Bioindicators Of Pollution Research Articles

Bakteriofagi jako czynniki biokontroli populacji niepożądanych bakterii

Bacteriophages as biocontrol agents of undesirable bacteria populations Bacteriophages, i.e. viruses that attack bacteria, are the largest group of biological life forms on Earth. Every species of bacteria has one or more bacteriophages, which act as a natural regulator of their population in environment. The specific way in which phages interact with bacteria makes them a promising alternative to antibacterial chemicals in controlling pathogenic and unwanted bacteria, including biofilm-producing strains or antibiotic-resistant ones. The ability of bacteriophages to control bacterial populations has led to their use in medicine, veterinary medicine, agriculture, aquaculture, wastewater treatment, the food industry, and as bioindicators of microbiological pollution. A promising solution could be the use of bacteriophages to eliminate pathogenic bacteria in the occupational environment, which would reduce the risk posed by harmful biological agents.

Evaluation of zinc, lead, and cadmium bioaccumulation in the liver of house sparrows (Passer domesticus) to assess environmental pollution in Meknes, Morocco

ABSTRACT Environmental pollution from heavy metals such as zinc (Zn), lead (Pb), and cadmium (Cd) poses serious risks to human health and ecosystems. This study examines the bioaccumulation of these metals in the livers of house sparrows (Passer domesticus) in Meknes, Morocco, using them as bioindicators of pollution. Fifty adult sparrows were collected from five areas: The Industrial Zone (IZ), Town Centre (TC), Sidi Said Bus Station (SS), Fes-Meknes Main Road (MR), and a Rural Site (Ref). Liver samples were analysed with Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The highest Zn concentrations were found at IZ (111.43 µg/g) and Ref (90.66 µg/g), Pb at TC (4.17 µg/g), and Cd at IZ and TC (0.70 µg/g and 0.71 µg/g). Statistical analyses revealed significant correlations between metal levels. Clustering techniques identified three distinct contamination profiles. These results highlight house sparrows as reliable bioindicators for monitoring heavy metal pollution.

Passing plastic: Traces of plastic in the fecal samples of a high Arctic seabird in Tunu (East Greenland)

Arctic seabirds are key bio-indicators of marine plastic pollution due to their transient movement and large populations. Although many studies have quantified the ingestion of microplastic particles (<5 mm in size) through necropsy or regurgitation sampling methods, little is known about post-digestive particle excretion. Due to the logistical challenges of non-lethally sampling feces from Arctic seabirds, this pathway remains largely understudied. We non-lethally collected 110 fecal samples from little auks (Alle alle) during the 2014 breeding season in Ukaleqarteq, Tunu (Kap Höegh, East Greenland). We identified 25 potential microplastic particles (>100 µm in size), 19 of which were analyzed for material composition using Fourier Transform Infrared Spectroscopy and Raman micro-spectroscopy. Of these, 13 particles were successfully matched to materials, with five as plastic. This produced an average concentration of 0.08 ± 0.28 microplastic particles per fecal sample, with no difference of occurrence between chicks and adults. Particle lengths ranged from 113 - 751 µm. The presence of microplastics larger than our lower limit of detectability of 100-µm suggests a need for analysis of smaller particles and microfibers in this species. We contribute to understanding how microplastics pass through little auks and characterize how this species interacts with the plastic pathways.

Stress biomarker response in Aporrectodea caliginosa earthworms exposed to single and combined pesticide treatments (Prosaro and Decis).

