Assessing the toxicity of chemical compounds associated with land-based marine fish farms: the sea urchin embryo bioassay with Paracentrotus lividus and Arbacia lixula

Occurrence, Bioaccumulation, Metabolism and Ecotoxicity of Fluoroquinolones in the Aquatic Environment: A Review

In recent years, there has been growing concern about antibiotic contamination in water bodies, particularly the widespread presence of fluoroquinolones (FQs), which pose a serious threat to ecosystems due to their extensive use and the phenomenon of "pseudo-persistence". This article provides a comprehensive review of the literature on FQs in water bodies, summarizing and analyzing contamination levels of FQs in global surface water over the past three years, as well as the bioaccumulation and metabolism patterns of FQs in aquatic organisms, their ecological toxicity, and the influencing factors. The results show that FQs contamination is widespread in surface water across the surveyed 32 countries, with ciprofloxacin and norfloxacin being the most heavy contaminants. Furthermore, contamination levels are generally higher in developing and developed countries. It has been observed that compound types, species, and environmental factors influence the bioaccumulation, metabolism, and toxicity of FQs in aquatic organisms. FQs tend to accumulate more in organisms with higher lipid content, and toxicity experiments have shown that FQs exhibit the highest toxicity to bacteria and the weakest toxicity to mollusk. This article summarizes and analyzes the current research status and shortcomings of FQs, providing guidance and theoretical support for future research directions.

Quality Control of Emerging Contaminants in Marine Aquaculture Systems by Spot Sampling-Optimized Solid Phase Extraction and Passive Sampling

The presence of organic pollutants such as pesticides and pharmaceuticals in the aquatic environment, and especially in regions where fish farms are installed, is a matter of major importance due to their possible risks to ecosystems and public health. The necessity of their detection leads to the development of sensitive, reliable, economical and environmentally friendly analytical methods for controlling their residue in various environmental substrates. In the present work, a solid-phase extraction method was developed, optimized and validated for the analysis of 7 pesticides and 25 pharmaceuticals in seawater using LC-HR-LTQ/Orbitrap-MS. The method was then applied in seawater samples collected from an aquaculture farm located in the Ionian Sea, Greece, in order to evaluate environmental pollution levels. None of the pesticides were detected, while paracetamol was the only pharmaceutical compound that was found (at trace levels). At the same time, passive sampling was conducted as an alternative screening technique, showing the presence of contaminants that were not detected with spot sampling. Among them, irgarol was detected and as far as pharmaceuticals is concerned, trimethoprim and sulfadiazine were found; however, all positive findings were at the very low ppt levels posing no threat to the aquatic environment.

Toxicological Impact of Rare Earth Elements (REEs) on the Reproduction and Development of Aquatic Organisms Using Sea Urchins as Biological Models

The growing presence of lanthanides in the environment has drawn the attention of the scientific community on their safety and toxicity. The sources of lanthanides in the environment include diagnostic medicine, electronic devices, permanent magnets, etc. Their exponential use and the poor management of waste disposal raise serious concerns about the quality and safety of the ecosystems at a global level. This review focused on the impact of lanthanides in marine organisms on reproductive fitness, fertilization and embryonic development, using the sea urchin as a biological model system. Scientific evidence shows that exposure to lanthanides triggers a wide variety of toxic insults, including reproductive performance, fertilization, redox metabolism, embryogenesis, and regulation of embryonic gene expression. This was thoroughly demonstrated for gadolinium, the most widely used lanthanide in diagnostic medicine, whose uptake in sea urchin embryos occurs in a time- and concentration-dependent manner, correlates with decreased calcium absorption and primarily affects skeletal growth, with incorrect regulation of the skeletal gene regulatory network. The results collected on sea urchin embryos demonstrate a variable sensitivity of the early life stages of different species, highlighting the importance of testing the effects of pollution in different species. The accumulation of lanthanides and their emerging negative effects make risk assessment and consequent legislative intervention on their disposal mandatory.

