Validation and Evaluation of Selected Organic Pollutants in Shrimp and Seawater Samples from the NW Portuguese Coast

The development of coastal regions has contributed to the intensification of environmental contamination, which can accumulate in aquatic biota, such as shrimps. These crustaceans, besides being delicious and being a good source of nutrients, can also accumulate environmental pollutants. Amongst others, these include organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs), brominated flame retardants (BFRs), polychlorinated biphenyls (PCBs) and synthetic musks (SMs). These pollutants, classified as endocrine disruptors, are related to adverse effects in humans and since one of the major routes of exposition is ingestion, this is a cause for concern regarding their presence in food. The aim of the present study was to quantify the presence of environmental pollutants in shrimp samples and in the water from their habitat along the northwest Portuguese coast. In seawater samples, only two OCPs (lindane and DDD) and one BFR (BTBPE) were detected, and in shrimp samples, one OCP (DDD) and three SMs (HHCB, AHTN and ketone) were found. Bioaccumulation and the risk assessment of dietary exposure of SMs in shrimp samples were investigated. It was observed that all shrimp samples analyzed significantly presented bioaccumulation of the three SMs found. Concentrations of SMs detected in shrimp samples do not present a health risk for the adult Portuguese population.

A Case Study of Natural Attenuation of Chlorinated Solvents Under Unstable Groundwater Conditions in Takahata, Japan

The natural attenuation behavior of chlorinated solvents and their risks to human health at a contaminated groundwater site in Takahata, Japan, were investigated. It was found that volatile organic compound (VOC) concentrations gradually decreased via two attenuation mechanisms, namely dilution and biodegradation. It was estimated that the VOC concentrations will be below the Japanese limits within 30 years after stopping the active remediation in 2003, which suggests that there is a high possibility that monitored natural attenuation can be adopted as the clean-up method at this contaminated site. The risk levels of VOCs at the present time are much lower than those at the time when the contamination was discovered. Vinyl chloride still presents a risk in some wells, and there were occasional unexpected increases in the risk levels of tetrachloroethylene, trichloroethylene, and cis-1,2-dichloloethylene, which means that continuous monitoring of the groundwater is necessary for forecasting risk levels.

Enrichment and physiological responses of dechlorane plus on juvenile marine macroalgae (Ulva pertusa)

Dechlorane Plus (DP), a chlorinated flame retardant, is increasingly reported in aquatic ecosystems worldwide. But little information is available regarding the toxicity of DP in marine organisms, especially in macroalgae. The objective of this study was to investigate effects of DP exposure on photosynthesis, oxidative stress and its enrichment in juvenile marine macroalgae (Ulva pertusa). Following 21- day uptake and 21- day depuration (10^-8 mol/L), algae accumulated 1.18 times of DP compared to the initial concentration. Anti-DP was prone to accumulate in juvenile macroalgae. The enrichment of DP affected the physiological responses in algae. After 1, 7 and 14 days DP exposure (10^-8, 10^-7 and 10^-6 mol/L), antioxidant enzymes (SOD and CAT) activities and MDA content changed in a dose and time depended manner. Chlorophyll fluorescence parameters, including F_v/F_m, Φ_PSII and ETR decreased with the increasing DP concentration. It indicated that DP leads to a low rate of light energy utilization in algae which may ascribe to the oxidative damage induced by DP enrichment. Present study provides insight into the toxicological effects of DP on marine macroalgae, which is useful for risk assessment of DP in intertidal zone ecosystems.

Easy and fast extraction methods to determine organochlorine pesticides in sewage sludge, soil, and water samples based at low temperature

Organochlorine pesticides present in sewage sludge can contaminate soil and water when they are used as either fertilizer or agricultural soil conditioner. In this study, the technique solid-liquid extraction with low temperature purification was optimized and validated for determination of ten organochlorine pesticides in sewage sludge and soil samples. Liquid-liquid extraction with low temperature purification was also validated for the same compounds in water. Analyses were performed by gas chromatography-mass spectrometry operating in the selective ion monitoring mode. After optimization, the methods showed recoveries between 70% and 115% with relative standard deviation lower than 13% for all target analytes in the three matrices. The linearity was demonstrated in the range of 20 to 70 µg L^-1, 0.5 to 60 µg L^-1, and 3 to 13 µg L^-1, for sludge, soil, and acetonitrile, respectively. The limit of quantification ranged between 2 and 40 µg kg^-1, 1 and 6 µg kg^-1, and 0.5 µg L^-1 for sludge, soil, and water, respectively. The methods were used in the study of pesticide lixiviation carried out in a poly vinyl chlorine column filled with soil, which had its surface layer mixed with sludge. The results showed that pesticides are not leached into soil, part of them is adsorbed by the sewage sludge (4-40%), and most pesticides are lost by volatilization.