This study aims to assess the impact of two pesticides commonly used in Algeria (Prosaro XRT and Decis 25 EC), as well as their combinations at recommended doses, on a non-target species bioindicator of soil pollution, the earthworm Aporrectodea caliginosa, using physiological (mortality and growth) and biochemical parameters (proteins, glutathione, catalase activity and glutathione S-transferase, acetylcholine esterase, lipoxygenase). The recommended dose and its double were tested individually and in combination for this. It should be noted that the protocol used and the initial concentrations selected are the same as those used in the field. After 7 and 14 days (7D/14D) of exposure, all dosages were administered. Our findings show that the pesticides tested had no effect on earthworm survival. However, a significant decrease in their growth rates depending on the different concentrations was observed for the different treatments over the entire exposure period of 7 or 14 D. The greatest reductions (31.62%, 35.04%) are reported after 14D for the high concentrations of Decis alone (D2) as well as for the combined treatment Prosaro/Decis (P2/D2). At the same time, an increase in total protein contents (more than 50% after 14D) as well as a decrease in acetylcholine esterase activity were reported for all treatments. We were also able to identify the induction of oxidative stress after xenobiotic exposure, which is more pronounced at the end of the treatment (14D), resulting in the stimulation of the antioxidant system (gluthione, glutathione S-transférase, catalase) as well as the induction of lipoxygenase, which is responsible for the oxidation of polyunsaturated fatty acids as well as the generation of reactive oxygen species (ROS) involved in the inflammatory phenomenon. Finally, it turns out that the species Aporrectodea caliginosa is sensitive to the different concentrations applied, even those used in the open field, and that Decis (deltamethrin) seems to be more toxic than Prosaro and that the combinaison P2/D2 is as toxic as Decis alone (D2).

Ecological risk assessment of heavy metals contaminated mining sites of eastern india using soil and moss.

The blooming industrialization and urbanization is leading to increased mining operations. These intensified mining activities emit heavy metals into the environment, posing serious threats to ecosystems. Hence, this study focused on assessing heavy metal pollution in mining soil, utilizing mosses as bioindicators. The ecological risk, geo-accumulation factor, and contamination factor have been calculated to know the harmful effect of heavy metals on ecosystem. The study covered three distinct mining sites of eastern India within Odisha: Jajpur's Sukinda Valley (SP1, Cr), Keonjhar's Joda-Barbil (SP2, Fe and Mn), and Sundargarh's Koira-Joda (SP3, Fe). The collection of 48 soil samples through random sampling revealed significant variations in heavy metal concentrations. SP1 recorded Cr concentration of 6572 ± 445mg/kg and Ni of 8042.47 ± 501.38mg/kg, surpassing eco-toxicological levels. The storage site in SP2 exhibited the highest Fe concentration at 9872 ± 502mg/kg, and Mn levels in SP3 were at 7884 ± 432mg/kg. Storage areas in all three regions held the highest concentrations of heavy metals. Mosses in studied area demonstrated as potential bioindicators for monitoring heavy metal pollution. EF and Igeo assessments showed Cd, Pb, Hg, and other heavy metal contamination compared to earlier investigations. This study indicated higher ecological risks for Pb, As, Cu, Ni, and Zn. The Hyophila involuta accumulates Mn, Cr, Cd, Pb, Fe, and Hg, while Barbula arcuata accumulates Mn, As, and Cu in SP1. Hyophila involuta and Trematodon longicollis accumulate Mn, Cr, Cd, Pb, Fe, Hg, and Zn in SP2. Trematodon ambiguous accumulates Cd, Fe, and Ni, while Fissidens diversifolius accumulates Mn, Cr, Hg, As, Cu, and Zn in SP3. These findings emphasize the necessity of monitoring heavy metal pollution in contaminated zones using moss as a potential bioindicator.

Metal variability of the shrimp Palaemon elegans across coastal zones: anthropogenic and geological impacts.

