Current Status of Antifouling Biocides Contamination in the Seto Inland Sea, Japan.

A monitoring survey of antifouling biocides was conducted in the Harima Nada Sea and Osaka Bay of the Seto Inland Sea, Japan to assess contamination by organotin (OT) compounds and alternative biocides. The concentrations of tributyltin (TBT) compounds in surface water ranged from 1.0 to 2.8 ng/L, and the detected TBT concentrations in the bottom water layer were higher than those in the surface water. The concentrations of TBT compounds in sediment samples ranged from 2.0 to 28 ng/g dry weight (dw), respectively. The concentrations of alternative biocides in the water and sediment were lower than those before the banning of TBT by the International Maritime Organization (IMO). Although triphenyltin (TPT) compounds were not detected in water samples, TPT compounds were detected in the range of < 0.1-2700 ng/g dw in sediment samples. Their concentrations in the water samples were as follows: diuron, < 1-53 ng/L; Sea-Nine 211, < 1-1.8 ng/L; Irgarol 1051, < 1-4.0 ng/L; dichlofluanid, < 1-343 ng/L; and chlorothalonil, < 1-1 ng/L, and the ranges of these alternative compounds in sediment samples were diuron, 32-488 ng/g dw; Sea-Nine 211, 47-591 ng/g dw; Irgarol, 33-128 ng/g dw; dichlofluanid, 67-8038 ng/g dw; and chlorothalonil, 31-2975 ng/g dw. Thus, the OTs and alternative biocides have still been detected in water and sediment samples from closed sea areas.

Desorption of polycyclic aromatic hydrocarbons from polyethylene microplastics in two morphologically different digestive tracts of marine teleosts: Gastric red seabream (Pagrus major) and agastric mummichog (Fundulus heteroclitus).

In this study, we elucidated the desorption potency of polycyclic aromatic hydrocarbons (PAHs) sorbed on microplastics (MP; polyethylene) in the digestive tract of two fish species: gastric red seabream and agastric mummichog. In our in vitro assay system using the real gut sample of unexposed fish, the digestive tract was firstly removed from the fish and divided into three parts. Then, MP that had previously been sorbed with 16 PAHs were incubated with extracts of the gut contents or tissue with buffer or only a buffer. The desorption potency of PAHs was individually assessed for gut contents and tissue, which revealed that PAH desorption from MP was elevated in extracts of the gut contents compared with that in the buffer alone for both fish species. PAH desorption potency was the highest in the midgut for gastric red seabream and in the foregut for agastric mummichog, which indicates that PAH desorption from MP varies among different parts of the digestive tract and among fish with distinct gut morphology. In the midgut contents of red seabream and foregut contents of mummichog, the desorption fraction was 5.6% and 8.1% of the total PAHs sorbed on MP, respectively. The desorption fraction enhancement achieved by adding gut contents extracts tended to be greater with an increase in the n-octanol/water partition ratio, suggesting that enhancement of the desorption fraction in the digestive tract depends on the physicochemical properties of PAHs. Thus, morphological differences in digestive tracts and PAH properties should be considered when evaluating the effect of MP vector on pollutant exposure in fish.

Microplastic uptake and gut retention time in Japanese anchovy (Engraulis japonicus) under laboratory conditions.

To explore the impact of microplastic (MP) pollution on planktivorous fish, we examined the uptake and retention of MPs by Japanese anchovy (Engraulis japonicus) under laboratory conditions. MP uptake was size selective in adult anchovy-0.3-mm MPs were taken up in significantly larger amounts than 0.85-mm MPs-but not in juveniles. There were no significant differences in the uptake of MPs of three different colors, suggesting that anchovy do not select for MP coloration. More than 90% of the MPs were excreted within 20 h of ingestion, indicating that MP retention time is similar to the processing time of food items. Our findings suggest that Japanese anchovy tend to take up MPs that are equivalent in size to prey items, but that the impacts of MP ingestion are likely to be limited under the current state of oceanic MP contamination.

Absence of calvarial fracture could predict the need for tracheostomy in traumatic brain injury.

