Variation in CO2 assimilation rate induced by simulated dew waters with different sources of hydroxyl radical (*OH) on the needle surfaces of Japanese red pine (Pinus densifora Sieb. et Zucc.)

The hydroxyl radical (*OH) is generated in polluted dew on the needle surfaces of Japanese red pine (Pinus densiflora Sieb. et Zucc.). This free radical, which is a potent oxidant, is assumed to be a cause of ecophysiological disorders of declining trees on the urban-facing side of Mt. Gokurakuji, western Japan. Mists of *OH-generating N(III) (HNO2 and NO2-) and HOOH + Fe + oxalate solutions (50 and 100 microM, pH 5.1-5.4) simulating the dew water were applied to the foliage of pine seedlings grown in open-top chambers in the early morning. Needles treated with 100 microM N(III) tended to have a greater maximum CO2 assimilation rate (Amax), a greater stomatal conductance (g(s)) and a greater needle nitrogen content (Nneedle), suggesting that N(III) mist acts as a fertilizer rather than as a phytotoxin. On the other hand, needles treated with 100 microM HOOH + Fe + oxalate solution showed the smallest Amax, g(s), and Nneedle, suggesting that the combination of HOOH + Fe + oxalate caused a decrease in needle productivity. The effects of HOOH + Fe + oxalate mist on pine needles were very similar to the symptoms of declining trees at Mt. Gokurakuji.     

Bioaccumulation of mercury in a vestimentiferan worm living in Kagoshima Bay,Japan

The present study reports on the mercury concentrations of the vestimentiferan worm, Lamellibrachia satsuma, (Annelida: Pogonophora) found near hydrothermal vents at a depth of 80-100 m in the northern parts of Kagoshima Bay. The vestimentiferan worms had total mercury concentrations of 238 ng/g in the anterior muscle of the body and 164 ng/g in the posterior trophosome. Methylmercury constituted only 7.6% of total mercury detected anteriorly and 16.3% posteriorly. The mean total mercury concentration in filtrated ambient seawater of the worm habitat was 1.1 ng/l. The worm should accumulate mercury in seawater by a one-step into the anterior and posterior parts as 2.2 x 10(%) and 1.5 x 10(5) times those of the filtered ambient seawater, respectively. The bioaccumulation factor of mercury by the worms with only their respiration would be actually larger than that by other marine animals through food webs. The high bioaccumulation factor of mercury in the worms suggest the following two possibilities: (i) the biological half-life of organomercury in the worm could be exceptionally long; or (ii) the lifetime of vestimentiferan worms examined in the present study could be extremely long. Various metals in one specimen of the worm were analyzed by using ICP-MS, and then gold as well as silver were detected in the worm. Gold was detected for the first time from marine animals.     

Composite tin and zinc oxide nanocrystalline particles for enhanced charge separation in sensitized degradation of dyes

Composite ZnO/SnO2 catalyst has been studied for the sensitized degradation of dyes e.g. Eosin Y (2', 4', 5', 7'-tetrabromofluorescein disodium salt) in relation to efficient charge separation properties of the catalyst. Improved photocatalytic activity was observed in the case of ZnO/SnO2 composite catalyst compared to the catalytic activity of ZnO, SnO2 or TiO2 powder. The suppression of charge recombination in the composite ZnO/SnO2 catalyst led to higher catalytic activity for the degradation of Eosin Y. Degradation of Eosin follows concomitant formation of CO2 and formation of CO2 followed a pseudo-first-order rate. Photoelectrochemical cells constructed using SnO2, ZnO, ZnO/SnO2 sensitized with Eosin Y showed V(oc) of 175, 306, 512 mV/cm2 and I(sc) of 50, 70, 200 microA/cm2 respectively. A higher irreversible degradation of Eosin Y and higher V(oc) observed on composite ZnO/SnO2 than ZnO and SnO2 separately can be considered as a proof of enhanced charge separation of ZnO/SnO2 catalyst. Eosin Y showed a higher emission decreases on ZnO/SnO2 composite than on individual ZnO, SnO2 or TiO2 indicating dominance of the charge injection process. Photoinjected electrons are tunneled from ZnO to SnO2 particles accumulating injected electrons in the conduction bands allowing wider separation of excited carriers.     