This study focused on 120 specimens of the shrimp Palaemon elegans collected in intertidal zones in eight selected areas. This study aimed to assess the suitability of P. elegans as a bioindicator of natural and anthropogenic marine pollution. Metal concentrations of aluminum (Al), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), and zinc (Zn) were measured in shrimp collected from various sites in the Canary Islands, including areas affected by volcanic activity, industrial activity, and control zones. The determination of metal concentrations was conducted using inductively coupled plasma optical emission spectrophotometry (ICP-OES). The results showed significant differences in metal concentrations across the studied sites, with the highest levels of Al, Cu, Fe, Pb, and Zn observed in areas impacted by the Tajogaite volcanic eruption and harbor activity. Sites near old landfills and sewage pipes also exhibited elevated levels of Cd, Cu, and Pb, indicating strong anthropogenic influence. Al was found in the highest concentration in Harbour, reaching 25.7 ± 6.2mg/kg, while the lowest concentration was observed in Control Lp at 11.5 ± 0.69mg/kg. Conversely, lower metal concentrations were detected in control zones and areas with high dinoflagellate presence, suggesting a potential role of bioremediation by marine phytoplankton. The ability of P. elegans to accumulate metals in its tissues, particularly in areas of high pollution, highlights its potential as a bioindicator species. This study underscores the importance of P. elegans in monitoring marine pollution and provides insights into the environmental impact of both natural and human-induced contamination on coastal ecosystems.

Geochemical fractionation of trace elements in ostreid and gastropod shells: A potential proxy for heavy metal pollution in Ghana’s coastal environment

The content of trace elements from Crassostrea tulipa (Ostreidae, Bivalvia) from four localities (Pra Estuary, Densu Estuary, Kpone Beach, and Anyanui Creek) along the coast of Ghana has been used as a bioindicator of environmental pollution. The lowest values of heavy metals correspond to the Crassostrea shells from Densu Estuary and Anyanui Creek, whereas the highest contents are recorded in the shells from Pra Estuary and Kpone Beach. Densu Estuary and Anyanui Creek are located in areas not affected by major industries, and only Densu is located in a densely urbanized setting. Crassostrea shells from Densu Estuary are only enriched in Ni. However, the Total Organic Carbon content of the sediments of the Densu Estuary indicates anthropogenic organic pollution not evidenced by the composition of Crassostrea shells. The Crassostrea shells from the Pra Estuary show enrichment in most of the analysed trace elements (Li, Be, V, Cu, Cr, Zn, Ga, Y, Sn, Pb, U, Th, ∑REE, and As) compared with other studied sites. This enrichment is related to heavy metals influx to the Pra River by the mining activities, extensive forest clearance, and loss of soil minerals. The Crassostrea shells from Kpone Beach present comparatively high content of some trace elements (Be, Ba, Cu, Zn, Nb, Pb, and REE). The metal pollutants are related to the input of the Heavy Industrial Area of Tema (located around 3.5 km west of Kpone Beach) and urban effluences from the Greater Accra Region. The high content of Ba, Cu, Zn, and Pb in Crassostrea is directly related to high phytoplankton productivity (mainly for diatoms) linked to the input of trace metals transferred into the marine food webs. In addition, some analyses of gastropod shells from Kpone Beach indicate that Cerithium and Nerita are more sensitive to accumulating Ni and As than Crassostrea. The values of trace metals from the Crassostrea shells of the Densu Estuary and Anyanui Creek are comparatively low. Considering the role of Crassostrea shells as bioindicators for heavy metals pollution, the less polluted localities are Anyanui Creek and Densu Estuary, whereas Pra Estuary and Kpone Beach are affected by anthropic activities such as mining, urban effluents, and industry.

Does long-term radiation exposure in Chornobyl impact the reproductive structures of Nuphar lutea (Linné) Smith?

