Measurements and analyses of nitrogen oxides and ozone in the yard and on the roof of a street-canyon in Suzhou

The concentrations of air pollutants such as nitrogen oxides and ozone characterised by very fast chemical reactions can significantly vary within urban street-canyon due to the short distances between sources and receptor. With the primary objective to analyse this issue, NO, NO₂, NO_x, O₃, BTX, and wind flow field were continuously measured for 1 week at two heights (a street-level yard and a 25-m-high rooftop) in an urban canyon in Suzhou (China). The yard ozone concentrations were found to be up to six times lower than on the roof. Different frequency distributions (FD), dynamical and chemical processes of the pollutant variations from yard to roof are discussed to explain the findings. The predominant factors for the dissimilar pollutant vertical diffusion at the two measurement locations were associated to dissimilar fluid-dynamic and heterogeneous removal effects that likely induced dissimilar ozone chemical processes relative to NO_x and BTX precursors.     

Evaluating the effect of age and area of residence in the metal and metalloid contents in human hair and urban topsoils

Monitoring the levels of trace elements in hair can allow estimating the effects of the geographical location and also can provide a notion of the metal body burden. However, the use of human hair is controversial due to the different confounding factors that could affect the presence of trace elements in hair. As a result, a comprehensive monitoring study was performed in Alcalá de Henares, one of the major cities in the Madrid region, Spain. Trace elements have been monitored in urban topsoils and in human hair of two well-defined and healthy groups of population: children (6–9 years) and adolescents (13–16 years). The city was divided into four areas or zones with different characteristics to assess the possible effect of area of residence and age in the presence of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Pb, Sn, Ti, Tl and Zn in soils and hair. There is no current hypothesis that explains the possible effect of the area of monitoring in the distribution of Be, Cr, Ni, Sn and Ti found in these urban soils, maybe because urban soils receive high disturbance, and there are many factors involved. The presence of most of the trace elements monitored was significantly higher in the hair of the children population, except for Sn and Zn. This could be attributed mainly to dietary habits. Other factors influencing metal content in hair such as environmental factors would have had a minimal effect in the population groups here studied. Finally, none of the levels of trace elements studied in hair were significantly correlated with levels measured in the topsoils of public parks in Alcalá de Henares, with the exception of Pb in adolescent participants.     

Trends in the occurrence of human and veterinary antibiotics in the sediments of the Yellow River, Hai River and Liao River in northern China

The occurrence of four classes of 17 commonly used antibiotics (including fluoroquinolones, tetracycline, sulfonamides, and macrolides) was investigated in the sediments of the Yellow River, Hai River and Liao River in northern China by using rapid resolution liquid chromatography-tandem mass spectrometry. Higher concentrations were detected for most antibiotics in the sediments of the Hai River than in the sediments of the other rivers. Norfloxacin, ofloxacin, ciprofloxacin and oxytetracycline in the three rivers were most frequently detected with concentrations up to 5770, 1290, 653 and 652 ng/g, respectively. High frequencies and concentrations of the detected antibiotics were often found in the downstream of large cities and areas influenced by feedlot and fish ponds. Good fitted linear regression equations between antibiotic concentration and sediment physicochemical properties (TOC, texture and pH) were also found, indicating that sediment properties are important factors influencing the distribution of antibiotics in the sediment of rivers.     

Absorption and metabolism of the chiral isomers of fonofos in the corn and cotton plant

Root absorption of chiral phenyl-35S-fonofos in cotton and corn plants revealed stereoselective differences between the two enantiomers. (S)p-Fonofos was absorbed at a faster initial rate and to a greater extent than the (R)p enantiomer in both plant species. Approximately 40% and 62% of the applied radioactivity was absorbed into the cotton plant 12 hr after application of (R)p- and (S)p-fonofos, respectively. In the corn plant, approximately 25% and 63% of the applied (R)p- and (S)p-fonofos was absorbed in the first 12 hrs. Little qualitative or quantitative difference in plant translocation between fonofos enantiomers was observed. (R)p-fonofos was found to be metabolized to a greater extent than the (S)p enantiomer in both cotton and corn plants.     

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.     