Antibiotics in mariculture systems: A review of occurrence, environmental behavior, and ecological effects

Antibiotics are widely applied to prevent and treat diseases occurred in mariculture. The often-open nature of mariculture production systems has led to antibiotic residue accumulation in the culturing and adjacent environments, which can adversely affect aquatic ecosystems, and even human. This review summarizes the occurrence, environmental behavior, and ecological effects of antibiotics in mariculture systems based on peer-reviewed papers. Forty-five different antibiotics (categorized into ten groups) have been detected in mariculture systems around the world, which is far greater than the number officially allowed. Indiscriminate use of antibiotics is relatively high among major producing countries in Asia, which highlights the need for stricter enforcement of regulations and policies and effective antibiotic removal methods. Compared with other environmental systems, some environmental characteristics of mariculture systems, such as high salinity and dissolved organic matter (DOM) content, can affect the migration and transformation processes of antibiotics. Residues of antibiotics favor the proliferation of antibiotic resistance genes (ARGs). Antibiotics and ARGs alter microbial communities and biogeochemical cycles, as well as posing threats to marine organisms and human health. This review may provide a valuable summary of the effects of antibiotics on mariculture systems.

Application of the Paracentrotus lividus sea-urchin embryo-larval bioassay to the marine pollution biomonitoring program in the Tunisian coast

The pollution of the marine environment by treated and untreated effluents has increased due to human activities. Monitoring the marine ecosystem is nowadays a global concern. In this work, we evaluated the effect of contaminated and uncontaminated seawater, from different Tunisian coastal areas, on the fertilization, gastrulation, and embryo-larval development events of sea urchins (Paracentrotus lividus). The station of Salakta (SA) is considered as a control station, while the stations of Hamdoun Wadi (HW), Port of Monastir (PM), Karaia Monastir (KM), Teboulba (TE), and Khniss Lagoon (KL) are considered to be contaminated stations. The analysis of seawater physicochemical characteristics showed that levels of the total suspended matter (TSM), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total organic carbon (TOC), and nitrate (NO^3-) were lower in the seawater of the reference site Salakta (SA) when compared to those of the contaminated seawater sites. In addition, a very strong variation in the levels of trace metals in seawaters sampled in the studied sites was noted. In fact, the highest concentrations of Pb and Cu were observed in Hamdoun Wadi (HW), port of Monastir (PM), and Karaia Monastir (KM), while the highest concentration of Zn was noted in the Teboulba lagoon (TE) and Khniss (LK). Alterations in physicochemical characteristics as well as elevated trace metal levels in the studied seawater samples were correlated with reduced fertility rate, gastrulation rate, and the frequency of normal sea urchin larvae. The total absence of normal sea urchin pluteus larvae in the sea waters of heavily polluted sites proves the great sensitivity of the larval frequency to mixed pollution. This work recommends the utility of urchin fertilization and gastrulation rates and normal pluteus larval frequencies as useful bioassays to monitor the exposure of marine ecosystems to mixed pollution.

Early-stage anomalies in the sea urchin (Paracentrotus lividus) as bioindicators of multiple stressors in the marine environment: Overview and future perspectives

The morphological anomalies of the early development stages of the sea urchin Paracentrotus lividus, caused by exposure to environmental stressors, are used as biomarker in ecotoxicological and ecological investigations. Here, we reviewed the available literature and classified the embryo and larval anomalies identified so far, to highlight potential commonalities or differences related to the biological action of the different stressors and their ecological impact. Morphological anomalies are influenced by a) the developmental stage of exposure to stressors; b) the intensity of the stress; c) the intra- and inter-cellular mechanisms affected by the exposure to environmental agents. The classification and analysis of embryo and larvae anomalies, either observed by the authors of this review and reported in literature, indicate that sea urchin abnormalities, caused by exposure to different stressors, can be very similar among them and classified into 18 main types, which can occur individually or mixed. All anomalies can be used to calculate an Index of Contaminant Impact to assess the impact of multiple stressors and to identify relationships between morphological anomalies and compromised biological mechanisms. This approach could be useful for a first screening of the presence of potential stressors impairing the growth and development of the early life stages of marine organisms, thus providing a relevant advancement for in future monitoring activities devoted to assess the health status in coastal marine ecosystems.

