Environmental Sentinels Research Articles

Proteogenomic reconstruction of organ-specific metabolic networks in an environmental sentinel species, the amphipod Gammarus fossarum

Metabolic pathways are affected by the impacts of environmental contaminants underlying a large variability of toxic effects across different species. However, the systematic reconstruction of metabolic pathways remains limited in environmental sentinel species due to the lack of available genomic data in many taxa of animal diversity. In this study we used a multi-omics approach to reconstruct the most comprehensive map of metabolic pathways for a crustacean model in biomonitoring, the amphipod Gammarus fossarum in order to improve the knowledge of the metabolism of this sentinel species.We revisited the assembly of RNA-seq data by de novo approaches to reduce RNA contaminants and transcript redundancy. We also acquired extensive mass spectrometry shotgun proteomic data on several organs from a reference population of G. fossarum males and females to identify organ-specific metabolic profiles.The G. fossarum metabolic pathway reconstruction (available through the metabolic database GamfoCyc) was performed by adapting the genomic tool CycADS and we identified 377 pathways representing 7630 annotated enzymes, 2610 enzymatic reactions and the expression of 858 enzymes was experimentally validated by proteomics. To our knowledge, our analysis provides for the first time a systematic metabolic pathway reconstruction and the proteome profiles of these pathways at the organ level in this sentinel species. As an example, we show an elevated abundance in enzymes involved in ATP biosynthesis and fatty acid beta-oxidation indicative of the high-energy requirement of the gills, or the key anabolic and detoxification role of the hepatopancreatic caeca, as exemplified by the specific expression of the retinoid biosynthetic pathways and glutathione synthesis.In conclusion, the multi-omics data integration performed in this study provides new resources to investigate metabolic processes in crustacean amphipods and their role in mediating the effects of environmental contaminant exposures in sentinel species. SynopsisThis study provide the first evidence that it is possible to combine multiple omics data to exhaustively describe the metabolic network of a model species in ecotoxicology, Gammarus fossarum, for which a reference genome is not yet available.

Tibetan lake sediment records reveal historical emission and long-range atmospheric transport of chlorinated paraffins

The Tibetan Plateau, a recognized global sink for Persistent Organic Pollutants (POPs), lies adjacent to two major emitting regions, inland China and India. This unique geographical setting makes it a pivotal site for examining the presence and compositional evolution of POPs following their long-range atmospheric transport (LRAT). This study focuses on the current predominant POPs, chlorinated paraffins (CPs). We comprehensively screened 675 homologues of the very short- (vSCCPs), short- (SCCPs), medium- (MCCPs), and long-chain CPs (LCCPs) in six dated sediment cores across the extensive Tibetan area. The findings unveiled pronounced temporal disparities in CP concentrations and compositions between Tibet's southern and eastern sectors, reflecting divergent usage and emission chronicles of inland China and India. Notably, a market shift in China from regulated SCCPs to the in-use MCCPs and LCCPs was observed in the 21st century, contrasting with India's unregulated production of SCCPs. The Organization for Economic Cooperation and Development (OECD) Screening Tool, developed to assess the overall persistence (POV) and long-range transport potential (LRTP) of organic chemicals, elucidated the erosion of CP source signatures induced by fractionation, a process that intensifies with transport distance from the source regions. This study enhances our understanding of the emission inventories and LRAT behavior of these transitional regulatory contaminants, highlighting the Tibetan Plateau's crucial role as an environmental sentinel in global pollution dynamics.

Canine on the Couch: The New Canary in the Coal Mine for Environmental Health Research.