Implication of organic acids in the long-distance transport and the accumulation of lead in Sesuvium portulacastrum and Brassica juncea

The implication of organic acids in Pb translocation was studied in two species varying in shoot lead accumulation, Sesuvium portulacastrum and Brassica juncea. Citric, fumaric, malic and α-cetoglutaric acids were separated and determined by HPLC technique in shoots, roots and xylem saps of the both species grown in nutrient solutions added with 200 and 400 μM of Pb(II). The lead content of the xylem saps was determined by ICP–MS. Results showed that S. portulacastrum is more tolerant to Pb than B. juncea. Lead concentration in xylem sap of the S. portulacastrum was significantly greater than in that of B. juncea. For both species, a positive correlation was established between lead and citrate concentrations in xylem sap. However minor relationship was observed for fumaric, malic and α-cetoglutaric acids. In the shoots lead treatment also induced a significant increase in citric acid concentration. Both observations suggest the implication of citric acid in lead translocation and shoot accumulation in S. portulacastrum and B. juncea. The relatively high accumulation of citric acid in xylem sap and shoot of S. portulacastrum could explain its high potential to translocate and accumulate this metal in shoot suggesting their possible use to remediate Pb polluted soils.     

Involvement of glutathione in the reduction of captan-induced in vivo inhibition of monooxygenases and liver toxicity in the rat

If given orally captan is relatively nontoxic, but it can be extremely toxic after parenteral exposure. Therefore, a single i.p. dose of captan (20 mg/kg) was given to male Sprague-Dawley rats and its effect on liver microsomal mixed function oxidases and certain serum enzymes (SDH, SGPT and SGOT) was studied. The single dose of captan caused marked depression of microsomal cytochrome P-450 and the activity of benzphetamine N-demethylase and aniline hydroxylase, and moderate elevation of the serum enzymes indicative of liver damage. However, reduced glutathione (100 mg/kg, i.p.) given prior to captan, appears to decrease the liver toxicity as measured by reduced inhibition of the microsomal enzymes and elevation of serum enzymes activity. The results suggest that glutathione and other compounds containing sulfhydryl groups may protect the subjects from captan-induced liver toxicity.     

Photodegradation of the herbicide EPTC and the safener dichlormid, alone and in combination

Photodegradation of the herbicide EPTC (S-ethyl-N, N-dipropylthiocarbamate), and the safener dichlormid (2,2-dichloro-N, N-diallylacetamide) has been examined in methanol and in water solutions. Irradiation of EPTC and dichlormid with UV light at 254 nm caused rapid degradation in both media. Remarkable and gradual changes in color of EPTC irradiated solution was observed from clear to yellow then to intense orange. EPTC half-life of elimination in water was 14.0, and 18.5 min, and in methanol 37.2 and 32.2 min, when irradiated with and without dichlormid, respectively. There was significant difference between rate of EPTC degradation in water and methanol in the presence or in the absence of dichlormid. Negligible degradation of EPTC or dichlormid at > 290 nm was observed. Photoproducts were separated and identified using GC or/and thin-layer chromatography then identified using mass spectrometry. It appeared that some products have high molecular weight that formed as a result of dimerization. This is possibly a result of the coupling of radicals that formed through EPTC degradation. The cleavage of C-S and C-N bonds accounted for the formation of these radicals. Gradual dealkylation of the acid chains of EPTC has also occurred. EPTC-sulfoxide, EPTC-sulfone, Propylamine and dipropylamine were detected as photoproducts of EPTC at 254 nm. Dichlormid pathways of degradation at 254 nm were characterized as dechlorination, dealkylation, and hydrolysis both in water and methanol. The findings showed that dichlormid did not significantly affect EPTC photodegradation either at 254 nm or at > 290 nm. The biological/toxicological properties of the photoproducts need further study, particularly the dimer compounds.     

Effect of the temperature and the exclusion of UVB radiation on the phenolics and iridoids in Menyanthes trifoliata L. leaves in the subarctic

The long-term effects of UVB exclusion and temperature on the methanol extractable (ME) phenolics (flavonoids, phenolic acids) and iridoids of Menyanthes trifoliata L. (Mt) leaves were studied in northern Finland (68°N) using wooden frames covered with filters for UVB exclusion (polyester filter), control (cellulose acetate filter) and ambient (no filter) conditions. Analysis of ambient plots showed no effect of the daily mean temperature (2σ = 1.58 °C) on the leaf ME compound content and composition, but minimum temperatures decreased the flavonol content. UVB exclusion did not affect the total ME compound content but significantly decreased the proportion of flavonols concomitantly with an increase in iridoids. Due to its high iridoid content, Mt appears as an interesting model plant for studying the iridoid biosynthesis and its regulation under stress conditions.     