A novel chloro-substituted pentenamide from the fruiting bodies of Amanita virgineoides

One unusual chloro-substituted pentenamide, (3R)-4-chloro-3-hydroxy-4-pentenamide (1), together with 11 known compounds (2-12) were isolated from the fruiting bodies of Amanita virgineoides. The structure of 1 including the absolute configuration was characterized by extensive spectroscopic analyses and quantum calculation. Compound 1 displayed no obvious activity against herpes simplex virus (HSV), human enterovirus 71 (EV71) or coxsackievirus B3 (CVB3).

Lepistatins A-C, chlorinated sesquiterpenes from the cultured basidiomycete Lepista sordida

Three new chlorinated sesquiterpenes, named lepistatins A-C, were isolated from the culture broth of Basidiomycete Lepista sordida. The structures were determined by the analysis of spectroscopic data including HREIMS and 1D and 2D NMR. The absolute configuration of lepistatin B was determined by comparing the specific rotation and circular dichroism spectrum with those of known structurally related compounds bearing the same chiral carbon. The structures of lepistatins A-C feature the indanone core structure, but differ from other indanone-containing sesquiterpenes of fungal origin by the alkyl substitution pattern. This indicates that lepistatins A-C probably possess a new sesquiterpene scaffold derived from the common precursor, trans-humulyl cation, by an alternative cyclization.

Partitioning of hydrophobic organic contaminants between polymer and lipids for two silicones and low density polyethylene

Polymers are increasingly used for passive sampling of neutral hydrophobic organic substances (HOC) in environmental media including water, air, soil, sediment and even biological tissue. The equilibrium concentration of HOC in the polymer can be measured and then converted into equilibrium concentrations in other (defined) media, which however requires appropriate polymer to media partition coefficients. We determined thus polymer-lipid partition coefficients (K_PL) of various PCB, PAH and organochlorine pesticides by equilibration of two silicones and low density polyethylene (LDPE) with fish oil and Triolein at 4 °C and 20 °C. We observed (i) that K_PL was largely independent of lipid type and temperature, (ii) that lipid diffusion rates in the polymers were higher compared to predictions based on their molecular volume, (iii) that silicones showed higher lipid diffusion and lower lipid sorption compared to LDPE and (iv) that absorbed lipid behaved like a co-solute and did not affect the partitioning of HOC at least for the smaller molecular size HOC. The obtained K_PL can convert measured equilibrium concentrations in passive sampling polymers into equilibrium concentrations in lipid, which then can be used (1) for environmental quality monitoring and assessment, (2) for thermodynamic exposure assessment and (3) for assessing the linkage between passive sampling and the traditionally measured lipid-normalized concentrations in biota. LDPE-lipid partition coefficients may also be of use for a thermodynamically sound risk assessment of HOC contained in microplastics.

Isolation, Synthesis, and Biological Activity of Chlorinated Alkylresorcinols from Dictyostelium Cellular Slime Molds

Eight chlorinated alkylresorcinols, monochasiol A-H (1-8), were isolated from the fruiting bodies of Dictyostelium monochasioides. Compounds 1-8 were synthesized to confirm their structures and to obtain sufficient material for performing biological tests. Monochasiol A (1) selectively inhibited the concanavalin A-induced interleukin-2 production in Jurkat cells, a human T lymphocyte cell line. Monochasiols were biogenetically synthesized by the combination of biosynthetic enzymes relating to the principal polyketides, MPBD and DIF-1, produced by Dictyostelium discoideum.

Multiphase hydrodechlorination of polychlorinated aromatics - Towards scale-up

We describe a chemical technology for the reductive catalytic multiphase hydrodechlorination (HDC) of chlorinated aromatics to greatly reduce their toxicity and aid the disposal of such species. The system requires no solvent and the catalyst displays a high recycling efficiency. In the present case, 1,3-dichlorobenzene (1,3-DCB) was used as a model compound, and was quantitatively hydrodechlorinated to benzene with hydrogen, in a tri-phasic liquid system consisting of the chlorinated aromatic itself as the top organic phase, an aqueous sodium hydroxide bottom phase (that neutralises acids formed), and an Aliquat^®336 (A336) intermediate phase containing a Pd/C catalyst. Once the reaction was complete the top phase (now just benzene) and the bottom phase (now principally aqueous NaCl) were removed and the remaining catalytic A336/(Pd/C) phase recycled. This model study was conducted on a multi-gram scale with a view of demonstrating its applicability to the detoxification of PCBs. Comparison of the Mass Intensity (MI) and turnover frequency (TOF) of our model reaction with three examples of published procedures for the HDC of DCB, indicated that the MI for our system (MI = 6.33) was lower by an order of magnitude or more than that of the others (MI = 27.9, 64.6, 96016), and that TOFs were comparable. A preliminary cost analysis indicates approximately 2000 €/tonne to treat tonne-scale amounts of chlorinated aromatics, making the system in principle useful for industrial implementation.

