Salicylic acid involved in the regulation of nutrient elements uptake and oxidative stress in Vallisneria natans (Lour.) Hara under Pb stress

In this study, the alterations in nutrient elements content, reactive oxygen species level and antioxidant response were studied in leaves of Vallisneria natans (Lour.) Hara exposed to salicylic acid (SA, 10 or 100 μM), or Pb (50 μM) or their combinations for 4 d. No significant alterations in Mn and Ca content were observed but content of Cu, Zn, Fe and P decreased in plants exposed to SA alone. SA application inhibited the uptake of Pb and partially reversed Pb-induced the alterations in Mn, Ca and Fe content in leaves of V. natans exposed to 50 μM Pb. The decreased chlorophyll (a + b) and increased malondialdehyde and O²⁻ and H₂O₂ content were detected in plants exposed to 100 μM SA, 50 μM Pb, 10 μM SA + 50 μM Pb or 100 μM SA + 50 μM Pb. Application SA partially inhibited Pb-induced the increase of malondialdehyde, O²⁻ and H₂O₂ content. 100 μM SA decreased the activity of NADH oxidase and the content of non-protein thiols, carotenoids and ascorbic acid and increased the content of dehydroascorbate in plants treated with or without Pb. SA alone decreased the ascorbate peroxidase activity and increased the catalase and peroxidase activity, while SA application increased catalase activity but had no significant effect on ascorbate peroxidase and peroxidase activity in V. natans exposed to Pb. The results indicate that SA involves in the regulation of Pb uptake, nutrient balance and oxidative stress.     

Spatial distribution of ciguateric fish in the Republic of Kiribati

Ciguatera is food poisoning caused by human consumption of reef fish contaminated with ciguatoxins (CTXs). The expanding international trade of tropical fish species from ciguatera-endemic regions has resulted in increased global incidence of ciguatera, and more than 50 000 people are estimated to suffer from ciguatera each year worldwide. The Republic of Kiribati is located in the Pacific Ocean; two of its islands, Marakei and Tarawa, have been suggested as high-risk areas for ciguatera. The toxicities of coral reef fish collected from these islands, including herbivorous, omnivorous and carnivorous fish (24% [n = 41], 8% [n = 13] and 68% [n = 117], respectively), were analyzed using the mouse neuroblastoma assay (MNA) after CTX extraction. The MNA results indicated that 156 fish specimens, or 91% of the fish samples, were ciguatoxic (CTX levels >0.01 ng g⁻¹). Groupers and moray eels were generally more toxic by an order of magnitude than other fish species. All of the collected individuals of eight species (n = 3-19) were toxic. Toxicity varied within species and among locations by up to 10 000-fold. Cephalapholis argus and Gymnothorax spp. collected from Tarawa Island were significantly less toxic than those from Marakei Island, although all individuals were toxic based on the 0.01 ng g⁻¹ threshold. CTX concentrations in the livers of individuals of two moray eel species (Gymnothorax spp., n = 6) were nine times greater than those in muscle, and toxicity in liver and muscle showed a strong positive correlation with body weight. The present study provides quantitative information on the ciguatoxicity and distribution of toxicity in fish for use in fisheries management and public health.     

Levels of polybrominated diphenyl ethers and hexabromocyclododecane in the atmosphere and tree bark from Beijing, China

Air samples in four seasons at one site and tree bark samples from four districts were determined to investigate seasonal variation and regional distribution of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) in Beijing, China. The total concentrations of PBDEs (∑PBDE) and HBCD (∑HBCD) were in the range of 57-470 and 20-1800 pg m⁻³ in the atmosphere, respectively. The ∑PBDE and ∑HBCD concentrations were significantly influenced by the total suspended particulate matter in atmosphere. The total concentrations of PBDEs and HBCD in tree bark samples were in the range of 99-3700 and 26-3400 ng g⁻¹ lipid weight. It was found that regional distribution of PBDEs and HBCD was related to the function of each district. In addition, the study found that weeping willow bark was an ideal atmospheric PBDEs and HBCD passive sampler. Finally, atmospheric levels of BDE-209 and HBCD at tree bark sampling districts were estimated via applying an established bark/air partitioning model, which had been verified by the measured concentrations in tree bark and atmosphere in Beijing.     

Virtual phosphorus ore requirement of Japanese economy

Phosphorus is indispensable for agricultural production. Hence, the consumption of imported food indirectly implies the import of phosphorus resources. The global consumption of agricultural products depends on a small number of ore-producing countries. For sustainable management of phosphorus resources, the global supply and demand network should be clarified. In this study, we propose the virtual phosphorus ore requirement as a new indicator of the direct and indirect phosphorus requirements for our society. The virtual phosphorus ore requirement indicates the direct and indirect demands for phosphorus ore transformed into agricultural products and fertilizer. In this study, the virtual phosphorus ore requirement was evaluated for the Japanese economy in 2005. Importantly, the results show that our society requires twice as much phosphorus ore as the domestic demand for fertilizer production. The phosphorus contained in “eaten” agricultural products was only 12% of virtual phosphorus ore requirement.     

