Study on polychlorinated dibenzo‐p‐dioxins and dibenzofurans in rivers and estuaries in Osaka Bay in Japan

In order to search the source of polychlorinated dibenzo‐p‐dioxins (PCDDs) and dibenzofurans (PCDFs) in blue mussel in Osaka bay, sediments from Osaka bay and from rivers running near an urban municipal incinerator were analysed for PCDDs, PCDFs and PCBs. The river and estuary sediments were all found to be contaminated with PCDDs at average levels of 9.8 and 12ppb on the dry basis, PCDFs of 7.8 and 5.1 ppb, and PCBs of 1600 and 1300ppb, respectively. The two sediments contained similar profiles of specific isomers and congeners of PCDDs and PCDFs with each other. In addition, there was observed positive close correlations between PCDD and PCDF levels in the two specimens as well as fly ash from urban municipal incinerators. These allow the conclusion that the main source of the two chemicals in Osaka bay is fly ash from waste incineration.     

Water — and nutrient and energy — systems in urbanizing watersheds

Driven by considerations of sustainability, it has become increasingly difficult over the past 15?C20 years ?? at least intellectually ?? to separate out the water infrastructure and water metabolism of cities from their intimately inter-related nutrient and energy metabolisms. Much of the focus of this difficulty settles on the wastewater component of the city??s water infrastructure and its associated fluxes of nutrients (N, P, C, and so on). Indeed, notwithstanding the massive volumes of these materials flowing into and out of the city, the notion of an urban nutrient infrastructure is conspicuous by its absence. Likewise, we do not tend to discuss, or conduct research into, ??soilshed?? agencies, or soilshed management, or Integrated Nutrient Resources Management (as opposed to its most familiar companion, Integrated Water Resources Management, or IWRM). The paper summarizes some of the benefits (and challenges) deriving from adopting this broader, multi-sectoral ??systems?? perspective on addressing water-nutrient-energy systems in city-watershed settings. Such a perspective resonates with the growing interest in broader policy circles in what is called the ??water-food-energy security nexus??. The benefits and challenges of our Multi-sectoral Systems Analysis (MSA) are illustrated through computational results from two primary case studies: Atlanta, Georgia, USA; and London, UK. Since our work is part of the International Network on Cities as Forces for Good in the Environment (CFG; see www.cfgnet.org), in which other case studies are currently being initiated ?? for example, on Kathmandu, Nepal ?? we close by reflecting upon these issues of water-nutrient-energy systems in three urban settings with quite different styles and speeds of development.     

Evaluation and remediation of organics,nutrients and heavy metals in landfill leachate – a case study in Beijing

Leachate pollution in landfill sites is a major source of environmental concern. This study evaluates organics, nutrients and heavy metals in a landfill site in Beijing, and introduces a method combining coagulation–flocculation with filtration for the advanced treatment of leachate. The results confirm that COD_Cr, TN, NH₄⁺ ? N, TP, Mn and As in leachate treated by an anaeobic–oxic biological method are unable to meet discharge or surface water quality standards. When treated with coagulation–flocculation combined with filtration under optimal conditions (cationic polyacrylamide dosage of 8.0 mg/L; polyaluminium chloride dosage of 350 mg/L; 0.4–0.6 mm ceramsite media in the filtration process), the residual NH₄⁺? N, TN, Mn and As in the leachate meet the maximum allowed values for landfill leachate discharge or surface water quality standards in China; the exceptions are chemical oxygen demand and total phosphorus. Leachate treatment processes could be further strengthened or improved.     

Recent advances in arsenic mutagenesis and carcinogenesis†

Arsenic is ubiquitously distributed in nature and is released into the environment through non‐ferrous smelting operations, generation of power from coal, and agriculture.

Epidemiological studies have shown that the incidences of epidermoid carcinomas of the skin and lungs, and of pre‐cancerous dermal keratoses are significantly increased in human subjects exposed to arsenic compounds by oral or respiratory routes. The negative results obtained on animals treated with arsenicals suggest strongly that this metal is probably a cocarcinogen.

The results of the short‐term tests suggest that the cocarcinogenic properties of arsenic could be related to its ability to inhibit DNA repair.     