The 1986 Chornobyl Nuclear Power Plant accident caused radioactive contamination of water bodies within the Pripyat River floodplain, resulting in the accumulation of radionuclides by macrophytes, which are fundamental species in water ecosystems. Yellow water lily Nuphar lutea (L.) Smith., a macrophyte playing a significant role in the formation of vegetation cover in aquatic ecosystems, is commonly considered as a bioindicator of water pollution. In this study, we investigate the potential of N. lutea as an indicator of radionuclide contamination in water bodies, particularly through changes in its reproductive structures, such as pollen viability, morphology of pollen grains, seeds, and fruits. Our findings reveal that pollen viability remains stable at total absorbed dose rates below 14.4 μGy/h, with only 1–4% of sterile grains. However, beyond this threshold the percentage of sterile grains increases nearly fivefold, pointing to high internal plant exposure to 90Sr. A similar trend was observed in the allometry and size of pollen grains, where small and flattened grains are formed in the reservoir with the highest external radiation dose rate (≥14.4 μGy/h). On the other hand, while morphometric parameters of fruits are influenced by radiation, their variation appears to be the result of a combination of physicochemical factors and the trophic status of a water body. Our research highlights the adverse impact of long-term radiation exposure on the male reproductive system of N. lutea and shows the potential of using the pollen grains sterility as an indicators of heavily radionuclide-contaminated water bodies. Additionally, we observed gradual changes in a pollen allometric length-to-width coefficient as the radiation dose level increases.

Report on high density population of a Cladoceran, Moina macrocopa and their gut microbes in anoxic sewage water: a potential bio-indicator of aquatic pollution

Report on high density population of a Cladoceran, Moina macrocopa and their gut microbes in anoxic sewage water: a potential bio-indicator of aquatic pollution

Faeces of Capybara (Hydrochoerus hydrochaeris) as a Bioindicator of Contamination in Urban Environments in Central-West Brazil

Along with exposure to parasites and other biological disease vectors, animal faeces can also contain heavy metals and metalloids. We quantified metals, metalloids, and non-metals in the faeces of capybara (Hydrochoerus hydrochaeris) that live in parks in the city of Campo Grande (Brazil). Quantification of metalloids was obtained after acid digestion using an inductively coupled plasma optical emission spectrometer. Higher mean concentrations in mg/kg of aluminium (Al) (140.322), arsenic (As) (0.010), cadmium (Cd) (1.042), chromium (Cr) (26.866), cobalt (Co) (1.946), copper (Cu) (50.764), lead (Pb) (8.762), manganese (Mn) (291.469), molybdenum (Mo) (3.634), nickel (Ni) (5.475), and zinc (Zn) (100.027) were quantified in samples of faeces of capybara that live on the banks of a lagoon that receives input from streams that cross the city. According to the risk assessment, potential risks to the health of children and adults may occur due to the presence of Al, As, Cd, Co, Cu, and Mn through involuntary oral ingestion of faeces, via inhalation and dermal contact. The hazard index (HI) due to oral ingestion was greater than 1 for children and adults. Therefore, we believe that faeces of H. hydrochaeris can be considered as a bioindicator of environmental pollution in urban parks.

