Assessment of the environmental fate and effects of the PPARgamma receptor agonist, pioglitazone

The environmental fate and effects of pioglitazone prescribed for the treatment of type 2 diabetes were evaluated in an environmental risk assessment following the European Medicines Agency (EMA) "Guideline on the Environmental Risk Assessment of Medicinal Products for Human Use"; EMEA/CHMP/SWP/4447/00. A predicted environment concentration (PEC) for surface water was estimated at 0.023μgL(-1), (action limit of 0.01μgL(-1)) triggering a comprehensive battery of laboratory evaluations. Pioglitazone and its major metabolites were determined not to significantly adsorb to sewage solids, were not persistent in the aquatic environment, did not bioaccumulate and were non-toxic to aquatic organisms. Pioglitazone does not pose an unacceptable risk to groundwater supplies, with concentrations not anticipated to be a risk to aquatic organisms or human drinking water supplies. Pioglitazone does not pose a risk of secondary poisoning.     

Evaluating the environmental fate of atrazine in France

Atrazine is used in large quantities in U.S. and European countries as a weed-control agent. As a result, numerous data on its environmental fate and hazards have been published. Analysis of the literature shows that this herbicide can be found with appreciable concentrations in groundwaters, rivers, lakes, and estuaries. This contamination principally results from leaching and runoff processes. Atrazine can also pollute fog and rain due to its release into the atmosphere through spray applications. This large amount of information constitutes a very attractive basis for assessing the simulation performances of environmental fate models. In this context, CHEMFRANCE, a regional fugacity model level III which calculates the environmental distribution of organic chemicals in twelve defined regions of France has been used to estimate the environmental fate of atrazine. The calculated values are comparable with field and laboratory results. Therefore, CHEMFRANCE can be considered as a useful tool for simulating the environmental fate of this agrochemical.     

Evaluating the environmental fate of lindane in France

Lindane, a highly persistent and lipophilic pesticide, is still used in large quantities. This chemical can be found with appreciable concentrations in biota, atmosphere, and in other environmental compartments in the adsorbed form. This information provided a basis for assessing the simulation performances of CHEMFRANCE, a regional level III fugacity model allowing to generate environmental behavior profile of organic chemicals in France. The comparison between the estimated environmental fate and field and laboratory observations suggests that this fugacity model can be used to determine the processes that control the environmental fate of lindane in France. CHEMFRANCE also provides accurate estimates of environmental compartment contaminations.     

An approach for the prediction of environmental distribution and fate of cypermethin

Some of the essential aspects of the environmental distribution and fate of cypermethrin (a synthetic pyrethroid insecticide) are evaluated by means of theoretical calculations of the equilibrium partitioning among the principal environmental media and by laboratory experiments in simulation chambers.     

Assessment of the fate of sulfur dioxide from a point source

A simplified plume transport model is adopted to assess reaction and scavenging processes. Experimental data on the conversion rate of SO₂ to SO₄²⁻ and the uptake rates by vegetation and soil are used to calculate the relative importance of the various fates of sulfur dioxide. Meteorological parameters include wind speed, day and night mixing heights, night diffusion above the mixing height and plume dispersion angle. Other parameters considered are length of day and night, region, season, type of canopy, and emission rate of SO₂ from a point source.     

Organophosphate and organophosphorothionate esters: Application of linear free energy relationships to estimate hydrolysis rate constants for use in environmental fate assessment

Hydrolysis rate constants required for assessing the environmental fate of certain organophosphate and organophosphorothionate esters may be estimated by use of linear free energy relationships (LFERs). LFERs for the second-order alkaline hydrolysis rate constants and the pKa of the conjugate acid of the leaving groups were established for 0,0-dimethyl- and 0,0-diethyl-0-substituted phosphates and phosphorothionates. Also, the second-order alkaline hydrolysis rate constants of selected triaryl phosphates were correlated with the Hammett-sigma constants. Existing LFERs for diaryl phosphate ester anions along with monoaryl phosphate ester mono- and dianions were used to predict hydrolytic half-lives under reaction conditions that are characteristic of aquatic environments.     

