Metal and metalloid bioaccumulation in dried red seaweed Hypnea musciformis and health risk assessment for consumers.

This study measured 22 metal and metalloid concentrations in Hypnea musciformis from the Bakkhali River estuary and Saint Martin's Island, Bangladesh and determined their potential impact on consumption. Student t-tests showed a significant variation in metal concentrations between the two sampling sites (p < 0.05). Mean concentrations of Co (2.49 ± 0.05 mg/kg), Fe (793.29 ± 11.76 mg/kg), Mn (368.72 ± 4.87 mg/kg), Pb (3.82 ± 0.02 mg/kg), V (11.23 ± 0.20 mg/kg) and Zn (16.60 ± 0.28 mg/kg) were higher in samples collected from the Bakkhali River estuary compared to Saint Martin's Island, while mean concentrations of Ca (484.18 ± 4.68 mg/kg), Cd (2.44 ± 0.03 mg/kg), Mg (2112.70 ± 17.80 mg/kg), Mo (1.57 ± 0.06 mg/kg), Sr (2377.57 ± 29.98 mg/kg), and Ti (258.27 ± 4.62 mg/kg) were higher in samples collected from Saint Martin's Island. Eight heavy metals (Pb, Cd, Zn, Cu, Ni, Mn, Cr, Fe) were used to assess potential health risks for adults, but no potential health risk was detected (HQ value>1). This study reveals positive Se-HBV for H. musciformis collected from both sampling sites, indicating no potential risks involved with Hg toxicity.

Heavy metals and metalloids in edible seaweeds of Saint Martin's Island, Bay of Bengal, and their potential health risks.

The present study aimed to assess the levels of heavy metals and metalloids present in six seaweeds and their potential impact on consumption. The highest concentration of 11 metals, i.e., Be (0.47 mg/kg), Co (4.34 mg/kg), Cr (23.46 mg/kg), Cu (11.96 mg/kg), Fe (2290.26 mg/kg), Li (11.55 mg/kg), Ni (13.75 mg/kg), Pb (6.67 mg/kg), Ti (736.62 mg/kg), Tl (0.14 mg/kg), and V (33.09 mg/kg) were observed in Enteromorpha intestinalis (green seaweeds). Besides, the highest concentration of Ca (1071.09 mg/kg), Cd (5.81 mg/kg), Mn (1003.41 mg/kg), Sr (2838.86 mg/kg), and Zn (41.95 mg/kg) were found in Padina tetrastromatica (brown seaweeds). Eight metals (Pb, Cd, Zn, Cu, Ni, Mn, Cr, Fe) have been used to assess the potential health risk for adults, but no potential health risk was detected (HQ value > 1). The HI value of E. intestinalis and P. tetrastromatica were >1, implying that these two seaweeds are not safe for human consumption as there is a carcinogenic health risk for adults.

A combination of six psychoactive pharmaceuticals at environmental concentrations alter the locomotory behavior of clonal marbled crayfish.

Pharmaceutically active compounds (PhACs) are ubiquitous in the aquatic environment worldwide and considered emerging contaminants. Their effects on growth, behavior, and physiological processes of aquatic organisms have been identified even at very low concentrations. Ecotoxicological investigations have primarily focused on single compound exposure, generally at a range of concentrations. In the natural environment, pollutants seldom occur in isolation, but little is known about the effects and risks of combinations of chemicals. This study aimed to investigate the effects of concurrent exposure to six psychoactive PhACs on locomotory behavior and life history traits of clonal marbled crayfish Procambarus virginalis. Crayfish were exposed to ~1 µg L-1 of the antidepressants sertraline, citalopram, and venlafaxine; the anxiolytic oxazepam; the opioid tramadol; and the widely abused psychostimulant methamphetamine. In the absence of shelter, exposed crayfish moved significantly shorter distances and at lower velocity and showed significantly less activity than controls. With available shelter, exposed crayfish moved significantly more distance, showed higher activity, and spent a significantly more time outside the shelter than controls. Molting, mortality, and spawning frequency did not vary significantly between the groups. Hemolymph glucose level did not vary among groups and was not correlated with observed behaviors. Results suggest that environmental concentrations of the tested compounds in combination can alter the behavior of non-target aquatic organisms as individual exposure of these compounds, which may lead to disruption of ecosystem processes due to their reduced caution in polluted conditions. Further research is needed using varied chemical mixtures, exposure systems, and habitats, considering molecular and physiological processes connected to behavior alterations.