Phytoplankton Diversity as Bioindicator of Pollution in Jenes River, Surakarta

AbstractThis research aims to identify the types of phytoplankton, identify the abundance of phytoplankton, and study the relationship between environmental factors and the abundance of phytoplankton. This research was carried out on January 10, 2023, at the Jenes River, Surakarta. Sampling was carried out at 3 observation stations to identify environmental factors (pH, DO, CO2, salinity, BOD, light intensity, temperature, and brightness). Observations were carried out at three stations, namely upstream, middle and downstream, namely, in the morning (06.00–07.00 WIB) and during the day (12.00–14.00 WIB). Measurements of environmental factors were carried out at the integrated laboratory at Sebelas Maret University, Surakarta. The results of the research showed that the phytoplankton found were 9 families consisting of 11 species with an average abundance of 6,834 individuals/L in the morning day and an average abundance of 13,088 individuals/L during the day. The most abundant phytoplankton in the morning observations was Ulothrix sp. Meanwhile, the most abundant phytoplankton in the afternoon observations was Chroococcus sp. This abundance is also influenced by environmental factors such as pH, DO, Salinity, BOD, CO2, and temperature. The research found that the middle station had the highest phytoplankton diversity index during the day (1.6), possibly because it was indicated to be lightly polluted, allowing the life of many phytoplankton such as Closterium sp. and Quadrigula sp. The highest abundance of phytoplankton in the morning is Ulothrix sp., in the afternoon, it is Chroococcus sp.AbstrakPenelitian ini bertujuan untuk mengidentifikasikan jenis fitoplankton, kelimpahan fitoplankton, dan analisis hubungan faktor lingkungan dengan kelimpahan fitoplankton di Sungai Jenes Surakarta. Penelitian ini dilaksanakan pada 10 Januari 2023 di Sungai Jenes, Surakarta. Pengambilan sampel dilakukan di 3 stasiun pengamatan untuk mengukur faktor lingkungan (pH, DO, CO2, salinitas, BOD, intensitas cahaya, suhu, dan kecerahan). Pengamatan dilakukan di tiga stasiun yaitu hulu, tengah dan hilir sebanyak 2 yaitu, pagi hari (06.00–07.00 WIB) dan siang hari (12.00–14.00 WIB). Pengujian faktor lingkungan dilakukan di laboratorium terpadu Universitas Sebelas Maret, Surakarta. Hasil penelitian menunjukkan bahwa fitoplankton ditemukan berjumlah 9 famili terdiri dari 11 spesies dengan rata-rata kelimpahan 6.834 individu/L pagi hari dan rata rata kelimpahan 13.088 individu/L pada siang hari. Fitoplankton yang paling melimpah pada pengamatan pagi hari adalah Ulothrix sp., sedangkan siang hari adalah Chroococcus sp. Kelimpahan ini juga dipengaruhi oleh faktor lingkungan seperti pH, DO, Salinitas, BOD, CO2 , dan suhu. Penelitian menemukan bahwa stasiun tengah memiliki indeks keanekaragaman fitoplankton tertinggi pada siang hari (1,6), kemungkinan karena terindikasi tercemar ringan, memungkinkan hidupnya banyak fitoplankton seperti Closterium sp. dan Quadrigula sp. Kelimpahan fitoplankton tertinggi pada pagi hari adalah Ulothrix sp., sementara pada sore hari adalah Chroococcus sp.

Interplay of heavy metal accumulation, physiological responses, and microbiome dynamics in lichens: insights and future directions.

Lichens are increasingly recognised as valuable bioindicators for environmental heavy metal pollution due to their sensitivity to spatial and temporal variations in pollution levels and their ability to adapt to diverse and often harsh habitats. This review initially examines the mechanisms of metal absorption in lichens, including particulate entrapment, ion exchange, and intracellular absorption, as well as their physiological responses to abiotic stressors such as heavy metal exposure and desiccation. In the latter part, we compile and synthesise evidence showing that secondary metabolites in lichens are significantly influenced by metal concentrations, with varying impacts across different species. Although extensive research has addressed the broader physiological effects of heavy metal hyperaccumulation in lichens, there remains a significant gap in understanding the direct or indirect influences of heavy metals on the lichen microbiome, possibly mediated by changes in secondary metabolite production. Our review integrates these aspects to propose new research directions aimed at elucidating the mechanisms underlying physiological responses such as resilience and adaptability in lichens. Overall, this review highlights the dynamic interplay between microbiome composition, secondary metabolite variation, and metal accumulation, suggesting that these factors collectively contribute to the physiological responses of lichens in polluted environments.