AIM: Tracheostomy is a common procedure for intubated patients with traumatic brain injury (TBI) in the intensive care unit (ICU) but optimal timing and the predictors of tracheostomy are still unclear. The aim of our study was to explore whether the traumatic variables of head injury predict the need for tracheostomy in intubated TBI patients. METHODS: A single-center, retrospective observational study including a series of TBI patients admitted to Fukui Prefectural Hospital from April 1, 2004 to March 31, 2020 was carried out. Our primary outcome was tracheostomy. Patients with TBI who were intubated and admitted into the ICU within 24 h after injury were enrolled. Exclusion criteria were age less than 18 years, pregnancy, mortality within 24 h, post-cardiac arrest syndrome, and patients for whom life-sustaining interventions were withheld. Radiologic images were also reviewed and the morphology of the head injury was categorized. RESULTS: Seventy-six patients were included. Forty-six patients (60.5%) underwent tracheostomy and 30 patients (39.5%) were successfully extubated. Calvarial fracture (odds ratio [OR] 0.34; 95% confidence interval [CI], 0.13-0.88; P = 0.03), Injury Severity Score (OR 1.07; 95% CI, 1.00-1.15; P = 0.04), and Glasgow Comas Scale score (OR 0.84; 95% CI, 0.73-0.96) were statistically significant in the univariable analysis. Multivariate logistic regression identified calvarial fracture as an independent predictor for tracheostomy. The model involving calvarial fracture, Injury Severity Score ≥16, and Glasgow Coma Scale score ≤8 showed the area under the receiver operating characteristic curve for the model was 0.737 (95% CI, 0.629-0.846). CONCLUSIONS: The absence of calvarial fracture could predict the necessity for tracheostomy in intubated TBI patients when combined with other factors. Further prospective randomized trials are necessary to confirm the findings.

Estimation of the uptake and gut retention of microplastics in juvenile marine fish: Mummichogs (Fundulus heteroclitus) and red seabreams (Pagrus major).

We investigated the impact of microplastics (MPs) on marine fish by estimating the uptake and retention by mummichogs (Fundulus heteroclitus) and red seabreams (Pagrus major) of MPs similar in size (≥0.25 mm) and composition (polyethylene) to MPs detected in fish intestines. Results revealed a correlation between MP concentrations in aquarium water and the content of MPs in the gastrointestinal tracts of exposed fish. More than 95% were excreted from both species within 25 h; this retention time is similar to the processing time of food items. The rate of excretion showed little dependence on MP size, but there was some dependence on fish species and MP shape. These results suggest that MPs similar to those we studied have little direct adverse impact on these two marine fish species.

Ecological risk assessment of an antifouling biocide triphenyl (octadecylamine) boron in the Seto Inland Sea, Japan.

In this study, we derived the predicted no-effect concentrations (PNEC) for triphenyl (octadecylamine) boron (TPB-18) and investigated the occurrence of triphenylboranes (TPBs), including TPB-18, for ecological risk assessment in the Seto Inland Sea, Japan. We tested algal growth inhibition, crustacean immobilization, and reproductive toxicity and performed toxicity tests in fish to assess acute and chronic toxicity and generate the PNEC for TPB-18. The minimum toxicity value was 0.30 µg/L, as determined by the 72-h no-observed-effect concentration (NOEC) for the alga Chaetoceros gracilis. The 5th-percentile of hazardous concentration (HC5), derived from NOECs using the species sensitivity distributions approach, was 0.059 µg/L, which indicated the PNEC of 0.0059 µg/L. In comparison, the highest concentration in seawater sampled from the Seto Inland Sea was 0.00034 µg/L, suggesting that the ecological risks posed by TPB-18 are currently low.

Point-of-care procalcitonin may predict the need for surgical treatment in patients with small bowel obstruction.

BACKGROUND: The early identification of patients with small bowel obstruction who require surgical treatment could potentially lead to improved patient outcomes. We evaluated the efficacy of point-of-care procalcitonin for predicting surgical treatment among patients with small bowel obstruction. METHODS: This was a prospective observational study. We measured serum procalcitonin levels in patients who presented to the emergency department and were diagnosed with small bowel obstruction from April 1, 2018 through March 31, 2019. Patients were grouped into two groups: the elevated procalcitonin and normal procalcitonin groups. Our primary outcome was surgical treatment. RESULTS: A total of 53 patients with small bowel obstruction were included in the study, and 11 patients (20.8%) were treated operatively. Baseline characteristics were similar, except for age, between the elevated procalcitonin (≥0.12 ng/ml) and normal procalcitonin groups. The elevated procalcitonin level was significantly correlated with surgical treatment and hospital length of stay (p < 0.05). The sensitivity, specificity, and positive likelihood of procalcitonin for the former were 45.5%, 85.7%, and 5.0 respectively. CONCLUSION: The patients with small bowel obstruction who had elevated procalcitonin levels on presentation showed significantly higher rate of surgical treatment than those who had normal procalcitonin levels. Point-of-care procalcitonin might predict the need for surgical treatment in patients with small bowel obstruction and could be used as an additional diagnostic test. Further studies with more patients are needed to investigate the predictive value of point-of-care procalcitonin for surgical treatment.

Effect of taurine supplementation on hepatic metabolism and alleviation of cadmium toxicity and bioaccumulation in a marine teleost, red sea bream, Pagrus major.

