Polychlorinated dibenzo-p-dioxins,polychlorinated dibenzofurans and non-ortho,mono-ortho chlorine substituted biphenyls in Japanese human liver and adipose tissue

We measured PCDDs/DFs levels in Japanese human livers and adipose tissues in 1999, and TEQ were calculated with WHO TEF. The mean total levels of PCDDs/DFs in livers and adipose tissues were 57 pg TEQ/g on a lipid basis and 49 pg TEQ/g on a lipid basis, respectively. 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDD, OCDD, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, 2,3,4,6,7,8-HxCDF, 1,2,3,7,8,9-HxCDF and 1,2,3,4,6,7,8-HpCDF concentrations in livers considerably differed from those in 1989 (p < 0.05). The mean non-ortho-chlorine substituted biphenyls levels showed 20 pg TEQ/g on a lipid basis and 17 pg TEQ/g on a lipid basis in livers and adipose tissues, respectively. In livers, the mean of 3,3',4,4'-TCB concentrations was 131 pg/g on a lipid basis, and 7.7-fold higher than that in 1989. The mean total mono-ortho-chlorine substituted biphenyls level was 13.0 pg TEQ/g on a lipid basis in livers and 21.6 pg TEQ/g on a lipid basis in adipose tissues. 3,3',4,4',5-PeCB and 3,3',4,4',5,5'-HxCB levels decreased in adipose tissues, and 3,3',4,4',5-PeCB level only decreased in livers. PCDDs, PCDFs, and mono- and non-ortho-chlorine substituted biphenyls levels may have decreased in livers and adipose tissues because of a governmental policy on dioxins discharge for the decade. Then, we estimated the correlations of PCDDs, PCDFs and the related compound levels between livers and adipose tissues. The correlative PCDDs congeners may have had a similar behavior to that between liver and adipose tissue. On the contrary, most PCDFs isomers may have different behavior between liver and adipose tissue, while 2',3,4,4',5-PeCB (IUPAC No. 123) may also have a different behavior between liver and adipose tissue.     

Stabilities of 58 volatile organic compounds in fused-silica-lined and SUMMA polished canisters under various humidified conditions

Fused-silica-lined (FSL) canisters and SUMMA polished (SUMMA) canisters were compared for the recoveries and the stabilities of 58 volatile organic compounds (VOCs) at low ppbv (volume/volume) levels under various humidified conditions using a three-stage preconcentration method followed by GC-MS analysis. The target VOCs included non-polar VOCs (e.g. halogenated hydrocarbons and aromatic hydrocarbons) and polar VOCs (e.g. alcohols, ketones, esters, ethers, nitriles and thiols). The three-stage preconcentration method was initially optimized for simultaneous analysis of non-polar and polar VOCs because determination of canister stability is dependent on the accuracy of analytical measurements. The method showed good linearity over the concentration range from 1 to 25 ppbv for all target analytes, and the correlation coefficients were higher than 0.9974. The method detection limits ranged from 0.023 to 0.39 ppbv. The test mixtures loaded in both type of canisters (n = 3) had concentrations of 1.7-2.5 ppbv per compound at ambient pressure under various humidified conditions (%RH = 1.6, 8.0, 27, 39, 53 and >99% with excess water present). All canister samples were initially analyzed on day 0 (after 6-12 h). The effect of competitive adsorption of water vapor and polar VOCs on active sites of interior surface was remarkably observed for SUMMA canisters. Polar VOCs had a greater requirement for water vapor to be present. The RH percentages that ensured good recovery on day 0 were RH > 8% for non-polar VOCs and RH > 27% for polar VOCs (except alcohols under the condition of RH > 99%). All thiols were not recovered from SUMMA canisters under all conditions. FSL canisters showed good recoveries of more than 86% for all VOCs under all conditions on day 0 (except alcohols under the condition of RH > 99%). The recoveries of alcohols in both canisters under the condition of RH > 99% displayed relatively low recoveries in the range 25-76% because of the partitioning effect into condensed water. The canister samples under the conditions of RH 8.0, 27, 53 and > 99% were analyzed for the stability test on days 3, 7, 14 and 28 after loading. All non-polar VOCs were reasonably stable in the FSL canisters under all examined conditions over 28 days. However, several polar VOCs that have relatively lower vapor pressure, e.g. MIBK, butyl acetate and alcohols except ethanol, showed unstable characteristics under relatively dry conditions (RH 8 and 27%) during 28 days. RH > 53% was needed to ensure good stabilities of all analytes except thiols with the recoveries of > 80% over 28 days for both canisters. Although the FSL canister showed good recoveries of more than 86% for thiols on day 0, drastic degradations were observed after day 3 and they were not detected after day 14.     

Experimental assessment of factors influencing microhabitat selection by the two tidepool fishes Oligocottus maculosus and O. snyderi

Oligocottus maculosus Girard and O. snyderi Greeley are two similar tidepool fishes with differing, but overlapping, intertidal distribution patterns. The factors influencing microhabitat selection and distribution patterns were experimentally assessed to elucidate the mechanisms by which the two species partition the resources of the intertidal environment. O. snyderi displays a much more rigid substrate-cover requirement. This, combined with its stenothermal nature serve to strongly restrict the intertidal distribution of this species. O. maculosus has a more generalized substrate-cover requirement and is also known to be eurythermal and euryhaline. Thus, O. maculosus is a ubiquitous intertidal species. Other behavioral attributes of O. maculosus, such as its tide-related locomotor activity and preference for shallow water, facilitate its particular intertidal distribution pattern. Similar depth preferences or tide-related activity were not observed in O. snyderi. Interspecific competition and related agonistic behavior were absent from both species and are probably not important to their microhabitat selection and intertidal distribution patterns.Based on a portion of a dissertation submitted in partial fulfillment of the requirements for the Ph.D. degree at the University of British Columbia, Vancouver, B.C., Canada     

