Manufactured Nanomaterials （MNs） are excellent industrial materials that are not only widely used in the manufacture of displays, Micro Electro Mechanical Systems （MEMS）, composite materials, energy cells, fibers, actuators and heat-exchangers, but also in cosmetics, medical equipment and pharmaceutical products. Accordingly, the concerned regulating authorities are those involved in the control of chemicals for industrial use, drugs, food, the environment, scientific technology, as well as communications, etc. As of August 2012, however, no specific laws that regulate the safety evaluation of MNs exist. Each of the major MN producers, such as EU, the United States, and Japan, is separately going through the process of discussing the methodology of systematically evaluating and regulating MNs. The MN producers have started to organize independent consortiums or working groups to discuss the safety assessments of the products. In this context, we investigated the activities towards the setting of regulations in each country, and clarified the differences between their directions. We also introduce reference materials that have been published as a general scheme for safety evaluation.

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Anti-fouling agents are usually used for the ship hulls to prevent biofouling by sessile organisms. There is little information available on triphenylborane pyridine (TPBP) which is one of the substitutes of banned organotin compounds. The purpose of this study was to evaluate the effects of sunlight on the fate of TPBP released from commercial anti-fouling paint into seawater. A glass plate applied anti-fouling paint was immersed in artificial seawater for a month. The solutions in a bottle containing the specimen under sunlight were periodically subjected for chemical analysis of TPBP and its degradation products and for ecotoxicity assessment using marine photobacteria Aliivibrio fischeri. TPBP released from the the specimen was almost 100 % degraded under sunlight after 2 weeks. Hydrolyzed TPBP in dark condition was 17 % after 28 day. The parent compound, TPBP, exhibited a more severe toxicity to the photobacteria than the other degradation products such as phenol and biphenyl. Toxicity of the solution under dark remained but the one under sunlight was reduced. It was suggested that other substances included in the anti-fouling paint and unkown products, which might have been produced, had less toxicity.

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We examined differences in the bioaccumulation of butyltin compounds (BTs) between blue mussels, Mytilus galloprovincialis, and green mussels, Perna viridis, with the expectation that these species could serve as biomonitors of the status of recovery of various regions of the Asian waters from tributyltin (TBT) contamination after the global ban on the use of organotin compounds by the International Maritime Organization. The mussels were reared for eight weeks at sites highly polluted and slightly polluted by TBT. There was no difference in the concentrations of total BTs (sum of monobutyltin, MBT; dibutyltin, DBT; and tributyltin, TBT) between the two species reared at these sites, and the total BTs (ΣBTs) reflected the TBT concentrations in the seawater at the sites. The results suggest that the ΣBTs concentrations in these two species are comparable and that transplanted mussels can be good indicators of the extent of TBT contamination in coastal waters. At both sites, the compositions of the BTs were different between the species. The ratios of the metabolites (DBT or (MBT+DBT)) to TBT were higher in blue mussels than green mussels. The difference in BTs composition seems to have been caused by interspecies differences in the potential to metabolize TBT.

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The estrogenic action of hexestrol and hexestrol propionate for inducing sex reversal was examined using a single brief treatment of early stage medaka （Oryzias latipes） embryos. Treatment of embryos with hexestrol or hexestrol propionate at high concentrations for 24 hrs resulted in complete sex reversal of genotypic males （XY） to functional females. The percentages of sex reversal varied from about 3.6% to 100% in the broad range of 1-1,000 ng/mL of hexestrol, dependent upon concentration. Hexestrol propionate at concentrations of 100 and 1000 ng/mL also induced the male-to-female sex reversal in about 9% to 83% of young fish. These results suggest that in the medaka, the brief exposure of early embryos to hexestrol or hexestrol propionate epigenetically affected sex differentiation in the late larval stage of growth.

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