This study was performed to unravel the mechanism of the beneficial action of taurine on marine teleost fish, red sea bream (Pagrus major), by analyzing the hepatic metabolism. Moreover, the ameliorative effects of the nutrient against cadmium toxicity and bioaccumulation were further evaluated. The fish were fed a diet containing 0 % (TAU0 %), 0.5 % (TAU0.5 %), or 5.0 % (TAU5.0 %) taurine for 40-55 days (d) and subjected to cadmium acute toxicity and bioaccumulation tests. Taurine deficiency in feed severely affected growth and the hepatic metabolic profiles of the fish, including a remarkable increase in myo-inositol, aspartate, and ß-alanine in the TAU0 % group, which indicates a complementary physiological response to taurine deficiency. For the acute toxicity test, fish were fed the test diets for 55 d and were then exposed to different dose of cadmium ranging from 0 to 5.6 mg/L for 96 h. Fish fed taurine had a higher tolerance to cadmium than those not fed taurine. For the bioaccumulation test, fish were fed the test diets for 40 d and then were chronically exposed to 0.2 mg/L of cadmium for 28 d followed by depuration for 21 d. Cadmium concentrations in the liver and muscle of fish fed TAU5.0 % were significantly lower than those of fish fed TAU0 % for the first 7 d of exposure and the first 7 d of elimination. Our findings suggest a possible mechanism for the beneficial role played by taurine and that the inclusion of taurine in fish aquaculture feed may reduce cadmium contamination of fish intended for human consumption.

Dietary taurine supplementation ameliorates the lethal effect of phenanthrene but not the bioaccumulation in a marine teleost, red sea bream, Pagrus major.

The present study was performed to evaluate the effect of dietary taurine on the hepatic metabolic profiles of red sea bream (Pagrus major) and on phenanthrene (a polyaromatic hydrocarbon) toxicity and bioaccumulation. The fish were fed a diet supplemented with 0% (TAU0%), 0.5% (TAU0.5%), or 5% (TAU5%) taurine for 40-55d and subjected to phenanthrene acute toxicity and bioaccumulation tests. Taurine deficiency in feed severely affected the hepatic metabolic profiles of fish, which indicated a complementary physiological response to taurine deficiency. For the acute toxicity test, fish were fed the test diets for 55d and were then exposed to 0-893µg/L phenanthrene for 96h. Tolerance to phenanthrene was significantly improved by 0.5% of taurine inclusion in feed relative to TAU0%, but not by 5.0% inclusion. Reduced glutathione in the liver, which acts as an oxygen-free radical scavenger, was associated with a reduction in the toxicity of phenanthrene. For the bioaccumulation test, fish were fed the test diets for 40d and were thereafter chronically exposed to 20µg/L phenanthrene for 13d followed by depuration for 3d. The activity of hepatic biomarker, ethoxyresorufin-O-deethylase, was increased by phenanthrene exposure in the taurine inclusion groups. However, phenanthrene concentrations in the liver and muscle of fish fed TAU5.0% tended to be higher than those of fish fed TAU0% and TAU0.5% during the exposure period. These results indicate that 0.5% of taurine inclusion in feed plays an important role in the alleviation of phenanthrene toxicity but not bioaccumulation. Furthermore, larger amount of taurine inclusion (TAU5%) did not show marked beneficial effects against phenanthrene exposure. This study provides insight about a major concern of environmental contaminants into aquatic environment and can be effectively used for improvement of aquaculture.

Bioconcentration and Elimination of the Dithiocarbamate Fungicide Polycarbamate in Marine Teleost Fish and Polychaete.

We evaluated the bioconcentration and elimination of polycarbamate, a popular antifoulant classified as a dithiocarbamate fungicide, in a marine teleost fish, mummichog (Fundulus heteroclitus), and a polychaete (Perinereis nuntia). Following polycarbamate exposure and depuration, the calculated bioconcentration factor (BCF) and elimination rate constant (k2) were 3.1 and 0.17 day(-1) in fish and 1.5-7.8 and 0.13-0.18 day(-1) in the polychaete, indicating that the fungicide has low bioconcentration potential in both organisms. Given the BCF of 3.1, the permissible environmental concentration level of polycarbamate in water was calculated to be 6.1 µg L(-1) to satisfy the threshold pesticide residue levels in fish permitted by law, which is far below the permissible levels in Hiroshima Bay, Japan. Therefore, we consider that the current polycarbamate contamination level in terms of bioconcentration is not likely to be an alarming issue in coastal environments.

Primary risk assessment of dimethyldithiocarbamate, a dithiocarbamate fungicide metabolite, based on their probabilistic concentrations in a coastal environment.