Human health is intimately connected and tied to the health of our environment and ecosystem, with only a very small fraction of the risk for chronic diseases explained by genetics alone. Companion animals are prone to disease types that are shared with people, including cancers and endocrine disorders, reinforcing the thought that environmental factors contribute to the risks for chronic diseases. These factors include air and water pollution and the built environment. As such, there is increasing interest in pursuing research with companion animals, and specifically dogs, as sentinel species to inform comparative health assessments and identify risk factors for disease. Of the canine diseases for which environmental exposure research has been published, cancers have received the most attention. This review summarizes two main aspects of this comparative approach: (1) cancers that occur in dogs and which are similar to humans and (2) research investigating environmental exposures and health outcomes in dogs. The goal of this review is to highlight the diverse conditions in which pet dogs may provide unique perspectives and advantages to examine relationships between environmental exposures and health outcomes, with an emphasis on chemical pollution and cancer. Furthermore, this review seeks to raise awareness and stimulate discussion around the best practices for the use of companion animals as environmental health sentinels.

PAHs in franciscana dolphins from the Southwestern Atlantic Ocean: Concentration and maternal transfer assessments

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds ubiquitous in the environment and known for their toxic, mutagenic, and carcinogenic effects. These compounds can bioaccumulate in the biota and be transferred through trophic webs. The franciscana dolphin (Pontoporia blainvillei), as top predators, can be an environmental sentinels. Thus, this study aimed to provide data about PAHs concentration in their hepatic tissue collected on the coast of Espírito Santo (Franciscana Management Area, FMA Ia), Rio de Janeiro (FMA IIa), and São Paulo states (FMA IIb), in Southeastern Brazil. PAHs were detected in 86 % of franciscana dolphins (n = 50). The highest ∑PAHsTotal median concentration was reported in FMA Ia followed by FMA IIb and FMA IIa (1055.6; 523.9, and 72.1 ng.g-1 lipid weight, respectively). Phenanthrene was detected in one fetus and two neonates, showing maternal transfer of PAHs in these dolphins. Evaluating PAHs with potential toxic effects is of utmost importance for the conservation of a threatened species.

Domestic dogs as environmental sentinel in comparative toxicologic pathology: Assessment of metals and rare earth elements concentrations in healthy and neoplastic mammary glands

Quantification of trace element concentrations in human and animal tissues has acquired great importance in the last few years, considering the pivotal role of these elements in several physiological and pathological processes. Variations in their concentrations appear to have a role in the development and advancement of diseases in both humans and animals, for example, cancer. The purpose of this study was to investigate the concentration of rare earth elements and metals in healthy and neoplastic Formalin-Fixed Paraffin-Embedded (FFPE) mammary gland tissue of dogs. All samples were processed to have a quantitative determination of inorganic elements including metals of known toxicological interest such as Pb, Cd, Tl, As, Hg, the trace elements Mn, Fe, Co, Cu, Zn, Se, and other elements including Cr, V, Mo, Ni, Sb, W, Sn. Moreover, rare earth elements (REEs) (Sc, Y, Lu, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) were also investigated. Cu and Mo concentrations in mammary cancerous tissue were greater than those in normal mammary glands (p < 0.05). In non-neoplastic tissue increased concentrations of Cd, Co, Ni, Tl, and V were also reported (p < 0.05). The mammary tissue of healthy individuals had greater concentrations of REEs than the neoplastic mammary glands (p < 0.05). The results of our study confirmed differences in mammary inorganic element concentrations between healthy and neoplastic groups, highlighting the potential relevance of these fluctuations in toxicologic pathology.

Concomitant investigation of crustacean amphipods lipidome and metabolome during the molting cycle by Zeno SWATH data-independent acquisition coupled with electron activated dissociation and machine learning

