Rate of iodine volatilization and accumulation by filamentous fungi through laboratory cultures

Five strains of basidiomycetes (Lentinula edodes, Coprinus phlyctidosporus, Hebeloma vinosophyllum, Pleurotus ostreatus and Agaricus bisporus), one strain of ascomycete (Hormoconis resinae) and six strains of imperfect fungi (Penicillium chrysogenum, Penicillium roquefortii, Cladosporium cladosporioides, Alternaria alternata, Aspergillus niger and Aspergillus oryzae) were cultured in a liquid medium containing a radioactive iodine tracer (¹²⁵I), and were tested for their abilities to volatilize or accumulate iodine. Of the fungal strains tested, 11 strains volatilized a considerable amount of iodine, with L. edodes showing the highest volatilization rate of 3.4%. The volatile organic iodine species emitted from imperfect fungi cultures was identified as methyl iodide (CH₃I). In contrast, six fungal strains in 12 strains accumulated a considerable amount of iodine from the medium with concentration factors of more than 1.0. Among these, Alt. alternata and Cl. cladosporioides accumulated more than 40% of the iodine in their hyphae, and showed high concentration factors of 22 and 18, respectively. These results suggest that filamentous fungi have a potential to influence the mobility and speciation of iodine by volatilization and accumulation. Considering their great biomass in soils, filamentous fungi may contribute to the global circulation of stable iodine and also the long-lived radioiodine, ¹²⁹I (half-life: 1.6 × 10⁷ years), released from nuclear facilities into the environment.     

Rate of iodine volatilization and accumulation by filamentous fungi through laboratory cultures

Five strains of basidiomycetes (Lentinula edodes, Coprinus phlyctidosporus, Hebeloma vinosophyllum, Pleurotus ostreatus and Agaricus bisporus), one strain of ascomycete (Hormoconis resinae) and six strains of imperfect fungi (Penicillium chrysogenum, Penicillium roquefortii, Cladosporium cladosporioides, Alternaria alternata, Aspergillus niger and Aspergillus oryzae) were cultured in a liquid medium containing a radioactive iodine tracer (¹²⁵I), and were tested for their abilities to volatilize or accumulate iodine. Of the fungal strains tested, 11 strains volatilized a considerable amount of iodine, with L. edodes showing the highest volatilization rate of 3.4%. The volatile organic iodine species emitted from imperfect fungi cultures was identified as methyl iodide (CH₃I). In contrast, six fungal strains in 12 strains accumulated a considerable amount of iodine from the medium with concentration factors of more than 1.0. Among these, Alt. alternata and Cl. cladosporioides accumulated more than 40% of the iodine in their hyphae, and showed high concentration factors of 22 and 18, respectively. These results suggest that filamentous fungi have a potential to influence the mobility and speciation of iodine by volatilization and accumulation. Considering their great biomass in soils, filamentous fungi may contribute to the global circulation of stable iodine and also the long-lived radioiodine, ¹²⁹I (half-life: 1.6 × 10⁷ years), released from nuclear facilities into the environment.     

Dispersibility of crude oil in fresh water

The effects of surfactant composition on the ability of chemical dispersants to disperse crude oil in fresh water were investigated. The objective of this research was to determine whether effective fresh water dispersants can be designed in case this technology is ever considered for use in fresh water environments. Previous studies on the chemical dispersion of crude oil in fresh water neither identified the dispersants that were investigated nor described the chemistry of the surfactants used. This information is necessary for developing a more fundamental understanding of chemical dispersion of crude oil at low salinity. Therefore, we evaluated the relationship between surfactant chemistry and dispersion effectiveness. We found that dispersants can be designed to drive an oil slick into the freshwater column with the same efficiency as in salt water as long as the hydrophilic-lipophilic balance is optimum.     

