PCDD/Fs and dioxin-like PCBs in human milk and estimation of infants' daily intake: a review

This paper reviews the recent scientific literature on PCDDs, PCDFs and dioxin-like PCBs in human milk. All the papers reporting levels of these contaminants in human breast milk published from January 2000 to January 2009 and available on the www.sciencedirect.com web site were identified and included. The aim was (1) to study levels of PCDDs, PCDFs and PCBs in human milk in mothers from different geographical areas and assess infant exposure to these contaminants; (2) to study the effect of variables such as the mother’s age, number of deliveries, dietary and smoking habits and her own nutrition in infancy, and the environment, on levels of the contaminants in breast milk; (3) to study time patterns, and (4) to identify data gaps.     

A simple and convenient empirical survey method with a soil electrical conductivity meter for incineration residue-derived soil contamination

To facilitate field surveys for identifying areas of incineration residue-derived soil contamination, a simple and convenient method with a soil electrical conductivity meter was examined. First, the leaching test specified by Notification No. 13 of the Ministry of the Environment, 1973, was conducted on 506 samples of 11 types of wastes and compost, and the relationship between the concentrations of toxic elements [total Hg (T-Hg), Cd, Pb, Cr⁶⁺, and As] and values of electrical conductivity (EC) was examined. The results showed that bottom ash and fly ash were wastes with high EC values and that these wastes indicated higher levels of toxic elements. Second, an estimation method for the soil EC value of contaminated soil (ECc) was proposed based on the EC values of noncontaminated soil, and its usefulness was examined. The results of field surveys conducted at sites whose soils were suspected of contamination by dioxins and other pollutants derived from incineration residues showed that the contaminated spots and areas were identified by using ECc values. Moreover, comparison of the elemental contents of soils in terms of Cr, Ni, Zn, Na, K, Ca, Fe, Mn, and others, in addition to the above-mentioned toxic elements (excluding Cr⁶⁺), with those of the potential sources of pollution was verified to be effective for identifying the source of soil contamination.     

Effects of dioxins and polychlorinated biphenyls (PCBs) on thyroid function in infants born in Japan – the second report from research on environmental health

Dioxins (PCDD + PCDF) and polychlorinated biphenyl (PCB) are potentially hazardous compounds and have structural similarity to thyroid hormones. Our research group on “Dioxins and PCB in Human Milk” was organized in 1997 and has been active for the past three years. We collected breast milk from 80 mothers living in Tokyo, Saitama, Ishikawa and Osaka Prefecture in Japan at 5, 30, 150, 300 postpartum days and measured PCDDs, PCDFs and PCBs during 1998–1999. We added another 20 prefectures and cities during 1999–2000. Breast milk was obtained from 415 mothers at 30 postpartum days (breast-feeding group). Blood was taken from infants who were breast-fed at the age of 1 year for evaluation of thyroid and immune functions. Blood was also taken from 53 infants who were bottle-fed (bottle-feeding group) as a control. Serum T4, T3, FT4 and TSH levels in the breast-feeding (n=337) and bottle-feeding (n=53) groups were within normal ranges and were not significantly different between the two groups. Although there were a large geographic differences of dioxins and co-PCB content in breast milk, there were no differences in serum T4, T3, FT4, TSH levels and no significant correlation between the mean serum levels of TSH and TEQ in breast milk. There was a significant correlation between serum TSH at 1 year of age and that from blood on dried filter paper TSH at 5 days of age. We concluded that dioxin intake from breast milk in Japanese infants did not impair thyroid function. However, long-term effects remain to be evaluated.     

Distribution of polychlorinated dibenzo-p-dioxins,polychlorinated dibenzofurans,dioxin-like polychlorinated biphenyl and polycyclic aromatic hydrocarbons in the sediment of Temsah lake,Suez Canal,Egypt

Lake Temsah is one of the main wetlands in the Suez Canal region, and the main source for fish for the area. The lake is the end-point of several wastewater effluents. In the present study, residues of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbons (PAH) were monitored in the sediment of the lake. Samples were collected from six different sampling stations around the lake using a box-corer sampler, then kept frozen. Samples were extracted and cleaned up before residue determination was conducted using an HRGC/HRMS. An HP 6890 plus gas chromatograph was coupled to a Micromass Autospec Ultima mass spectrometer operating in EI mode at 35 eV and with a resolution of 10.000 (5% valley). PCDDs and PCDFs were detected in all sediment samples collected from various sampling stations. Results showed some progressive increase in PCDDs concentrations relevant to increase in chlorination. In the PCDD group of congeners, 1, 2, 3, 4, 6, 7, 8, 9 octa-CDD had the highest detected concentrations in all samples, while 2, 3, 7, 8 tetra-CDD showed the lowest concentrations. The World Health Organization toxicity equivalents ranged from 0.387 to 11.20 ng kg^?1 d.w. For PCDD homologues, hexa-CDD was the most dominant homologue in all sediment samples analysed. Regarding dioxin-like PCBs, results showed that IUPAC No. 118 congener, 2, 3, 4, 4, 5, pentachlorobiphenyl was the most concentrated of all detected congeners, with concentrations ranging between 0.039 and 43.201 µg kg^?1. For polycyclic aromatic hydrocarbons, benzo(b+k+j)fluoranthene had the highest concentrations in almost all sampling stations. However, fluorene was the smallest detected concentration in almost all stations. This result would indicate that PAH contamination of the lake seems to be coming from one main source in all sampling stations. The present work is the first record of PCCDs, PCCFs, and dioxin-like PCBs in the Temsah lake. The concentrations of the contaminants monitored in this study, especially those of PAHs, are rather alarming. Efforts should be made to stop point sources that contaminate the lake.     

Gas phase equilibria for dibenzo‐p‐dioxin,dibenzo‐p‐furan and biphenyl in the C‐H‐O system

The gas phase equilibrium calculation for the C‐H‐O system at atmospheric pressure and temperature from 773 to 1773 K at intervals of 250 K was performed to understand the generation and decomposition behavior of dibenzo‐p‐dioxin (DD), dibenzo‐p‐furan (DF) and biphenyl (BP) in relation to the existing oxygen potential. It is possible to categorize these results into three regions from the viewpoint of this potential: region (A), region (B) and region (C) are that of the higher, modest and lower oxygen potential, respectively. In region (A), the equilibrium amounts of DD, DF and BP are nearly zero. In region (B), they increase once and then decrease with rise in temperature. In the most characteristic region (C), they increase uniformly with rise in temperature.     

污染源废气中二噁英监测采样应注意的几个问题

解析废气中二噁英监测采样的现状及不足,针对生活垃圾焚烧炉(炉排炉)、蓄热式焚烧炉(RTO)和危险废物焚烧炉(回转窑)3种不同类型焚烧炉,考察了采样过程中烟道类型、采样时间和采样时间间隔不同对二噁英监测的影响。结果表明,在水平烟道和垂直烟道采样测得二噁英排放浓度水平相当,有垂直烟道时,优先在垂直烟道采样;间隔采样和连续采样二噁英测定结果基本一致,为了便于操作,建议均采用连续采样方式;采样时间上,生活垃圾焚烧炉应保证超过1 h,蓄热式焚烧炉以2 h左右为宜;间歇投料危险废物焚烧炉应尽量满足2 h以上,条件不许可时,可通过增加采样流量缩短采样时间保证采样量,并在危险废物完全燃烧前结束采样工作。