The fate of linear alcohol ethoxylates during activated sludge sewage treatment

Model continuous activated sludge (CAS) plants (Husmann units) were used to study the fate of two commercial, alcohol ethoxylate (AE) surfactants during aerobic sewage treatment. The surfactants were produced by the ethoxylation of an essentially linear C(12-15) alcohol (NEODOL 25) with an average of 7 (C(12-15)EO7) or 3 (C(12-15)EO3) moles of ethylene oxide (EO). Recent analytical developments made it possible to measure levels of AE that included the free alcohol and EO1 oligomers across the CAS system, from the influent feed, on the activated sludge, through to the effluent. Measured concentrations of AE (as C(12-15)EO(0-20)) in the synthetic sewage feeds to the test CAS plants lay in the range 11-13 mg/l. During stable operation at 20 degrees C, an average of 5 microg/l AE were present in the C(12-15)EO7 CAS plant effluent, giving a removal (bioelimination) of >99.9%. When levels of AE on the sludge, and polyethylene glycols (PEGs--an expected biodegradation intermediate) in the effluent and on the sludge were also taken into account, biodegradation was considered to be responsible for >98.7% of the observed removal. During operation at a winter temperature (10 degrees C), an average of 26 microg/l AE were present in the C(12-15)EO7 CAS plant effluent, giving a removal of 99.8%. Biodegradation was estimated to be responsible for >97.2% of the observed removal. During operation at 20 degrees C, an average of 7 microg/l AE were present in the C(12-15)EO3 CAS plant effluent, giving a removal of >99.9%. No analysis for PEG was performed in this case but the low level of AE on the sludge (0.2 mg/g dry solids) suggested that biodegradation was responsible for most of the observed removal. Neither surfactant had any adverse effect on the sewage treatment efficiencies of the CAS plants in terms of dissolved organic carbon (DOC) removal, nitrification or biomass levels.     

自然生态系统中含硫气体的产生机理与环境归趋

基于当前可获得的与该课题相关的资料 ,本文综述了陆地生态系统产生挥发性含硫气体的微观和宏观机理过程。讨论了控制生物硫气体产生的环境因素。阐述了含硫气体释放进入大气后的环境归趋     

An assessment of the environmental fate and exposure of benzene and the chlorobenzenes in Canada

Systematic modelling of the fate of benzene and the chlorobenzenes is presented which follows a four-stage process of chemical classification, quantifying discharge rates and environmental concentrations, evaluative assessment of fate and regional mass balance modelling has been carried out for the southern Ontario region. The EQC model was applied to determine the principal transport and transformation processes experienced by this group of chemicals, which vary considerably in volatility and hydrophobicity. Observed environmental concentrations are in satisfactory agreement with the predictions of the steady state Level III ChemCAN model of chemical fate. A multiple pathway human exposure model which estimates intake of contaminants by residents of southern Ontario has been developed and applied to these chemicals. A novel method of deducing maximum tolerable environmental concentrations is presented. Results suggest that benzene and 1,4-dichlorobenzene are present in the environment at levels sufficient to cause exposures near allowable daily intake (ADI) levels for the general population, but the other substances are present at levels which result in exposure ranging from 1/10 to 1/1000 of the ADI.     

Evaluation of aquatic environmental fate of 2,4,6-trichlorophenol with a mathematical model

A mathematical model, Simplified Approach for Fate Evaluation of Chemicals in Aquatic Systems (SAFECAS), was applied to evaluate fate of 2,4,6-trichlorophenol(TCP) in three types of aquatic environments; a river, an oligotrophic lake, and an eutrophic lake.Since phenols are dissociative substances, equilibrium constants and rate constants for transfer and transformation processes were measured or estimated as a function of pH.Results suggest that most of TCP is distributed to the water phase in aquatic environments, and is almost removed by the advective outflow in the river and by the photodegradation in lakes.     

Assessment of the environmental persistence and long-range transport of endosulfan

Concentrations of the insecticide endosulfan (α- and β-isomer) and its degradation product endosulfan sulfate in air, seawater and soil are calculated with the global environmental fate model CliMoChem. As model input, physicochemical properties of all three compounds were assembled and a latitudinally and temporally resolved emission inventory was generated. For concentrations in air, model and measurements are in good agreement; a bimodal seasonality with two peaks in spring and fall as it is observed in Arctic air is reproduced by the model. For seawater, the agreement of model and measurements depends on the values of the hydrolysis activation energy of endosulfan used in the model; with relatively high values around 100 kJ/mol, model results match field data well. The results of this assessment of the levels, persistence, and global distribution of endosulfan are also relevant for the evaluation of endosulfan as a Persistent Organic Pollutant under the Stockholm Convention.     

