The spatial distribution, partitioning, and time trends of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) were investigated in the water column and bottom sediment of Tokyo Bay, Japan, during 2004-2006. A total of 480 water and 60 sediment samples obtained by regular 20-station samplings ascertained the three-dimensional distributions of these compounds and changes in the seawater structure in the whole bay. The median of volume-based average water-borne concentrations of PFOS and PFOA was 3.7 and 12 ng/L, respectively. The median concentrations in sediment were 0.61 (PFOS) and 0.20 (PFOA) ng/g-dry. Vertical mixing of the water column probably affected the vertical distribution of these compounds. The negative correlations between PFOS and PFOA concentrations and water salinity and the horizontal distributions of their concentrations suggested that freshwater inputs into the bay were the source of these compounds. A mixing model estimated the average PFOS concentration in the freshwater inputs to be 29 ng/L. The common logarithm of the partition coefficients between the dissolved and suspended-particle-sorbed phases varied among samples, with the average of 4.2 (PFOS) and 3.5 (PFOA). Our analyses indicated no apparent time trends in the concentrations of these compounds during 2004-2006 in either the freshwater input or the bay.

Modular construction, which involves factory-based modular unit manufacturing followed by installation at a construction site, has been recognized as one of the sustainable construction methods. Its advantages are known to be implemented through (1) standardized design, (2) standardized production method, and (3) large-scale development (mass production system). These three conditions are basic requirements for modular construction market expansion, but it is difficult to define that these conditions are a prerequisite for judging whether modular construction applied or not. Nevertheless, public development companies in regions or countries where modular construction has just begun thought that modular construction should meet all three conditions that are suitable for applying public construction projects. This is because it is difficult to compare conventional construction projects with similar conditions to modular construction projects. This paper analyzes the cost and duration data of three small-scale public construction rental housing (PCRH) projects involving modular construction in Korea. These cases presented herein include a public college student dormitory, public low-rise rental housing, and public mid-rise rental housing in small-scale development projects. Those were applied not standardized design (common design and regulation), but were reflected in each project’s demands (different design and regulation). To compare it, this paper analyzed 91 public housing provision projects’ construction data from 2011 to 2017 from one of the public rental housing provision companies in Korea. Among them, 19 small-scale public rental housing data were extracted for comparing with modular construction project data. The results show that, even if not standardized, the design and production process, and modular construction durations, were more effective—but costs were similar or expensive. Based on the conclusion drawn from three cases, this paper presents important considerations for the application of modular construction in other small-scale public construction rental housing projects from the perspective of public development companies.

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We evaluated the extent of shrinkage in body size of juvenile marbled sole Pseudopleuronectes yokohamae after preservation in 70% ethanol for 6, 12, 24, or 48 h, or 4 weeks. Standard length (SL, range of the analyzed specimens: 22.82-53.01 mm) decreased by 5.6% after 12 h and body weight (BW 0.174-2.964 g) decreased 27.8% after 24 h preservation in 70% ethanol. There was no further decrease in SL or BW after 12 or 24 h of preservation, respectively. The original body size could be estimated based on the size after preservation in 70% ethanol for 4 weeks using the following equations: SL original = 1.05 SL preserved ? 0.37 and BW original = 1.36 BW preserved ? 0.04. The condition factor calculated using the body size of preserved individuals was 16.0 and 15.8% lower than that calculated from the original body size and the body size back-calculated using the linear regression equations described above, respectively. Thus, our data suggest that the shrinkage of body size due to preservation in ethanol can cause errors in estimation of the condition factor. Our results can be used to improve the accuracy of estimating size-related biological parameters based on juvenile marbled sole that are preserved in ethanol.

The authors investigated the kinetics of transfer of perfluorooctane sulfonate (PFOS) from water, suspended sediment, and bottom sediment to a marine benthic fish, the marbled flounder (Pseudopleuronectes yokohamae). Fish were exposed in 3 treatments to PFOS in combinations of these exposure media for 28 d and then depurated for 84 d. A major part (37–66%) of PFOS in the fish was in the carcass (i.e., whole body minus muscle and internal organs). Three first-order-kinetic models that differed in exposure media, that is, 1) sum of dissolved and particulate phases and sediment; 2) dissolved phase, particulate phase, and sediment; and 3) dissolved phase only, were fitted to the data assuming common rate constants among the treatments. The uptake efficiency of dissolved PFOS at the respiratory surfaces was estimated to be 3.2% that of oxygen, and the half-life of PFOS in the whole body to be 29 d to 31 d. The better fit of models 1 and 2 and the values of the estimated uptake rate constants suggested that the PFOS in suspended and bottom sediments, in addition to that dissolved in water, contributed to the observed body burden of the fish. Based on an evaluation of several possible contributing factors to the uptake of PFOS from suspended and bottom sediments, the authors propose that further investigation is necessary regarding the mechanisms responsible for the uptake. Environ Toxicol Chem 2013;32:2009–2017. © 2013 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc., on behalf of SETAC. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.