A strategy for the assessment of continuous and pulsed contaminants in river and estuary ecosystems in the Arctic

A transfer of contaminants from the land through the rivers forms a significant part of the Arctic seas' pollution. A whole ecosystem is the target of this harmful action. The response of the ecosystem can be considered as the measure of the impact. To assess this impact we designed a mathematical approach based on the Liebig-Shelford law of tolerance, the "narrow path" principle and the Shannon index of diversity to evaluate a prosperity function and a comprehensive risk index for a river or estuary ecosystem. To illustrate this general approach we consider the propagation of the pollutant along the river bed after (1) continuous and (2) pulsed release of a pollutant. The results of calculations show good correspondence with the actual behaviour of natural ecosystems. Further studies are necessary to find out the actual values of the parameters for different pollutants.     

Outdoor air pollution exposure and the risk of asthma and wheezing in the offspring

Environmental Science and Pollution Research - According to the “fetal origin of disease” hypothesis, air pollution exposure in pregnancy may play an important role in stimulating the...     

Organochlorines in different fractions of sediments and in different planktonic compartments of the Belgian continental shelf and the Scheldt estuary

PCB levels in sediments (bulk and fraction <63 microm), suspended matter and zooplankton from the Belgian continental shelf of the North Sea and the Scheldt estuary were evaluated in relation to their organic carbon content, their lipid content and, for sediments, their particle size distribution. PCB accumulation mechanisms are discussed, considering the importance of direct contamination (adsorption onto the cell surfaces, absorption through the cell walls and partitioning into the cell lipids) for suspended matter and sediments, and of indirect contamination through the food for zooplankton. Geographical and seasonal variations are described.     

17 β-estradiol mineralization in human waste products and soil in the presence and the absence of antimicrobials

Natural steroidal estrogens, such as 17 β-estradiol (E2), as well as antimicrobials such as doxycycline and norfloxacin, are excreted by humans and hence detected in sewage sludge and biosolid. The disposal of human waste products on agricultural land results in estrogens and antibiotics being detected as mixtures in soils. The objective of this study was to examine microbial respiration and E2 mineralization in sewage sludge, biosolid, and soil in the presence and the absence of doxycycline and norfloxacin. The antimicrobials were applied to the media either alone or in combination at total rates of 4 and 40 mg kg^?1, with the 4 mg kg^?1 rate being an environmentally relevant concentration. The calculated time that half of the applied E2 was mineralized ranged from 294 to 418 days in sewage sludge, from 721 to 869 days in soil, and from 2,258 to 14,146 days in biosolid. E2 mineralization followed first-order and the presence of antimicrobials had no significant effect on mineralization half-lives, except for some antimicrobial applications to the human waste products. At 189 day, total E2 mineralization was significantly greater in sewage sludge (38 ±0.7%) > soil (23 ±0.7%) > biosolid (3 ±0.7%), while total respiration was significantly greater in biosolid (1,258 mg CO₂) > sewage sludge (253 mg CO₂) ≥ soil (131 mg CO₂). Strong sorption of E2 to the organic fraction in biosolid may have resulted in reduced E2 mineralization despite the high microbial activity in this media. Total E2 mineralization at 189 day was not significantly influenced by the presence of doxycycline and/or norfloxacin in the media. Antimicrobial additions also did not significantly influence total respiration in media, except that total CO₂ respiration at 189 day was significantly greater for biosolid with 40 mg kg^?1 doxycycline added, relative to biosolid without antimicrobials. We conclude that it is unlikely for doxycycline and norfloxacin, or their mixtures, to have a significant effect on E2 mineralization in human waste products and soil. However, the potential for E2 to be persistent in biosolids, with and without the presence of antimicrobials, is posing a challenge for biosolid disposal to agricultural lands.     

