Determination of PCDD/Fs and dioxin-like PCBs in fish oils for feed ingredients by congener-specific chemical analysis and CALUX bioassay

The present research was intended to determine the suitability of the CALUX assay as a screening method for dioxins in fish oil used as a feed ingredient in Japan. Alteration of TEQ in fish oil according to newly proposed toxic equivalency factors (TEF) is also discussed. In the analysis, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in 41 fish oil samples were determined by using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) and CALUX bioassay. The mean TEQ values derived from 1998 WHO-TEF of PCDD/Fs and DL-PCBs were 2.6 and 9.9 pg g(-1) (ww), respectively. The levels of TEQ derived from the recently re-evaluated 2005 WHO-TEF were slightly lower than those of the former in both groups. Notably, the contribution of mono-ortho DL-PCBs to total 2005 WHO-TEQ was considerably decreased compared to the case of 1998 WHO-TEQ, resulting from the reduction in its TEF values, while the non-ortho DL-PCBs contribution was increased. The mean TEQ determined by CALUX assay for PCDD/Fs was approximately three times higher, whereas DL-PCBs was approximately two times lower than WHO-TEQ determined by HRGC/HRMS; the sum of PCDD/Fs and DL-PCBs was very similar by both methods. The correlation coefficients of TEQ between the CALUX assay and HRGC/HRMS analysis were 0.84, 0.89, and 0.90 for PCDD/Fs, DL-PCBs, and the sum, respectively. These results suggest that the CALUX assay is a very useful method for the screening of dioxin-related compounds in fish oils.     

Simultaneous removal of dissolved organic matter and bromide from drinking water source by anion exchange resins for controlling disinfection by-products

Anion exchange resins （AERs） with different properties were evaluated for their ability to remove dissolved organic matter （DOM） and bromide, and to reduce disinfection by-product （DBP） formation potentials of water collected from a eutrophic surface water source in Japan. DOM and bromide were simultaneously removed by all selected AERs in batch adsorption experiments. A polyacrylic magnetic ion exchange resin （MIEX） showed faster dissolved organic carbon （DOC） removal than other AERs because it had the smallest resin bead size. Aromatic DOM fractions with molecular weight larger than 1600 Da and fluorescent organic fractions of fulvic acid- and humic acid-like compounds were efficiently removed by all AERs. Polystyrene AERs were more effective in bromide removal than polyacrylic AERs. This result implied that the properties of AERs, i.e. material and resin size, influenced not only DOM removal but also bromide removal efficiency, MIEX showed significant chlorinated DBP removal because it had the highest DOC removal within 30 rain, whereas polystyrene AERs efficiently removed brominated DBPs, especially brominated trihalomethane species. The results suggested that, depending on source water DOM and bromide concentration, selecting a suitable AER is a key factor in effective control of chlorinated and brominated DBPs in drinking water.     

Environmental impact evaluation of feeds prepared from food residues using life cycle assessment

There is increasing concern about feeds prepared from food residues (FFR) from an environmental viewpoint; however, various forms of energy are consumed in the production of FFR. Environmental impacts of three scenarios were therefore investigated and compared using life cycle assessment (LCA): production of liquid FFR by sterilization with heat (LQ), production of dehydrated FFR by dehydration (DH), and disposal of food residues by incineration (IC). The functional unit was defined as 1 kg dry matter of produced feed standardized to a fixed energy content. The system boundaries included collection of food residues and production of feed from food residues. In IC, food residues are incinerated as waste, and thus the impacts of production and transportation of commercial concentrate feeds equivalent to the FFR in the other scenarios are included in the analysis. Our results suggested that the average amounts of greenhouse gas (GHG) emissions from LQ, DH, and IC were 268, 1073, and 1066 g of CO(2) equivalent, respectively. The amount of GHG emissions from LQ was remarkably small, indicating that LQ was effective for reducing the environmental impact of animal production. Although the average amount of GHG emissions from DH was nearly equal to that from IC, a large variation of GHG emissions was observed among the DH units. The energy consumption of the three scenarios followed a pattern similar to that of GHG emissions. The water consumption of the FFR-producing units was remarkably smaller than that of IC due to the large volumes of water consumed in forage crop production.     