Macrophytes as Bioindicators of Heavy Metal Pollution in Belarusian Rivers

ABSTRACTMacrophytes are well‐known for accumulating a large number of various substances, including metals, and they may consequently serve as biogeochemical indicators of aquatic system pollution. In general, the sequence of analyzed metal accumulation in river macrophytes is as follows (mg/kg): Mn (141) > Cu (2.53) > V (0.89) > Cr (0.70) > Pb (0.68) > Ni (0.23). Submersed species are conspicuous for their increased metal accumulation capacity, with statistically significant differences compared to other ecological groups. Among the aquatic plant genera examined (Potamogéton, Ceratophýllum, Elodea, Núphar, Butomus, Glycéria, and Spargánium), an increased capacity to accumulate Mn, Cu, and Pb is observed in all submersed macrophytes, while Cr, V, and Ni are particularly accumulated by Ceratophýllum and Elodea. Potamogéton has the largest range of V, Cr, Mn, Ni, and Cu variations. The overall bioaccumulation capability evaluated by the metal accumulation index was ordered as follows: Núphar (6.94) > Potamogéton (5.53) > Butomus (3.48) > Glycéria (2.86) > Spargánium (2.62) > Elodea (2.33) > Ceratophýllum (1.98). Bio‐accumulation factors (BAFs) (macrophytes/sediment) vary depending on the metal and macrophyte ecological groups. For submersed macrophytes, the sequence of BAFs is Mn > Cu > Ni > Pb > Cr > V. In the submersed plants of watercourses taken at the anthropogenic impact sites, the accumulation of Ni, V, Mn, Pb, and Cu is statistically significantly higher compared to those in natural conditions. Compositional data analysis has revealed such biogeochemical signatures of the anthropogenic impact as the formation of the anthropogenic Cr–Ni association, which is associated with the identified multivariate anomalies, as well as an increase in Cu variability and a decrease in Mn.

Cytome analysis (micronuclei and nuclear anomalies) in bioindication of environmental pollution in animals with nuclear erythrocytes

Assessment of cytogenetic homeostasis of indicator animals is of great importance in ecological monitoring. The simplest method of its study is micronucleus analysis. Animals with nuclear erythrocytes are often used as indicator animals. In addition to the micronuclei usually recorded, a wide range of cytological nuclear and cellular abnormalities (cytomic analysis) is encountered when assessing the spontaneous level and under the influence of anthropogenic factors. Spontaneous frequency of cytogenetic disorders in 36 species of fish, amphibians, reptiles and birds was studied. Ecological monitoring of territories of Kazakhstan with different types of pollution (radiation, petrochemical, pesticide, heavy metals, due to rocket and space activities) was carried out with the help of separate species of animals. The results of the study include comparative descriptions, schematics and microphotographs clearly demonstrating a wide range of cytological anomalies of nuclear erythrocytes of animals of different classes. The greatest spectrum of nuclear anomalies in the studied animals was registered at petrochemical and pesticide contamination of territories. Depending on the tasks and climatic-geographical conditions, all investigated species can be used as bioindicators. Testudo horsfieldii is an exception for desert regions due to high spontaneous micronuclei level in this species. A review of the names of the main nuclear anomalies is carried out and variants of its ordering are proposed.

Metal tolerance in enterococci isolated from seabirds in Abrolhos Archipelago, Brazil: Evaluating their role as bioindicators of marine pollution

Microbiota exposed to pollution provide insights into host physiology and ecosystem disruption. This study evaluated Enterococcus spp. tolerant to arsenic (As), copper (Cu), and mercury (Hg) from red-billed tropicbirds (Phaethon aethereus) and brown boobies (Sula leucogaster), which previously showed these metals in their blood and feathers, and their potential use as bioindicators of metal contamination. Enterococcus casseliflavus (47.9 %), E. faecalis (34.1 %), E. hirae (11.7 %), and E. faecium (5.3 %) were identified. Both seabird species had a high incidence of As-tolerant bacteria (84.0 %), with 40.4 % of these strains containing As efflux system genes (arsA_I and arsA_II). Cu efflux pump gene (tcrB) was detected in 30.9 % of strains, while Hg reductase genes (mer) were not found. As- and Cu-tolerance in enterococci observed in this study underlines their potential as bioindicators in metal-polluted marine environments. Further research may elucidate the role of these metal-tolerant enterococci in seabird gut and their adaptability to polluted environments.