BackgroundDIA (Data-Independent Acquisition) is a powerful technique in Liquid Chromatography coupled with high-resolution tandem Mass Spectrometry (LC-MS/MS) initially developed for proteomics studies and recently emerging in metabolomics and lipidomics. It provides a comprehensive and unbiased coverage of molecules with improved reproducibility and quantitative accuracy compared to Data-Dependent Acquisition (DDA). Combined with the Zeno trap and Electron-Activated Dissociation (EAD), DIA enhances data quality and structural elucidation compared to conventional fragmentation under CID. These tools were applied to study the lipidome and metabolome of the freshwater amphipod Gammarus fossarum, successfully discriminating stages and highlighting significant biological features. Despite being underused, DIA, along with the Zeno trap and EAD, holds great potential for advancing research in the omics field. ResultsDIA combined with the Zeno trap enhances detection reproducibility compared to conventional DDA, improving fragmentation spectra quality and putative identifications. LC coupled with Zeno-SWATH-DIA methods were used to characterize molecular changes in reproductive cycle of female gammarids. Multivariate data analysis including Principal Component Analysis and Partial Least Square Discriminant Analysis successfully identified significant features. EAD fragmentation helped to identify unknown features and to confirm their molecular structure using fragmentation spectra database annotation or machine learning. EAD database matching accurately annotated five glycerophospholipids, including the position of double bonds on fatty acid chain moieties. SIRIUS database predicted structures of unknown features based on experimental fragmentation spectra to compensate for database incompleteness. SignificanceReproducible detection of features and confident identification of putative compounds are pivotal stages within analytical pipelines. The DIA approach combined with Zeno pulsing enhances detection sensitivity and targeted fragmentation with EAD in positive polarity provides orthogonal fragmentation information. In our study, Zeno-DIA and EAD thereby facilitated a comprehensive and insightful exploration of pertinent biological molecules associated with the reproductive cycle of gammarids. The developed methodology holds great promises for identifying informative biomarkers on the health status of an environmental sentinel species.

Capitella (Annelida: Capitellidae) species in the Gulf of Mexico: Delimitation, phylogeography and phylogeny

AbstractCapitella spp. are found in marine and estuarine benthos world‐wide. They are often treated as environmental sentinels because they occur in high densities in areas of anthropogenic disturbance and organic pollution. However, there are many cryptic species around the world, often grouped into the Capitella capitata complex. Historically, these have been differentiated using allozymes and developmental studies. Recently, single‐gene sequencing, especially cytochrome c oxidase subunit I, and phylogenetic methods have been used to characterise populations around the world. We present molecular support and provide descriptions for five new Capitella spp. from the Gulf of Mexico: Capitella gomexa sp. n., Capitella mandingensis sp. n., Capitella tampe sp. n., Capitella maculosa sp. n. and Capitella loucindae sp. n. Two were recently differentiated on the basis of larval development and morphology. Additionally, we present an updated look at global Capitella phylogeny. While no apparent patterns of phylogeography were recovered, we did find support for a single origin of thoracic acicular spines.

Intraspecific genetic lineages of a marine mussel show behavioural divergence when exposed to microplastic leachates

Worldwide, microplastic pollution has numerous negative implications for marine biota, exacerbating the effects of other forms of global anthropogenic disturbance. Mounting evidence shows that microplastics (MPs) not only cause physical damage through their ingestion, but also act as vectors for hazardous compounds by leaching absorbed and adsorbed chemicals. Research on the effects of plastic pollution has, however, largely assumed that species respond uniformly, while ignoring intraspecific diversity (i.e., variation within a single species). We investigated the effects of plastic leachates derived from factory-fresh (virgin) and beached microplastics on the behavioural responses of two genetic lineages of the Mediterranean mussel Mytilus galloprovincialis. Through laboratory behavioural experiments, we found that during exposure to leachates from beached microplastics (beached MPLs), Atlantic specimens moved significantly less than Mediterranean individuals in terms of both (i) proportion of individuals responding through movement and (ii) net and gross distances crawled. In contrast, no significant intraspecific differences were observed in the behaviour of either adults or recruits when exposed to MPLs from virgin microplastics (virgin MPLs). Additionally, the reception of cues from three amino acids (L-cysteine, proline and L-leucine) at increasing concentrations (10−5 M to 10−3 M in charcoal-filtered seawater) was tested by electrophysiological analysis using mussels exposed to beached MPLs or control seawater. We found significant intraspecific differences in response to 10−3 M L-cysteine (regardless of treatment) and 10−4 M L-cysteine (in mussels exposed to beached MPLs) and to 10−3 M proline (in mussels exposed to beached MPLs) and 10−5 M L-leucine. Our study suggests that intraspecific variation in a marine mussel may prompt different responses to plastic pollution, potentially triggered by local adaptation and physiological variability between lineages. Our work highlights the importance of assessing the effects of intraspecific variation, especially in environmental sentinel species as this level of diversity could modulate responses to plastic pollution.

