Isao Watanabe

Environmental release and behavior of brominated flame retardants.

Recently, environmental problems relating to brominated flame retardants (BFRs) have become a matter of greater concern than ever before, because of the recent marked increase in levels of polybrominated diphenyl ethers (PBDEs) found in human milk in Sweden and North America. The question that arises is whether environmental levels of PBDEs and other BFRs will continue to increase, causing toxic effects to humans. In an attempt to elucidate the current state of the science of BFRs, we review the consumer demand for BFRs (mainly in Japan), the characteristics of waste flame-retarded products, sources of emission, environmental behavior, routes of exposure of humans, temporal trends, and thermal-breakdown products of BFRs. At present, flame-retarded consumer products manufactured 10-20 years ago, when PBDEs were frequently used, are being dumped. The possible major sources of emission of BFRs into the environment are effluent and flue gases from BFR factories and other facilities processing BFRs. With respect to the environmental behavior of BFRs, the lower brominated compounds are, on the whole, predicted to be more volatile, more water soluble, and more bioaccumulative than the higher brominated compounds. The most probable route for exposure of the general human population to PBDEs, especially the lower brominated congeners, is through the diet. The release of BFRs from consumer products treated with these compounds could also lead to human exposure. Temporal trends in PBDE levels in the environment and in humans worldwide seem to vary considerably, depending on the regions or country, with possible reflections of the historic and current use of PBDEs. The environment and the general human population are also exposed to the thermal-breakdown products of PBDEs, such as polybrominated and mixed brominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PBDDs/DFs and mixed PXDDs/DFs).

Polybrominated biphenyl ethers in marine fish, shellfish and river and marine sediments in Japan

Abstract The presence of polybrominated biphenyl ethers (PBBEs), commonly used as flame retardants, was confirmed in marine fish, shellfish and river and marine sediments in Japan. These compounds were detected in seven out of 17 marine fish and shellfish, though at low levels. Tetrabrominated biphenyl ether was a major component in marine organisms. However, sediment pollution by PBBEs, particularly that by decabrominated biphenyl ether, pose a serious problem in the rivers of Osaka but not in marine areas.

Perfluorooctanesulfonate and perfluorooctanoate in raw and treated tap water from Osaka, Japan

Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) have been recognized as emerging environmental pollutants because of their ubiquitous occurrence in the environment, biota, and humans. PFOS and PFOA have been detected in water in Japan. Nevertheless, occurrence of PFOS and PFOA in potable water from municipal water treatment plants is not clearly known. We analyzed PFOS and PFOA in raw and tap water samples collected from 14 drinking water treatment plants in winter and summer seasons in Osaka to determine the concentrations of PFOS and PFOA in raw and potable tap water samples. PFOS and PFOA were detected in all raw water samples. Concentration ranges of PFOS and PFOA in raw water were 0.26-22 ng/l and 5.2-92 ng/l, respectively. Whereas the concentrations PFOS in raw water from Osaka were similar to those in other areas in Japan, the concentrations of PFOA were higher than in other areas. Concentration ranges of PFOS and PFOA in potable tap water were 0.16-22 ng/l and 2.3-84 ng/l, respectively. There were positive correlations between PFC concentrations in raw water and tap water samples. Therefore, the removal efficiency of PFCs by the present water treatment may be low. Based on the current action value reported by U.S. Environmental Protection Agency, PFOA concentrations found in tap water in Osaka is not expected to pose health risks.

Fate of perfluorooctanesulfonate and perfluorooctanoate in drinking water treatment processes.

Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) have been recognized as global environmental pollutants. Although PFOS and PFOA have been detected in tap water from Japan and several other countries, very few studies have examined the fate, especially removal, of perfluorinated compounds (PFCs) in drinking water treatment processes. In this study, we analyzed PFOS and PFOA at every stages of drinking water treatment processes in several water purification plants that employ advanced water treatment technologies. PFOS and PFOA concentrations did not vary considerably in raw water, sand filtered water, settled water, and ozonated water. Sand filtration and ozonation did not have an effect on the removal of PFOS and PFOA in drinking water. PFOS and PFOA were removed effectively by activated carbon that had been used for less than one year. However, activated carbon that had been used for a longer period of time (>1 year) was not effective in removing PFOS and PFOA from water. Variations in the removal ratios of PFOS and PFOA by activated carbon were found between summer and winter months.

The flame retardant tetrabromobisphenol-A and its metabolite found in river and marine sediments in Japan

Abstract Tetrabromobisphenol-A (TBBP), used as a flame retardant, was detected in river sediments collected in Osaka, Japan, at a concentration range from 22 to 140 μg/kg (ppb), as determined on a dry weight basis. TBBP was also found in marine sediments collected at Osaka Bay, though the TBBP levels of these samples were much lower than those from river sediments. Dimethyl ether derivative of TBBP (TBBP-DM), thought to be a decomposition product from microbial methylation, was found in the river sediments but in none of the marine sediments. TBBP-DM residues were about one-hundredth of the TBBP levels.

