Surfactant solubilization of hydrophobic compounds in soil and water

The soil/water partition coefficient (K_d) of hexachlorobenzene (HCB) ranged from 220 1/kg to 1800 1/kg for eight soils having a wide range of physico-chemical properties. K_d normalised to soil organic carbon (K_oc) was found to be 28000 ± 4800 1/kg. Anionic surfactant dodecylsulphate (DS) present at concentrations above the critical micellar concentration (CMC) caused reductions in the apparent soil/water partition coefficient (K_d ^*) in the range of 3–26 times for most soils and up to 36–91 times for sandy soils. Below CMC, at environmentally relevant surfactant concentrations, K_d ^* was reduced by a factor of 1–13. For clay and calcareous soils significant adsorption/complexation/precipitation of DS occurred. At the lowest DS concentration this produced a two-fold increase in K_d ^*. At increasing DS concentrations this effect was shielded by the solubihzing effect from DS. Monomer (K_mn) and micellar (K_mc) surfactant/water partition coefficients for HCB were determined to be, 980 ± 190 1/kg and 21000 ± 1600 1/kg, respectively.     

Occupational exposure

Concentrations of polychlorinated biphenyls (PCB), polychlorinated naphthalenes (PCN), polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), hexachlorobenzene and methylsulphonyl metabolites of PCB were determined in blood plasma from potentially exposed workers and controls. Three of the potentially exposed subjects had worked with cable incineration and two were electricians. Extraction of the organochlorine compounds and lipids were performed using the lipophilic gel Lipidex. Different adsorbents and gel permeation chromatography were applied for further purification of the samples and separation of analytes. Determinations of the chlorinated compounds were made by using gas chromatography with electron-capture detection and gas chromatography-mass spectrometry. Only small differences in the concentrations of organochlorine compounds were found in the plasma from the three subject groups. Thus, specific exposure of the workers could not be confirmed.     

Geochemical and Pb isotopic evidence for sources and dispersal of metal contamination in stream sediments from the mining and smelting district of Príbram, Czech Republic

Stream sediments from the mining and smelting district of Príbram, Czech Republic, were studied to determine the degree, sources and dispersal of metal contamination using a combination of bulk metal and mineralogical determinations, sequential extractions and Pb isotopic analyses. The highest metal concentrations were found 3-4 km downstream from the main polymetallic mining site (9800 mg Pb kg(-1), 26 039 mg Zn kg(-1), 316.4 mg Cd kg(-1), 256.9 mg Cu kg(-1)). The calculated enrichment factors (EFs) confirmed the extreme degree of contamination by Pb, Zn and Cd (EF>40). Lead, Zn and Cd are bound mainly to Fe oxides and hydroxides. In the most contaminated samples Pb is also present as Pb carbonates and litharge (PbO). Lead isotopic analysis indicates that the predominant source of stream sediment contamination is historic Pb-Ag mining and primary Pb smelting (206Pb/207Pb=1.16), while the role of secondary smelting (car battery processing) is negligible.     

Breakdown products on metabolic pathway of degradation of benz[a]anthracene by a ligninolytic fungus

Cultures of the ligninolytic fungus Irpex lacteus incubated in a nutrient liquid medium degraded more than 70% of the initially applied benz[a]anthracene within 14 days. At the first step of metabolization, benz[a]anthracene was transformed via a typical pathway of ligninolytic fungi to benz[a]anthracene-7,12-dione (BaAQ). The product was further transformed by at least two ways, whereas one is complied with the anthracene metabolic pathway of I. lacteus. Benz[a]anthracene-7,12-dione was degraded to 1,2-naphthalenedicarboxylic acid and phthalic acid that was followed with production of 2-hydroxymethyl benzoic acid or monomethyl and dimethylesters of phthalic acid. Another degradation product of BaAQ was identified as 1-tetralone. Its transformation via 1,4-naphthalenedione, 1,4-naphthalenediol and 1,2,3,4-tetrahydro-1-hydroxynaphthalene resulted again in phthalic acid. None of the intermediates were identified as dead-end metabolites. Metabolites produced by ring cleavage of benz[a]anthracene using the ligninolytic fungus are firstly presented in this work.     