Formation of PCDDs and PCDFs during the combustion of polyvinylidene chloride and other polymers in the presence of HCl

PVDC and three non-chlorinated polymers (PP, PET, and PA) were incinerated at 700-850 degrees C in a laboratory-scale quartz tubular furnace in the presence of HCl (ca. 500 ppm congruent with 0.8 mg/l), and the gas-phase formation of PCDD/Fs, their putative precursors and their homologue profiles were investigated. The addition of HCl had little or no apparent effect on the level of PCDD/Fs formation during PVDC combustion, and their homologue profiles were quite different from those of the three non-chlorinated polymers. With PVDC, O8CDD and particularly O8CDF were by far most prevalent, apparently as a result of the selective formation of the precursors. With each of the three non-chlorinated polymers, combustion at 800 degrees C or higher in the presence of HCl resulted in PCDD/Fs formation at levels equaling or exceeding those observed with PVDC. In trials made with one of them (PP) under the same conditions but using a large polymer sample (100 mg vs 20 mg in all other trials), the level of PCDD/Fs formation was far higher than with the smaller polymer samples, and thus demonstrated the importance of appropriate combustion conditions for polymer incineration.     

Degradation of organophosphoric esters in leachate from a sea-based solid waste disposal site

Degradation of organophosphoric esters (OPEs) in leachate from a sea-based solid waste disposal site was investigated by laboratory experiment. Aryl-phosphates, tricresyl phosphate and triphenyl phosphate, in leachate rapidly decreased to less than the detection limit within 20 days under aerobic condition, suggesting high biodegradability. These phosphates also decreased in sterilized leachate, which suggested a contribution to degradation by reactions (adsorption and chemical degradation) with chemicals in the leachate. Concerning alkyl-phosphates, tributyl phosphate decreased rapidly after one week, which is considered to have been caused by biodegradation. Tris-2-ethylhexyl phosphate and tris-2-butoxyethyl phosphate decreased slowly in all samples but that of sterilized distilled water. This however, suggested contribution of biodegradation because the velocity of decrease in the leachate was higher than in control samples. Among chloro alkylphosphates, decrease of tris-2-chloroethyl phosphate and tris-dichloropropyl phosphate were observed though it was not obvious whether by biodegradation or not. Decrease of tris-2-chloropropyl phosphate (TCPP) was not observed for 80 days suggesting that TCPP remains in the leachate over a long period of time. Except for aryl-phosphates decrease of OPEs was not observed under anaerobic condition. It was considered that the composition ratio and the behavior of OPEs in leachate in the field reflects the biological and chemical degradation as well as the chemical properties of OPEs.     

A global transport model of lead in the atmosphere

A global atmospheric transport model is used to calculate lead concentrations in the atmosphere. The model performance is evaluated through comparisons with observations in Europe. The model results of lead concentrations in surface air were compared with measurements in East Asia. The detailed comparisons showed generally good agreement for recent decades, although systematic underestimation was found in China. Anthropogenic lead emissions in China are estimated from economic statistics to be 56 000 t yr^?1, which is not small considering the economic scale of China. The underestimations suggest a hidden source of lead emissions. The emissions in Japan and Korea are derived from optimization by the model. The magnitude is about 2000 t yr^?1, which is much greater than that reported by the Pollutant Release and Transfer Register in Japan and Toxics Release Inventory in Korea.     

Evaluation of pressurized liquid extraction for the determination of neonicotinoid pesticides in green onion

Abstract

A pressurized liquid extraction (PLE) method was presented for the determination of six neonicotinoid pesticides, acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam in green onion. The critical parameters of PLE, e.g. extraction solvent, temperature, pressure, number of cycles, and static extraction time, were optimized by test on the spiked green onion with six neonicotinoids and the incurred green onion applied with four commercial neonicotinoid insecticide formulations (acetamiprid, dinotefuran, imidacloprid, and thiamethoxam). As a result, the recoveries of six neonicotinoids obtained by one cycle PLE with acetonitrile at 140?°C and 50?bar for 10?min were 94.7–99.5%. These results were acceptable according to the validation guideline for testing method of agricultural chemicals in food by Ministry of Health, Labour, and Welfare in Japan. PLE was also validated by the test on the incurred green onion. The analytical values of four neonicotinoids obtained by PLE were good agreement with those obtained by solid–liquid extraction with homogenizer, which is employed for Japanese official method for the analysis of pesticide residues in food (the ratios of analytical values obtained by PLE to those obtained by solid–liquid extraction were 99.7–101.2%). These results indicate that PLE is applicable for the determination of neonicotinoids in green onion.     

Novel enzymatic activity of cell free extract from thermophilic Geobacillus sp. UZO 3 catalyzes reductive cleavage of diaryl ether bonds of 2,7-dichlorodibenzo-p-dioxin

We characterized the ability of the cell free extract from polychlorinated dibenzo-p-dioxins degrading bacterium Geobacillus sp. UZO 3 to reduce even highly chlorinated dibenzo-p-dioxins such as octachlorodibenzo-p-dioxins in incineration fly ash. The degradation of 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD) as a model dioxin catalyzed by the cell free extract from this strain implicates that the ether bonds of 2,7-DCDD molecule undergo reductive cleavage, since 4′,5-dichloro-2-hydroxydiphenyl ether and 4-chlorophenol were detected as intermediate products of 2,7-DCDD degradation.