Monochlorinated calocerins A-D and 9-oxostrobilurin derivatives from the basidiomycete Favolaschia calocera

Eight previously undescribed compounds were isolated and characterised from the supernatant and mycelium of a culture of the basidiomycete Favolaschia calocera originating from Kakamega equatorial rainforest in Kenya. These were: 9- oxostrobilurins A, G, K and I and the four monochlorinated calocerins A, B, C and D. The calocerins extend our knowledge of halogenated compounds obtained from natural sources. Four further known compounds were also identified: strobilurin G, favolon, pterulinic acid and 2,3 -dihydro-1-benzoxepin derivative. The four oxostrobilurins exhibited prominent antifungal and cytotoxic activities while the four calocerins only showed cytotoxic activity.

A comparison of the dechlorination mechanisms and Ni release styles of chloroalkane and chloroalkene removal using nickel/iron nanoparticles

In this study, we compared the removal kinetics and Ni release styles of 1,1,1-trichloroethane (1,1,1-TCA), trichloroethylene (TCE), and tetrachloroethene (PCE) that result from the use of Ni/Fe nanoparticles in water. Compared to TCE and PCE, 1,1,1-TCA was more readily removed, and the concentration profiles of the three chlorinated aliphatic hydrocarbons (CAHs) during the reduction processes fit pseudo-first-order reaction rate models well. The surface area-normalized rate constants show that the 11% Ni Ni/Fe nanoparticles, which has the largest Brunauer-Emmett-Teller surface area, has the highest capacity for 1,1,1-TCA removal per unit surface area and that the 6% Ni sample was the best for removing TCE and PCE. The observed by-products suggested that hydrogenolysis was responsible for the dechlorination of CAHs in the presence of Ni/Fe nanoparticles. More Ni2+ was released during the degradation of 1,1,1-TCA than that of TCE and PCE because Ni will reduce the CAHs directly as a zerovalent metal does when hydrogen atoms in the Ni lattice are not sufficient due to the rapid incomplete dechlorination of 1,1,1-TCA. The different modes of adsorption of chloroalkane and chloroalkene onto the surfaces of Ni/Fe particles might play an important role in their dechlorination process.

Catalytic hydrodechlorination of PCDD/Fs from condensed water with Pd/γ-Al2O3

A continuous pyrolysis system (CPS) with effective air pollution control devices (APCDs) is designed and constructed to remediate the soil containing high-concentration PCDD/Fs. The quench tower of the APCDs system can capture the pollutants of high boiling points from the flue gas of CPS and produces condensed water of high PCDD/Fs concentration (16-44 ng I-TEQ/L), and needs further treatment. First, the result of activated carbon adsorption test displays the PCDD/Fs toxicity concentration of effluents meet the regulatory standards as the liquid to solid ratio is controlled at 3: 1. However, large amount of activated carbon need to achieve the high removal efficiency leads to high cost, so catalytic hydrodechlorination technology with Pd/Al2O3 as catalyst is applied to treat the condensed water. The PCDD/Fs mass removal efficiency achieved without the reducing agent is 53.21% with the operating time of 180 min. As 5% reducing agent (methanol) is added, the removal efficiency increases to 71.86%. In addition, to better understand the differences between molecular hydrogen and hydrogen donor, the condensed water was pre-aerated with hydrogen and catalytic hydrodechlorination test with palladium as catalyst was conducted. The results show that the PCDD/Fs mass removal efficiency increases to 97.34% with the operating time of 180 min, demonstrating the high PCDD/Fs removal efficiency of catalytic hydrodechlorination.

Laboratory tests for the phytoextraction of heavy metals from polluted harbor sediments using aquatic plants

The aim of this study was to investigate the concentrations and pollution levels of heavy metals, organochlorine pesticides, and polycyclic aromatic hydrocarbons in marine sediments from the Leghorn Harbor (Italy) on the Mediterranean Sea. The phytoextraction capacity of three aquatic plants Salvinia natans, Vallisneria spiralis, and Cabomba aquatica was also tested in the removal of lead and copper, present in high concentration in these sediments. The average detectable concentrations of metals accumulated by the plants in the studied area were as follows: >3.328 ± 0.032 mg/kg dry weight (DW) of Pb and 2.641 ± 0.014 mg/kg DW of Cu for S. natans, >3.107 ± 0.034 g/kg DW for V. spiralis, and >2.400 ± 0.029 mg/kg DW for C. aquatica. The occurrence of pesticides was also analyzed in the sediment sample by gas chromatography coupled with mass spectrometry (GC/MS). Due to its metal and organic compound accumulation patterns, S. natans is a potential candidate in phytoextraction strategies.