Enzymatic and microbial transformation assays for the evaluation of the environmental fate of diclofenac and its metabolites

Diclofenac has been of environmental concern due to the potential harmful effects on non-target organisms at environmentally relevant concentrations. In this study, we evaluated the transformation kinetics of diclofenac and its two major metabolites in two laboratory-scale experiments: the transformation of diclofenac in the presence of rat liver S9 fraction with co-factors, and the transformation of diclofenac, 4′-hydroxy-diclofenac and diclofenac β-O-acyl glucuronide in the inoculum used for the OECD 301C ready-biodegradability test. 4′-Hydroxy-diclofenac was identified as the major phase I metabolite and diclofenac β-O-acyl glucuronide was identified as the major phase II metabolite in the S9 assay. Transformation of diclofenac in the microbial degradation test did not occur significantly for 28 d, whereas 4′-hydroxy-diclofenac degraded slowly, indicating that the biological removal of diclofenac is not likely to occur in conventional STPs unless sorptive removal is significant. However, diclofenac β-O-acyl glucuronide deconjugated to form equimolar diclofenac within 7 d, in the microbial degradation test. The mixture of diclofenac and its two metabolites, formed after incubating diclofenac in S9 medium for 2 h, was spiked in the inoculum to link both assays. The concentrations of diclofenac and its metabolites, measured over time, agreed well with predicted values, using rate parameters obtained from independent experiments. The results show that phase II metabolites generated in mammals may deconjugate easily in conventional STPs to form a parent compound and that these processes should be considered during the environmental monitoring and risk assessment of diclofenac.     

Bioavailability assessment and environmental fate of polycyclic aromatic hydrocarbons in biostimulated creosote-contaminated soil

When hydrocarbon-contaminated soil is subjected to bioremediation technology, hydrocarbon depletion is typically marked by an initially rapid reduction rate. This rate decreases over time and frequently a residual concentration remains in the soil. This kinetic has been attributed primarily to the enrichment of more recalcitrant fractions, as well as to the lack of resting hydrocarbon bioavailability. Thus, at the end of the bioremediation process, a part of the residual hydrocarbon soil concentration represents the non-bioavailable fraction, which is difficult to degrade by microbial populations and which poses a minor hazard. Therefore, determination of the bioavailable fraction in a bioremediation project represents both an estimation of the maximum level of achievable biodegradation, as well as an additional indication of the environmental health hazard. In the present study, aged creosote-contaminated soil was subjected to biostimulation processes, and the bioavailable fraction for several target polycyclic aromatic hydrocarbons (PAHs) was calculated using a mild extraction with cyclodextrines. The amount of PAH extracted corresponded to the desorbing fraction and can be regarded as the bioavailable fraction. The non-desorbing fraction data obtained from this procedure were compared to the remaining PAH concentrations following bioremediation treatment of soil microcosms. These results permitted the establishment of a theoretical biodegradation limit based on the desorbing fraction. In addition, neither accumulation of intermediate metabolites, nor the formation of bound-residues or reduced acute toxicity was observed.     

Degradation half-life times of PCDDs, PCDFs and PCBs for environmental fate modeling

Literature search of the knowledge on the degradation of persistent organic pollutants (POPs) in environmental compartments air, water, soil and sediment was done in purpose to find properties of POPs of interest for modeling. One degradation process, hydrolysis (chemical degradation), was omitted as negligibly slow for POPs studied. The other two, photolysis and biodegradation processes, were considered separately in purpose to develop estimation procedures. The estimates can be given as pseudo first-order rate constants kP for photolysis and kB for biodegradation. For each compartment, an overall degradation rate is k(tot) = kP + kB and lifetime t(1/2) = ln 2/k(tot). The latter values, lifetimes in each compartment, will be used as input parameters to the Baltic Sea model.     

Assessing the environmental fate of chemicals of emerging concern: a case study of the polybrominated diphenyl ethers

It is suggested that assessments of chemicals of emerging concern can be rationally structured around a multistage process in which fate and risk are evaluated with increasing accuracy as new data become available. An initial tentative and approximate assessment of fate and risk can identify key data gaps and justify and direct further investigations, which progressively improve the reliability of the assessment. This approach is demonstrated for a class of chemicals, the polybrominated diphenyl ethers (PBDEs), which is of increasing concern, but about which there is presently a lack of comprehensive data on properties, sources, fate and effects. Specifically, 20 PBDE congeners are investigated using the suggested approach and research needs are identified.     