One Health Approach to Leptospirosis: Dogs as Environmental Sentinels for Identification and Monitoring of Human Risk Areas in Southern Brazil.

Leptospirosis has been a neglected, widespread and reemerging zoonotic disease of global importance. The One Health holistic approach combining human, animal and environmental health has been important for control and prevention of zoonotic disease. An urban municipality in Southern Brazil with a high prevalence of leptospirosis was selected by convenience, with asymptomatic human and canine individuals serologically tested using MAT against 30 Leptospira spp. serovars. Epidemiological questionnaires were assessed along with the historical national database, with associated risk factors to dog and human seropositivity analyzed using multiple logistic regression. The spatial distribution of retrospective human leptospirosis cases was analyzed using a Kernel map and overlapped dog seropositivity and historical flooding areas, demonstrating that domestic and asymptomatic dogs may be important environmental sentinels for leptospirosis in such urban areas, even in the absence of human seropositivity and low canine seropositivity. Associated risk factors for leptospirosis in dogs and humans according to multiple regression included healthy dogs (p = 0.02, odds ratio-OR = 0.17, confidence interval of 95%CI 0.03-0.71) with indoor access (p = 0.059, OR = 5.12, 95%CI 1.10-37.7) and human males (p = 0.042, OR = 2.44, 95%CI 1.08-6.11) with presenting calf pain (p = 0.005, OR = 3.14, 95%CI 1.46-7. 14), jaundice (p < 0.001, OR = 4.61, 95%CI 2.11-10.10) and renal failure (p = 0.008, OR = 4.49, 95%CI 1.49-13.76). The greater the rain precipitation (above 3 mm of average annual precipitation), the higher the number of leptospirosis cases in humans. In conclusion, dog active serosurvey and rain precipitation should be systematically reported and plotted altogether as a basis for the early detection and monitoring of human risk areas. Such findings may serve as a basis for public health policies in Brazil and other endemic countries worldwide.

Serological Evidence Supporting the Occurrence of Ehrlichia chaffeensis or a Closely Related Species in Brazilian Dogs.

Ehrlichia chaffeensis is a tick-borne bacterium that causes human monocytotropic ehrlichiosis, an emerging life-threatening disease in humans transmitted by Amblyomma americanum. Although most studies have reported bacterial isolations and clinical cases in the United States, their occurrence is not restricted to North America. Some studies in the Southern Cone of South America have molecularly detected a close phylogenetic relative of E. chaffeensis in ticks and wild mammals. Even so, many gaps must be filled to confirm the presence of this agent in the region. To add new data on this issue, we report the first detection of specific anti-E. chaffeensis antibodies in dogs collected from all regions of Brazil. By means of IFA and ELISA with crude and specific antigens of E. chaffeensis, sera from 1134 dogs were analyzed. Serological analyses using ELISA showed nine (0.7%) seropositive dogs, with seven of them exhibiting IFA titers ranging from 160 to 5120. All regions of Brazil had at least one seropositive dog. Our results support the evidence for the occurrence of E. chaffeensis in South America. As dogs have a close relationship with humans, they can be used as an environmental sentinel for these infections because they can act as a bridge to human parasitism or infection with ehrlichial agents.

Biomonitoring of heavy metal signatures in urbanized contaminated ecosystems of Southern India: A case study using raptor, Athene brama