Comparison of emissions estimates derived from atmospheric measurements with national estimates of HFCs,PFCs and SF6

This paper assesses the feasibility of using atmospheric measurement of fluorinated greenhouse gases (HFCs, PFCs and SF6) for the review and verification of greenhouse gas inventories provided by national governments. For this purpose, available data were compiled. It was found that atmospheric measurements of these gases are available and provide an indication of global annual emissions with sufficient certainty to reach the following conclusions: Within the uncertainty of the method, it was found that emissions of HFC-23, a by-product of HCFC-22 production, as obtained from atmospheric measurements did not decrease as fast, as the countries have reported. In contrast, SF6 concentrations in the atmosphere suggest higher emissions than reported by countries. Regional emission estimates from atmospheric measurements are still in a more pioneering state and cannot be compared to national estimates. Intensified efforts to measure HFCs, PFCs and SF6 in the atmosphere are recommended.     

The measurement of cholinesterase activities as a biomarker in chub (Leuciscus cephalus): the fish length should not be ignored

Biomarkers are early warning systems of the exposure of aquatic organisms to pollutants. Among them, the measurement of the cholinesterase (ChE) activities in fish muscle is a biomarker of the exposure to organophosphosphates and carbamates pesticides. As such it has been used in numerous field studies both in marine and continental waters. Cyprinids (chub, Leuciscus cephalus) were sampled in river sites (France) in relatively clean and polluted areas. We performed the statistical analysis of the ChE activities and we generally observed a statistical relationship between ChE activities and fish length, the larger fish having the lower ChE activities. We concluded that the great majority of the significant differences in ChE activities between sites could be due in fact to differences in fish length between field samples. We stress the importance of taking into account the fish length whenever differences in ChE levels between field sites must be interpreted.     

Arsenic and other heavy metals in soils from an arsenic-affected area of West Bengal,India

Domkal is one of the 19, out of 26 blocks in Murshidabad district where groundwater contains arsenic above 0.05 mg/l. Many millions of cubic meters of groundwater along with arsenic and other heavy metals are coming out from both the hand tubewells, used by the villagers for their daily needs and shallow big diameter tubewells, installed for agricultural irrigation and depositing on soil throughout the year. So there is a possibility of soil contamination which can moreover affect the food chain, cultivated in this area. A somewhat detailed study was carried out, in both micro- and macrolevel, to get an idea about the magnitude of soil contamination in this area. The mean concentrations (mg/kg) of As (5.31), Fe (6740), Cu (18.3), Pb (10.4), Ni (18.8), Mn (342), Zn (44.3), Se (0.53), Mg (534), V (44.6), Cr (33.1), Cd (0.37), Sb (0.29) and Hg (0.54) in fallow land soils are within the normal range. The mean As (10.7), Fe (7860) and Mg (733) concentrations (mg/kg) are only in higher side whereas Hg (0.17 mg/kg) is in lower side in agricultural land soils, compared to the fallow land soils. Arsenic concentrations (11.5 and 28.0 mg/kg respectively) are high in those agricultural land soils where irrigated groundwater contains high arsenic (0.082 and 0.17 mg/l respectively). The total arsenic withdrawn and mean arsenic deposition per land by the 19 shallow tubewells per year are 43.9 kg (mean: 2.31 kg, range: 0.53-5.88 kg) and 8.04 kg ha(-1) (range: 1.66-16.8 kg ha(-1)) respectively. For the macrolevel study, soil arsenic concentration decreases with increase of distance from the source and higher the water arsenic concentration, higher the soil arsenic at any distance. A proper watershed management is urgently required to save the contamination.     

Chapter three: methodology of exposure modeling

In this chapter, the concept of exposure assessment and its evolution is introduced, and evaluated by critically appraising the pertinent literature as it applies to exposures to Particulate Matter (PM). Exposure measurement or estimation methodologies and models are reviewed. Three exposure/measurement methodologies are assessed. Estimation methods focus on source evaluation and attribution, sources include those outdoors and indoors as well as in occupational and in-transit environments. Fate and transport models and their inputs are addressed to estimate concentrations outdoors and indoors; source attribution techniques help focus on the contributing sources. Activity pattern techniques are also reviewed and their use in exposure models to estimate inhalation exposure to PM is presented. Deterministic, regression and other stochastic models of exposure to PM are reviewed and evaluated. Strengths, limitations, assumptions and affirmations of the use of exposure assessment as an integral component of risk assessment and risk management are discussed in the conclusions and discussions section of this work.     