Ammonia volatilization loss from surface applied livestock manure

Ammonia (NH₃) emission from livestock manures used in agriculture reduces N uptake by crops and negatively impacts air quality. This laboratory study was conducted to evaluate NH₃emission from different livestock manures applied to two soils: Candler fins sand (CFS; light-textured soil, pH 6.8 and field capacity soil water content of 70 g kg^{? 1}) from Lake Alfred, Florida and Ogeechee loamy sand (OLS; medium-textured soil, pH 5.2 and field capacity soil water content of 140 g kg^{? 1}) from Savannah, Georgia. Poultry litter (PL) collected from a poultry farm near Douglas, Georgia, and fresh solid separate of swine manure (SM) collected from a farm near Clinton, North Carolina were used. Each of the soil was weighed in 100 g sub samples and amended with either PL or SM at rates equivalent to either 0, 2.24, 5.60, 11.20, or 22.40 Mg ha^{? 1} in 1L Mason jars and incubated in the laboratory at field capacity soil water content for 19 days to monitor NH₃ volatilization. Results indicated a greater NH₃ loss from soils amended with SM compared to that with PL. The cumulative NH₃volatilization loss over 19 days ranged from 4 to 27% and 14 to 32% of total N applied as PL and SM, respectively. Volatilization of NH₃ was greater from light-textured CFS than that from medium-textured OLS. Volatilization loss increased with increasing rates of manure application. Ammonia volatilization was lower at night time than that during the day time. Differences in major factors such as soil water content, temperature, soil type and live stock manure type influenced the diurnal variation in volatilization loss of NH₃ from soils. A significant portion (> 50%) of cumulative NH₃ emission over 19 d occurred during the first 5–7 d following the application of livestock manures. Results of this study demonstrate that application of low rates of livestock manure (≤ 5.60 Mg ha^{? 1}) is recommended to minimize NH₃ emissions.     

Photolytic degradation of methyl-parathion and fenitrothion in ice and water: Implications for cold environments

Here we investigate the photodegradation of structurally similar organophosphorus pesticides; methyl-parathion and fenitrothion in water (20 °C) and ice (−15 °C) under environmentally-relevant conditions with the aim of comparing these laboratory findings to limited field observations. Both compounds were found to be photolyzed more efficiently in ice than in aqueous solutions, with quantum yields of degradation being higher in ice than in water (fenitrothion > methyl-parathion). This rather surprising observation was attributed to the concentration effect caused by freezing the aqueous solutions. The major phototransformation products included the corresponding oxons (methyl-paraoxon and fenitroxon) and the nitrophenols (3-methyl-nitrophenol and nitrophenol) in both irradiated water and ice samples. The presence of oxons in ice following irradiation, demonstrates an additional formation mechanism of these toxicologically relevant compounds in cold environments, although further photodegradation of oxons in ice indicates that photochemistry of OPs might be an environmentally important sink in cold environments.     

Effect of UV radiation and temperature on mineralization and volatilization of coumaphos in water

This study was undertaken to determine the dissipation and degradation of coumaphos [O-(3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl) O,O-diethyl phosphorothioate] under different sunlight conditions and at different temperatures. The effect of the ultra violet (UV) component of solar radiation was also studied using quartz tubes in addition to other radiation in the visible range using glass tubes and the results were compared with those obtained under the dark light conditions. Water suspensions of coumaphos were incubated at three temperatures viz. 22 degrees C, 37 degrees C and 53 degrees C in closed systems to study the effect of temperature. Volatilization, mineralization and degradation of coumaphos increased with an increase in temperature and exposure to solar radiation, particularly under the UV component of the solar radiation. Major loss of the pesticide occurred through volatilization. The optimum temperature for the degradation of coumaphos was found to be at 37 degrees C. The data obtained from the mineralization and degradation studies indicated that 53 degrees C crosses the biological range for suitable growth of microorganism. UV radiation exposure along with maintaining temperature at 37 degrees C may prove useful in the dissipation and/or degradation of coumaphos prior to its disposal as waste from cattle dipping vats.     

Estimation of the volatilization of organic compounds from soil surfaces

Several simple models for the estimation of the half-life (t(1/2)) for the depletion of an organic chemical from a soil surface to air were examined. For moist surfaces, two models are proposed: the first requires knowledge of the soil/organic carbon partition coefficient (K(oc)) and the Henry's law constant (H) and the second the vapor pressure (P(s)) of the chemical involved. Due to uncertainties in the experimental K(oc) values those ones predicted by the group-contribution model of Meylan et al. [Environ. Sci. Technol. 26 (1992) 1560]-and proposed by the U.S. Environmental Protection Agency (EPA)-should be used. If reliable experimental P(s) values are not available, the first model is proposed, where in cases when H values are not available, predicted ones by the Bond-Contribution method of Meylan and Howard [Environ. Toxicol. Chem. 10 (1991) 1283]-and also proposed by EPA-can be used. In general, the agreement of the predicted t(1/2) values with the measured ones is within a factor of 3-5. Similar expressions, but with somewhat poorer results, are presented for dry field soils. In all cases, the obtained results represent a substantial improvement over those obtained with the currently used Dow method: t(1/2) = 1.58 x 10(-8)((K(oc) x S)/P(S)), where S is the solubility of the compound in water.     