Glyoxal-Urea-Formaldehyde Molecularly Imprinted Resin as Pipette Tip Solid-Phase Extraction Adsorbent for Selective Screening of Organochlorine Pesticides in Spinach

A new kind of glyoxal-urea-formaldehyde molecularly imprinted resin (GUF-MIR) was synthesized by a glyoxal-urea-formaldehyde (GUF) gel imprinting method with 4,4'-dichlorobenzhydrol as a dummy template. The obtained GUF-MIR was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) and applied as a selective adsorbent of miniaturized pipet tip solid-phase extraction (PT-SPE) for the separation and extraction of three organochlorine pesticides (dicofol (DCF), dichlorodiphenyl dichloroethane (DDD), and tetradifon) in spinach samples. The proposed pretreatment procedures of spinach samples involved only 5.0 mg of GUF-MIR, 0.7 mL of MeOH-H2O (1:1, v/v) (washing solvent), and 0.6 mL of cyclohexane-ethyl acetate (9:1, v/v) (elution solvent). In comparison with other adsorbents (such as silica gel, C18, NH2-silica gel, and neutral alumina (Al2O3-N)), GUF-MIR showed higher adsorption and purification capacity for DCF, DDD, and tetradifon in aqueous solution. The average recoveries at three spiked levels ranged from 89.1% to 101.9% with relative standard deviations (RSDs) ≤ 7.1% (n = 3). The presented GUF-MIR-PT-SPE method combines the advantages of molecularly imprinted polymers (MIPs), GUF, and PT-SPE and can be used in polar solutions with high affinity and selectivity to the analytes in complex samples.

Mesoporous TiO₂ nanoparticles for highly sensitive solid-phase microextraction of organochlorine pesticides

Mesoporous TiO2 nanoparticles were synthesized with the hydrothermal method and characterized by powder X-ray diffraction (PXRD) and transmission electron microscope (TEM). Then a superior solid-phase microextraction (SPME) fiber was fabricated by sequentially coating the stainless steel fiber with silicone sealant film and mesoporous TiO2 powder. The developed fiber possessed a homogeneous surface and a long life-span up to 100 times at direct immersing (DI) extraction mode. Under the optimized conditions, the extraction efficiencies of the self-made 17 μm TiO2 fiber for six organochlorine pesticides (OCPs) were higher than those of the two commercial fibers (65 μm PDMS/DVB and 85 μm PA fibers) which were much thicker than the former. As for analytical performance, low detection limits (0.08-0.60 ng L(-1)) and wide linearity (5-5000 ng L(-1)) were achieved under the optimal conditions. The repeatabilities (n=5) for single fiber were between 2.8 and 12.3%, while the reproducibilities (n=3) of fiber-to-fiber were in the range of 3.7-15.7%. The proposed fiber was successfully applied to the sensitive analysis of OCPs in real water samples and four of the six analytes were detected from the rainwater and the lake water samples.

Chlorinated polyketide obtained from a Daldinia sp. treated with the epigenetic modifier suberoylanilide hydroxamic acid

A new chlorinated pentacyclic polyketide, daldinone E (1), was purified from a Daldinia sp. fungal isolate treated with the epigenetic modifier suberoylanilide hydroxamic acid (SAHA). A biosynthetically related epoxide-containing daldinone analogue, 2, was also purified from the same fungus. The structures of both compounds were established by spectroscopic methods, and the absolute configurations were assigned by analysis of their NMR data (coupling constants and ROESY correlations) and DFT calculations of specific rotations and ECD spectra. During the course of these studies it was determined that metabolite 2 and the previously reported daldinone B shared the same spectroscopic data, leading to a revision of the reported structure. Both compounds 1 and 2 also exhibited DPPH radical scavenging activities with potency comparable to the positive control ascorbic acid.

Freeze drying reduces the extractability of organochlorine pesticides in fish muscle tissue by microwave-assisted method

Samples of animal origin are usually dried before solvent extraction for analysis of organic contaminants. The freeze drying technique is preferred for hydrophobic organic compounds in practice. In this study, it was shown that the concentration of organochlorine pesticides (OCPs) extracted from fish muscle tissue significantly decreased after the samples were freeze dried. And the reason for this reduced extractability seemed to be the resistance of OCPs associated with freeze-dried muscle protein to solvent extraction. The extractability can be recovered by adding water prior to extraction. It suggests that the dietary exposure risk of OCPs from fish might be underestimated if freeze-dried samples are used.

Accelerated identification of halogenated monoterpenes from Australian specimens of the red algae Plocamium hamatum and Plocamium costatum

Two species of red algae belonging to the genus Plocamium, P. hamatum from Moreton Bay, Queensland, and P. costatum, from Pandalowie Bay, South Australia, were investigated to assess their chemical variation and as potential sources of new halogenated monoterpenes. The hyphenated technique HPLC-UV-MS-SPE-NMR was used to assess the algal extracts and to determine its potential for accelerated identification of halogenated monoterpenes generally. A combination of the hyphenated and traditional chromatographic techniques resulted in the isolation and characterization of a total of 10 halogenated monoterpene metabolites, eight of which are reported for the first time. Their structures, including configurations, were determined through interpretation of their 1D and 2D NMR, mass spectrometric, infrared, and X-ray data. The two species of Plocamium produced different secondary metabolites and contained a significant number of new polyhalogenated monoterpenes. The investigation also showed the hyphenated technique HPLC-UV-MS-SPE-NMR to be useful for preliminary investigation of the chemical content of algal extracts.