Background: Heavy metals remain tenacious in the environment which further leads to emerging bioaccumulation, rising through the food chain. Birds are great environmental sentinels that can spot even the smallest changes. The aim of this study was to determine the quantity of heavy metals, specifically Ni, copper (Cu), aluminum (Al), titanium (Ti), and Se, in the feathers, liver, kidney, muscle, and bones of spotted owlets (Athene brama), which were opportunistically collected from a variety of contaminated ecosystems in the urbanized landscapes of Visakhapatnam on India’s East Coast. Methods: Opportunistic sample collection was done followed by necropsy. Following standard protocols, organic samples were digested by adding 10 mL HNO3 , 5 mL of HClO4 , and 2 mL of H2 O2 to eliminate the excess organic matter. Results: Based on the GIS data, raptors were shown to occur in production landscapes and mostly in urban spaces, and currently, are under several anthropogenic threats. The findings showed that the sequence of heavy metal concentrations was Ti&gt;Al&gt;Cu&gt;Ni&gt;Se, but the tissues of birds in which metals accumulated are in the following order: liver&gt;kidney&gt;bones&gt;muscle. The tissues of A. brama showed the signs of significant concentrations of Ti and Al. The results obtained were analyzed using Kruskal-Wallis non-parametric test. Conclusion: Heavy metal studies on various matrices of the environment have been performed over time with certain metals either neglected or not being documented properly. The main finding of this study is the first report of Ti and Al in bird species from India as there is a lacuna in this context.

Feline Susceptibility to Leptospirosis and Presence of Immunosuppressive Co-Morbidities: First European Report of L. interrogans Serogroup Australis Sequence Type 24 in a Cat and Survey of Leptospira Exposure in Outdoor Cats.

Leptospirosis is one of the most widespread zoonotic diseases and can infect both humans and animals worldwide. The role of the cat as a susceptible host and potential environmental reservoir of Leptospira is still not well understood, due to the lack of obvious clinical signs associated with Leptospira spp. infection in this species. This study aims to describe the first European detection of Leptospira interrogans serogroup Australis ST 24 in a young outdoor cat with a severe comorbidity (feline panleukopenia virus). In addition, the results of a preliminary study conducted in 2014-2016 are presented (RC IZSVE 16/12), which reports an investigation of Leptospira exposure of outdoor cats in Northeast Italy by means of serological investigation and molecular evaluation of urine. The animals included in the survey are part of samples collected during active and passive surveillance (diagnostic samples). The study reported a seroprevalence of 10.5% among outdoor cats and the serogroups identified were Grippotyphosa, Icterohaemorrhagiae, Bratislava, Canicola and Ballum. Symptomatic cats reported high MAT titres (ranging from 1:800 to 1:1600) towards antigens belonging to the serovars Grippotyphosa (1:800), Bratislava (1:1600), Icterohaemorrhagiae (1:200) and Copenhageni (1:200-1:800). In one subject, urine tested positive for Leptospira PCR. Cats with high antibody titres for Leptospira and/or positivity on molecular test suffered from immunosuppressive comorbidities (feline immunodeficiency virus and feline leukaemia virus; feline herpesvirus and lymphoma; hyperthyroidism). The overall prevalence of serum antibodies against Leptospira found in free-ranging cats (10.53%, 95% CI: 4.35-16.70%) and the identification of L. interrogans ST 24 in a young cat with immunosuppressive disease (feline panleukopenia virus) suggest the possibility of natural resistance to clinical leptospirosis in healthy cats. In a One Health perspective, further studies are needed to better define the pathogenesis of leptospirosis in cats and their epidemiological role as environmental sentinels or possible carriers of pathogenic Leptospira.

The co-administration of live fowlpox and Newcastle disease vaccines by non-invasive routes to chickens reared by smallholders in Tanzania and Nepal