Polychlorinated naphthalenes (PCNs) in riverine and marine sediments of the Laizhou Bay area, North China

PCN congeners were analyzed in marine and riverine sediments of the Laizhou Bay area, North China. Concentrations of PCNs ranged from 0.12 to 5.1 ng g⁻¹ dry weight (dw) with a mean value of 1.1 ng g⁻¹ dw. The levels of PCNs varied largely, with industrial group approximately ten folds higher than those of the rural in riverine sediment. A strong impact by direct discharge from local factories was suggested. Similar compositional profiles were found within groups. High resemblance of compositional profiles between industrial samples and Halowax 1014 was observed. It was indicated that PCNs in riverine sediments were mainly from release of industrial usage, with additional contributions from industrial thermal process at certain sites. In marine sediments, it was suggested that PCNs along the coast of Laizhou Bay were mainly controlled by riverine input. While in the central bay, PCN distributions were possibly impacted by combined multiple factors.     

Leaching of bisphenol A (BPA) to seawater from polycarbonate plastic and its degradation by reactive oxygen species

In this study, (1) change in the concentration of bisphenol A (BPA) leached from polycarbonate (PC) tube to control water (BPA free), seawater and river water at 20 and 37 degrees C as a function of time, (2) the fate of BPA caused by addition of H(2)O(2) and Fe(3+) to seawater containing BPA leached from PC tube were assessed. BPA leached from PC tube to all water samples increased with the ascendant of temperature and with the passage of time. The BPA leaching velocity in seawater was the fastest in three samples (11 ng/day for seawater, 4.8 ng/day for river water 0.8 ng/day for control water at 37 degrees C).BPA leaching velocity from PC tube was significantly high at pH 8 (50 mM Na(2)HPO(4)) and increased dose-dependently. There was no difference in the velocity of BPA among the 50 mM phosphate-buffers at pH 6.5, 7.0 and 7.5. BPA was leached three times higher by addition of Na(+) than K(+). However, the higher the K(+) concentration, the larger the BPA leached from PC tube. Na(+) mixed with PO(4)(-) was effective on BPA leaching from PC tube, but not with SO(4)(-) or Cl(-). The results suggested that BPA leaching from PC tube would be attributed to the concentration of bibasic phosphate such as Na(2)HPO(4) and K(2)HPO(4) in water samples. BPA was degraded in both control water and seawater in the presence of radical oxygen species, but the degradation rate was lower in seawater than in control water, suggesting that anti-oxidative system exists in seawater. Neo-synthesized substance in both control water and seawater in the presence of reactive oxygen species was identified as BPA-quinone by LC-MS.     

Effects of four chlorobenzenes on serum sex steroids and hepatic microsome enzyme activities in crucian carp, Carassius auratus

Four chlorobenzenes (chlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, p-chloro-methylbenzene) were administrated to the crucian carps (Carassius auratus) by peritoneal injections in the laboratory for 30 days. Serum testosterone and 17 beta-estradiol concentrations were detected using radioimmunology assay (RIA), and the activities of two hepatic microsome enzymes, glutathione s-transferase (GST) and UDP-glucuronosyltransferase (UDPGT), were measured using the modified methods as described by Habig and Owens. Results showed that the four chlorobenzenes caused significant increases in serum testosterone concentration in the crucian carps (P < 0.05) compared to the controls, but they caused no significant effect on 17 beta-estradiol level. All test chemicals caused a change in hepatic GST activity in crucian carps, with significant increases in enzyme activity (P < 0.05). Chlorobenzene, 1,3-dichlorobenzene and p-chloro-methylbenzene resulted in a marked inhibition to UDPGT activity in crucian carp (P < 0.05) except 1,4-dichlorobenzene. The changes in hepatic microsome enzyme activities may have resulted in the alterations of serum sex steroids levels in the crucian carps. The results indicated that these four chlorobenzenes may result in the changes of endocrine functions and may affect the reproductive success of this and other species.     

The influence of pH on the degradation of phenol and chlorophenols by potassium ferrate

This paper presents information concerning the influence of solution pH on the aqueous reaction between potassium ferrate and phenol and three chlorinated phenols: 4-chlorophenol (CP), 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP). The redox potential and aqueous stability of the ferrate ion, and the reactivity of dissociating compounds, are known to be pH dependent. Laboratory tests have been undertaken over a wide range of pH (5.8-11) and reactant concentrations (ferrate:compound molar ratios of 1:1 to 8:1). The reactivity of trichloroethylene was also investigated as a reference compound owing to its non-dissociating nature. The extent of compound degradation by ferrate was found to be highly pH dependent, and the optimal pH (maximum degradation) decreased in the order: phenol/CP, DCP, TCP; at the optimal pH the degree of degradation of these compounds was similar. The results indicate that for the group of phenol and chlorophenols studied, the presence of an increasing number of chlorine substituent atoms corresponds to an increasing reactivity of the undissociated compound, and a decreasing reactivity of the dissociated compound.     

农林生物质在含铬废水处理中的应用

农林生物质作为低成本吸附剂在环境污染治理中日益受到重视。综述了农林生物质在含铬废水处理中的应用研究进展，分析了生物质处理含铬废水的机理、影响因素，指出了生物质法处理含铬废水的发展方向。     

从委托代理理论谈中国的环境影响评价制度

根据委托代理理论，分析了中国环境影响评价制度中存在的问题，立足于绿色招商的理念，理顺建设项目环评委托代理关系，明确了建设单位、环评单位、招商部门、环保部门等相互之间的关系和职责，以使中国的环境影响评价制度更适应新型工业化道路发展的要求。