In situ and laboratory bioassays using Poecilia reticulata Peters, 1859 in the biomonitoring of an acidic lake at Camaçari, BA, Brazil

The suitability and viability of acute in situ bioassays were investigated in the biomonitoring program of an acidic lake contaminated with sulphur residues. Responses of organisms observed in laboratory and in situ bioassays were also assessed to determine whether or not they were similar and comparable, regarding accuracy and precision. Newborn Poecilia reticulata were employed as test organisms and exposed to the same water samples under in situ and laboratory conditions. Mortality/immobility was the endpoint assessed and dead/immobile organisms were counted at various time intervals during exposure. The mean calculated LT50 values and 95% confidence intervals were 1.61 (1.36-1.87) h in the laboratory bioassays and 0.72 (0.55-0.89) h in the in situ bioassays. Statistical comparison of these values revealed a significant difference (p<0.05). In situ bioassays were more accurate than those carried out in the laboratory, demonstrating higher sensitivity and better reproduction of what occurs in nature, while laboratory bioassays were more precise.     

Passive air sampler as a tool for long-term air pollution monitoring: Part 1. Performance assessment for seasonal and spatial variations

The potential of passive air sampling devices (polyurethane foam disks) to assess the influence of local sources on the quality of the surrounding environment was investigated. DEZA Valasske Mezirici, a coal tar and mixed tar oils processing plant, and Spolana Neratovice, a chemical factory with the history of high production of organochlorinated pesticides (OCPs), were selected as the point sources of PAHs, and OCPs, respectively. Levels of PCBs, OCPs and PAHs were determined for all sampling sites and sampling periods. The study brought useful data about the air concentrations of POPs in the investigated regions. More important, it provided information on the transport and fate of POPs in the vicinity of local sources of contamination useful for the estimation of their influence. Very good capability of passive samplers to reflect temporal and spatial fluctuation in concentrations of persistent organic pollutants in the ambient air was confirmed which makes them applicable for monitoring on the local scale.     

Evaluation of ozone-nitrogen oxides-volatile organic compound sensitivity of Cincinnati, Ohio

Ambient concentrations of ozone (O3), nitrogen oxides (NOx), total reactive nitrogen (NOy), nitric acid (HNO3), and hydrogen peroxide (H2O2) were measured during September 2003 at an urban site of Cincinnati, OH. The aim of this study was two-fold: to investigate whether O3 formation in this population exposure-type site is NOx, sensitive or volatile organic compound (VOC) sensitive and to test the practicality of using two combined observational-based methods to identify the sensitivity of O3 formation in midlevel polluted locations. The evaluation of the indicator species: NOy, O3/NOy, O3/HNO3, H2O2/ HNO3, and O3/(estimated NOx reaction products), as well as the combined hypothesis testing analysis of the weekend/weekday (WE/WD) differences of 1-hr and 8-hr average maximum O3 and of the 6:00 a.m.-9:00 a.m. average nitric oxide and NOx concentrations, show evidence that Cincinnati is likely VOC sensitive. Average WE 1-hr and 8-hr maximum O3, as well as duration of WE O3 accumulation, were not lower than the corresponding WD levels in spite of the observed significant reduction in NO, emissions on WE, a typical situation in VOC-sensitive locations. The possibility that the seasonal transition from summer to autumn could have influenced the results was also investigated through an exploratory analysis of the afternoon O3 maximum/NOx measured and of the WE/WD differences of peak O3 and morning average NO and NO, concentrations observed at this site from June through September 2003. The results suggest that a VOC-sensitive chemistry regime dominated along the summer season. The findings of this study suggest that additional reductions in regional NO, emissions in Cincinnati, a potential nonattainment area under the 8-hr O3 standard, may cause an increase in local O3. Future strategies to reduce O3 in Southwest Ohio should be further evaluated carefully. The combination of observational-based methods might provide a consistent complementary approach in the identification of the NO,-VOC sensitive characteristics of mid-to-moderate polluted urban areas.     

