Polychlorinated biphenyls (PCBs) and hydroxy-PCBs in adipose tissue of women in Southeast Spain

Polychlorinated biphenyls (PCBs) and hydroxylated PCBs (OH-PCBs) were investigated in human adipose tissue samples collected from 20 women undergoing surgery. Mean sum of PCB and sum of OH-PCB levels were 737ng/g of lipid and 8pg/g of lipid, respectively. Among PCBs, congeners 180, 153, 138 and 170 were the most frequent and abundant, and together constituted 72% of the total amount of PCBs in adipose tissue. The PCB congener pattern and the frequencies and concentrations of non-dioxin-like and non-hydroxylated congeners observed in adipose tissue were similar in distribution and order of magnitude to the profile previously published in Spain but lower than that found in other European countries. Among OH-PCB congeners studied, 4-OH-PCB 107/118 was found at the highest concentrations followed by 3'-OH-PCB 180 and 3-OH-PCB 138. To date, no information on levels of PCB metabolites in the Spanish population is available for comparison. These three predominant OH-PCBs contributed 97% of all OH-PCBs. Twelve dioxin-like PCBs contributed around 8% of the total PCB exposure, and all were present in all study subjects. Further research is required to determine trends in human exposure to PCBs and OH-PCBs and how existing banning measures affect exposure.     

Effect of a full-grown vegetative filter strip on herbicide runoff: maintaining of filter capacity over time

Narrow vegetative filter strips (VFS) proved to effectively reduce herbicide runoff from cultivated fields mainly due to the ability of vegetation to delay surface runoff, promote infiltration and adsorb herbicides. Since VFS are dynamic systems, their performance would not remain constant over the years indicating the need to define suitable buffer management. In order to evaluate the performance of different five and six year-old VFS, the runoff of the herbicides metolachlor and terbuthylazine was monitored in 2002 and 2003 in an experimental site in northern Italy. The structure of the herbaceous cover in the buffers changes over time. When rows of trees are present, the grass cover is decreased by the shading action of the trees, but the leaf litter gains importance. In VFS with grass cover only, the cover composition changes because of the substitution of grass by broadleaf species. Six metres wide VFS are very effective in reducing runoff volume and concentration during both wet and dry years. Classification analysis showed that runoff concentration and volume are linked to the characteristics of the rainfall event, buffer, source of herbicides and time after application. Regression analysis showed that the significant predictors for runoff volume are rainfall amount and intensity, total vegetal cover in the VFS, crop leaf area index and time after treatment; for concentration they are rainfall intensity, crop leaf area index and total vegetal cover in the VFS. The role of VFS is complex, so appropriate management is required to maintain its increasing filtering capacity over time.     

Removal and degradation of aromatic compounds from a highly polluted site by coupling soil washing with photocatalysis

The possible application of two environmental remediation technologies - soil washing and photocatalysis - to remove and decompose various aromatic pollutants present in excavated soils of a contaminated industrial site has been investigated. Aqueous solutions containing the non-ionic surfactant Brij 35 were used to extract the contaminants from the soil samples. The photocatalytic treatment of the obtained washing wastes, performed in the presence of TiO(2) suspensions irradiated with simulated sunlight, showed a slow abatement of the toxic compounds due to the relevant concentrations of organics in the waste. A neat improvement of the process performances, obtained by operating in the presence of added potassium peroxydisulfate, suggests a feasible treatment route.     

Ozonation of oil sands process water removes naphthenic acids and toxicity

Naphthenic acids are naturally-occurring, aliphatic or alicyclic carboxylic acids found in petroleum. Water used to extract bitumen from the Athabasca oil sands becomes toxic to various organisms due to the presence of naphthenic acids released from the bitumen. Natural biodegradation was expected to be the most cost-effective method for reducing the toxicity of the oil sands process water (OSPW). However, naphthenic acids are poorly biodegraded in the holding ponds located on properties leased by the oil sands companies. In the present study, chemical oxidation using ozone was investigated as an option for mitigation of this toxicity. Ozonation of sediment-free OSPW was conducted using proprietary technology manufactured by Seair Diffusion Systems Inc. Ozonation for 50min generated a non-toxic effluent (based on the Microtox bioassay) and decreased the naphthenic acids concentration by approximately 70%. After 130min of ozonation, the residual naphthenic acids concentration was 2mgl(-1): <5% of the initial concentration in the filtered OSPW. Total organic carbon did not change with 130min of ozonation, whereas chemical oxygen demand decreased by approximately 50% and 5-d biochemical oxygen demand increased from an initial value of 2mgl(-1) to a final value of 15mgl(-1). GC-MS analysis showed that ozonation resulted in an overall decrease in the proportion of high molecular weight naphthenic acids (n> or = 22).     

Bioaugmentation of aerobic microbial granules with Pseudomonas putida carrying TOL plasmid

This paper describes results of a successful bioaugmentation experiment on aerobic granular sludge using Pseudomonas putida KT2442 cells bearing the TOL (pWWO) plasmid. The methodology was designed to monitor incorporation of the added donor cells into pre-existent microbial granules and the subsequent plasmid transfer to the autochthonous microbial community using shake flask microcosms. Expression of reporter proteins (GFP and DsRed) allowed in situ monitoring of donor cell attachment and plasmid transfer to the recipient cells using confocal laser scanning microscopy. Concomitant with donor integration and transconjugant proliferation in the granules, a significant increase in degradation of benzyl alcohol (used as sole substrate) was observed in the augmented microcosms. In contrast, control microcosms (with non-augmented granules) did not show any noticeable increase in the degradation of the substrate. This study shows that bioaugmentation of aerobic granular sludge via donor colonization and plasmid transfer is feasible for enhanced biodegradation.     