Metalaxyl—its persistence and metabolism in soil

Different biotic and abiotic factors were found to play a vital role in attenuating metalaxyl residues in soil. In addition to metalaxyl many other products were found by HPLC and GC‐MS analysis while studying its soil metabolism in presence of natural sunlight. Three compounds were identified and characterized: 2,6‐dimethylaniline, 2,6‐dimethyl‐N‐ethylacetanilide and N‐(2,6‐dimethyl phenyl) alanine methyl ester.     

Input and fate of anthropogenic estrogens and gadolinium in surface water and␣sewage plants in the hydrological basin of Prague (Czech Republic)

The concentration of the estrogens 17β-estradiol, estriol, estrone, 17α-ethinylestradiol, mestranol and norethisterone and of the anthropogenic gadolinium (Gd_ant) has been determined in the creeks and rivers, sewage treatment plants and water works of the city of Prague. The rapid degradation of estrogens in surface water allows the estrogen concentration gradient to be used as a very precise and sensitive guideline by which to pin-point sewage leaks into surface run-off water. The rather conservative behavior of Gd_ant in surface and ground water documents in the present case the presence of sewage water in the surface water cycle.     

Constitutive and herbivore‐induced volatiles in pear,alder and hawthorn trees

Summary. Qualitative and quantitative differences among pear cultivars were found in constitutive and Cacopsylla-induced volatiles, depending on experimental treatment of the trees (i.e., uninfested and partly or completely infested by psyllids). Blend differences were also found between pear cultivars and wild-type pear, alder and hawthorn–the latter trees are frequently present in pear orchard hedgerows. ?Interesting differences were found in the presence of methyl salicylate and (E,E)-α-farnesene, two compounds previously found to mediate attraction of predatory bugs towards psyllid-infested pear trees. Methyl salicylate is expressed constitutively and is induced systemically by infestation in the whole plant of all four cultivars. (E,E)-α-farnesene on the other hand showed also systemic induction in Bartlett, NY10355 and Beurré Hardy, but in partially infested Conference trees it was induced locally, only in herbivore-damaged leaves. No methyl salicylate or (E,E)-α-farnesene were identified in honeydew. In field collected headspace samples of alder leaves infested by aphids and leaf beetles we found methyl salicylate but no (E,E)-α-farnesene, whereas in uninfested hawthorn neither were identified. Insight in the variability of damage-related pear volatiles will have important implications for integrated pest management in the field. Received 27 August 2002; accepted 28 November 2002 R1D=" Correspondence to: Petru Scutareanu, e-mail:scuterea@science.uva.nl     

Do honey bees tune error in their dances in nectar-foraging and house-hunting?

The "tuned-error" hypothesis states that natural selection has tuned the divergence angle in the dances of the honey bee to produce an optimal scatter of recruits across a resource. Weidenmüller and Seeley (Behav Ecol Sociobiol 46:190–199, 1999) supported this hypothesis by finding smaller divergence angles in dances indicating potential home sites, which are always point sources, than in dances indicating food sources, which often occur in patches. This study tested for the same effect, but controlled for variables, e.g., substrate and context, that may have confounded those results. When performed on the same substrate, divergence angle does not differ between dances for the two resources. Furthermore, dances performed for food within an observation hive exhibit significantly greater divergence angle when performed on comb (as Weidenmüller and Seeley measured food dances) than on hardware cloth (as they measured home-site dances on a swarm). These findings suggest that the angular variance in direction indication in dances is more likely an artifact of physical constraints, rather than an adaptive modification of a behavior that a bee could perform more precisely.     

Source and Distribution of Heavy Metals in Food†

Diet is the major route of exposure to contaminants, therefore food monitoring programs are essential to estimate the degree of human risk. We present a study undertaken in Austria dealing with the total uptake of mercury, cadmium, arsenic and lead. The dates were calculated from diet as well as from commercial food. Higher contaminated foodstuffs are registered and a comparison was made between body burden of babies and adults on the basis of bodyweight. It was pointed out, that cooked or washed food ready to eat has a lower burden of lead and cadmium than non prepared food due to household processing, which may decontaminate food to some extent’ Arsenic content was not reduced, because it is bound chemically and not primarily deposited on the surface of food such as in the case of lead. It was mentioned that the type of compound plays an important role in the assessment of action of those elements on humans.

Their biological activity is not necessarily related to their concentration in food. As in the case of selenium and chromium one has to take into consideration that there is a narrow range between benefit and harm, toxicity, and minor supply.

