibly constitute a much larger percentage of overall consumption volume for local residents. This study dealt with the presence of POPs in the above-mentioned fish species via GC-MS/MS analysis. None of the analytes for which maximum limits are in place showed concentrations above those limits. Moreover, none of the substances without maximum limits exceeded the provisional tolerable daily intake (PTDI) when given, nor did they exceed the more general values considered safe, even for 99th percentile consumers.

Comprehensive screening of polar emerging organic contaminants including PFASs and evaluation of the trophic transfer behavior in a freshwater food web

Bioaccumulation and trophic transfer of persistent legacy contaminants have been intensively characterized, but little is known on the contaminants of emerging concern (CECs) in freshwater food webs. Herein, we comprehensively screened CECs with a focus on polar substances and further evaluated their trophic transfer behavior in selected items from the food web of Lake Templin, Germany. Weselected one plankton, two mussel, and nine fish samples covering three trophic levels. With an effective multi-residue sample preparation method and high-resolution mass spectrometry-based target, suspect, and non-target screening, we characterized 477 targets and further screened unknown features in complex biota matrices. Of the 477 targets, 145 were detected and quantified in at least one species (0.02-3640 ng/g, dry weight). Additionally, the suspect and non-target analysis with experimental mass spectra libraries and in silico techniques (MetFrag and SIRIUS4/CSI:FingerID) enabled further identification of 27 unknown compounds with 19 confirmed by reference standards. Overall, the detected compounds belong to a diverse group of chemicals, including 71 pharmaceuticals, 27 metabolites, 26 pesticides, 16 per- and polyfluoroalkyl substances (PFASs), 4 plasticizers, 3 flame retardants, 11 other industrial chemicals and 14 others. Moreover, we determined the trophic magnification factor (TMF) of 34 polar CECs with >80% detection frequency, among which 6 PFASs including perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), perfluorotridecanoic acid (PFTrA), perfluorotetradecanoic acid (PFTeA), and perfluoroundecanoic acid (PFUnA), exhibited biomagnification potential (TMF =1.8 - 4.2, p < 0.05), whereas 5 pharmaceuticals (phenazone, progesterone, venlafaxine, levamisole, and lidocaine) and 1 personal care product metabolite (galaxolidone) showed biodilution potential (TMF = 0.4 - 0.6, p < 0.05).

Levels and Trophic Transfer of Selected Pesticides in the Lake Ziway Ecosystem

The levels of 30 selected pesticides and trophic biomagnification of DDT were investigated in biota samples of the Lake Ziway in the Rift valley region, Ethiopia. Carbon source and trophic position were calculated by using ¹³C and ¹⁵N stable isotopes, individually, and trophic magnification factors (TMFs) were inferred. Only DDT and its metabolites were quantified in all samples analyzed. The most prominent metabolite was p,p'-DDE with mean concentration ranging from the 0.82-33.69 ng g^-1 lipid weight. Moreover, the ratio of DDT/DDD + DDE in all the biota samples was less than 1 signifying historical DDT application. Regression of log [ΣDDT] vs TL (trophic level) among all biota species showed a significant correlation, indicating that DDTs are biomagnifying along with the food web of Lake Ziway with an estimated TMF of 2.75. The concentrations of DDTs and other organochlorine pesticides found in biota from Lake Ziway were, in general, lower than studies found in previous studies carried out in the same lake.