The effects of the herbicides terbuthylazine and metazachlor at environmental concentration on the burrowing behaviour of red swamp crayfish.

Despite their low concentrations in many aquatic environments, evidence exists to suggest that herbicides do affect non-target organisms. Given that burrowing is a primary life-history trait in crayfish, herbicides could potentially have serious negative effects on these ecologically important freshwater macroinvertebrates. In this study, we exposed the red swamp crayfish Procambarus clarkii to terbuthylazine (a triazine) and metazachlor (a chloroacetanilide) at an environmental concentration of 2.0 µg/L for 28 days, and then observed their burrowing behaviour for two days. The metazachlor-exposed males excavated a greater number of burrows than the other tested groups, with comparable depths and volumes relative to individual specimen weight. The relative depth and volume of female burrows were identical in all groups. The natural habit of female crayfish of constructing deeper burrows than males was marginally significant in the control and META groups but was not significant for relative volume. The hypothesized adverse effects of chronic exposure to real environmental concentrations of herbicides were not documented in terms of either relative depth or volume. However, the increased number of burrows in metazachlor-exposed animals may mean that this invasive species will cause greater damage to embankments and river banks. The mechanisms behind these effects require closer study.

Psychoactive compounds at environmental concentration alter burrowing behavior in the freshwater crayfish.

Pharmaceutically active compounds (PhAC) have been increasingly detected in freshwater and marine waterbodies worldwide and are recognized as major emerging micropollutant threat to the aquatic environment. Despite their low concentrations in the environment, there is evidence of effects on non-target aquatic organisms in natural habitats. To assess the potential effects of PhACs on its burrowing behavior, we exposed the red swamp crayfish Procambarus clarkii to methamphetamine or tramadol at the environmentally relevant concentration of 1 µg/L. Methamphetamine-exposed females constructed burrows of lower depth and volume relative to individual weight than did controls. Tramadol-exposed females consistently exhibited a tendency for smaller burrows, but this difference was not significant. Exposed males showed a non-significant tendency to excavate larger burrows compared with the control. Control and tramadol-treated females maintained the natural tendency of constructing relatively deeper and/or larger-volume burrows compared with males. This sex-related pattern was not detected in the methamphetamine group. The rate of human therapeutic PhAC usage is relatively stable year-round, and impacts on crayfish burrowing can be particularly damaging during periods of drought, when the dilution of waste waters is reduced, and burrowing becomes a critical survival strategy. Our results suggest that an increasingly broad range of environmental impacts of PhACs on non-target organisms can be expected in natural ecosystems.

Exposure paradigm of fluoxetine impacted the Faxonius virilis agonistic behavior differently.

