Transplacental transfer of butyltins to fetus of Dall's porpoises (Phocoenoides dalli)

Here we provided evidence, for the first time, on the placental transfer of butyltin species in Dall's porpoise (Phocoenoides dalli). The maternal to fetal transfer of butyltins including monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) was investigated in a mother-fetus pair collected off the Sanriku coast of Japan. The maternal individual was found contaminated as its liver accumulated the highest concentrations of all MBT, DBT and TBT. This study revealed that the transfer rate was about 0.3% for total butyltins to a fetus of about 6 months old. Unlike in the mother, the fetal liver does not appear to be a preferential organ for accumulation of all the butyltins. In a approximately 100 kg-weight mother Dall's porpoise and its fetus of 2.21 kg-weight about 1,269 microg (TBT, 578 microg; DBT, 480 microg; MBT, 211 microg) and 4.2 microg of total butyltins (TBT, 1.1 microg; DBT, 2.1 microg; MBT, 0.96 microg) were found, respectively.     

Prospects for a self-sustainable sewage treatment system: a case study on full-scale UASB system in India's Yamuna River Basin

The government of India decided to launch a project to implement 16 full-scale Upflow Anaerobic Sludge Blanket (UASB) reactors (with a total capacity of 598,000 m(3)/d) in the Yamuna River basin under its Yamuna Action Plan (YAP). A polishing pond called the Final Polishing Unit (FPU) was utilized for post-treatment. This paper evaluates the sewage treatment efficiency of the combined system of full-scale UASB reactors and polishing ponds under Indian climatic conditions. Results have shown that the effluent from the sewage treatment plants (STPs) investigated failed to comply with applicable discharge standards in terms of BOD, SS, and fecal coliform removal. Therefore, it is proposed that such proper operation and maintenance as removing excess sludge and scum be conducted in order to increase treatment efficiency. Moreover, trained and experienced workers are also required to operate and maintain the systems, along with a scientific approach.     

The Impact of Accidental Deviation by Natural Disaster-Prone Countries on Renegotiation-Proof Climate Change Agreements

This study provides a new framework for international environmental agreements (IEAs), which include punishment exceptions for accidental deviation, using repeated games. We consider that deviation from an agreement can occur accidentally because of phenomena such as natural disasters, even if the agreement is sustained as a weakly renegotiation-proof equilibrium. If an IEA signatory deviates accidentally, it fails to achieve its emission abatement target. In the repeated game, a cooperative relationship among signatories is sustained by a strategy that prescribes rules of cooperation and punishment for deviation. We present a new strategy, called Regional Cooperative, which integrates accidental deviations into an IEA. Our model reveals that punishing countries tend to revoke the punishment of deviators and return to cooperation if an accidental deviator increases its abatement volume. That is, the abatement efforts of the accidental deviator can lead to renegotiation. The Regional Cooperative strategy motivates the accidental deviator to try to engage in abatement and the punishing countries to restart cooperation by renegotiation. We conclude that social welfare loss by punishment is prevented through renegotiation in cases of accidental deviation.     

Multi-agent traffic simulations to estimate the impact of automated technologies on safety

Abstract

Objective: The objective of this article was to develop a multi-agent traffic simulation methodology to estimate the potential road safety improvements of automated vehicle technologies.

Methods: We developed a computer program that merges road infrastructure data with a large number of vehicles, drivers, and pedestrians. Human errors are induced by modeling inattention, aimless driving, insufficient safety confirmation, misjudgment, and inadequate operation. The program was applied to simulate traffic in a prescribed area in Tsukuba city. First, a 100% manual driving scenario was set to simulate traffic for a total preset vehicle travel distance. The crashes from this simulation were compared with real-world crash data from the prescribed area from 2012 to 2017. Thereafter, 4 additional scenarios of increasing levels of automation penetration (including combinations of automated emergency braking [AEB], lane departure warning [LDW], and SAE Level 4 functions) were implemented to estimate their impact on safety.

Results: Under manual driving, the system simulated a total of 859 crashes including single-car lane departure, car-to-car, and car-to-pedestrian crashes. These crashes tended to occur in locations similar to real-world crashes. The number of crashes predicted decreased to 156 cases with increasing level of automation. All of the technologies considered contributed to the decrease in crashes. Crash reductions attributable to AEB and LDW in the simulations were comparable to those reported in recent field studies. For the highest levels of automation, no assessment data were available and hence the results should be carefully treated. Further, in modeling automated functions, potentially negative aspects such as sensing failure or human overreliance were not incorporated.

Conclusions: We developed a multi-agent traffic simulation methodology to estimate the effect of different automated vehicle technologies on safety. The crash locations resulting from simulations of manual driving within a limited area in Japan were preliminary assessed by comparison with real-world crash data collected in the same area. Increasing penetration levels of AEB and LDW led to a large reduction in both the frequency and severity of rear-end crashes, followed by car-to-car head-on crashes and single-vehicle lane departure crashes. Preliminary estimations of the potential safety improvements that may be achieved with highly automated driving technologies were also obtained.     