Overview and assessment of techniques to measure ammonia emissions from animal houses: the case of the Netherlands

In order to comply with the ammonia (NH(3)) emission reduction assigned to the Netherlands development of new measures are needed, which should be supported by fast and accurate measurements to arrive at new estimates of the NH(3) emission from each agricultural source. This paper gives an overview of the current methods used in the Netherlands to measure NH(3) emissions from animal houses, and provides alternative methods for some particular situations. For mechanically ventilated animal houses, passive flux samplers placed in the ventilation shafts of the animal house are presented as alternative to measure a larger number of animal houses (replicates) with the same housing system at a low price. For naturally ventilated animal houses, when mixing in the animal house is not good enough to allow measurements within the animal house (internal tracer gas ratio method), two measurement methods are discussed: the Gaussian plume dispersion model, which is usually not suitable for agricultural situations, and the flux frame method, which is not always applicable because of distortion of the flow around the building. Finally, for animal houses with outside yards for the animals, there are at this moment no methods available to measure the NH(3) emissions from these complex situations, although quick box methods (for the outside yards) and a combination of a backward Lagrangian stochastic model with open-path concentration measurements with a tunable diode laser (TDL), look promising.     

Avoidance behaviour of Enchytraeus albidus: effects of benomyl, carbendazim, phenmedipham and different soil types

Enchytraeids are typical inhabitants of many soils, contributing to vital processes of this environmental compartment. Indirectly they are involved in regulating the degradation of organic matter, as well as improving the pore structure of the soil. Due to their behaviour, they are able to avoid unfavourable environmental conditions. Avoidance tests with enchytraeids, initially developed with earthworms by several authors, are quick and easy to perform. With these tests a first assessment of the toxicity of a (contaminated or spiked) soil is possible in just 48 h by using the reaction of the enchytraeids as measurement endpoint. In this period of time the organisms can choose between the control soil and the other soil (a contaminated or spiked or another soil with different physico-chemical properties). In the tests reported here, the enchytraeids were exposed to control soils spiked with the fungicides Benomyl and Carbendazim and the herbicide Phenmedipham. Several chemical concentrations were tested in order to evaluate the avoidance behaviour to toxic substances. In fact, often these short-term screening tests gave results showing avoidance at concentrations in a range similar to the acute test results but, higher than in chronic tests. Further tests are needed to decide whether the results gained in this study can be extrapolated to other chemicals. It is proposed to standardize the Enchytraeid Avoidance Test as it is currently done for the Earthworm Avoidance Test by the International Standard Organization (ISO).     

An integrated assessment of estrogenic contamination and biological effects in the aquatic environment of The Netherlands

An extensive study was carried out in the Netherlands on the occurrence of a number of estrogenic compounds in surface water, sediment, biota, wastewater, rainwater and on the associated effects in fish. Compounds investigated included natural and synthetic hormones, phthalates, alkylphenol(ethoxylate)s and bisphenol-A. The results showed that almost all selected (xeno-)estrogens were present at low concentrations in the aquatic environment. Locally, they were found at higher levels. Hormones and nonylphenol(ethoxylate)s were present in concentrations that are reportedly high enough to cause estrogenic effects in fish. Field surveys did not disclose significant estrogenic effects in male flounder (Platichthys flesus) in the open sea and in Dutch estuaries. Minor to moderate estrogenic effects were observed in bream (Abramis brama) in major inland surface waters such as lowland rivers and a harbor area. The prevalence of feminizing effects in male fish is largest in small regional surface waters that are strongly influenced by sources of potential hormone-disrupting compounds. High concentrations of plasma vitellogenin and an increased prevalence of ovotestes occurred in wild male bream in a small river receiving a considerable load of effluent from a large sewage treatment plant. After employing in vitro and in vivo bioassays, both in situ and in the laboratory, we conclude that in this case hormones (especially 17 alpha-ethynylestradiol) and possibly also nonylphenol(ethoxylate)s are primarily responsible for these effects.