The co-administration of commercial live fowlpox (FP) and Newcastle disease (ND) vaccines when given by non-invasive (needle-free) routes was demonstrated to be safe and to elicit immunity in two field studies, one in Tanzania the other in Nepal. Both studies were of a cluster-randomised controlled design in which birds were randomly assigned to one of five treatment groups: (i) administration with FP vaccine alone (feather follicle), (ii) administration with ND vaccine alone (eye-drop), (iii) concurrent administration of FP (feather follicle) and ND (eye-drop) vaccines, (iv) concurrent administration of FP (wing-web) and ND (eye-drop) vaccines, and (v) unvaccinated, acting as environmental sentinels. Data from a total of 1167 birds from seven villages in Hanang District of Tanzania together with 1037 birds from eleven villages in Dhading District of Nepal were collected over a period of 21 and 28 days, respectively. Immune responses to FP vaccination were evaluated by local take reactions, while those to ND vaccination were evaluated serologically by haemagglutination inhibition test. The two studies demonstrated that the concurrent vaccination of free-range, indigenous breeds of chicken with live FP and ND vaccines, both administered by non-invasive routes, was safe and induced immunity against FP and ND that were non-inferior to the administration of FP and ND vaccines alone. These findings are important to appropriately trained small-scale backyard poultry farmers as well as to paraprofessionals and community health workers helping to increase vaccine uptake and the control of both FP and ND in low- to middle-income countries.

Trends of key surveillance performance indicators of acute flaccid paralysis: a descriptive analysis, Uganda, 2015–2020

BackgroundPolio is disease caused by poliovirus which can in turn cause irreversible paralytic disease, presenting as Acute Flaccid Paralysis (AFP). A sensitive AFP surveillance system, in which all reported AFP cases are evaluated, first to determine if they are true AFP cases or not, is key for tracking polio eradication. True AFP cases are then later categorized as polio AFP or non-polio AFP (NPAFP) cases. Sensitivity is defined by meeting an annual NPAFP rate/100,000 population < 15 years of ≥ 4/100,000, and an annual stool adequacy (SA) rate of ≥ 80%. We describe Uganda’s AFP surveillance performance between 2015–2020, based on the WHO-recommended indicators, including; NPAFP and stool adequacy rate.MethodsWe performed a descriptive analysis of national AFP surveillance data, 2015–2020 obtained from ministry of health. We evaluated proportion of reported AFP cases that were true AFP, and changes in NPAFP and stool adequacy (SA) rate over the study period. We evaluated the trends in achieving the targeted NPAFP and SA rates from 2015–2020. We used QGIS to illustrate patterns in NPAFP and SA rates across districts and subregions.ResultsAmong 3,605 AFP cases reported and investigated countrywide from 2015–2020, 3,475 (96%) were true AFP cases. All the true AFP cases were non-polio related. District reporting was near-complete (97–100% each year). Overall, the mean NPAFP rate declined from 3.1/100,000 in 2015 to 2.1/100,000 in 2020. Less than 40% of districts met the NPAFP target rate in all years. The proportion of districts achieving the NPAFP target rate of ≥ 4/100,000 significantly declined from 35% in 2015 to 20% in 2020. The mean annual SA rate nationally was 88% from 2015–2020. Only 66% of districts achieved the SA target rate of ≥ 80% in the study period. The proportion of districts with SA rate ≥ 80% significantly increased from 68 to 80% between 2015 and 2020.ConclusionMost districts reported AFP cases. However, there was a decline in the NPAFP rate from 2015–2020 and few districts achieved the target rate. The suboptimal AFP surveillance system performance leaves the country at risk of missing ongoing poliovirus transmission. We recommend health worker training on active AFP searches, intensified supportive supervision, increase the number of environmental surveillance sentinel sites to boost AFP surveillance in the country, and periodic review meetings with districts to assess AFP surveillance performance.

One health approach on serosurvey of anti-Leptospira spp. in homeless persons and their dogs in South Brazil

Although leptospirosis has been described as a worldwide bacterial zoonosis primarily affecting vulnerable populations, to date no study has focused on concomitant serosurvey of homeless persons and their dogs. The aim of the present study was, to use a One Health approach to serologically assess homeless persons and their dogs in 3 major cities of south Brazil (São Paulo, Curitiba, and Foz do Iguaçu). Environmental information was obtained with an epidemiological questionnaire given to all participants. A total of 200 human and 75 dog samples were tested for anti-Leptospira spp. antibodies to thirty different serovars using the microscopic agglutination test. None of the homeless persons were positive while 5 of the 75 (6.7%) dogs were positive. Among homeless population, 89% (177 of 200) were male, 61% (122 of 200) self-declared Non-white, and 67% (134 of 200) were educated up to the 8th school grade. Lower exposure of homeless persons to Leptospira spp. in the present study when compared to other vulnerable populations (slum and low-income residents) may be result of less direct exposure as they are able to rapidly change locations in response to flooding events. In addition, these results may reflect the effectiveness of a specific healthcare service provided to people living in the streets in the 3 cities. While dogs may be used as environmental sentinels for leptospirosis, the low seropositivity results found in this report may indicate low transmission risk to homeless owners in direct daily contact with their dogs.