Spiromastixones A-O, antibacterial chlorodepsidones from a deep-sea-derived Spiromastix sp. fungus

Fifteen new depsidone-based analogues named spiromastixones A-O (1-15) were isolated from the fermentation broth of a deep-sea Spiromastix sp. fungus. Their structures were elucidated on the basis of extensive NMR and mass spectroscopic analysis in association with chemical conversion. Spiromastixones A-O are classified into two subtypes based on the orientation of ring C relative to ring A, while the n-propyl substituents on rings A and C are rarely seen in natural products. Most analogues are substituted by various numbers of chlorine atoms. All compounds exhibited significant inhibition against Gram-positive bacteria including Staphylococcus aureus, Bacillus thuringiensis, and Bacillus subtilis with MIC values ranging from 0.125 to 8.0 μg/mL. In addition, compounds 6-10 displayed potent inhibitory effects against methicillin-resistant bacterial strains of S. aureus (MRSA) and S. epidermidis (MRSE), while 10 also inhibited the growth of the vancomycin-resistant bacteria Enterococcus faecalis and E. faecium (VRE). The structure-activity relationships are discussed.

New branches in the degradation pathway of monochlorocatechols by Aspergillus nidulans: a metabolomics analysis

A collective view of the degradation of monochlorocatechols in fungi is yet to be attained, though these compounds are recognised as key degradation intermediates of numerous chlorinated aromatic hydrocarbons, including monochlorophenols. In the present contribution we have analysed the degradation pathways of monochlorophenols in Aspergillus nidulans using essentially metabolomics. Degradation intermediates herein identified included those commonly reported (e.g. 3-chloro-cis,cis-muconate) but also compounds never reported before in fungi revealing for 4-chlorocatechol and for 3-chlorocatechol unknown degradation paths yielding 3-chlorodienelactone and catechol, respectively. A different 3-chlorocatechol degradation path led to accumulation of 2-chloromuconates (a potential dead-end), notwithstanding preliminary evidence of chloromuconolactones and protoanemonin simultaneous formation. In addition, some transformation intermediates, of which sulfate conjugates of mono-chlorophenols/chlorocatechols were the most common, were also identified. This study provides critical information for understanding the role of fungi in the degradation of chlorinated aromatic hydrocarbons; furthering their utility in the development of innovative bioremediation strategies.

Coupling Fenton and biological oxidation for the removal of nitrochlorinated herbicides from water

The combination of Fenton and biological oxidation for the removal of the nitrochlorinated herbicides alachlor, atrazine and diuron in aqueous solution has been studied. The H2O2 dose was varied from 20 to 100% of the stoichiometric amount related to the initial chemical oxygen demand (COD). The effluents from Fenton oxidation were analyzed for ecotoxicity, biodegradability, total organic carbon (TOC), COD and intermediate byproducts. The chemical step resulted in a significant improvement of the biodegradability in spite of its negligible or even slightly negative effect on the ecotoxicity. Working at 60% of the stoichiometric H2O2 dose allowed obtaining highly biodegradable effluents in the cases of alachlor and atrazine. That dose was even lower (40% of the stoichiometric) for diuron. The subsequent biological treatment was carried out in a sequencing batch reactor (SBR) and the combined Fenton-biological treatment allowed up to around 80% of COD reduction.

Biogenic nanopalladium based remediation of chlorinated hydrocarbons in marine environments

Biogenic catalysts have been studied over the last 10 years in freshwater and soil environments, but neither their formation nor their application has been explored in marine ecosystems. The objective of this study was to develop a biogenic nanopalladium-based remediation method for reducing chlorinated hydrocarbons from marine environments by employing indigenous marine bacteria. Thirty facultative aerobic marine strains were isolated from two contaminated sites, the Lagoon of Mar Chica, Morocco, and Priolo Gargallo Syracuse, Italy. Eight strains showed concurrent palladium precipitation and biohydrogen production. X-ray diffraction and thin section transmission electron microscopy analysis indicated the presence of metallic Pd nanoparticles of various sizes (5-20 nm) formed either in the cytoplasm, in the periplasmic space, or extracellularly. These biogenic catalysts were used to dechlorinate trichloroethylene in simulated marine environments. Complete dehalogenation of 20 mg L(-1) trichloroethylene was achieved within 1 h using 50 mg L(-1) biogenic nanopalladium. These biogenic nanoparticles are promising developments for future marine bioremediation applications.

