化学质量平衡受体模型新技术的应用──TEDA大气颗粒物来源解析实例

本文结合实例介绍了大气颗粒物来源解析最常用的模型－化学质量平衡（ＣＭＢ）的原理、有效方差最小二乘解法及诊断检验技术，并用ＭＰＩＮ矩阵检验了拟合元素对拟合源的灵敏度，奇异值分解法（ＳＶＤ）鉴别了共线源，得出天津市经济技术开发区（ＴＥＤＡ）的ＴＳＰ主要来源为风沙、扬尘，其次为燃煤飞灰和木灰。     

Receptor modeling for analyzing PCDD/F and dioxin-like PCB sources in Hong Kong

A total of 96 ambient air samples were collected from January 2004 to December 2004 for the investigation of dioxins (polychlorinated dibenzo-para-dioxins and polychlorinated dibenzofurans [PCDD/Fs]) and dioxin-like profile for polychlorinated biphenyls (PCBs) in the atmosphere of Hong Kong. Two-day back-trajectories were obtained using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model from National Oceanic and Atmospheric Administration (NOAA) Air Resources Laboratory. Receptor models – potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) – were built based on the measured PCDD/Fs and dioxin-like PCBs total toxic equivalent (TEQ) concentrations. Both models were modified in this study so as to integrate the information obtained from three sampling sites in Hong Kong. The PSCF modeling resolved two main PCDD/F and dioxin-like PCB polluting paths from Mainland China. In line with previous studies, the northerly path around the Pearl River Delta might be one of the pollution sources of Hong Kong air. On the other hand, the receptor models also indicated another potential northeasterly source from Yangtze River Delta, which was seldom mentioned as the source region of Hong Kong air. Results from the CWT modeling suggested that the most toxic air mass affecting Hong Kong is probably attributable to the northeast path rather than the north path.     

Ozone distribution in central Italy and its effect on crop productivity

The focus of the present study was to assess the ozone levels in a typical area of the Mediterranean basin, viz. Tuscany (central Italy). Eighty-thousand hourly mean ozone concentrations were recorded by 10 automatic analysers in the districts of Florence, Pisa, Lucca and Prato, from May to September 1995 to 1997. The highest daily mean concentrations were reached in Florence, with a maximum hourly average of 197 ppb. In Lucca and Pisa, the peaks were close to 100 ppb. Data from Prato were much lower. Long-term critical levels for vegetation, as set by United Nations Economic Commission for Europe (UNECE), were constantly exceeded in Florence and Pisa, occasionally in Lucca, never in Prato. The results were used to fit exposure/yield response relationships proposed by UNECE and US National Crop Loss Assessment Network for some important crops. The estimated yield losses varied in Florence from 8% for corn and alfalfa to 27% for soybean, in Pisa from 5% for corn to 24% for soybean, in Lucca from 3% for corn to 17% for soybean. A preliminary economic estimate for corn, wheat, barley, soybean, tomato and alfalfa, calculated annual damage to be 4.6 M Euro in Florence, 0.5 M Euro in Lucca and 3 M Euro in Pisa. The picture must be regarded as only partial, as exposure/yield response relationships for important Italian crops (such as grapevine and vegetables) are not available.     

Myasthenia gravis with polyhydramnios in the fetus of an asymptomatic mother

Transient myasthenia gravis was observed in an infant whose mother had no signs of neuro-muscular disease. The case presented with severe polyhydramnios at 31 weeks. Sonographic and invasive work-up showed only an absence of fetal swallowing. At birth, the infant had severe muscle weakness and respiratory distress. He had high titres of anti-acetylcholine receptor (anti-AChR) antibodies of maternal origin. Anti-AChR antibodies were also found in stored samples of fetal serum and amniotic fluid. To our knowledge, this is the first case of neonatal myasthenia gravis for which neither past nor present evidence of disease could be obtained in the mother. Anti-AChR antibody testing should be considered in cases of unexplained polyhydramnios.     

Prediction of liquid chromatography retention factors for α-branched phenylsulfonyl acetates using quantum chemical descriptors

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BANKFULL HYDRAULIC GEOMETRY RELATIONSHIPS AND RECURRENCE INTERVALS FOR NORTH CAROLINA'S COASTAL PLAIN1

ABSTRACT: Bank full hydraulic geometry relationships relate stream channel geometry to watershed size for specific physiographic regions. This paper presents bank full hydraulic geometry relationships and recurrence intervals for the Southeastern Plain coercion and the flat woods subtype of the Middle Atlantic Coastal Plain ecoregion found within North Carolina's Coastal Plain physiographic province. Cross‐sectional and longitudinal survey data from gated and unpaged streams were used to compute channel dimension and profile information. Power functions were developed, relating drainage area to bank full discharge, cross‐sectional area, width, and mean depth. Recurrence intervals of bank full events were estimated from gagged streams using both a Log‐Pearson Type III distribution of peak annual discharge and a partial‐duration series of average daily discharge. Results from both methods indicate that average bank full recurrence intervals for the study area are below one year. Determinations of recurrence intervals by the Log‐Pearson Type III distribution were for the most part inconclusive (less than one year), while a partial duration series estimated a 0.19 year average, ranging from 0.11 to 0.31 years.     