Chronic amoxicillin exposure affects Labeo rohita: assessment of hematological, ionic compounds, biochemical, and enzymological activities

Labeo rohita were exposed to amoxicillin at a concentration of 1 mg/L (Treatment -I) and 0.5 mg/L (Treatment-II) for a period of 35 days. Numerous alterations were found in amoxicillin treatment groups when compared to the control group. Hemoglobin (Hb), hematocrit (Hct), and erythrocytes (RBCs) levels were significantly (P < 0.05) decreased. Leukocytes (WBC), mean cell volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) levels were significantly (P < 0.05) increased. In the plasma and gill tissues, ionic compounds (sodium, potassium, and chloride) levels were significantly declined throughout the treatment period. The plasma biochemical profiles were significantly altered: glucose level remained low (except at the end of 7th day in Treatment -I) till 35 days of the treatment period. Biphasic trend occurred in the protein level, significant increase was observed on 7th and 28th day (Treatment -I and -II), and 35th day (Treatment -I), and in remaining days its level was found to be decreased. Glutamate oxaloacetate transaminase (GOT) activity in the plasma was inhibited significantly, whereas in the gill, liver, and kidney tissues the enzyme activity was elevated. Plasma glutamate pyruvate transaminase (GPT) activity was inhibited throughout the study period. GPT activity in the gill was found to be elevated during the treatment period. Liver GPT activity was elevated in all the treatments except 28th (Treatment-I) and 35th day (Treatment-I, and II). GPT activity in the kidney was elevated (except 14th day in Treatment-II). Lactate dehydrogenase (LDH) activity was inhibited in plasma (except 14th day in Treatment-II), gill, liver (except 7th day in Treatment-I), and kidney tissues significantly (P < 0.05). The present study emphasizes that amoxicillin at 1 and 0.5 mg/L concentrations affects the hematological/biochemical/electrolytes/enzymological parameters of fish and these biomarkers serve as an effective test system for environmental risk assessment of pharmaceuticals in the aquatic environment.

Occurrence, distribution, and ecological-health risks of selected antibiotics in coastal waters along the coastline of China

Information on ecological and health risks posed by antibiotics in coastal waters at continental or national scale is limited although antibiotics have continuously entered the natural environments due to extensive usage for human beings and animals. This study collected coastal water samples along nearly 18,000 km of coastline of China to investigate the distribution, possible sources, and potential ecological-health risks of antibiotics. Only 7 out of 13 target antibiotics were detected in coastal water samples. Total concentrations of antibiotics ranged from 389 to 3302.3 ng/L. Norfloxacin (NFC), roxithromycin (RTM), and ciprofloxacin (CFC) were the most frequently detected antibiotics, with the maximal concentrations of 1990, 1230, and 109 ng/L, respectively. Antibiotics in coastal waters might be affected by three possible factors including veterinary-drug sources, anthropogenic sources, and mixed sources. Detected NFC and sulfamethoxazole (SMX) exerted high ecological risks in the short and long terms. CFC posed moderate short-term risks but insignificant long-term risks for aquatic organisms. RTM exerted low short-term risks while it posed moderate risks in the long term. Antibiotics exerted very low cancer risks and negligible non-cancer risks for both adults and children at all sampling sites. Health risks for children posed by antibiotics were generally higher than those for adults. Antibiotics in coastal waters of China still need effective control due to potential ecological-health risks they pose.