Chlorinated coumarins from the polypore mushroom Fomitopsis officinalis and their activity against Mycobacterium tuberculosis

An EtOH extract of the polypore mushroom Fomitopsis officinalis afforded two new naturally occurring chlorinated coumarins, which were identified as the previously synthesized compounds 6-chloro-4-phenyl-2H-chromen-2-one (1) and ethyl 6-chloro-2-oxo-4-phenyl-2H-chromen-3-carboxylate (2). The structures of the two isolates were deduced by ab initio spectroscopic methods and confirmed by chemical synthesis. In addition, an analogue of each was synthesized as 7-chloro-4-phenyl-2H-chromen-2-one (3) and ethyl 7-chloro-2-oxo-4-phenyl-2H-chromen-3-carboxylate (4). All four compounds were characterized physicochemically, and their antimicrobial activity profiles revealed a narrow spectrum of activity with lowest MICs against the Mycobacterium tuberculosis complex.

Quantitative analysis of organochlorine pesticides in human serum using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry

Persistent organochlorine pesticides (OCPs) are well known to accumulate in environment and to instigate disruptions in endocrine system. In the present study, 18 kinds of OCPs were bio-monitored from 1904 adult serums. Analysis was performed with headspace gas chromatography (HS-GC) which has the advantage to require small volume of serum (1mL) without complex pretreatment and (13)C isotope labeled internal standard mix was used for quantitation. As a result, eleven out of 18 OCPs, including hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethane metabolites (DDTs) were detected. HCB was the most frequently detected OCP (8.0%) with an average concentration of 1.74ngg(-1) lipid (2.10ngg(-1) lipid-99.80ngg(-1) lipid). p,p'-Dichlorodiphenyldichloroethylene (p,p'-DDE) had the highest average concentration of 21.65ngg(-1) lipid (12.80ngg(-1) lipid-2270ngg(-1) lipid) and was detected from 7.5% of serum samples. The average concentration of ∑DDT metabolites was 32.04ngg(-1) lipid (6.61ngg(-1) lipid-2800ngg(-1) lipid) with detection frequency of 9.0%. Results interpreted with respect to age groups showed increase in ∑OCPs and ∑DDTs concentrations as age increases, except for the 20. Results interpreted with respect to gender, in general, illustrated higher detected concentration of OCPs in male serums than in female serums; however, the result trend was reversed in age group of the sixties. The above results will be applicable to health impact assessment of Koreans in relation to environmental contaminations.

Extraction and clean-up methods for organochlorine pesticides determination in milk

Organochlorine pesticides (OCPs) can cause environmental damage and human health risks since they are lipophilic compounds with high resistance to degradation and long half-lives in humans. As most persistent OCPs have been banned years ago, it is expected to find these compounds at trace levels in environment. Therefore, increasingly sensitive and reliable analytical techniques are required to ensure effective monitoring of these compounds. The aim of this review is to discuss extraction and clean-up methods used to monitor OCP residues in milk, reported in the last 20 years. To carry out this review, an exhaustive bibliographic review was conducted. Despite the disadvantages of conventional extraction and clean-up methods, such as liquid-liquid, solid-phase or Soxhlet extractions, these procedures are still used due to their reliability. New extraction methods, like solid-phase microextraction, matrix solid-phase dispersion or QuEChERS, have not been thoroughly evaluated for OCP determination in milk. Almost all the methodologies analyzed in this review presented good performance characteristics according to the performance acceptability criteria set in SANCO's procedure. Comparison between limits of quantification (LOQ) and detection (LOD), for the reported methodologies, is not always possible due to the heterogeneity of the units. Thus, researchers should take into account an homogenization of LOD and LOQ units, according to the international regulations and MRLs established. Finally, more research is necessary to obtain the ideal methodology for OCPs determination in milk, which comprises the environmentally friendly characteristics of the new techniques and the reliability of the traditional methodologies.

Presence of organochlorine pesticides in breast milk samples from Colombian women

The presence of organochlorine pesticides (OCPs) in biological and environmental samples has been studied for decades in many countries. Nonetheless, studies in Latin American countries like Colombia have been scarce. Determining the presence of OCPs in breast milk will be of relevance to assess exposures, potential health risks, and for surveillance among Latin American populations. Thirty-two breast-feeding mothers were selected to voluntarily participate in the study. Breast milk samples were analyzed for 10 OCPs (α-, β-, γ-, δ-HCH, Heptachlor, α-, γ-Chlordane, 4,4' DDT, 4,4' DDE, 4,4' DDD). Milk samples were analyzed using liquid-liquid extraction, followed by sulfuric acid clean-up, and quantified using GC/μECD. Results were confirmed by GC/MS. OCPs concentrations were normalized using fat content. In all but one sample, 4,4' DDE was quantified in concentrations ranging between<17 and 14948 ng g(-1) (ng of OCP per g of lipids), with a mean value of 203 ng g(-1). One woman had 4,4' DDE concentrations that were orders of magnitude above the average concentrations observed worldwide. Concentrations of 4,4' DDE in a second breast milk sample collected in a different time period of lactation from a sub-group of 13 women from the original participants, showed no statistically significant difference with the concentrations found in the first sample. Based on the results obtained from the Persistent Organic Pollutants Global Monitoring Plan report of 2009 of the Stockholm Convention, Colombia ranks fourth from bottom to top in terms of 4,4' DDE average concentrations.

