Many scleractinian corals only spawn once a year, so opportunities for collecting their gametes are limited. Consequently, the induction of spawning in coral would be useful, not only for studies on ...the mechanisms of coral reproduction, but also for stock enhancement. A spawning-induction method using hydrogen peroxide (H
2
O
2
) has already been developed for coral, but most adult corals died after exposure to H
2
O
2
. In the present study, a comparison of the effects of low concentrations of H
2
O
2
(0.5–1.5 mM) on adult corals indicated that 1 mM H
2
O
2
was the upper threshold for inducing spawning without harmful effects. In addition, the effect of repeated exposure to H
2
O
2
on the same colony, and the relationship between the timing of H
2
O
2
exposure and the lunar phase, were investigated. The success rate of induced spawning was dependent not on H
2
O
2
concentration but largely on the time lag between exposure to H
2
O
2
and timing of natural mass spawning. Spawning was induced in ≥ 70% of coral colonies when they were exposed to H
2
O
2
within the 2-day period prior to a natural mass spawning event. The described technique is not only useful for the collection of artificially induced coral gametes, but also for estimating the specific timing of natural mass spawning of coral.
Background: The Japan Environment and Children’s Study (JECS), known as Ecochil-Chosa in Japan, is a nationwide birth cohort study investigating the environmental factors that might affect children’s ...health and development. We report the baseline profiles of the participating mothers, fathers, and their children. Methods: Fifteen Regional Centres located throughout Japan were responsible for recruiting women in early pregnancy living in their respective recruitment areas. Self-administered questionnaires and medical records were used to obtain such information as demographic factors, lifestyle, socioeconomic status, environmental exposure, medical history, and delivery information. In the period up to delivery, we collected bio-specimens, including blood, urine, hair, and umbilical cord blood. Fathers were also recruited, when accessible, and asked to fill in a questionnaire and to provide blood samples. Results: The total number of pregnancies resulting in delivery was 100,778, of which 51,402 (51.0%) involved program participation by male partners. Discounting pregnancies by the same woman, the study included 95,248 unique mothers and 49,189 unique fathers. The 100,778 pregnancies involved a total of 101,779 fetuses and resulted in 100,148 live births. The coverage of children in 2013 (the number of live births registered in JECS divided by the number of all live births within the study areas) was approximately 45%. Nevertheless, the data on the characteristics of the mothers and children we studied showed marked similarity to those obtained from Japan’s 2013 Vital Statistics Survey. Conclusions: Between 2011 and 2014, we established one of the largest birth cohorts in the world.
We are developing techniques to restore coral populations by enhancing larval supply using “artificial spawning hotspots” that aggregate conspecific adult corals. However, no data were available ...regarding how natural larval supply from wild coral populations is influenced by fertilization rate and how this is in turn affected by local population density and genetic diversity. Therefore, we assessed population density and genetic diversity of a wild, arborescent coral, Acropora yongei, and compared these parameters with those of an artificially established A. yongei population in the field. The population density of wild arborescent corals was only 0.27% of that in the artificial population, even in a high‐coverage area. Genetic diversity was also low in the wild population compared with the artificial population, and approximately 10% of all wild colonies were clones. Based on these results, the larval supply in the artificial population was estimated to be at least 1,400 times higher than that in wild A. yongei populations for the same area of adult population.
Plastic pollution has become one of the most pressing environmental issues. Recycling is a potential means of reducing plastic pollution in the environment. However, plastic fragments are still ...likely released to the aquatic environment during mechanical recycling processes. Here, we examined the plastic inputs and effluent outputs of three mechanical recycling facilities in Vietnam dealing with electronic, bottle, and household plastic waste, and we found that large quantities of microplastics (plastics <5 mm in length) are generated and released to the aquatic environment during mechanical recycling without proper treatment. Comparisons with literature data for microplastics in wastewater treatment plant effluents and surface water indicated that mechanical recycling of plastic waste is likely a major point source of microplastics pollution. Although there is a mismatch between the size of the microplastics examined in the present study and the predicted no-effect concentration reported, it is still possible that microplastics generated at facilities pose risks to the aquatic environment because there might be many plastic particulates smaller than 315 μm, as suggested by our obtained size distributions. With mechanical recycling likely to increase as we move to a circular plastics economy, greater microplastics emissions can be expected. It is therefore an urgent need to fully understand not only the scale of microplastic generation and release from plastic mechanical recycling but also the environmental risk posed by microplastics in the aquatic environment.
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•Mechanical recycling without wastewater treatment was at least a source of microplastic.•Effluent microplastic concentrations were from 1.1 × 105–2.0 × 108 MP particulates/m3.•Annual microplastic emissions from these facilities were from 0.014 to 5.8 t/year.