Occurrence of Histamine Toxicity and Metal and Mineral Contaminants in Invasive Lionfish (Pterois volitans) in Grenada, West Indies

Targeted fishing of invasive lionfish (Pterois volitans and P. miles) in the Caribbean creates an opportunity to monitor lionfish for food safety and to examine their utility as environmental sentinel species. The goals of this study were to assess P. volitans for histamine toxicity (scombroid poisoning) and to quantify mineral and heavy metal contaminants in lionfish in Grenada, West Indies. Histamine concentrations in lionfish muscle significantly increased after heat stress but remained below maximum allowable concentrations for consumption. Mineral and heavy metal concentrations were tested in muscle and liver from lionfish from two separate reef systems using inductively coupled plasma–mass spectrometry. Total arsenic levels in liver were significantly higher in fish sampled from Boss's Reef than those from Halifax Harbor, but they were not interpreted as clinically significant. Lead, mercury, cadmium, copper, molybdenum, and cobalt were below the detectable limit of the analyzer. Thallium, selenium, iron, zinc, and manganese were detected in muscle and/or liver tissue at expected concentrations. Lionfish represent a low risk for histamine toxicity and have not bioaccumulated significant heavy metals in Grenada to pose a food safety risk. The higher arsenic concentrations in Boss's Reef suggest that the location should be monitored and studied in the future. The potential for lionfish to act as bioindicators for heavy metals is uncertain and needs further validation.

Testate Amoeba and Chironomid assemblages from Balma Lake (Piedmont, Italy): a multi-proxy record to identifying recent climate and environmental changes in alpine areas

Alpine lakes are well known as “environmental sentinels”, which are sensitive to anthropogenic impacts, and paleoecological studies provide useful information regarding the effects of local and global changes. In the present study we investigate, for the first time, the temporal variations in testate amoeba assemblages in relation to environmental factors and anthropogenic impacts in a high-altitude lake located in the Italian Alps (Balma Lake, Piedmont, Italy). The testate amoebae are well-suited as bioindicators and have been employed to reconstruct past climate and environmental changes from lake sediments. However, these organisms have not been thoroughly studied in alpine lakes, especially in Europe. We detected significant changes in testate amoeba assemblages along an alpine lake sedimentary profile over the last 2000 years. These changes were mainly associated with variations of trace elements, nutrients, and grain size. Moreover, five different time periods were identified and related to pluvial/drought events of the last 2000 years and to the “Late Antique Little Ice Age” (LALIA). Alpine lakes are originally fishless and fish introductions for recreational purposes could cause important changes in these ecosystems. However, the introduction of brook trout in Balma Lake during the 1970s seems to have had little influence on testate amoeba assemblages. The present work provides new insights for the evaluation of temporal changes in testate amoebae through paleoecological investigations. Similarly, the comparison of testate amoeba and chironomid proxies offered an important tool for analyzing recent climatic and environmental changes in alpine lakes (in lacustrine environments), especially for the European Alps.