Barau's petrel, Pterodroma baraui, as a bioindicator of plastic pollution in the South-West Indian Ocean: A multifaceted approach

Marine plastic pollution is well described by bioindicator species in temperate and polar regions but remains understudied in tropical oceans. We addressed this gap by evaluating the seabird Barau's petrel as bioindicator of plastic pollution in the South-West Indian Ocean. We conducted a multifaceted approach including necropsies of birds to quantify plastic ingestion; GPS tracking of breeding adults to identify their foraging areas; manta trawling of plastic debris to measure plastic pollution at sea and modelling of plastic dispersal. We developed a spatial risk index of seabird exposure to plastic ingestion. Seventy-one percent of the analysed birds had ingested plastic. GPS tracking coupled with manta trawling and dispersal modelling show that adults consistently foraged at places with high level of plastic concentration. The highest ingestion risk occurred in the northwest of Reunion Island and at latitude 30°S. Our findings confirm that Barau's petrel is a reliable bioindicator of plastic pollution in the region.

Mercury contamination and potential health risk to French seabirds: A multi-species and multi-site study

Mercury (Hg) is a naturally occurring highly toxic element which circulation in ecosystems has been intensified by human activities. Hg is widely distributed, and marine environments act as its main final sink. Seabirds are relevant bioindicators of marine pollution and chicks are particularly suitable for biomonitoring pollutants as they reflect contamination at short spatiotemporal scales. This study aims to quantify blood Hg contamination and identify its drivers (trophic ecology inferred from stable isotopes of carbon (δ13C) and nitrogen (δ15N), geographical location, chick age and species) in chicks of eight seabird species from 32 French sites representing four marine subregions: the English Channel and the North Sea, the Celtic Sea, the Bay of Biscay and the Western Mediterranean. Hg concentrations in blood ranged from 0.04 μg g−1 dry weight (dw) in herring gulls to 6.15 μg g−1 dw in great black-backed gulls. Trophic position (δ15N values) was the main driver of interspecific differences, with species at higher trophic positions showing higher Hg concentrations. Feeding habitat (δ13C values) also contributed to variation in Hg contamination, with higher concentrations in generalist species relying on pelagic habitats. Conversely, colony location was a weak contributor, suggesting a relatively uniform Hg contamination along the French coastline. Most seabirds exhibited low Hg concentrations, with 74% of individuals categorized as no risk, and < 0.5% at moderate risk, according to toxicity thresholds. However, recent work has shown physiological and fitness impairments in seabirds bearing Hg burdens considered to be safe, calling for precautional use of toxicity thresholds, and for studies that evaluate the impact of Hg on chick development.

Biomonitoring of Heavy Metal Toxicity in Freshwater Canals in Egypt Using Creeping Water Bugs (Ilyocoris cimicoides): Oxidative Stress, Histopathological, and Ultrastructural Investigations.

The abundance of metal pollutants in freshwater habitats poses serious threats to the survival and biodiversity of aquatic organisms and human beings. This study intends for the first time to assess the pernicious influences of heavy metals in Al Marioteya canal freshwater in Egypt, compared to Al Mansoureya canal as a reference site utilizing the creeping water bug (Ilyocoris cimicoides) as an ecotoxicological model. The elemental analysis of the water showed a significantly higher incidence of heavy metals, including cadmium (Cd), cobalt (Co), chromium (Cr), nickel (Ni), and lead (Pb), in addition to the calcium (Ca) element than the World Health Organization's (WHO) permitted levels. The Ca element was measured in the water samples to determine whether exposure to heavy metals-induced oxidative stress engendered Ca deregulation in the midgut tissues of the creeping water bug. Remarkably, increased levels of these heavy metals were linked to an increase in chemical oxygen demand (COD) at the polluted site. Notably, the accumulation of these heavy metals in the midgut tissues resulted in a substantial reduction in antioxidant parameters, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and ascorbate peroxidase (APOX), along with a marked rise in malondialdehyde (MDA), cytochrome P450, and protein carbonyl levels. These results clearly indicate a noticeable disturbance in the antioxidant defense system due to uncontrollable reactive oxygen species (ROS). Notably, the results demonstrated that oxidative stress caused disturbances in Ca levels in the midgut tissue of I. cimicoides from polluted sites. Furthermore, the comet and flow cytometry analyses showed considerable proliferations of comet cells and apoptotic cells in midgut tissues, respectively, exhibiting prominent correlations, with pathophysiological deregulation. Interestingly, histopathological and ultrastructural examinations exposed noticeable anomalies in the midgut, Malpighian tubules, and ovarioles of I. cimicoides, emphasizing our findings. Overall, our findings emphasize the potential use of I. cimicoides as a bioindicator of heavy metal pollution in freshwater to improve sustainable water management in Egypt.