Ligerin, an antiproliferative chlorinated sesquiterpenoid from a marine-derived Penicillium strain

A new chlorinated sesquiterpenoid analogue of fumagillin, ligerin (1), was isolated from a marine-derived strain of Penicillium, belonging to the subgenus Penicillium, along with the known compounds penicillic acid (2), orcinol, and orsellinic acid. Chemical structures were established by an interpretation of spectroscopic data including IR, UV, and HRESIMS, together with analyses of 1D and 2D NMR spectra and X-ray analysis for the determination of the absolute configuration. Ligerin (1) displayed strong inhibitory activity against an osteosarcoma cell line. This is the first report of the isolation of a fumagillin analogue from a marine-derived Penicillium strain.

Behavior, fate, and mass loading of short chain chlorinated paraffins in an advanced municipal sewage treatment plant

Sewage treatment plants (STP) are an important source of short chain chlorinated paraffins (SCCPs) to the ambient environment through discharge of effluent and application of sludge. In this work, a field study was conducted to determine the behavior and possible removal of SCCPs during the sewage treatment process in an advanced municipal STP in Beijing, China. SCCPs were detected in all sewage water and sludge samples, and 97% of the initial mass loading in raw sewage was found to be associated with suspended matter. The total concentrations in raw influent, tertiary effluent, and dewatered sludge were 184 ± 19 ng/L, 27 ± 6 ng/L, and 15.6 ± 1.4 μg/g dry weight (d.w.), respectively. The dissolved concentrations of total SCCPs (∑SCCPs) significantly decreased during mechanical, biological, and chemical treatments. SCCP homologue profiles in aqueous phase were distinctly different from those in solid phase. Along the treatment process, the relative abundance of shorter chain and lower chlorinated congeners gradually increased in sewage water, but no obvious variations of homologue profiles were found in sludge. Mass flow analysis indicated, the removal efficiency in aqueous phase for ∑SCCPs was 82.2%, and the congener-specific removal efficiencies were positively related to their solid-water partition coefficients (K(d)). Mass balance results indicated that 0.8% and 72.6% of the initial SCCP mass loading were ultimately found in the effluents and dewatered sludge, respectively, while the remaining 26.6% was lost mainly due to biodegradation/biotransformation. It was suggested that the activated sludge system including basic anaerobic-anoxic-aerobic processes played an effective role in removing SCCPs from the wastewater, while the sorption to sludge by hydrophobic interactions was an important fate of SCCPs during the sewage treatment.

Biosorption: a mechanistic approach

The ability of microbial cells to sequester solutes selectively from aquatic solutions, via nonmetabolically mediated pathways, has been termed biosorption. The mechanism of biosorption has been shown not to be simple and often specific to the biomass-solute pair. The understanding of the mechanism at play, in each biosorption system, is a prerequisite for the understanding of the stoichiometry, the equilibrium, the kinetics, the selectivity, and the engineering process application potential. Biosorption has been studied mostly for inorganic ionic solutes, but there is also reported work on the biosorption of organic molecules. Reference is also made to the biosorption engineering application issues.

Removal of chloropyrifos ethyl, tetradifon and chlorothalonil pesticide residues from citrus by using ozone

The removal of chloropyrifos ethyl, tetradifon and chlorothalonil pesticide residues from the lemon, orange and grapefruit matrices were achieved by ozonation. All of chlorothalonil residues adsorbed onto the orange matrix were completely removed after 5 min ozonation. The highest removal percentages of tetradifon and chloropyrifos ethyl were achieved as 98.6 and 94.2%, respectively for the lemon and grapefruit matrices. All of diffused chlorothalonil and chloropyrifos ethyl residues were completely removed from both orange and grapefruit matrices after 5 min ozonation. Increasing of applied ozone dosage was not significantly effect on the removal percentages of pesticides whereas increasing of ozonation temperature caused a negative effect on the removal percentages of pesticides. The washing of the matrices with tap water was not as effective as ozonation in the removal of residual pesticides. Our results show that ozone treatment has a great potential for removing of residual pesticides from lemon, orange and grapefruit matrices.

Evaluation of organochlorine pesticides in breast milk samples in Turkey applying features of the partial order technique

Exposure data to organochlorine pesticides (OCPs) of mothers' breast milk samples were measured in different locations in the Taurus Mountains/Turkey. Villages at five altitudes were looked upon. The data analysis method applied is the Hasse diagram technique, based on Discrete Mathematics. For each of the five regions, one Hasse diagram was calculated and showed the same maximal object, namely, p-p'-Dichlorodiphenyldichloroethane (DDE). In a further data investigation step, we performed the similarity analyses of the locations in order to quantify the similarities and incomparabilities. It was revealed that no correlation exists between most altitudes and the pattern of contamination of breast milk samples. The two lowest situated areas, Sahil at sea level and Ciftlikköy at 121 m above sea level were similar. We reduced the datasets by applying the interval analysis followed by similarity analyses. We observed that endrin (END1), mirex (MIRE), and pentachlorobenzene (PECB) reduce most severely the similarity.