Franciscana dolphins, Pontoporia blainvillei, as environmental sentinels of the world's largest mining disaster: Temporal trends for organohalogen compounds and their consequences for an endangered population

On November 5th, 2015, the Fundão dam collapsed in Minas Gerais, southeastern Brazil, releasing millions of cubic meters of mud containing mining residue into the Doce River. Two weeks later, the mud arrived to the marine environment, triggering changes in franciscana dolphin habitat, Pontoporia blainvillei, from Franciscana Management Area Ia. This is an isolated population of the most endangered cetacean species in the South Atlantic Ocean. Organohalogen compounds (OHCs) may pose a threat to this endangered population because of their endocrine disrupting properties. Hence, this study sought to determine if there were differences in the bioaccumulation profile of OHC (PCBs, DDTs, Mirex, HCB, HCHs, PBDEs, PBEB, HBBZ and MeO-BDEs) in franciscana dolphins before and after dam collapse and to build a temporal trend. Blubber of 33 stranded individuals was collected in Espírito Santo state for organohalogen assessment between 2003 and 2019. Differences were found between franciscana dolphins collected prior to and after the disaster. Additionally, significant temporal trends for organochlorine pesticides and natural and anthropogenic organobromine were detected. The increase in pesticide concentrations after 2015 is suggestive of their reavailability in the environment. The decline in organobromine over time could be due to their debromination in the marine environment and alterations in the composition of their natural producers. PCBs remained stable during the period of the study. Our findings show an increase in endocrine disruptor concentrations, which is of great concern for this endangered population.

The High Risk of Bivalve Farming in Coastal Areas With Heavy Metal Pollution and Antibiotic-Resistant Bacteria: A Chilean Perspective.

Anthropogenic pollution has a huge impact on the water quality of marine ecosystems. Heavy metals and antibiotics are anthropogenic stressors that have a major effect on the health of the marine organisms. Although heavy metals are also associate with volcanic eruptions, wind erosion or evaporation, most of them come from industrial and urban waste. Such contamination, coupled to the use and subsequent misuse of antimicrobials in aquatic environments, is an important stress factor capable of affecting the marine communities in the ecosystem. Bivalves are important ecological components of the oceanic environments and can bioaccumulate pollutants during their feeding through water filtration, acting as environmental sentinels. However, heavy metals and antibiotics pollution can affect several of their physiologic and immunological processes, including their microbiome. In fact, heavy metals and antibiotics have the potential to select resistance genes in bacteria, including those that are part of the microbiota of bivalves, such as Vibrio spp. Worryingly, antibiotic-resistant phenotypes have been shown to be more tolerant to heavy metals, and vice versa, which probably occurs through co- and cross-resistance pathways. In this regard, a crucial role of heavy metal resistance genes in the spread of mobile element-mediated antibiotic resistance has been suggested. Thus, it might be expected that antibiotic resistance of Vibrio spp. associated with bivalves would be higher in contaminated environments. In this review, we focused on co-occurrence of heavy metal and antibiotic resistance in Vibrio spp. In addition, we explore the Chilean situation with respect to the contaminants described above, focusing on the main bivalves-producing region for human consumption, considering bivalves as potential vehicles of antibiotic resistance genes to humans through the ingestion of contaminated seafood.

Fish parasites can reflect environmental quality in fish farms

AbstractIn the aquatic environment, fish are subject to different pollutants and environmental variations that favour stress on animals, making them vulnerable to pathogens. Fish parasites are excellent biological indicators of environmental quality, as their parasitic population may increase or decrease in response to changes in water parameters and/or the presence of pollutants. Ectoparasites are considered excellent indicators of environmental quality because they have a monoxenic life cycle with high reproductive rates that have been responsible for the immediate response to changes in aquatic biota. In turn, parasites with a heteroxenous life cycle are also responsive to environmental variation because, with the mortality of intermediate hosts, their population can be easily changed. However, studies with endoparasites and their relation with the environment are more numerous, as they are accumulators of pollutants, especially trace elements, either via fish or through stages of development outside the host that also contribute to the accumulation of metals. Moreover, Digenea, Acanthocephala, Nematoda and Cestoda parasites can compete for trace elements that are bioavailable in the environment, as fish with a greater abundance of parasites have a lower concentration of toxic metals in their tissues. Furthermore, they have a high affinity for trace elements that are toxic to human and fish health (arsenic, mercury, lead and cadmium). This review is a comprehensive overview of the use of fish parasites as environmental sentinels and describes their potential as bioindicators of effect and accumulation, and evaluates their application in fish farms environments.