Effect of UV radiation and temperature on mineralization and volatilization of coumaphos in water

This study was undertaken to determine the dissipation and degradation of coumaphos [O-(3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl) O,O-diethyl phosphorothioate] under different sunlight conditions and at different temperatures. The effect of the ultra violet (UV) component of solar radiation was also studied using quartz tubes in addition to other radiation in the visible range using glass tubes and the results were compared with those obtained under the dark light conditions. Water suspensions of coumaphos were incubated at three temperatures viz. 22°C, 37°C and 53°C in closed systems to study the effect of temperature. Volatilization, mineralization and degradation of coumaphos increased with an increase in temperature and exposure to solar radiation, particularly under the UV component of the solar radiation. Major loss of the pesticide occurred through volatilization. The optimum temperature for the degradation of coumaphos was found to be at 37°C. The data obtained from the mineralization and degradation studies indicated that 53°C crosses the biological range for suitable growth of microorganism. UV radiation exposure along with maintaining temperature at 37°C may prove useful in the dissipation and/or degradation of coumaphos prior to its disposal as waste from cattle dipping vats.     

Ammonia volatilization from crop residues and frozen green manure crops

Agricultural systems can lose substantial amounts of nitrogen (N). To protect the environment, the European Union (EU) has adopted several directives that set goals to limit N losses. National Emission Ceilings (NEC) are prescribed in the NEC directive for nitrogen oxides and ammonia. Crop residues may contribute to ammonia volatilization, but sufficient information on their contribution to the national ammonia volatilization is lacking. Experiments were carried out with the aim to assess the ammonia volatilization of crop residues left on the soil surface or incorporated into the soil under the conditions met in practice in the Netherlands during late autumn and winter.Ammonia emission from residues of broccoli, leek, sugar beet, cut grass, fodder radish (fresh and frozen) and yellow mustard (frozen) was studied during two winter seasons using volatilization chambers. Residues were either placed on top of soil or mixed with soil. Mixing residues with soil gave insignificant ammonia volatilization, whereas volatilization was 5–16 percent of the N content of residues when placed on top of soil.Ammonia volatilization started after at least 4 days. Total ammonia volatilization was related to C/N-ratio and N concentration of the plant material. After 37 days, cumulative ammonia volatilization was negligible from plant material with N concentration below 2 percent, and was 10 percent of the N content of plant material with 4 percent N. These observations can be explained by decomposition of plant material by micro-organisms. After an initial built up of the microbial population, NH₄⁺ that is not needed for their own growth is released and can easily emit as NH₃ at the soil surface.The results of the experiments were used to estimate the contribution of crop residues to ammonia volatilization in the Netherlands. Crop residues of arable crops and residues of pasture topping may contribute more than 3 million kg NH₃–N to the national ammonia volatilization of the Netherlands, being more than 3 percent of the national emissions in 2005. This contribution should therefore be considered when focusing on the national ceilings for ammonia emissions.     

Effect of a cationic surfactant on the volatilization of PAHs from soil

Purpose

Cationic surfactants are common in soils because of their use in daily cosmetic and cleaning products, and their use as a soil amendment for the mitigation and remediation of organic contaminated soils has been proposed. Such surfactant may affect the transfer and fate of organic contaminants in the environment. This study investigated the effect of a cationic surfactant, dodecylpyridinium bromide (DDPB), on the volatilization of polycyclic aromatic hydrocarbons (PAHs) from a paddy soil.

Materials and methods

The volatilization of PAHs from moist soil amended with different concentrations of DDPB was tested in an open system. The specific effects of DDPB on the liquid?Cvapor and solid?Cvapor equilibriums of PAHs were separately investigated in closed systems by headspace analysis.

Results and discussion

DDPB affects both liquid?Cvapor and solid?Cvapor processes of PAHs in soil. At DDPB concentrations below the critical micelle concentration (CMC), movement of PAHs from the bulk solution to the gas?Cliquid interface appeared to be facilitated by interaction between PAHs and the surfactant monomers adsorbed at the gas?Cliquid interface, promoting the volatilization of PAHs from solution. However, when DDPB was greater than the CMC, volatilization was inhibited due to the solubilization of PAHs by micelles. On the other hand, the formation of sorbed surfactant significantly inhibited the solid?Cvapor volatilization of PAHs.