Hexabromobenzene and its debrominated compounds in river and estuary sediments in Japan.

HBB has been found in estuary sediments collected at Tokyo, Japan, though at extremely low levels. It has not been found in any river, estuary or marine sediments collected outside the Tokyo area. A peak having the same retention time as HBB was found in the gas chromatogram of an extract of the river sediment collected at Osaka, Japan. The shake extraction method for HBB in sediment using organic solvents such as acetone and benzene was found less efficient. This paper describes a method for the extraction of HBB from sediment, and an attempt has been made to determine more accurately HBB in sediments in Japan. Also an examination has been made of the decomposition products of HBB in the environment.

Concentrations of organochlorine pesticides (OCPs) residues in foodstuffs collected from traditional markets in Indonesia.

A total 23 of organochlorine pesticides (OCPs) residues were determined in five groups of foodstuffs, i.e.: vegetables (carrot, potato, cucumber, corn, and onion), rice, pulses (green bean and soybean), nuts (peanut), and fish (milkfish), which collected from traditional markets in three big cities of Indonesia; Jakarta, Bogor, and Yogyakarta. OCPs were only detected in fatty foodstuffs, such as soybean, peanut, and milkfish. The concentration of HCB (expressed as ng g(-1) on a whole basis), ΣDrins, ΣDDTs, ΣHeptachlors, and ΣHCHs were in the range of <0.3-0.74 ng g(-1), <0.03-0.42 ng g(-1), <0.02-0.41 ng g(-1), <0.03-0.14 ng g(-1), and <0.03-0.06 ng g(-1), respectively, which were far below the maximum residue limits (MRLs) as established by FAO/WHO. These very low concentrations of OCPs residues in foodstuffs indicated that OCPs were used only in past time and no recent input into the environment. Furthermore, the estimated daily intake (EDI) of HCB, ΣDDTs, ΣDrins, ΣHeptachlors, and ΣHCHs in five group foodstuffs, which were 60% of total daily diet of Indonesian, were 0.09 ng kg(-1) bw d(-1), 0.04 ng kg(-1) bw d(-1), 0.01 ng kg(-1) bw d(-1), 0.003 ng kg(-1) bw d(-1), and 0.002 ng kg(-1) bw d(-1), respectively. These results were far below the acceptable daily intake (ADI) as established by FAO/WHO, which indicated that consumption of foodstuffs from Indonesia were at little risk to human health in term of OCPs at present.

A study of organic bound halogens in human adipose, marine organisms and sediment by neutron activation and gas chromatographic analysis

Abstract Organic bound halogens were determined simultaneously by the neutron activation and gas chromatographic analysis of crude and FlorisilR- chromatographed extracts of human adipose, marine organisms and river and marine sediment in Japan. Although about 60% of the total organic chlorine in Japanese human adipose could be accounted for as known chlorinated compounds, the remaining 40% of the total organic chlorine was found in the fraction containing fat, and identified as the chlorinated compounds similar to fat. Most of the organic bound bromine and iodine in human adipose was also found in the fat fraction though at very low levels. The amount of organic bound chlorine as determined by known chlorinated hydrocarbons in marine organisms was low, only 1 – 20% the total organic bound chlorine in the samples. Most of the organic bound chlorine, bromine and iodine in marine organisms was also found in the fat fraction. The organic bound chlorine and bromine based on known compounds constituted a small part of the total organic bound chlorine and bromine detected in river and marine sediment. The total organic bound halogen levels in river sediment were also found to be significantly higher than those in marine sediment.

Distribution differences between polychlorinated terphenyls and polychlorinated biphenyls in human tissues.

Polychlorinated terphenyls (PCTs) are compounds which require further studies to investigate their effects on human health and on the environment. PCTs are similar to polychlorinated biphenyls (PCBs) in their chemical characteristics and have been used industrially in the same way as PCBs, which are ubiquitous pollutants. PCT residues were identified in the eggs and fatty tissue of herring gulls. In Japan, PCT residues were subsequently reported in various samples, including human tissues. It was also reported that the PCT distributions in the environment and human body were not necessarily the same as those of PCBs. For instance, the levels of PCTs in human fat and blood were almost equal to those of PCBs, although the PCT residue levels in environmental samples such as water, fish and foodstuffs were much lower than those of PCBs. The present study was performed in order to clarify the tissue distribution of PCTs in the human body. Several differences between the PCT and PCB distributions in human tissues were found.

Brominated phenol production from the chlorination of wastewater containing bromide ions

Brominated phenols such as bromodichlorophenol, dibromochlorophenol and 2,4,6-tribromophenol along with chlorinated phenols have been detected in the river sediment collected in Osaka, Japan, but in very low concentrations. The authors found that these phenols in sediments were formed primarily by the chlorination of wastewater. This study presents a discussion of brominated phenol production from the chlorination of wastewater.