Screening of agonistic activities against four nuclear receptors in wastewater treatment plants in Japan using a yeast two-hybrid assay

To assess the potential endocrine disruptive effects through multiple nuclear receptors(NRs),especially non-steroidal NRs,in municipal wastewater,we examined the agonistic activities on four NRs(estrogen receptor α,thyroid hormone receptor α,retinoic acid receptor α and retinoid X receptor α) of untreated and treated wastewater from municipal wastewater treatment plants(WWTPs) in Japan using a yeast two-hybrid assay.Investigation of the influent and effluent of seven WWTPs revealed that agonistic activities...     

Estrogen-related receptor disruption of source water and drinking water treatment processes extracts

Environmental chemicals in drinking water can impact human health through nuclear receptors. Additionally, estrogen-related receptors (ERRs) are vulnerable to endocrine-disrupting e ects. To date, however, ERR disruption of drinking water potency has not been reported. We used ERR two-hybrid yeast assay to screen ERR disrupting activities in a drinking water treatment plant (DWTP) located in north China and in source water from a reservoir, focusing on agonistic, antagonistic, and inverse agonistic activity to 4-hydroxytamoxifen (4-OHT). Water treatment processes in the DWTP consisted of pre-chlorination, coagulation, coal and sand filtration, activated carbon filtration, and secondary chlorination processes. Samples were extracted by solid phase extraction. Results showed that ERR antagonistic activities were found in all sample extracts, but agonistic and inverse agonistic activity to 4-OHT was not found. When calibrated with the toxic equivalent of 4-OHT, antagonistic e uent e ects ranged from 3.4 to 33.1 g/L. In the treatment processes, secondary chlorination was e ective in removing ERR antagonists, but the coagulation process led to significantly increased ERR antagonistic activity. The drinking water treatment processes removed 73.5% of ERR antagonists. To our knowledge, the occurrence of ERR disruption activities on source and drinking water in vitro had not been reported previously. It is vital, therefore, to increase our understanding of ERR disrupting activities in drinking water.     

Predation and aggressiveness in host plant protection: a generalization using ants from the genus Azteca

In studying the ant genus Azteca, a Neotropical group of arboreal species, we aimed to determine the extent to which the ants use predation and/or aggressiveness to protect their host plants from defoliating insects. We compared a territorially dominant, carton-nester, Azteca chartifex, and three plant-ant species. Azteca alfari and Azteca ovaticeps are associated with the myrmecophyte Cecropia (Cecropiaceae) and their colonies shelter in its hollow branches; whereas Azteca bequaerti is associated with Tococa guianensis (Melastomataceae) and its colonies shelter in leaf pouches situated at the base of the laminas. Whereas A. bequaerti workers react to the vibrations transmitted by the lamina when an alien insect lands on a leaf making it unnecessary for them to patrol their plant, the workers of the three other species rather discover prey by contact. The workers of all four species use a predatory behaviour involving spread-eagling alien insects after recruiting nestmates at short range, and, in some cases, at long range. Because A. alfari and A. ovaticeps discard part of the insects they kill, we deduced that the workers' predatory behaviour and territorial aggressiveness combine in the biotic defence of their host tree.     

Thyroid disruption by technical decabromodiphenyl ether （DE-83R） at low concentrations in Xenopus laevis

Decabromodiphenyl ether (decaBDE), as a flame retardant, is widely produced and used. To study the thyroid disruption by technical decaBDE at low concentrations, Xenopus laevis tadpoles were exposed to technical decaBDE mixture DE-83R (1–1000 ng/L) in water from stage 46/47 (free swimming larvae, system of Nieuwkoop and Faber) to stage 62. DE-83R at concentration of 1000 ng/L significantly delayed the time to metamorphosis (presented by forelimb emergence, FLE). Histological examination showed that DE- 83R at all tested concentrations caused histological alterations – multilayer follicular epithelial cell and markedly increased follicle size accompanied by partial colloid depletion and increase in the peripheral colloid vacuolation, in thyroid glands. All tested concentrations of DE-83R also induced a down-regulation of thyroid receptor mRNA expression. These results demonstrated that technical decaBDE disrupted the thyroid system in X. laevis tadpoles. Analysis of polybrominated diphenyl ethers (PBDEs) (sum of 39 congeners) in X. laevis indicated that mean concentrations of total PBDEs in X. laevis exposed to 1, 10, 100, 1000 ng/L were 11.0, 128.1, 412.1, 1400.2 ng/g wet weight, respectively. Considering that PBDEs burden of X. laevis tadpoles was close to PBDEs levels in amphibians as reported in previous studies, our study has raised new concerns for thyroid disruption in amphibians of technical decaBDE at environmentally relevant concentrations.