Biomonitoring of transboundary pollutants using moss in Japan's mountains

Long-range transported atmospheric pollutants (or transboundary pollutants) include trace metals with isotope ratios and compositions that vary from those of domestic pollutants, which threaten mountain ecosystems. These differences can be applied as indices to evaluate the influence of transboundary pollutants on mountain ecosystems. Mosses play important ecological functions in mountains and are sensitive to atmospheric deposition. Therefore, using these indices for moss biomonitoring can provide a more accurate indication of ecosystem health. However, studies on indices that are appropriate for moss biomonitoring are limited. Here, the effectiveness of moss biomonitoring using trace metal indices was examined to evaluate transboundary pollutants in mountainous areas in Japan. Transboundary pollutants in these areas originate from mainland Asia and are characterized by high lead isotope ratios, lead-to-zinc (Pb/Zn) ratios, and arsenic-to-vanadium (As/V) ratios. Given that the abundance of transboundary pollutants decreases with distance from mainland Asia, these three indices are also expected to vary with distance. The Pb isotope ratios were found to decrease with distance from mainland Asia; in contrast, the Pb/Zn and As/V ratios did not display any notable relationship with distance. These results are likely attributed to biological and environmental factors that affect trace metal content in moss. Thus, moss Pb isotope ratios are useful indicators of transboundary pollutants in Japan's mountains, offering an important tool for comparable moss biomonitoring studies in East Asia.

Determination of 56 per- and polyfluoroalkyl substances in top predators and their prey from Northern Europe by LC-MS/MS

Per- and polyfluoroalkyl substances (PFAS) are a group of emerging substances that have proved to be persistent and highly bioaccumulative. They are broadly used in various applications and are known for their long-distance migration and toxicity. In this study, 65 recent specimens of a terrestrial apex predator (Common buzzard), freshwater and marine apex predators (Eurasian otter, harbour porpoise, grey seal, harbour seal) and their potential prey (bream, roach, herring, eelpout) from northern Europe (United Kingdom, Germany, the Netherlands and Sweden) were analyzed for the presence of legacy and emerging PFAS, employing a highly sensitive liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method. 56 compounds from 14 classes were measured; 13 perfluoroalkyl carboxylic acids (PFCAs), 7 perfluoroalkyl sulphonic acids (PFSAs), 3 perfluorooctane sulfonamides (FOSAs), 4 perfluoroalkylphosphonic acids (PFAPAs), 3 perfluoroalkylphosphinic acids (PFPi's), 5 telomer alcohols (FTOHs), 2 mono-substituted polyfluorinated phosphate esters (PAPs), 2 di-substituted polyfluorinated phosphate esters (diPAPs), 6 saturated fluorotelomer acids (FTAS), 3 unsaturated fluorotelomer acids (FTUAs), 2 N-Alkyl perfluorooctane sulfonamidoethanols (FOSEs), 3 fluorotelomer sulphonic acids (FTSAs), 2 perfluoroether carboxylic acids (PFECAs) and 1 chlorinated perfluoroether sulphonic acid (Cl-PFESA). All samples were lyophilized before analysis, in order to enhance extraction efficiency, improve the precision and achieve lower detection limits. The analytes were extracted from the dry matrices through generic methods of extraction, using an accelerated solvent extraction (ASE), followed by clean-up through solid phase extraction (SPE). Method detection limits and method quantification limits ranged from 0.02 to 1.25 ng/g wet weight (ww) and from 0.05 to 3.79 ng/g (ww), respectively. Recovery ranged from 40 to 137%. Method precision ranged from 3 to 20 %RSD. The sum of PFAS concentration in apex predators livers ranged from 0.2 to 20.2 μg/g (ww), whereas in the fish species muscle tissues it ranged from 16 to 325 ng/g (ww). All analyzed specimens were primarily contaminated with PFOS, while the three PFPi's included in this study exhibited frequency of appearance (FoA) 100 %. C9 to C13 PFCAs were found at high concentrations in apex predator livers, while the overall PFAS levels in fish fillets also exceeded ecotoxicological thresholds. The findings of our study show a clear association between the PFAS concentrations in apex predators and the geographical origin of the specimens, with samples that were collected in urban and agricultural zones being highly contaminated compared to samples from pristine or semi-pristine areas. The high variety of PFAS and the different PFAS composition in the apex predators and their prey (AP&P) samples is alarming and strengthens the importance of PFAS monitoring across the food chain.