A review of particle formation events and growth in the atmosphere in the various environments and discussion of mechanistic implications

This review highlights recent observations from a large number of studies investigating formation and growth within different environments and discusses the importance of various mechanisms of particle formation and growth between the different environments. Whilst, several mechanisms for new particle formation which proposed the importance of each mechanism are still the centre of much debate. Proposed nucleation mechanisms include condensation of a binary mixture of sulphuric acid and water; ternary nucleation of sulphuric acid, water and a third molecule, most likely ammonia; ion-induced nucleation; secondary organic aerosol formation involving condensation of low- or non-volatile organic compounds and homogeneous nucleation of iodine oxides. Laboratory and modelling studies have shown these mechanisms can occur in the atmosphere although the contribution depends on the concentrations of precursor compounds present. In addition, atmospheric particle formation events are significantly affected by environmental factors, such as temperature, humidity and the surface area of pre-existing particles, which is also discussed here. One major problem hampering our current understanding is that these new particles are smaller than the lower size detection limit of most instruments and are only observed after some particle growth has occurred.Particles growth occurs through condensation of supersaturated vapours on the surface of the nucleated particles. This requires a lower degree of supersaturation than nucleation and thus condensation of the nucleating species reduces the rate of particle formation. Therefore, it is believed that particle growth often occurs through the condensation of other gases, including organic and inorganic compounds, than those responsible for nucleation. This decoupling of nucleation and growth means that the individual gases responsible for nucleation and growth can be unclear.Since observations of particle formation only occur following growth to observable sizes it is possible that a pool of undetectable particles exist at all times but are only observed following significant condensational growth.     

On the possible role of the biosphere in the control of atmospheric clouds and precipitation

It is well documented that atmospheric sulfate particles constitute the major class of cloud condensation nuclei. Under natural conditions, not disturbed by human activities, sulfate particles form from gaseous precursors released by the biosphere. In this way the biosphere plays an important role in the control of the cloud cover and consequently of the albedo of the Earth-atmosphere system. On the other hand, cloud condensation nuclei of biospheric origin make the redistribution of water on the Earth surface possible which is of crucial importance for the existence of living species.     

Excretion and toxicity of Cyolane in the rat

The excretion of ¹⁴C-labelled Cyolane, 24 hours after single oral application was found to be about 50% of the applied dose in urine, faeces and expired air.The activity of Acetylcholine esterase in brain, plasma and erythrocytes, and liver succinate dehydrogenase was studied for 16 weeks in 4 groups of rats after repeated orally daily doses of Cyolane, 0.9, 0.45, 0.09 and 0.045 mg/kg.It has been found that at all the dose levels there were cumulative inhibition effects in brain and blood choline esterase and liver succinate dehydrogenase till the 2nd week and then there was a recovery at low dose rates in blood choline esterase and liver succinate dehydrogenase activities. After 6 - 16 weeks the effects were nearly compensated. At higher doses almost all the rats died after 6 weeks due to the insecticide toxicity.     

Levels of ²¹⁰Po and ²¹⁰Pb in fish and molluscs in Slovenia and the related dose assessment to the population

²¹⁰Po and ²¹⁰Pb activity concentrations in fish from the Slovenian part of Adriatic Sea, in the vicinity of a former uranium mine at ?irovski vrh and from the Slovenian market were determined. In addition, ²¹⁰Po and ²¹⁰Pb activity concentrations in squid from the Slovenian market and in mussels from the Slovenian part of the Adriatic Sea were also determined. Fish, squid and mussel consumption in Slovenia was assessed from the data available from Eurostat and Food and Agriculture Organisation (FAO) and the data used for the corresponding dose calculation. Fish species with the highest activity concentrations were grilled to assess possible loss of ²¹⁰Po during the food preparation process. Samples were freeze dried and radiochemical separation of ²¹⁰Po and ²¹⁰Pb was performed. Measurements of ²¹⁰Po were performed by alpha spectrometry and ²¹⁰Pb by a low background gas-flow proportional counter. ²¹⁰Po activity concentrations in fish, squid and mussels were from 0.039 to 35.0 Bq kg⁻¹ fresh weight and ²¹⁰Pb activity concentrations were from 0.08 to 3.03 Bq kg⁻¹ fresh weight. Grilling of fish resulted in no significant loss of ²¹⁰Po at 90 °C. The assessed combined annual effective ingestion dose due to ²¹⁰Po and ²¹⁰Pb for fish, squid and mussels consumed in Slovenia is 47.6 μSv year⁻¹.