The primary ecological risk of dimethyldithiocarbamate (DMDC), a dithiocarbamate fungicide (DTC) metabolite, was evaluated based on their probabilistic environmental concentration distributions (ECDs) in the coastal environment, Hiroshima Bay, Japan. And their behavior and temporal trends was further considered. This is the first report of the identification of DMDC from environmental seawater and sediment samples. DMDC concentrations in bottom seawater were substantially higher than those in surface seawater, which are associated with the leachability from sediments in bottom seawaters, and with photodegradation in surface seawaters. Furthermore, seasonal risks are dominated by higher concentrations from April to June, indicating temporal variation in the risk to exposed species. Hierarchical Bayesian analysis offered DMDC ECD medians and range (5th to 95th percentiles) of 0.85 ng L(-1) (0.029, 22), 12 ng L(-1) (3.2, 48) and 110 ng kg dry(-1) (9.5, 1200) in surface seawater, bottom seawater and sediment, respectively. Considering that DMDC and DTCs have similar toxicological potential to aquatic organisms, the occurrence of the compound in water is likely to be of biological relevance. In summary, this work provides the first demonstration that the ecological risk of DMDC and its derived DTCs in Hiroshima Bay is relatively high, and that DTCs should be a high priority for future research on marine contamination, especially in bottom seawaters.

Dioxin transfer from sediment to the infaunal surface deposit-feeding polychaete Perinereis nuntia in a laboratory-rearing experiment.

In the presented study a laboratory experiment was conducted to investigate the transfer of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) from environmentally contaminated marine sediment to an infaunal surface deposit-feeding polychaete, Perinereis nuntia. Polychaetes were exposed to contaminated sediment for 42 d, and elimination of these compounds was studied for an additional 28 d. The sediment uptake rate coefficients (ks), elimination rate constants (k2), and the biota-sediment accumulation factors (BSAFs) were determined for PCDDs, PCDFs (PCDD/Fs), and dioxin-like PCBs. Each of these compounds was transferred from sediment to polychaete except for hepta- and octachlorinated PCDD/Fs. The BSAFs for dioxin-like PCBs (0.13-2.2) were significantly higher than those for PCDD/Fs (0.00022-0.36). The BSAF, ks, and k2 values obtained in the present study indicate that the bioaccumulation characteristics of PCDD/Fs in polychaete are similar to those in fish, and depend on their physical and chemical properties such as hydrophobicity and size of molecules. The ks values for PCDD/Fs and dioxin-like PCBs declined with an increase in their log KOW values, indicating a decrease in bioavailability. The negative exponential relationships of k2 versus KOW were observed for these compounds. The slope for the log-normalized regression of k2 versus KOW for the PCDD/Fs was smaller than that for the dioxin-like PCBs and that of ks versus KOW for the PCDD/Fs. Therefore, the negative exponential relationship of BSAF versus KOW was observed for PCDD/Fs, but not for dioxin-like PCBs.

Molecular and histological evaluation of tributyltin toxicity on spermatogenesis in a marine fish, the mummichog (Fundulus heteroclitus).

There is still concern about the effects of organotin compounds (OTs) on marine organisms, and especially on their reproductive systems. We investigated the toxicity of tributyltin oxide (TBTO) on spermatogenesis in a marine fish, mummichog, Fundulus heteroclitus. TBTO exposure caused serious histological damage to the testis, including reduction in counts of spermatids and spermatozoa and malformation of somatic cells around the seminal duct. Analysis of the incorporation of bromodeoxyuridine into spermatogenic cells revealed inhibition of the proliferation of germ cells. To find a biomarker for evaluation of the effects of TBTO on fish spermatogenesis, we cloned genes downregulated by TBTO exposure in the mummichog testis, and identified mummichog creatine kinase (mCK). The cDNA sequence of mCK contained an open reading frame encoding 387 amino acid residues (M(r)=43,344). The derived amino acid sequence of mCK was very similar to that of the testicular-type CK of the rainbow trout, Oncorhynchus mykiss. Furthermore, Northern blot analysis revealed that mCK was produced specifically in the testis. We therefore identified mCK in the mummichog as a testicular-type CK. Real-time PCR revealed that exposure of the fish to TBTO significantly reduced mCK expression in the testis. To some extent, this reduction was coincident with that of bromodeoxyuridine incorporation into spermatogenic cells. The mCK gene can therefore be used as a biomarker for evaluating the effects of TBTO on fish spermatogenesis. In addition, levels of expression of the mCK gene in control fish were well correlated with increments in the gonad somatic index (GSI) below 4%. Individuals that were thought to have testicular damage caused by TBTO could be discriminated from those considered normal. The results suggest that TBTO is involved in the suppression of fish spermatogenesis and that analysis of both GSI values and mCK gene expression is useful for evaluating the levels of xenobiotic pollution in coastal areas.