Influence of dispersants on bioconcentration factors of seven organic compounds with different lipophilicities and structures

Seven compounds with different lipophilicities and structures—1,3,5-trichlorobenzene, pentachlorobenzene, acenaphthylene, 1,4-dimethyl-2-(1-methylphenyl)benzene, 4-ethylbiphenyl, 4,4′-dibromobiphenyl, and 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane—were subjected to bioconcentration tests in carp at concentrations below the water solubilities of the compounds in the presence or absence of a dispersant (either an organic solvent or a surfactant). The bioconcentration factors (BCFs) of the compounds were on the order of 10²–10⁴. The BCF values remained in the range of 15–49% for all the compounds, whether or not a dispersant was present, i.e., the BCF values in the presence of an organic solvent or a surfactant at a concentration below the critical micelle concentration were not significantly smaller than the BCF values in the absence of the solvent or surfactant. This result indicates that the dispersants had no influence on the evaluation of the bioconcentration potential of these test substances.     

Fluoranthene fumigation and exogenous scavenging of reactive oxygen intermediates (ROI) in evergreen Japanese red pine seedlings (Pinus densiflora Sieb. et. Zucc.)

Generation of reactive oxygen intermediates (ROI) such as O(2)(-), H(2)O(2), and *OH is known to be a major mechanism of damage in biological systems. This study investigated and compared effectiveness of scavenging ROI generated in fluoranthene (FLU) pre-fumigated Japanese red pine seedlings. Three kinds of eco-physiological assessments were used to express the impact of the different fumigants used inside the green house. Gas exchange measurements showed negative changes induced by 10 microM FLU on Japanese pine seedlings during a 10 d exposure period whilst no negative change was found during a 5 d exposure period. Moreover, during a 14 d FLU exposure incorporating ROI scavengers, results revealed that chlorophyll fluorescence, needle chemical contents and needle dry mass per unit area of the seedlings were affected. The negative effects of FLU on the conifer were dependent on both the dose and period of FLU fumigation. Peroxidase (PERO), superoxide dismutase (SOD) and mannitol (MANN) were all effective scavengers of ROI. MANN scavenged *OH, the most lethal of the ROI. For practicable use, MANN is more economical, and may be the best ROI scavenger among the three considered. It can be concluded that efficient scavenging of ROI in biological systems is important to mitigate the negative effects of FLU on Japanese red pine trees.     

Study on the early stage of runaway reaction using Dewar vessels

In this paper, compared with a UN cylindrical 500 mL Dewar (H.4 in the UN tests), a spherical 1 L Dewar vessel was used to study the early stages of runaway reactions of several liquid and solid samples, including three organic peroxides and a reactive material. The samples were filled in the vessels and the temperature profiles versus times at different positions of the samples were measured. As a result, the minimum temperatures, defined as the SADT, were averagely 10 K lower than those measured in the cylindrical Dewar vessels. At the same time, the temperature profiles of solids in the spherical Dewars tended to be homogeneous. The heat transfer coefficient of a spherical Dewar is only 0.18 W/K/m, one-eighth of a conventional cylindrical Dewar vessel. Meanwhile it has a low phi factor. These factors are essential to simulate low heat loss bulk conditions in the equilibrium process and at the early stage of a runaway reaction. To characterize the ability of the adiabaticity of a storage vessel, it can be seen that a spherical Dewar could simulate the plant process having critical storage size of a reactive-material, r₀, approximately 0.6 m. It is recommended that such a technique is used to investigate the SADT of an unstable material in larger scale packaging or a material with very weak heat release in industry.