Heavy metals effects on proteolytic system in sunflower leaves

Plant proteolytic system includes proteases, mainly localized inside the organelles, and the ubiquitin-proteasome pathway in both, the cytoplasm and the nucleus. It was recently demonstrated that under severe Cd stress sunflower (Helianthus annuus L.) proteasome activity is reduced and this results in accumulation of oxidized proteins. In order to test if under other heavy metal stresses sunflower proteolytic system undergoes similar changes, an hydroponic experiment was carried out. Ten days old sunflower plants were transferred to hydroponic culture solutions devoid (control) or containing 100 microM of AlCl(3), CoCl(2), CuCl(2), CrCl(3), HgCl(2), NiCl(2), PbCl(2) or ZnCl(2) and analyzed for protein oxidative damage and proteolytic activities. After 4 days of metal treatment, only Co(2+), Cu(2+), Hg(2+), and Ni(2+) were found to increase carbonyl groups content. Except for Al(3+) and Zn(2+), all metals tested significantly reduced all proteasome activities (chymotrypsin-like, trypsin-like and PGPH) and acid and neutral proteases activities. The effect on basic proteases was more variable. Abundance of 20S protein after metal treatments was similar to that obtained for control samples. Co(2+), Cu(2+), Hg(2+), Ni(2+), Cr(3+), and Pb(2+) induced accumulation of ubiquitin conjugated proteins. It is concluded that heavy metal effects on proteolytic system cannot be generalized; however, impairment of proteasome functionality and decreased proteases activities seem to be a common feature involved in metal toxicity to plants.     

An enzyme-linked immunosorbent assay for the determination of dioxins in contaminated sediment and soil samples

A 96-microwell enzyme-linked immunosorbent assay (ELISA) method was evaluated to determine PCDDs/PCDFs in sediment and soil samples from an EPA Superfund site. Samples were prepared and analyzed by both the ELISA and a gas chromatography/high resolution mass spectrometry (GC/HRMS) method. Comparable method precision, accuracy, and detection level (8 ng kg(-1)) were achieved by the ELISA method with respect to GC/HRMS. However, the extraction and cleanup method developed for the ELISA requires refinement for the soil type that yielded a waxy residue after sample processing. Four types of statistical analyses (Pearson correlation coefficient, paired t-test, nonparametric tests, and McNemar's test of association) were performed to determine whether the two methods produced statistically different results. The log-transformed ELISA-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin values and log-transformed GC/HRMS-derived TEQ values were significantly correlated (r=0.79) at the 0.05 level. The median difference in values between ELISA and GC/HRMS was not significant at the 0.05 level. Low false negative and false positive rates (<10%) were observed for the ELISA when compared to the GC/HRMS at 1,000 ng TEQ kg(-1). The findings suggest that immunochemical technology could be a complementary monitoring tool for determining concentrations at the 1,000 ng TEQ kg(-1) action level for contaminated sediment and soil. The ELISA could also be used in an analytical triage approach to screen and rank samples prior to instrumental analysis.     

In situ assay with the midge Kiefferulus calligaster for contamination evaluation in aquatic agro-systems in central Thailand

The aims of this study were to verify the suitability of in situ tests using the tropical midge Kiefferulus calligaster and to evaluate the most sensitive endpoint for the assessment of aquatic pesticide contamination. In situ tests were carried out in freshwater drainage channels (farm channels) that supply vegetable crops and receive considerable pesticide spray drift, and at channels outside farms (main channels). Moreover a pesticide-free farm was used as reference site. The endpoints analysed were: survival of the larvae, body length increment, capsule width increment, cholinesterase activity and glutathione S-transferase activity. Seasonal change was investigated as rainy season and dry season. Deleterious effects were observed at some farms especially during the rainy season when farmers apply heavier doses of pesticides. However, high mortality rates observed in main channels suggest that these water bodies are also affected by other impacts besides pesticide use. This work shows the potential of the in situ assay with K. calligaster as a tool for the environmental quality assessment of tropical aquatic ecosystems.     

Leaf accumulation of trace elements and polycyclic aromatic hydrocarbons (PAHs) in Quercus ilex L

Quercus ilex L. leaves were collected four times in one year at six urban sites and one remote area in order to determine trace element and PAH accumulation through concomitant analyses of unwashed and water-washed leaves. Both unwashed and washed leaves showed the highest amounts of trace elements and PAHs in the urban area. Unwashed leaves showed greater differences between urban and remote areas and among the urban sites than washed leaves for trace element and PAH concentrations. Water-washing resulted in a significant (P<0.001) decrease in leaf concentrations of Cr, Cu, Fe, Pb, V and Zn. By contrast, Cd and total PAH concentrations showed no differences between unwashed and washed leaves.     

Short- and medium-term effects of experimental nitrogen fertilization on arthropods associated with Calluna vulgaris heathlands in north-west Spain

We studied the short- and medium-term effects of experimental nitrogen fertilization (3 and 15 months after the treatment) on the arthropods of Calluna vulgaris heathlands in NW Spain. Three heathland sites were selected with two permanent plots per site: control and fertilized. Ammonium nitrate fertilizer (56 kg N ha(-1) yr(-1)) was applied monthly and insects were caught using pitfall traps. We found mainly species-level responses to nitrogen addition. Seven species (e.g. Lochmaea suturalis) showed a consistent trend (benefited or harmed) in both periods and were proposed as possible reliable indicators of the effects of nitrogen deposition in these ecosystems. We also found variable arthropod trophic-group responses: (a) herbivores (leaf beetles, true bugs) increased in abundance on a short-term scale; (b) predators (carabid beetles, true bugs) showed opposite and less clear responses in both periods. Further long-term studies are needed to determine the mechanisms underlying the observed arthropod responses.