Electrochemical remediation of amoxicillin: detoxification and reduction of antimicrobial activity

Amoxicillin (AMX) is one of the most commonly prescribed antibiotics around the world to treat and prevent several diseases in both human and veterinary medicine. Incomplete removal of AMX during wastewater treatment contributes to its presence in water bodies and drinking water. AMX is an emerging contaminant since its impact on the environment and human health remains uncertain. This contribution was aimed to evaluate the electrochemical oxidation (EO) of AMX using different anodes in tap water, NaCl or Na₂SO₄ solutions and to evaluate the potential toxicity of remaining AMX and its by-products on zebrafish early-life stages. Chemical intermediates generated after EO were determined by mass spectrometry and their resulting antimicrobial activity was evaluated. AMX did not induce significant mortality in zebrafish during extended exposure but affected zebrafish development (increased body length) from 6.25 mg/L to 25 mg/L and inhibited enzymatic biomarkers. Carbon modified with titanium oxide (TiO₂@C) anode achieved complete AMX removal in just a few minutes and efficiency of the supported electrolytes occurred in the following order: 0.1 M NaCl > 0.1 M Na₂SO₄ > 0.01 M NaCl > tap water. The order of potential toxicity to zebrafish early life-stages related to lethal and sublethal effects was as follows: 0.1 M Na₂SO₄ > 0.1 M NaCl >0.01 M NaCl = tap water. Additionally, the EO of AMX using TiO₂@C electrode with 0.01 M NaCl was able to inhibit the antimicrobial activity of AMX, reducing the possibility of developing bacterial resistance.

Assessing changes in the toxicity of effluents from intensive marine fish farms over time by using a battery of bioassays

Although intensive marine fish farming is often assumed to be eco-friendly, the associated activity can lead to chronic exposure of marine organisms to potentially toxic discharges. Moreover, despite the increasing popularity of integrated multi-trophic aquaculture (IMTA), studies of the effects of fish farm effluents are almost non-existent. In the present study, the changes in the toxic potential of effluents from five land-based marine fish farms in NW Spain subjected for different lengths of time to a biodegradation procedure (for 0, 48, 120, and 240 h) were assessed in a battery of bioassays including organisms from different trophic levels (Vibrio fischeri, Isochrysis galbana, and Paracentrotus lividus). The results of the bioassays at the different times were then considered together with farm water flow in the Potential Ecotoxic Effects Probe (PEEP) index. Despite the high volumes of effluents discharged, the generally low toxicity of the effluents hinders assessment of potentially toxic effects. However, dose-response curves and statistical analysis demonstrated the existence of toxic effects during the first five days of the biodegradation procedure, especially immediately after sampling. The proposed modification of the PEEP index better reflects the changes in toxicity over time. Graphical abstract ᅟ.

Comparative toxicity of seven rare earth elements in sea urchin early life stages

The widespread use of rare earth elements (REEs) in a number of technological applications raises unanswered questions related to REE-associated adverse effects. We have previously reported on the multiple impact of some REEs on the early life stages of the sea urchin Paracentrotus lividus. The present investigation was to evaluate REE toxicity to early life stages in two unrelated sea urchin species, Sphaerechinus granularis and Arbacia lixula. The comparative toxicities were tested of seven REEs, namely yttrium, lanthanum, cerium, neodymium, samarium, europium and gadolinium as chloride salts at concentrations ranging from 10^-7 to 10^-4 M. The evaluated endpoints included developmental defects and cytogenetic anomalies in REE-exposed embryos/larvae, and decreased fertilization success and offspring damage following sperm exposure. The results showed different toxicity patterns for individual REEs that varied according to test species and to treatment protocol, thus showing toxicity scaling for the different REEs. Further, the observed effects were compared with those reported for P. lividus either following embryo or sperm exposures. S. granularis showed a significantly higher sensitivity both compared to A. lixula and to P. lividus. This study provides clear-cut evidence for distinct toxicity patterns among a series of REEs. The differences in species sensitivity at micromolar REE levels may warrant investigations on species susceptibility to impacts along polluted coasts.

Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species

Gadolinium (Gd), a metal of the lanthanide series used as contrast agent for magnetic resonance imaging, is released into the aquatic environment. We investigated the effects of Gd on the development of four sea urchin species: two from Europe, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Exposure to Gd from fertilization resulted in inhibition or alteration of skeleton growth in the plutei. The similar morphological response to Gd in the four species indicates a similar mechanism underlying abnormal skeletogenesis. Sensitivity to Gd greatly varied, with the EC50 ranging from 56 nM to 132 μM across the four species. These different sensitivities highlight the importance of testing toxicity in several species for risk assessment. The strong negative effects of Gd on calcification in plutei, together with the plethora of marine species that have calcifying larvae, indicates that Gd pollution is urgent issue that needs to be addressed.

Assessment of the individual and mixture toxicity of cadmium, copper and oxytetracycline, on the embryo-larval development of the sea urchin Paracentrotus lividus

Multiple pollutions by trace metals and pharmaceuticals have become one of the most important problems in marine coastal areas because of its excessive toxicity on organisms living in this area. This study aimed to assess the individual and mixture toxicity of Cu, Cd, and oxytetracycline frequently existing in the contaminated marine areas and the embryo-larval development of the sea urchin Paracentrotus lividus. The individual contamination of the spermatozoid for 1 h with the increasing concentrations of Cd, Cu, and OTC decreases the fertility rate and increases larvae anomalies in the order Cu > Cd > OTC. Moreover, the normal larva frequency and the length of spicules were more sensitive than the fertilization rate and normal gastrula frequency endpoints. The mixture toxicity assessed by multiple experimental designs showed clearly that concentrations of Cd, Cu, and OTC superior to 338 μg/L, 0.56 μg/L, and 0.83 mg/L, respectively, cause significant larva malformations.

Developmental abnormalities and neurotoxicological effects of CuO NPs on the black sea urchin Arbacia lixula by embryotoxicity assay

The embryotoxicity of CuO NPs was evaluated in the black sea urchin Arbacia lixula embryos, by using 24-well plates. Fertilized eggs were exposed to five doses of CuO NPs ranging from 0.07 to 20 ppb, until pluteus stage. CuO NPs suspensions in artificial seawater formed agglomerates of 80-200 nm size, and copper uptake was 2.5-fold up in larvae exposed to high NP concentrations in respect to control. Developmental delay and morphological alteration, including skeletal abnormalities, were observed, as well as impairment in cholinergic and serotonergic nervous systems. These findings suggest the potential of CuO NPs to interfere with the normal neurotransmission pathways, thus affecting larval morphogenesis. Overall, the embryotoxicity tests are effective for evaluation of nanoparticle effects on the health of aquatic biota. Furthermore, as the black sea urchin A. lixula demonstrated to be vulnerable to NP exposure, it may be a valid bioindicator in marine biomonitoring and ecotoxicological programmes.

Assessment of toxic interactions between deltamethrin and copper on the fertility and developmental events in the Mediterranean sea urchin, Paracentrotus lividus

Deltamethrin pesticide and copper have intensively been used in agriculture and industrial activities and can finally reach the marine ecosystem at high concentrations affecting the health of organisms. In this study, we assessed under laboratory conditions the toxic interactions between deltamethrin and copper and their effects on the fertility rate, cell mitotic division rate, and embryo developmental events of the sea urchin (Paracentrotus lividus). The exposure of sperm to increasing concentrations of deltamethrin (6.10(-5) and 6.10(-2) μg/L) and copper (50 and 100 μg/L) or to their mixture (6.10(-5) μg/L of deltamethrin and 50 μg/L of CuSO4) caused a significant alteration on the fertilizing capability of spermatozoids. Concentration-dependent toxic effects on the early cleavage in P. lividus were observed in groups treated with copper, deltamethrin, and their mixture. The kinetics of early divisions was accelerated and the average size of pluteus larvae was decreased under pollutant treatments. Several developmental anomalies were identified in pluteus, including crossed skeletal tips at the hood apex, joined or atrophied arms, and alteration of general larva shape. In conclusion, the sea urchin represents a suitable and sensitive model for testing the toxicity and the effects of deltamethrin pesticide and copper in sea water. In addition, the sensitivity of various end points to studied contaminants, proved their utility in the infield biomonitoring studies.