Pharmaceutically active compounds are major contaminants of aquatic environments. The effects on aquatic organisms have been assessed mostly through eco-toxicological tests performed using static exposure systems or flow through systems with constant concentrations. Yet, constant concentration exposures ignore the spatio-temporal dynamics of chemicals in flowing environments. In dynamic systems, a chemical's effect on an organism will vary due to fluctuations in the frequency, magnitude, and duration of the chemical concentration within the plume, which develops due to turbulence interacting with the geomorphology of habitat. The aim of this study was to analyze how different exposure dynamics to the antidepressant fluoxetine might alter the agonistic behavior of aquatic organisms. Male crayfishes, Faxonius virilis, were subjected to 23 h exposures at different concentrations of fluoxetine (control, 0.05, 0.5, 1, 10 and 100 µg/l) in both static and dynamic mesocosm systems. After exposure, size-matched crayfishes, from the same exposure system and fluoxetine concentration, underwent a fifteen minute fight trial. The aggressive intensities and duration of agonistic interactions were quantified. The time spent performing a tailflip was significantly longer for fluoxetine concentrations of 1, 10, 100 µg/l in the static exposure than in the dynamic exposure. On other hand, the time spent at higher intensities and the time to escalate to the highest intensity of interactions in control treatments were significantly lower in the dynamic exposure than in the static exposure. Whereas, in elevated fluoxetine concentrations, these times were significantly higher in the dynamic than in static treatments. Therefore, we could conclude that the fight dynamics and duration of agonistic behavior in crayfish were affected by static and dynamic exposure paradigms differently. Despite these behavioral changes, serotonin levels in fluoxetine-exposed crayfish did not differ significantly between exposure paradigms. Future research should incorporate different exposure methods that more accurately represent chemical exposure in natural habitats.

Environmentally relevant concentrations of methamphetamine and sertraline modify the behavior and life history traits of an aquatic invertebrate.

Pharmaceutically active compounds are major contaminants of aquatic environments that show direct and indirect effects on aquatic organisms even at low concentrations. The aim of this study was to assess the effects of the illicit drug methamphetamine and the antidepressant sertraline on clonal marbled crayfish Procambarus virginalis. Crayfish exposed to the environmentally relevant concentrations of methamphetamine of ∼1 µg L-1 did not exhibit significant differences from unexposed controls in distance moved, velocity, and activity level with or without available shelter. Sertraline-exposed (∼1 µg L-1) crayfish were significantly more active, regardless of available shelter, and moved greater distances when shelter was available, compared to control crayfish. Crayfish exposed to methamphetamine and sertraline spent significantly more time outside the shelters compared to controls. Sertraline-exposed crayfish spawned more frequently and showed higher mortality than controls. The results suggest that the low environmental concentrations of the tested compounds could alter the behavior and life history traits of crayfish, resulting in higher reproductive effort and mortality.

Evaluation of seminal plasma composition and spermatozoa quality parameters of silver barb, Barbonymus gonionotus Bleeker, 1850.

Seminal composition and semen quality are the important determinants in assessing the reproductive performance of different fishes. This study was carried out to evaluate the seminal composition and sperm quality of Barbonymus gonionotus. The seminal plasma contained 17.2 ± 0.34 mmol/l, 20.9 ± 0.48 mmol/l, 0.72 ± 0.04 mmol/l, 3.8 ± 0.2 mmol/l, and 1.49 ± 0.02 g/dl of Na+, K+, Ca++, Mg++, and total protein, respectively. The physical spermatological parameters, such as sperm volume, sperm motility, motility duration, sperm density, osmolality, and pH values were 1.55 ± 0.15 ml, 89 ± 2%, 391.9 ± 8.5 s, 2.8 ± 0.2 × 1010 /ml, 400.6 ± 5.1 mmol/kg, and 8.75 ± 0.10, respectively. In correlation matrix, the K+ (R2 = 0.39, P < 0.01) and Ca++ (R2 = 0.27, P < 0.05) ions and osmolality (R2 = 0.29, P < 0.05) showed significant positive correlations with sperm motility. Similarly, fertilization rate significantly influenced by sperm motility (R2 = 0.26, P < 0.05) and K+ (R2 = 0.30, P < 0.05) and Ca++ (R2 = 0.26, P < 0.05) ions. Also, osmolality significantly and negatively correlated with Mg++ (R2 = 0.33, P < 0.05) and sperm motility duration (R2 = 0.28, P < 0.05). Therefore, based on this results, it can be concluded that seminal plasma ions, K+ and Ca++ and osmolality are the key factors for the determination of sperm quality of silver barb, and these parameters could be considered during standardization of artificial fertilization or cryopreservation technique of silver barb spermatozoa.