Therefore we conclude, that due to interactions of elements, their different biological activity and due to the difference of compounds present in food, we have to relativate the terms toxicity and essentiality. Then we can get a more profound insight into the problems of trace elements in food.     

Chromium accumulation,transport and toxicity in plants∗

The predominant pathway for human exposure to chromium in non‐occupationally exposed individuals is via food with a daily intake of around 30–100 μgd^–1, with vegetables providing a major contribution. Unlike reports of chromium essentiality to man and animals, plants appear not to require chromium in spite of some early reports of a stimulatory growth effect.

Most reports on chromium in plants have been concerned with their growth on soils amended with sewage sludge, pF‐ash, tannery waste, or on ultra basic soils, which contain extreme concentrations of the element. Experimental studies with plants grown in hydroponic solution have often been undertaken at unrealistically high concentrations to examine the uptake of chromium in various forms, either as CrIII or CrVI at different pHs. In most cases, reports on chromium in plants deal with element concentrations and plant/soil relationships rather than detailed biochemical and physiological processes.

In general, chromium is largely retained in the roots of plants, although the oxidation state of chromium, pH, presence of humates and fulvates and plant species, affect plant uptake and transport. Leaves usually contain higher concentrations than grains. The uptake of CrIII is largely a passive process, whereas CrVI uptake is a metabolically mediated process via the sulphate pathway and is thus readily transported around the plant. The presence of a compound similar to trioxalate CrIII has been recorded while little chromium has been reported to be associated with cell organelles or soluble proteins.     

Identification and expression of the COI1 gene family in Camellia sinensis and its expression in oolong tea processing北大核心CSCD

茉莉酸受体蛋白COI1(coronatine insensitive 1)是茉莉酸信号转导途径的重要组成部分,为鉴定分析茶树茉莉酸受体COI1基因家族,预测其潜在的分子功能,了解茉莉酸受体COI1基因在乌龙茶加工中应答胁迫的分子机制,利用生物信息学方法对茶树茉莉酸受体COI1进行家族成员鉴定,氨基酸序列、结构域、基因结构、进化分析以及启动子顺式元件分析,结合实时荧光定量分析CsCOI1基因在乌龙茶加工中的表达.结果显示,茶树茉莉酸受体CsCOI1家族有两个成员,均含有F-box和富亮氨酸重复序列(LRRs)两个结构域;单子叶、双子叶的COI1蛋白各聚一支,且与蜜柑进化关系较近;茶树COI1基因家族两个成员均含有3个内含子,启动子顺势元件主要有胁迫响应元件、激素响应元件以及光响应元件;转录组数据说明茶树CsCOI1基因具有较强的组织表达差异性.实时荧光定量分析表明,CsCOI1a基因在室内萎凋后表达显著上调,且15 min、30 min日光萎凋后CsCOI1b基因的表达水平显著上调,同时茉莉酸含量发生显著变化.本研究推测CsCOI1基因可能通过茉莉酸信号转导途径参与乌龙茶加工中萎凋的胁迫响应过程,该结果可为乌龙茶加工品质调控奠定基础.(图8表2参30)     

Metsulfuron‐methyl soil persistence and mobility in winter wheat and following green manure crops

A procedure has been developed for the analysis of metsulfuron‐methyl in the soil of field crops. The soil extracts are cleaned by repeated TLC, and metsulfuron‐methyl is simultaneously separated from its soil metabolites. Metsulfuron‐methyl is transformed by diazomethane into its N,N ‘‐dimethyl derivative which in the GC (electron capture detection) and GC‐MS apparatus is transformed into a benzisothiazole compound which is measured with great sensitivity. The sensitivity limit is 0.3 μg metsulfuron‐methyl kg^‐1 dry soil. The results of the chemical analyses are confirmed by bioassays using sugar beet as test plant. Metsulfuron‐methyl was measured in the soil of two winter wheat crops after post‐emergence application in the spring of 6 g metsulfuron‐methyl ha^‐1. In the 0–8 cm surface soil layer, the metsulfuron‐methyl soil half‐life was 78 days in 1997, and 67 days in 1998. During crop, metsulfuron‐methyl remained in the 0–8 cm surface soil layer. There, it was at a maximum concentration and herbicide efficiency in a 2 cm‐thick soil layer. This maximum concentration soil layer progressively moved down during crop, attaining the 4–6 cm surface soil layer at crop end. After the winter wheat harvest at the end of July, and the rotary‐tilling of the 0–10 cm surface soil layer before sowing of the green manures, 27% of the metsulfuron‐methyl initial dose still remained in the 0–10 cm surface soil layer. This residue progressively disappeared, and was no more detected at the middle of November. It had no, or only very low inhibiting effect on the growth of the green manures. Thus there is no concern about the possible phytotoxicity of persistent metsulfuron‐methyl soil residues towards the following crops, when metsulfuron‐methyl is applied at the rate of 6 g a.i.ha^‐1.     