An assessment of selected trace elements in intertidal surface sediments collected from the Peninsular Malaysia

Concentrations of 11 trace elements (V, Cr, Co, Ni, Cu, Zn, As, Ag, Cd, Pb, and U) were determined in the intertidal surface sediments of Peninsular Malaysia. The average trace element concentrations are ranked as follows: Zn>V>As>Cr>Pb>Cu>Ni>Co>U>g>Cd. Interim Sediment Quality Guidelines (ISQGs) employed in present study are the Australia and New Zealand joint guideline (ANZECC/ARMCANZ), and the Hong Kong authorities. From the pooled data, none of these trace elements have the average concentration above the ISQG-high values. However, As and Ag average concentrations were over the ISQG-low values. Some elements were found to have the average concentration above the ISQG-high and/or ISQG-low in certain locations, including Kampung Pasir Putih (JPP), Lumut Port (ALP), Kuala Perai (PKP), Port Dickson (NPD), and others. The lowest and highest concentrations in a specific sampling location and maritime area varied among the elements, variations that were greatly affected by natural and anthropogenic activities in a given area. For each trace element, there were various levels of concentration among the sampling locations and maritime areas. These patterns indicated pollutant sources of an element for each area perhaps derived from nearby areas and did not widely distributed to other locations. It is necessary for Malaysia to develop an ISQG for effective quick screening and evaluation of the coastal environment of Peninsular Malaysia.     

Concentrations of organotin compounds in sediment and clams collected from coastal areas in Vietnam

Levels of butyltin (BT) and phenyltin (PT) compounds were determined in sediments and clam Meretrix spp. collected from north and central coastal areas in Vietnam. Concentrations of TBT in sediments ranged from 0.89 to 34 ng g(-1) dry wt and those in clams ranged from 1.4 to 56 ng g(-1) wet wt. The levels of TBT in sediments and clams from Vietnam were within limits reported from other countries. Further, the TBT level in clams was lower than the tolerable average residue level (TARL) estimated based on tolerable daily intake (TDI). Trace amounts of PTs were also found in both sediment and clam samples. In sediments from north and central Vietnam, the concentrations of TBT were highest in the order of Hue (28 ng g(-1) dry wt), Cua Luc (15 ng g(-1) dry wt), Sam Son (6.3 ng g(-1) dry wt), and Tra Co (5.5 ng g(-1) dry wt). Among the clams from north and central Vietnam, the levels of TBT in clams from Cua Luc were dramatically high at 47 ng g(-1) wet wt. TBT formed the principal butyltin species in sediment at all sites studied. The ratios of TBT in sediment were higher among BT compounds at all study sites. Of total BTs, TBT was the dominant species in clams from almost all sites studied. In spatial distribution, TPT showed a pattern similar to TBT, suggesting the use of TPT as an antifouling paint. The partition coefficient between sediment and calms was calculated. The partition coefficients of TBT and TPT were 2.01 (0.56-5.5) and 9.23 (3.1-20), respectively. These results show that sediment-bound TBT is a source of contamination to clams in addition to dissolved TBT.     

Organochlorine concentrations in breast milk and prevalence of allergic disorders in Japanese women

Persistent organic pollutants have been shown to have immunomodulating effects in humans. However, epidemiological evidence regarding the relationships between organochlorine compound exposure and allergic disorders coming from studies of children has been limited and inconsistent. The current cross-sectional study examined the associations between the concentrations of β-hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), p,p'-dichlorodiphenyldichloroethylene (DDE), and trans-nonachlordane in breast milk and the prevalence of allergic disorders in 124 adult Japanese women. The definition of wheeze and asthma was based on criteria from the European Community Respiratory Health Survey whereas that of eczema and rhinoconjunctivitis was based on criteria from the International Study of Asthma and Allergies in Childhood. Adjustment was made for age, smoking, family history of allergic disorders, and education. The prevalence values of wheeze, asthma, eczema, and rhinoconjunctivitis in the past 12 months were 9.7%, 4.8%, 13.7%, and 29.8%, respectively. The median concentrations of β-HCH, HCB, p,p'-DDE, and trans-nonachlordane in breast milk were 28.3, 7.0, 71.6, and 23.9 ng g(-1) lipid, respectively (range, 4.5-253, 2.1-14.5, 7.5-362, and 1.8-130 ng g(-1) lipid, respectively). When the exposures were treated as continuous variables, no significant associations were found between concentrations of HCB, β-HCH, p,p'-DDE, or trans-nonachlordane and the prevalence of wheeze, asthma, eczema, or rhinoconjunctivitis. Our results suggest that concentrations of β-HCH, HCB, p,p'-DDE, and trans-nonachlordane in breast milk are not evidently associated with the prevalence of wheeze, asthma, eczema, or rhinoconjunctivitis in young female Japanese adults.     

Mercury and its relation with selenium in the liver of Dall's porpoises (Phocoenoides dalli) off the Sanriku coast of Japan

Liver samples of 22 Dall's porpoises (Phocoenoides dalli) collected off the Sanriku coast of Japan were analyzed for investigation on bioaccumulation of total mercury (SigmaHg), organic mercury (OrgHg), inorganic mercury (InHg) and selenium (Se). In the liver, detoxification of Hg was evident by transformation of OrgHg. Se showed different Hg detoxification patterns in the liver with a threshold range of hepatic SigmaHg concentration of about 20-30 microg/g dry weight. The molar ratios of Se/InHg or Se/SigmaHg were obviously higher than 1 when hepatic SigmaHg levels were less than the range, while both ratios were close to 1 when SigmaHg levels were higher than the threshold, suggesting a mechanism by detoxification of OrgHg into less toxic mercuric selenide (HgSe) forms in the latter.