Are WWTPs effluents responsible for acute toxicity? Seasonal variations of sediment quality at the Bay of Cádiz (SW, Spain)

Adverse effects of wastewater treatment plants (WWTPs) on sediment quality at the Bay of Cádiz (SW, Spain) were evaluated by a battery of acute bioassays and chemical contamination. Five sites directly affected by WWTPs effluents and one control site were chosen. Results evidenced clear deterioration of ecological sediment quality parameters and possible effects on aquatic communities towards WWTPs areas. Acute toxicity and chemical contamination varied significantly across the studied sites and differed between winter and summer seasons. The Bay of Cádiz is contaminated by PAHs, metals, detergents (SAS) and pharmaceutical products. Principal Component Analyses indicated metals, SAS and pharmaceutical products as the major environmental stresses. Sea-urchin embryo-larval and microalgae growth rate were the most sensitive bioassays to evaluate resuspension of contaminants (elutriate) from bulk sediment. Amphipods mortality and Microtox(®) solid phase test bioassays were recommended to evaluate bulk sediment quality. Therefore, the use of multiple-bioassays, sensitive to sediment pollution, may provide complementary information to diagnose environmental factors that can impair aquatic communities. The battery of bioassays is recommended to assess and monitor marine sediments directly affected by a mixture of contaminants released from WWTPs.

Effects of chemical disturbances on intertidal benthic assemblages

Contamination is a particular harmful type of chemical disturbance and predicting their effects on natural systems is very complex. Effects of disturbances vary in space and time and depend, among other things, on the type and age of organisms, the habitat being studied and the complex interactions occurring in the systems. Most impact analyses of contaminants are however still done with limited number of selected organisms under laboratory conditions. Manipulative experiments done in situ are important to measure ecologically relevant responses of contaminant effects on marine systems. Ecological approaches on contamination studies, accounting for interactions among species and the environment are essential to understand how such disturbances affect systems. We evaluated the effects of bleach and permethrin, two common and pervasive contaminants, on intertidal benthic assemblages in two different successional stages, mature and young. There were no impacts on the overall structure of assemblages, regardless of their age. The lack of effects on the structure of assemblages might be due to the intrinsic characteristic of the habitat studied, which provide few sinks for contaminants, as well as the inherent features of the organisms themselves. Bleach did cause, however, a decrease in the abundance of limpets, which can have further consequences to these systems. This study shows the importance of studies on chemical disturbances done under relevant natural scenarios and that efficient management policies of natural systems will only achieve successful responses with properly designed experiments under natural conditions.

The matrix influences direct and indirect effects of an anthropogenic disturbance on marine organisms

The magnitude and direction of direct and indirect effects of disturbances can be context-dependent, with the matrix (surrounding habitat) in which populations are embedded either mitigating or worsening the impacts of disturbances. Chemical disturbances are particularly harmful and can affect organisms directly or indirectly. We used bleach, a common stressor in marine systems, to test hypotheses about direct and indirect effects of anthropogenic disturbances on intertidal grazers and the influence of the surrounding macro-algal matrix on such effects. We manipulated the contaminant, food (biofilm) and surrounding macro-algal matrix. Fewer limpets were found in contaminated areas. Bleach had a strong direct negative effect on limpets and caused a reduction in biofilm food, indirectly affecting limpets. This effect was strongest in the presence of macro-algal matrix. Anthropogenic disturbances can have major consequences via direct and indirect effects on key interacting species. We showed that such effects are, however, context-dependent. Capsule: Pollution is a major driver of biodiversity declines. We show that direct and indirect effects of contaminants on organisms depend on the context in which they occur.