Assessment of environmental impact zones in the Kola Peninsula forest ecosystems

This paper describes the condition of forest ecosystems subjected to smelter pollution in the Kola peninsula. This assessment is based on the parameters of the biogeochemical cycle. The defoliation index was used to delimit three basic forest states: background, defoliating, sparse. Close to the smelter, due to expansion of the area not covered by vegetation, a fourth type of state, so-called "industrial deserts", has been observed. The concentrations of sulphur, copper and nickel in the precipitation in the forests generally declined with distance from the smelter. The defoliating forests are noted for the highest Ca, Mg, K concentrations in the summer precipitation. In sparse forests and industrial deserts a decrease in the Ca, Mg, K concentrations in the summer precipitation in comparison with the defoliating forests, despite the particle emissions, could be attributed to the reduction in forest biomass. The higher levels of soil and soil leachate carbon and acidity in the defoliating forests was due to higher litterfall and to the higher dissolution of fulvic acids by the acidic precipitation. This increase in organic matter levels affects soil cation exchange capacity and cation saturation. The pine trees demonstrated significant changes in the uptake of elements in all types of forests under pollution. Elevated levels of S, Ni, Cu and K and reduced levels of Mg, Mn and Zn were found in the needles of different age classes.     

The environmental fate of the primary degradation products of alkylphenol ethoxylate surfactants in recycled paper sludge.

Alkylphenol ethoxylates (APEOs) are a group of non-ionic surfactants that are degraded microbially into more lipophilic degradation products with estrogenic potential, including nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), octylphenol (4-tOP) and nonylphenol (4-NP). Nonylphenol ethoxylates are used in paper recycling plants for de-inking paper and have the potential to be released into the environment through spreading of wastewater treatment sludge for soil amendment. Three samples of recycled paper sludge were collected from farmers' fields and analyzed for concentrations of NP1EO, NP2EO, 4-NP and 4-tOP. Each sample differed in the amount of time elapsed since the sludge was placed on farmers' fields. Primary degradation products of APEOs were present at low micrograms/g concentrations in the sludge samples. Differences in the concentrations of these analytes in sludge samples indicated that APEO concentrations declined by 84% over a period of 14 weeks on farmers' fields. Changes in the chromatographic patterns of acetylated 4-NP indicated that there is a group of recalcitrant nonylphenol isomers that degrades more slowly than other isomers. These data indicate that microbial degradation may reduce the risk of environmental contamination by these compounds, but more work is required to assess the toxic potential of APEOs in sludges used for soil amendment.     

An environmental fate, exposure and risk assessment of ethylene oxide from diffuse emissions

Ethylene oxide (EO) is mainly used as a chemical intermediate and as a fumigant and sterilizing agent. Through its manufacturing and intended uses, EO may be released into the environment. Therefore, an assessment of the environmental significance of those potential emissions was conducted. Data were collected describing pertinent physical properties, degradation and other loss mechanisms that control the fate of EO in the environment. Available aquatic and terrestrial ecotoxicity data were assembled and used as the basis of calculating critical toxicity values to characterize hazard. Environmental compartment concentrations of EO were calculated using Level III fugacity-based modeling. Six scenarios were developed to account for different climatic conditions in various portions of the US. Finally, potential regional-scale risks to aquatic and terrestrial wildlife were determined. In the conceptual model that was developed in this assessment, EO diffuses into air, partitions between environmental compartments, is transported out of the different compartments via advection, and undergoes abiotic and biological degradation within each compartment. All known emissions within the continental USA were assumed to enter a modeled region roughly the size of the State of Ohio. Organisms (receptors) were assumed to dwell in both terrestrial and aquatic compartments. Receptors were assumed to include small mammals, soil invertebrates, water column (pelagic) organisms, and sediment benthos. The goal of this assessment was to characterize any potential adverse risks to terrestrial and aquatic wildlife populations. Hazard Quotients (HQ) were calculated by dividing predicted concentrations of EO in air, water, sediment, and soil by their critical toxicity values. Maximum calculated HQ values in air were 1.52x10(-7), in water were 1.17x10(-5), in sediment were 2.25x10(-4), and in soil were 1.37x10(-5). The results of this assessment suggest that EO as currently manufactured and used does not pose adverse risks to aquatic or terrestrial wildlife. In all cases, the HQ values were much less than the maximum desired HQ value of 1.0 (4,400-6,600,000 times), indicating that the potential for diffuse emissions of EO to pose adverse environmental risks is quite low.