Modelling the extra and intracellular uptake and discharge of heavy metals in Fontinalis antipyretica transplanted along a heavy metal and pH contamination gradient

Samples of the aquatic bryophyte Fontinalis antipyretica Hedw. were transplanted to different sites with the aim of characterizing the kinetics of the uptake and discharge of heavy metals in the extra and intracellular compartments. The accumulation of metals in extracellular compartments, characterized by an initial rapid accumulation, then a gradual slowing down over time, fitted perfectly to a Michaelis-Menten model. The discharge of metals from the same compartment followed an inverse linear model or an inverse Michaelis-Menten model, depending on the metal. In intracellular sites both uptake and discharge occurred more slowly and progressively, following a linear model. We also observed that the acidity of the environment greatly affected metal accumulation in extracellular sites, even when the metals were present at relatively high concentrations, whereas the uptake of metals within cells was much less affected by pH.     

The combined use of chemical and biochemical markers to assess water quality along the Ebro River

Carp (Cyprinus carpio) and barbel (Barbus graellsii) were collected from five sites along the Ebro River. The study was designed to assess levels of persistent organic pollutants and metals bioaccumulated by fish, and some biochemical responses (cytochrome P450 system, phase II activities, and metallothioneins) against those pollutants. The highest levels of PCBs and DDTs were detected in carp from industrialised areas, which also showed high levels of mercury and cadmium in the liver, and high levels of nonylphenol in bile. Significant alterations in some biochemical markers were observed and associated to combined exposure to pollutants. The activity 7-ethoxyresorufin O-deethylase ranged from 69 pmol/min/mg protein in carp from the reference site to 415 pmol/min/mg protein in those from polluted sites. Carp from the Ebro Delta, an agricultural area, had depressed acetylcholinesterase in muscle tissue. Metallothionein concentrations were positively correlated with copper residues, but no significant differences among sampling points were observed.     

Increased thyroid volume and frequency of thyroid disorders signs in schoolchildren from nitrate polluted area

Thyroid volume (ThV) and echogenicity by ultrasound were estimated in 324 schoolchildren (aged between 10 and 13-years) from high nitrate area (HNA) located in agricultural lowland with high nitrate drinking water supply (51-274 mg/l) from shallow wells. The data were compared to children of the same age from low nitrate area (LNA) consisting of 168 children from the neighboring area with very low nitrate (< 2 mg/l) drinking water and of 596 children from the city of Kosice located in a vicinity of LNA and also supplied by low nitrate water. Blood samples were obtained from 315 willing children from HNA and 109 children from LNA and the levels of thyrotropin (TSH), total thyroxine (TT4), free triiodothyronine (FT3) and thyroperoxidase antibodies (anti-TPO) in serum were determined. ThV (mean +/- SE) in 10-year (5.10 +/- 0.14 ml) and 13-year (5.97 +/- 0.11 ml) old children from HNA was significantly higher than that in two groups of respective age from LNA, 4.58 +/- 0.17 (p < 0.02) and 5.23 +/- 0.15 ml (p < 0.05), and from the city of Kosice, 4.77 +/- 0.10 ml (p < 0.05) and 4.87 +/- 0.1 0ml (p < 0.0001). The frequency of hypoechogenicity in HNA was also significantly higher than that in pooled LNA plus Kosice, 13.7% vs. 4.7% (p < 0.01) in 10-year and 10.6% vs. 5.7% (p < 0.03) in 13-year, respectively. The frequency of TSH level in the range of subclinical hypothyroidism (> 4.0 mU/l) in pooled age groups from HNA was 13/324 (4.0%) and that of positive anti-TPO was 8/324 (2.5%), while no case of either increased TSH or positive anti-TPO was found in 109 children from LNA. Finally, no differences in the levels of TT4 and FT3 were found between HNA and LNA. It was concluded that long-term exposure to high nitrate intake by drinking water and home made meals from local products results in increased thyroid volume and increased frequency of signs of subclinical thyroid disorders (thyroid hypoechogenicity by ultrasound, increased TSH level and positive anti-TPO).