Masayuki Someya

Persistent organochlorines in human breast milk from major metropolitan cities in India

The present study was carried out to understand the current contamination status of organochlorine compounds (OCs) in human breast milk from three metropolitan cities in India (New Delhi, Mumbai and Kolkata). Among the OCs analyzed, DDTs were predominant followed by HCHs and PCBs. CHLs and HCB levels were much lower. Contamination patterns were different in human milk found in our previous study in Chennai, a metropolitan city in southern India, indicating region specific exposure routes and variable sources. In comparison with previous data, levels of DDTs and HCHs generally declined with time, implying the effect of various bans and restrictions on their usage. No association between concentrations of OCs and demographic characteristics such as parity and age of mothers was observed which might be due to narrow range of mothers age. Estimated daily intake shows that some infants are exposed to OCs to a greater extent, particularly HCHs than the guideline standard.

Flame retardant emission from e-waste recycling operation in northern Vietnam: Environmental occurrence of emerging organophosphorus esters used as alternatives for PBDEs

Three oligomeric organophosphorus flame retardants (o-PFRs), eight monomeric PFRs (m-PFRs), tetrabromobisphenol A (TBBPA), and polybrominated diphenyl ethers (PBDEs) were identified and quantified in surface soils and river sediments around the e-waste recycling area in Bui Dau, northern Vietnam. Around the e-waste recycling workshops, 1,3-phenylene bis(diphenyl phosphate) (PBDPP), bisphenol A bis(diphenyl phosphate) (BPA-BDPP), triphenyl phosphate (TPHP), TBBPA, and PBDEs were dominant among the investigated flame retardants (FRs). The respective concentrations of PBDPP, BPA-BDPP, TPHP, TBBPA and the total PBDEs were 6.6-14000 ng/g-dry, <2-1500 ng/g-dry, 11-3300 ng/g-dry, <5-2900 ng/g-dry, and 67-9200 ng/g-dry in surface soils, and 4.4-78 ng/g-dry, <2-20 ng/g-dry, 7.3-38 ng/g-dry, 6.0-44 ng/g-dry and 100-350 ng/g-dry in river sediments. Near the open burning site of e-waste, tris(methylphenyl) phosphate (TMPP), (2-ethylhexyl)diphenyl phosphate (EHDPP), TPHP, and the total PBDEs were abundantly with respective concentrations of <2-190 ng/g-dry, <2-69 ng/g-dry, <3-51 ng/g-dry and 1.7-67 ng/g-dry in surface soils. Open storage and burning of e-waste have been determined to be important factors contributing to the emissions of FRs. The environmental occurrence of emerging FRs, especially o-PFRs, indicates that the alternation of FRs addition in electronic products is shifting in response to domestic and international regulations of PBDEs. The emissions of alternatives from open storage and burning of e-waste might become greater than those of PBDEs in the following years. The presence and environmental effects of alternatives should be regarded as a risk factor along with e-waste recycling.

Persistent organic pollutants in breast milk of mothers residing around an open dumping site in Kolkata, India: Specific dioxin-like PCB levels and fish as a potential source

Concentrations of persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and organochlorine pesticides were measured in human breast milk collected from mothers residing near an open dumping site and a reference site in Kolkata, India during 2004-2005. POPs were detected in all the human milk samples analyzed, suggesting that residents of Kolkata are widely exposed to these contaminants. Concentrations of dioxin-like PCBs in the samples from the dumping site were significantly higher than in the reference site samples, whereas no such difference was found for PCDDs and PCDFs. In addition, significantly higher concentrations of total PCBs were also observed in the samples from the dumping site than the reference site. Interestingly, concentrations of total and dioxin-like PCBs in the breast milk of mothers from the dumping site significantly increased with the number of years of residence near the dumping site. These results indicate that significant pollution sources of PCBs are present in the dumping site of Kolkata and the residents living around are exposed to relatively higher levels of PCBs. When the residue levels of dioxins and related compounds in fish collected from ponds near the Kolkata dumping site and the reference site were measured, it was found that dioxin-like PCB and TEQ levels in fish from the dumping site were notably higher than those from the reference site. This result indicates that fish is a potential source of PCBs for residents living near the Kolkata dumping site.

Dioxin-like activity in Japanese indoor dusts evaluated by means of in vitro bioassay and instrumental analysis: brominated dibenzofurans are an important contributor.