Conclusions

The overall effect of the two simultaneous effects of DDPB on liquid?Cvapor and solid?Cvapor processes was a decreased volatilization loss of PAHs from soil. Inhibition of PAH volatilization was more significant for the soil with a lower moisture content.     

Field test of volatilization models

Four volatilization models were tested against field data from the Manchester Ship Canal and the River Main. The equations byMacKay andYeun, using Schmidt number and wind speed for the calculation of volatilization rate, were found to give the best results for the slowly flowing Ship Canal. Models using flow velocity grossly underestimated the real values for this waterway but were found to be superior for the faster flowing River Main. The results of this work indicate that volatilization models should be carefully chosen for a particular environmental situation. Additionally, the importance of the validation of such models against field data is emphasised.     

Outdoor experiments on enhanced volatilization by venting of kerosene component from soil

The effect of soil properties on the retention of kerosene in soils, at equilibrium and under venting, was studied. Eleven soils were studied, which represent a wide range of chemical properties and mechanical composition. The retention of kerosene in dry soils ranges from 3.5 to 18.1 mL/(100 g), and was related linearly to clay, silt and organic matter (OM) contents. A coarsely-aggregated dry vertisol (2–5 mm aggregates) retained half as much kerosene as its finely-aggregated (<2 mm) counterpart. Moisture content had a strong inverse effect on kerosene retention. The soil factors that inversely affected kerosene retention also enhanced kerosene stripping by venting. Of these, soil aggregation and porosity were the most important. In addition, kerosene volatilized faster and more completely from an initially moist soil, as compared with an initially dry soil. Differential volatilization of lighter components of kerosene changed the chemical composition of the residue in the soil substantially, as compared with the initial composition.     

Transfer of the fungicide vinclozolin from treated to untreated plants via volatilization

Head lettuce plantlets (Lactuca sativa L. var. capitata) were potted, treated with vinclozolin at the six-leaf stage according to application standards and allowed to dry for 24 h. The potted plantlets were then placed in either growth chambers with controlled temperature (20 and 25 degrees C, respectively) or in a greenhouse (approximately 12 degrees C), together with untreated spinach (Spinacia oleracea L.) and standardized grass cultures (Lolium multiflorum Lam. ssp.) While the treated lettuce pots remained in the respective growing compartments until the end of the experiments, spinach and grass were exposed to the compartment air for 24 h and their shoot material was analyzed for vinclozolin by GC-ECD and GC-high resolution mass spectrometry. Exposure and analysis of untreated spinach and grass were carried out at two- or three-day intervals during the course of the experiments. Also, air samples were taken from the compartments at intervals and analyzed for vinclozolin. Maximum vinclozolin concentration in the growth chamber air was about 330 ng m(-3) while vinclozolin contamination of the untreated plants ranged from 50 to 200 microg kg(-1) FW (fresh weight). In the greenhouse atmospheric vinclozolin concentration reached approximately 15 ngm(-3) and maximum contamination of spinach and grass were 30-40 microg kg(-1) FW. Our data clearly show that unintended contamination of plants growing in the vicinity of vinclozolin-treated plants can occur even if the fungicide layer is completely dry. Implications for safety testing and food plants are discussed.     

Different stabilities of multiwalled carbon nanotubes in fresh surface water samples

The stability of multiwalled carbon nanotubes (MWNTs) in particulate aggregates and surfactant-facilitated suspensions after being mixed into eight types of fresh surface water samples was investigated. MWNTs in particulate aggregates could not be stabilized in any of the water samples except for the one having relatively high content of dissolved organic matter with the aid of sonication. Sodium dodecyl benzenesulfonate (SDBS), polyethylene glycol octylphenyl ether (TX100) and cetyltrimethyl ammonium bromide (CTAB) were used to prepare MWNT suspensions. SDBS- and TX100-stabilized MWNTs could partly remain suspending after being mixed into the water samples, whereas CTAB-stabilized MWNTs readily sedimentated due to the surface charge neutralization by the surface water contained negatively-charged anions and colloids. This is a first systematic study examining the stability of carbon nanotubes in natural surface waters, the results from which will be useful for understanding the transport, fate and ecological effect of carbon nanotubes in the aqueous environment.     