Here, we characterized the dioxin-like activities of 42 polychlorinated naphthalenes (PCNs) and 6 technical Halowax formulations by using the DR-CALUX (dioxin-responsive chemically activated ...luciferase expression) assay with rat hepatoma luciferase-expressing H4IIE cells. Of the 42 PCNs examined, 31 showed dioxin-like activities, for which the mass-based REP-EC5TCDD (potency relative to that of 2,3,7,8-tetrachlorodibenzo-p-dioxin based on the 5% effective concentration determined from the dose–response curve for 2,3,7,8-TCDD) ranged from 0.00000012 to 0.0051, indicating that some of the PCNs (e.g., 1,2,3,6,7,8-HxCN and 1,2,3,4,6,7-HxCN) had dioxin-like activities that were equal to or higher than the WHO-TEFs and the mass-based REP-EC5TCDD reported for dioxins such as octachlorodibenzo-p-dioxin, octachlorodibenzofuran, 3,3′,4,4′-tetrachlorobiphenyl (PCB-77), 3,4,4′,5-tetrachlorobiphenyl (PCB-81), and 3,3′,4,4′,5,5′-hexachlorobiphenyl (PCB-169). For PeCNs to OCN with high dioxin-like activities, REPs determined in previous studies were comparable to the REP values obtained in the present study. The TCDD-EQs (2,3,7,8-TCDD equivalents) obtained experimentally for the Halowax formulations decreased in the order HW1051 (37 mg/kg) > HW1014 (30 mg/kg) > HW1013 (5.6 mg/kg) > HW1099 (2.9 mg/kg) > HW1001 (0.60 mg/kg) > HW1031 (<0.10 mg/kg) and were comparable to the theoretical TCDD-EQs calculated by multiplying the concentration and REP of each PCN. In addition, the theoretical TCDD-EQs for PCNs in emission gases produced by thermal processes were below the Japanese emission standard of 0.1–10 ng WHO-toxicity equivalent (TEQ)/m3N, and 3 to 4 orders of magnitude lower than the corresponding WHO-TEQ. Based on a comparison of theoretical and experimental TCDD-EQs, we found that our REP-based approach was suitable for the risk management of industrially produced and unintentionally generated dioxin-like PCNs. This approach will be particularly useful for the risk management of unintentionally generated PCNs in emission gases because the contribution of dioxin-like PCNs to the whole dioxin-like toxicity of emission gases can be elucidated.
•Dioxin-like activities of 42 PCNs and 6 Halowax formulations were evaluated by DR-CALUX assay.•REPs and TCDD-EQs were obtained for 31 PCNs and 5 Halowax formulations.•Theoretical and experimental TCDD-EQs were comparable for the Halowax formulations.•Theoretical TCDD-EQs were lower than the emission standards for dioxins in exhaust gases.•REP-based approaches will be useful for risk management of dioxin-like PCNs.
Although numerous dinoflagellate species (Family Symbiodiniaceae) are present in coral reef environments, Acropora corals tend to select a single species, Symbiodinium microadriaticum, in early life ...stages, even though this species is rarely found in mature colonies. In order to identify molecular mechanisms involved in initial contact with native symbionts, we analyzed transcriptomic responses of Acropora tenuis larvae at 1, 3, 6, 12, and 24 h after their first contact with S. microadriaticum, as well as with non-native symbionts, including the non-symbiotic S. natans and the occasional symbiont, S. tridacnidorum. Some gene expression changes were detected in larvae inoculated with non-native symbionts at 1 h post-inoculation, but those returned to baseline levels afterward. In contrast, when larvae were exposed to native symbionts, we found that the number of differentially expressed genes gradually increased in relation to inoculation time. As a specific response to native symbionts, upregulation of pattern recognition receptor-like and transporter genes, and suppression of cellular function genes related to immunity and apoptosis, were exclusively observed. These findings indicate that coral larvae recognize differences between symbionts, and when the appropriate symbionts infect, they coordinate gene expression to establish stable mutualism.
Nanoplastics are likely ubiquitous in the environment, and their potential toxic effects are a concern. However, quantitative information about the distribution of nanoplastics is still lacking, and ...toxicity tests are limited to a few select polymers because of the lack of appropriate standard materials, which should be nanoscale particles with standardizable morphologies, properties comparable to those of commercial polymers, and no impurities. Here, a precipitation‐based method for preparing spherical nanoscale particles without the introduction of impurities is developed. The similarity of the molecular weight distributions, crystallinities, and thermal properties of five major polymers prepared using this method—low‐density polyethylene, high‐density polyethylene, polypropylene, polyvinyl chloride, and polystyrene—to those of commercial polymers indicate their potential for use as standard nanoplastic particles. This study provides a fundamental approach for the synthesis of standard nanoplastic particles that will facilitate quantification of the concentrations of nanoplastics in the environment and tests of their toxicity, which are required to assess the risks associated with exposure to them.
This paper reports precipitation‐based methods for preparing spherical nanoscale particles of five major polymers—low‐density polyethylene, high‐density polyethylene, polypropylene, polyvinyl chloride, and polystyrene—without the introduction of impurities. Subsequent analysis reveals their potential for use as standard nanoplastic particles that could facilitate quantification of the concentrations of nanoplastics in the environment and determination of their toxicity.