Accumulation of Selected Trace Elements in Shads from Three Lakes: First Insights from Italian Pre-Alpine Area

The investigation of trace element pollution is important for the environmental assessment and management of lacustrine ecosystems, especially when these represent critical freshwater resources in densely populated areas. In this context, this study determined the levels of 15 trace elements in muscles of shad, Alosa agone (Scopoli 1786), a commercialized zooplanktivourous fish, from three primary, but currently still poorly studied, Italian lakes, namely, Lake Como, Iseo, and Garda. Research findings show that shads present similar trace element accumulation patterns among lakes, except for arsenic, which occurs at lower levels in Lake Como. Results provide evidence also for mercury biomagnification in fish, whereas all the other selected trace elements undergo bio-dilution through the same trophic chain. Maximum allowable limits for foodstuff were exceeded for chromium and selenium in shads, whereas mercury levels exceeded the European Environmental Quality Standard biota. These results highlight the need for regular monitoring activities of trace elements in the biota of these lakes.

Perfluoroalkyl Substance Contamination Levels of Pike (Esox lucius L.) and Roach (Rutilus rutilus L.) from Selected Masurian Lakes in Eastern Europe

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are of increased concern because of their bioaccumulation in humans and the biota, the health risk they pose to humans and other animals, and their persistence in the environment. In the present study, the occurrence of PFAS in selected tissues from pike (Esox lucius L.) and roach (Rutilus rutilus L.) collected from two lakes in the Masurian Lake District (Poland) in eastern Europe was addressed. Ten PFAS were analyzed in the tissue of the brain, liver, kidneys, gonads, and muscles by micro-high-performance liquid chromatography coupled with tandem mass spectrometry. Only perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid, and perfluorodecanoic acid were detected above the limit of quantification. Concentrations in pike and roach from Ełckie Lake and Hańcza Lake were estimated to be 14/27 and 4.4/3.2 ng/g wet weight, respectively. The contributions of PFOS and PFOA to the sum of PFAS calculated for particular tissues for each fish species were higher than those of the other analyzed compounds: PFOS was found to be predominant in fish from Ełckie Lake, whereas PFOA predominated in fish from Hańcza Lake. It was noted that PFAS concentrations in tissues declined in the following order: kidney > gonads ≈ brain > liver > muscle. The sum of the greatest estimated PFAS concentration was 9.7 ng/g wet weight in kidneys of pike collected from Hańcza Lake. No correlation was noted between PFAS concentration and fish size. The information provided in our study gives a better understanding of the potential dependencies in PFAS distribution and accumulation in biota. Environ Toxicol Chem 2021;40:3317-3327. © 2021 SETAC.

Characterizations of novel pesticide-degrading bacterial strains from industrial wastes found in the industrial cities of Pakistan and their biodegradation potential

Background

Lack of infrastructure for disposal of effluents in industries leads to severe pollution of natural resources in developing countries. These pollutants accompanied by solid waste are equally hazardous to biological growth. Natural attenuation of these pollutants was evidenced that involved degradation by native microbial communities. The current study encompasses the isolation of pesticide-degrading bacteria from the vicinity of pesticide manufacturing industries.

Methods

The isolation and identification of biodegrading microbes was done. An enrichment culture technique was used to isolate the selected pesticide-degrading bacteria from industrial waste.

Results

Around 20 different strains were isolated, among which six isolates showed significant pesticide biodegrading activity. After 16S rRNA analysis, two isolated bacteria were identified as Acinetobacter baumannii (5B) and Acidothiobacillus ferroxidans, and the remaining four were identified as different strains of Pseudomonas aeruginosa (1A, 2B, 3C, 4D). Phylogenetic analysis confirmed their evolution from a common ancestor. All strains showed distinctive degradation ability up to 36 hours. The Pseudomonas aeruginosa strains 1A and 4D showed highest degradation percentage of about 80% for DDT, and P. aeruginosa strain 3C showed highest degradation percentage, i.e., 78% for aldrin whilst in the case of malathion, A. baumannii and A. ferroxidans have shown considerable degradation percentages of 53% and 54%, respectively. Overall, the degradation trend showed that all the selected strains can utilize the given pesticides as sole carbon energy sources even at a concentration of 50 mg/mL.