In our previous study, we demonstrated that dioxin-like activity in sulfuric-acid-treated extracts of Japanese indoor dust was higher than the activity in contaminated sediments. In the current study, we used high-performance liquid chromatography (HPLC) fractionation in combination with the dioxin-responsive chemical-activated luciferase gene expression (DR-CALUX) assay and gas chromatography-high-resolution mass spectrometry (GC-HRMS) to quantitatively evaluate dioxin-like compounds in indoor dusts. Selected four sulfuric-acid-treated extracts of indoor dusts were fractionated into seven fractions by means of HPLC with a nitrophenylpropylsilica column, and the activity in the first fraction of each extract was much higher than the activities in the other fractions. Therefore, each of the first fractions was further fractionated into 90 fractions by HPLC with an octadecylsilica column, and all the fractions were analyzed by means of the DR-CALUX assay. On the basis of elution characteristics, the active compounds in the fractions showing high activity were determined to be polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), coplanar polychlorinated biphenyls (Co-PCBs), and polychlorinated naphthalenes (PCNs), or supposed to be polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs). These compounds in the 33 dusts extracts were quantified by means of GC-HRMS, and their median-based contributions of the theoretical CALUX-TEQs [2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-tetraCDD) equivalent] chemically calculated for PBDFs, PCDDs, PCDFs, non-ortho Co-PCBs, PCNs, and mono-ortho Co-PCBs to the experimental values (38-1400 pg/g, median 160 pg/g) were 17%, 14%, 8.8%, 0.98%, 0.10%, and 0.019%, respectively. Our results indicate that PBDFs, which are not internationally regulated dioxins, were important contributors to dioxin-like activity in Japanese dust and that further analysis of PBDFs in indoor dust is required so that the risk of exposure to these compounds via dust can be assessed.

Influence of solid-liquid separation method parameters employed in soil leaching tests on apparent metal concentration

Soil leaching tests are commonly used to evaluate the leachability of hazardous materials, such as heavy metals, from the soil. Batch leaching tests often enhance soil colloidal mobility and may require solid-liquid separation procedures to remove excess soil particles. However, batch leaching test results depend on particles that can pass through a 0.45μm membrane filter and are influenced by test parameters such as centrifugal intensity and filtration volume per filter. To evaluate these parameters, we conducted batch leaching experiments using metal-contaminated soils and focused on the centrifugal intensity and filtration volume per filter used in solid-liquid separation methods currently employed in standard leaching tests. Our experiments showed that both centrifugal intensity and filtration volume per filter affected the reproducibility of batch leaching tests for some soil types. The results demonstrated that metal concentrations in the filtrates significantly differed according to the centrifugal intensity when it was 3000 g for 2h or less. Increased filtration volume per filter led to significant decreases in filtrate metal concentrations when filter cakes formed during filtration. Comparison of the filtration tests using 0.10 and 0.45μm membrane filters showed statistically significant differences in turbidity and metal concentration. These findings suggest that colloidal particles were not adequately removed from the extract and contributed substantially to the apparent metal concentrations in the leaching test of soil containing colloidal metals.

Spatio-temporal trends of polybrominated dibenzo-p-dioxins and dibenzofurans in archived sediments from Tokyo Bay, Japan

The present study examined the occurrence and potential sources of mono- to octa-brominated dibenzo-p-dioxins/dibenzofurans (Mo-OBDD/Fs) in Tokyo Bay, Japan, using surface sediments and 210Pb-dated sediment cores (covering the period 1895-2000) collected in 2002. The results showed a clear difference in the spatio-temporal trend between PBDFs and PBDDs. The spatial distribution of PBDF concentrations in the surface sediments showed a decreasing trend from the head to the mouth of the bay, which was similar to that of polybrominated diphenyl ethers (PBDEs) reported previously for the same sediment samples. In the sediment cores, PBDF and PBDE concentrations increased drastically after the 1960s and reached the highest levels in the late 1990s. In addition, a significant positive correlation was observed between the concentrations of their predominant congeners, 1,2,3,4,6,7,8-HpBDF and BDE-209. These results indicate that main contamination sources of PBDFs were technical PBDE formulations, especially DecaBDE. In contrast, total PBDDs in the surface sediments were rather uniform in the whole area of the bay. Furthermore, in the sediment cores, PBDD levels showed marginal fluctuation over the past century, with the predominance of 2,7-/2,8-DiBDDs and 1,3,7-/1,3,8-TrBDDs in all the sediment layers. It is noteworthy that these PBDD congeners were also found in the sediment layers corresponding to the pre-industrial era, supporting their natural formation in the coastal environment.