The environmental geochemical baseline,background and sources of metal and metalloids present in urban,peri-urban and rural soils in the O´Higgins region,Chile

Environmental Geochemistry and Health - The importance of environmental geochemistry baseline in soils of O´Higgins Region, Chile, since it hosts in its eastern area one of the major Cu-Mo...     

Parent–offspring and sibling conflict in Galápagos fur seals and sea lions

Parent–offspring conflict theory is well supported by theoretical arguments. However, empirical observations are often difficult to interpret and have contradicted one of its most appealing predictions that parent and offspring should disagree over killing of nest or littermates. We present the first examples of deadly conflict between siblings of different cohorts. In Galápagos fur seals (Arctocephalus galapagoensis) and sea lions (Zalophus wollebaeki), mothers often wean their single offspring at 2 years. This leads to a situation where up to 23% of all pups are born while the older sibling is still being nursed. Younger siblings are disadvantaged by being born lighter than neonates without older still dependent siblings. Pups born while an older sib is still dependent grow less in early life (fur seal) and suffer increased early mortality (both species) through direct aggression or scramble competition with the older sibling. This effect is much stronger in years of high sea surface temperature (El Niño) indicating low marine productivity and if the older offspring is a male. In both species, mothers interfere aggressively in this conflict by defending the younger offspring. In years of El Niño, intense resistance to maternal aggression by the older offspring happens frequently in the fur seal. Such resistance against weaning can induce maternal neglect of the newborn. Given substantial year to year variation in offspring growth, maternal aggression forces weaning in the older sibling only if it has reached sufficient size to support itself by foraging. In Galápagos fur seals, pups with older siblings can either represent insurance against loss of older offspring or extra reproductive value.     

Progress in study of Salix characteristics and its application in sediment phytoremediation北大核心CSCD

For its difficulty in remediation and possibility of vicious spiral formation, contaminated sediment becomes a hot spot of recent pollution control study. Among all methods, phytoremediation is widely used in treatment of polluted sediment because of its high efficiency and sustainability. The fast-growing willow, a perennial woody plant with long vegetative season and great adaptation in harsh environments, has been suggested to be a low-cost and ecologically sound solution for the phytoremediation of contaminated sediment. This article introduces the characteristics of Salix and the ecological significance of Salix adaption to harsh environment, and reviews research progress and mechanisms including phytoextraction, phytotransformation, phytostabilization, phytodegradation and phytovolatilization of Salix. It also analyzes the effect of Salix in accumulating heavy metal, degrading organic matter and changing the characteristic of sediment, to point out the potential application of Salix in phytoremediation of polluted sediment. The article also puts forward the existing problems and possible solutions in phytoremediation by Salix of sediment, including paying more attention to field experiment, extending of the test cycle, emphasizing on optimal allocation of remediation plant communities.     

Cleanup by solid‐phase extraction and HPLC of organochlorine insecticides and PCBS in various nonfatty and fatty samples

An accurate, simple and cheap extraction and cleanup procedure for capillary GC analysis of organo‐chlorine insecticides (OCs) in vegetables (cabbage and carrots) at the ng/g level, and for soil at the μg/g level is presented. The cleanup is carried out on solid‐phase extraction (SPE) cartridges, filled with 500 mg silica, 1 g of deactivated Florisil (10% w/w water), and 100 mg of anhydrous sodium sulphate. Recoveries >90% are obtained. The cleanup of OCs in fatty samples on an HPLC LiChrosorb Si 100 column is evaluated for subsequent capillary GC analysis. Fractionation of OCs and Aroclor 1254 and 1260 on an HPLC Nucleosil 100 column appears to be satisfactory.