Conclusion

This study provided strong evidence for utilizing these strains to remove persistent residual pesticide; thus, it gives potential for soil treatment and restoration.

Chemical hazard in glacial melt? The glacial system as a secondary source of POPs (in the Northern Hemisphere). A systematic review

Toxicity of compounds belonging to persistent organic pollutants (POPs) is widely known, and their re-emission from glaciers has been conclusively demonstrated. However, the harmful effects associated with such secondary emissions have yet to be thoroughly understood, especially in the spatial and temporal context, as the existing literature has a clear sampling bias with the best recognition of sites in the European Alps. In this review, we elaborated on the hazards associated with the rapid melting of glaciers releasing organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs). To this end, we collated knowledge on: (1) the varying glacier melt rate across the Northern Hemisphere, (2) the content of POPs in the glacial system components, including the less represented areas, (3) the mechanisms of POPs transfer through the glacial system, including the importance of immediate emission from snow melt, (4) risk assessment associated with POPs re-emission. Based on the limited existing information, the health risk of drinking glacial water can be considered negligible, but consuming aquatic organisms from these waters may increase the risk of cancer. Remoteness from emission sources is a leading factor in the presence of such risk, yet the Arctic is likely to be more exposed to it in the future due to large-scale processes shifting atmospheric pollution and the continuous supply of snow. For future risk monitoring, we recommend to explore the synergistic toxic effects of multiple contaminants and fill the gaps in the spatial distribution of data.

Per- and Polyfluoroalkyl Substances (PFAS) in Fish from European Lakes: Current Contamination Status, Sources, and Perspectives for Monitoring

Concentrations in fish of per- and polyfluoroalkyl substances (PFAS) were reported for 7 deep lakes in the European subalpine area: Lakes Geneva, Lugano, Maggiore, Iseo, Como, Garda, and Mergozzo; one shallow lowland lake (Varese); and 2 high-altitude alpine lakes (>2000 m a.s.l). Fillets and, in selected cases, other body fractions (viscera, liver, and residual carcass) from 8 fish species were analyzed. The possibility of harmonizing the monitoring protocols was tested. Results suggest that the sampling season is not critical for PFASs and the total protein content cannot be used for normalization of tissue concentrations because PFASs bind to specific proteins. Moreover, the polar lipid content could be used to reduce the variability of PFAS concentrations in phospholipid rich fractions of fish such as viscera and carcass. The data comparison and analysis show that the PFAS contamination in lake fish is generally correlated with the degree of urbanization of the lake catchment; however, it is sometimes difficult to compare absolute concentrations in lake fish because the lake hydro-morphological characteristics play a substantial role in determining the chemical concentrations of persistent and mobile contaminants. Environ Toxicol Chem 2021;40:658-676. © 2020 SETAC.

Trophic Niches, Trophic Positions, and Niche Overlaps between Non-Native and Native Fish Species in a Subalpine Lake

In the last century, Italian freshwater ecosystems have been invaded by several non-native fish species. In the subalpine Lake Mergozzo (northern Italy), several recently introduced non-native species dramatically expanded their populations. We used carbon and nitrogen stable isotopes to describe the isotopic niches and trophic positions of native and non-native fish species in Lake Mergozzo. We evaluated their trophic niches, trophic diversity, trophic redundancy and trophic evenness utilizing isotopic niche metrics, and estimated asymmetrical niche overlaps. The trophic traits of non-native fish species and Perca fluviatilis clearly define them as trophic generalists, in terms of among-individual variability of their isotopic niches. The historical increase in abundance of fish non-native species in this lake, their dominance by numbers and biomass within the assemblage, and their broad asymmetrical niche overlaps suggest that their higher degree of trophic generalism might have been one of the key factors that have promoted the invasion of the recipient community.