Four commercial oligomeric organophosphorus flame retardants (o-PFRs) were characterized using a refractive index detector and atmospheric pressure photoionization (APPI)-quadrupole time-of-flight ...mass spectrometry (QTOF-MS) compatible with gel permeation chromatography (GPC). Commercial o-PFRs consisted of approximately 90% or more oligomers and several impurities. Triphenyl phosphate (TPHP), tris(dimethylphenyl) phosphate (TDMPP), tris(2-chloroisopropyl) phosphate (TCIPP), and some new impurities were identified as byproducts of some manufacturing process of commercial o-PFRs for the first time. The concentrations of TPHP, TDMPP, and TCIPP were more than 1 weight %, whereas those of new impurities might be approximately 1 weight % by comparison among their abundances acquired through GPC-APPI-QTOF-MS analysis. Based on their vapor pressure and water solubility estimations, the potential environmental emissions of low molecular weight impurities were expected to be higher than those of oligomers. The presence and environmental emissions of low molecular weight impurities might be regarded as risk factors along with commercial o-PFRs.
Because more than 80% of species of gamete-spawning corals, including most Acroporidae species, do not inherit Symbiodiniaceae from their parents, they must acquire symbiont cells from sources in ...their environment. To determine whether photosynthetically competent Symbiodiniaceae expelled as fecal pellets from giant clams are capable of colonizing corals, we conducted laboratory experiments in which planula larvae of Acropora tenuis were inoculated with the cells in fecal pellets obtained from Tridacna crocea. T. crocea fecal pellets were administered once a day, and three days later, cells of Symbiodiniaceae from the fecal pellets had been taken up by the coral larvae. T. crocea fecal pellets were not supplied from the 4th day until the 8th day, and the cell densities in the larvae increased until the 8th day, which indicated the successful colonization by Symbiodiniaceae. The control group exhibited the highest mean percentage of larvae (100%) that were successfully colonized by culture strains of Symbiodiniaceae, and larvae inoculated with fecal pellets reached a colonization percentage of 66.7 ~ 96.7% on the 8th day. The highest colonization rate was achieved with the fecal pellets containing cells with high photosynthetic competency (Fv/Fm). Interestingly, the genetic composition of Symbiodiniaceae in the larvae retrieved on the 8th day differed from that in the fecal pellets and showed exclusive domination of the genus Symbiodinium. A minor but significant population of the genus Cladocopium in the fecal pellets was not inherited by the larvae. These experiments provided the first demonstration that the Symbiodiniaceae from tridacnine clams provided via fecal pellets can colonize and even proliferate in coral larvae.
Three oligomeric organophosphorus flame retardants (o-PFRs), eight monomeric PFRs (m-PFRs), tetrabromobisphenol A (TBBPA), and polybrominated diphenyl ethers (PBDEs) were identified and quantified in ...surface soils and river sediments around the e-waste recycling area in Bui Dau, northern Vietnam. Around the e-waste recycling workshops, 1,3-phenylene bis(diphenyl phosphate) (PBDPP), bisphenol A bis(diphenyl phosphate) (BPA-BDPP), triphenyl phosphate (TPHP), TBBPA, and PBDEs were dominant among the investigated flame retardants (FRs). The respective concentrations of PBDPP, BPA-BDPP, TPHP, TBBPA and the total PBDEs were 6.6–14000ng/g-dry, <2–1500ng/g-dry, 11–3300ng/g-dry, <5–2900ng/g-dry, and 67–9200ng/g-dry in surface soils, and 4.4–78ng/g-dry, <2–20ng/g-dry, 7.3–38ng/g-dry, 6.0–44ng/g-dry and 100–350ng/g-dry in river sediments. Near the open burning site of e-waste, tris(methylphenyl) phosphate (TMPP), (2-ethylhexyl)diphenyl phosphate (EHDPP), TPHP, and the total PBDEs were abundantly with respective concentrations of <2–190ng/g-dry, <2–69ng/g-dry, <3–51ng/g-dry and 1.7–67ng/g-dry in surface soils. Open storage and burning of e-waste have been determined to be important factors contributing to the emissions of FRs. The environmental occurrence of emerging FRs, especially o-PFRs, indicates that the alternation of FRs addition in electronic products is shifting in response to domestic and international regulations of PBDEs. The emissions of alternatives from open storage and burning of e-waste might become greater than those of PBDEs in the following years. The presence and environmental effects of alternatives should be regarded as a risk factor along with e-waste recycling.
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•Open storage and burning of e-waste contributed to emission of FRs.•Types of FRs currently in emission are shifting in response to regulations of PBDEs.•Emerging PFRs were detected in soils and sediments around e-waste recycling area.•Presence of alternatives for PBDEs should be regarded as a risk factor.
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