The present state of leech fauna (Annelida: Hirudinea) in Dal Lake, Jammu &amp; Kashmir, India

Dal Lake supports a diverse group of fauna, including fishes, aquatic birds, zooplankton, and macrobenthic invertebrates. This study is the first taxonomic documentation of the leech fauna of Dal Lake. A total of nine leech taxa belonging to four families were identified and described: Glossiphoniidae – Alboglossiphonia weberi, A. heteroclita, Glossiphonia complanata, Helobdella stagnalis, Hemiclepsis marginata asiatica, and Theromyzon sp.; Erpobdellidae – Erpobdella octoculata; Hirudinidae – Poecilobdella granulosa; and Haemopidae – Haemopis indicus. Leeches play key roles in prey-predator dynamics and host-parasite relationships in freshwater ecosystems and as bioindicators of water pollution. This study provides essential data for taxonomic accounts and the diversity of leech fauna in Dal Lake.

Feather mercury content of grey-faced petrels (Pterodroma gouldi): Relationships with age, breeding success, and foraging behaviour, in known age individuals

Seabirds have been touted as excellent bioindicators of mercury pollution. We utilised grey-faced petrel (Pterodroma gouldi) feathers to assess interannual differences in total mercury (THg) concentrations in adults (2020−2021) and chicks (2019–2021) breeding in the Auckland region of New Zealand. For adults, we also correlated feather THg with bird age (3–37+ years) and breeding outcome (i.e., Non breeder, Egg failed, Chick reared) recorded for that season i.e., 2020 and 2021. Interannual differences in chick feather THg were matched with bulk stable isotopes (δ13C, δ15N) to map the influence of adult foraging behaviour on chick feather THg values.Adult feather THg levels were similar across the years investigated i.e., mean ± S.D. 38.2 ± 12.8 (2020), and 39.5 ± 14.7 (2021) ug g−1 (some of the highest THg values recorded for seabirds). A slight, but significant decrease in THg accumulation was evident as age increased but feather THg had no significant influence on breeding outcome.Interannual differences in chick feather THg concentrations were 7.78 ± 1.6 (2019), 4.23 ± 1.45 (2020) and 6.97 ± 4.41 (2021) μg g−1, (p < 0.01); and correlated with a significantly lower δ13C value i.e., −17.2 ± 0.4 ‰ (2019), −17.8 ± 0.3 ‰ (2020) and -17.6 ± 0.2 ‰ (2021). This suggests that the lower feather THg values in 2020 chicks resulted from more oceanic, rather than shelf-edge, prey being consumed by chicks that year. Values of δ15N in chick feathers remained consistent among years i.e., 15.2 ± 1.2 ‰ (2019), 15.2 ± 0.2 ‰ (2020) and 15.3 ‰ (± 0.4). Due to these interannual differences, we recommend using grey-faced petrel chicks to monitor Hg pollution over adults. Chicks are also subject to cultural harvests by Māori communities, offering partnership opportunities to generate mutually beneficial information streams for Māori communities and scientists alike.