Changes in mutagenicity during biodegradation of fenitrothion

In order to investigate changes in the mutagenicity of fenitrothion during its biodegradation in solution, measurements were conducted at intervals in batch cultures incubated under anaerobic or aerobic conditions. Fenitrothion-degrading bacteria were obtained from a green onion field on the west side of Gifu University, Japan. Fenitrothion was almost completely decomposed by day 12 under both types of incubation condition. The indirect mutagenicity of the solution to strains YG1029 and YG1042, however, increased markedly during anaerobic biodegradation. The increase in mutagenicity was partially due to amino-fenitrothion, a metabolite formed during anaerobic biodegradation of fenitrothion.     

Mutagenicity of anaerobic fenitrothion metabolites after aerobic biodegradation

Previous studies have revealed that the mutagenicity of fenitrothion increases during anaerobic biodegradation, suggesting that this insecticide's mutagenicity could effectively increase after it pollutes anaerobic environments such as lake sediments. To investigate possible changes to the mutagenicity of fenitrothion under aerobic conditions after it had already been increased by anaerobic biodegradation, batch incubation cultures were maintained under aerobic conditions. The mutagenicity, which had increased during anaerobic biodegradation, decreased under aerobic conditions with aerobic or facultative bacteria, but did not disappear completely in 22 days. In contrast, it did not change under aerobic conditions without bacteria or under continued anaerobic conditions. These observations suggest that the mutagenicity of anaerobically metabolized fenitrothion would not necessarily decrease after it arrives in an aerobic environment: this would depend on the presence of suitable bacteria. Therefore, fenitrothion-derived mutagenic compounds may pollute the water environment, including our drinking water sources, after accidental pollution of aerobic waters. Although amino-fenitrothion generated during anaerobic biodegradation of fenitrothion was the principal mutagen, non-trivial contributions of other, unidentified metabolites to the mutagenicity were also observed.     

Perceptions of the sustainable city and implications for fresh water resources management

Following the emergence of sustainable development as a key environmental management concept in the late 1980s, much discussion and debate has occurred on how the general concept can be understood in the context of particular resources, economic sectors and fields of academic study. This paper attempts to integrate two such particular areas of study, urban development and fresh water resources management. Following an overview of the concept of sustainable development, where the fresh water resource base is used to illustrate different interpretations of sustainability, the paper advances a number of perceptions of the sustainable city and the implications for fresh water management. Key concepts that emerge include a need to reduce the urban ecological sphere of influence, best understood in the context of a quasi-autonomous vision of the sustainable city, requiring a radical shift away from 'engineering-fix' water supply augmentation towards demand management and other approaches that sit more easily with the prime need to maintain the functional integrity of ecosystems.     

Changes in water quality after addition of sea salts to fresh water: implications during toxicity testing

Sea salts (seven brands from six commercially-available sources) were dissolved in water to develop 30 g/l solutions, and selected water quality characteristics were then monitored for 96 h. One or more water quality characteristics changed significantly during the 96 h period in six of the reconstituted sea salts. Measured characteristics of sea water diluted to 30 g/l demonstrated no changes during the observation period. The sea salts from different sources also demonstrated differences in absolute concentrations of some characteristics measured. Application of the Biotic Ligand Model to predict copper toxicity to the bivalve Mytilus edulis in solutions of the salts tested yielded 96-h median-lethal concentrations that ranged from 2 to 13 μg/l. Since water quality affects toxicity of many environmental pollutants, the source of the sea salt and equilibration time should be considered when planning toxicity tests.     

表面活性剂对动态水体中对氯硝基苯挥发的影响

研究了在表面活性剂聚氧乙烯失水三梨酸醇(Tween20)、十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)和氯代十六烷吡啶(CPC)存在下,搅拌对水体中对氯硝基苯挥发行为影响的规律及机制.结果表明,水体的搅拌速度对对氯硝基苯的挥发行为有着显著的影响,表面活性剂的存在降低了对氯硝基苯的液膜/液相分配比,增大了传质阻力而抑制了对氯硝基苯的挥发,其抑制挥发的能力由表面活性剂的浓度和性质决定.从质量浓度看,抑制对氯硝基苯挥发的能力大小顺序为Tween20＞SDS＞SDBS＞CPC,从临界胶束浓度(CMC)倍数看,抑制对氯硝基苯挥发的能力大小顺序为SDS＞SDBS＞Tween20＞CPC.