Halogenated anthraquinones from the marine-derived fungus Aspergillus sp. SCSIO F063

Metabolomic investigations focusing on the marine-derived fungus Aspergillus sp. SCSIO F063 have unveiled seven new chlorinated anthraquinones (1-7) related to averantin, together with five known analogues (11-15) when the fungus was fermented using sea salt-containing potato dextrose broth. Through the addition of sodium bromide to the broth, two new brominated anthraquinones (8, 9) and one new nonhalogenated anthraquinone (10) were obtained from the fungal mycelia. Their structures were elucidated by extensive spectroscopic analyses including MS and 1D and 2D NMR data. One metabolite, 6-O-methyl-7-chloroaveratin (2), displayed inhibition activity against three human tumor cell lines, SF-268, MCF-7, and NCI-H460, with IC(50) values of 7.11, 6.64, and 7.42 μM, respectively.

Polyelectrolyte gels comprising a lipophilic, cost-effective aluminate as fluorine-free absorbents for chlorinated hydrocarbons and diesel fuel

Superabsorbent polymers comprising a lipophilic, halogen-free, and cost-effective aluminate ("altebate") anion have been synthesized. The polyelectrolytes are based on octadecyl acrylate monomers, 0.8-1 mol % ethylene dimethacrylate cross-linker, and 5 mol % N-3-acroyloxypropyl trialkylammonium altebate. At 30 °C, swelling degrees of 70 (chlorobenzene), 102 (CHCl3), 130 (THF), 163 (ClCH2CH2Cl), 171 (dichlorobenzene), and 208 (CH2Cl2) have been determined. The polyelectrolyte absorbs reversibly diesel fuel with a swelling degree of 34, even in the presence of water. Swelling times and critical swelling temperatures have also been determined. The challenges for the development of oil absorbents are discussed.

Two new chlorophenyl glycosides from the bulbs of Lilium brownii var. viridulum

Two rare new chlorophenyl glycosides, 2,4,6-trichlorol-3-methyl-5-methoxy-phenol 1-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside (1) and 4-chlorol-5-hydroxyl-3-methyl-phenol 1-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranoside (2), along with three known compounds (3-5) were isolated from the bulbs of Lilium brownii var. viridulum. The structures of the new compounds were elucidated on the basis of spectroscopic and chemical methods. All the compounds exhibited weak inhibition of NO production in LPS-stimulated RAW 264.7 cells.

An investigation on the sorption behaviour of montmorillonite for selected organochlorine pesticides from water

The sorption behaviour of montmorillonite towards organochlorine pesticides (OCPs) from aqueous solutions is reported. After preliminary investigation of the sorption capability of clay for selected OCPs, aldrin was used as a model compound for further experiments. The batch sorption experiments were carried out as functions of contact time, pH of the solution, initial aldrin concentration and dosage of the montmorillonite. After traditional liquid-liquid extraction, the determination of OCPs was carried out by gas chromatography coupled with a micro-electron capture detector (GC-microECD). The results indicated that sorption of aldrin followed the second-order kinetic model and that the equilibrium time depended on the initial aldrin concentration. The film diffusion was found to be a main sorption rate control mechanism. The removal was explained according to the electrostatic bonding mechanism. The Freundlich isotherm model better represented the sorption data than the Langmuir model. The montmorillonite was also used efficiently for the removal of OCPs from fortified tap and surface (lake) water samples.

Dynamics of Fe(II), sulphur and phosphate in pilot-scale constructed wetlands treating a sulphate-rich chlorinated hydrocarbon contaminated groundwater

Long-term investigations were carried out in two pilot-scale horizontal subsurface flow constructed wetlands (planted and unplanted) with an iron-rich soil matrix for treating sulphate-rich groundwater which was contaminated with low concentrations of chlorinated hydrocarbons. The temporal and spatial dynamics of pore-water sulphide, Fe(II) and phosphate concentrations in the wetland beds were characterized and the seasonal effects on sulphide production and nitrification inhibition were evaluated. The results demonstrated that the pore-water sulphide concentrations gradually increased from less than 0.2 mg/L in 2005 to annual average concentrations of 15 mg/L in 2010, while the pore-water Fe(II) concentrations decreased from 35.4 mg/L to 0.3 mg/L. From 2005 to 2010, the phosphate removal efficiency declined from 91% to 10% under a relatively constant inflow concentration of 5 mg/L. The pronounced effect of plants was accompanied by a higher sulphate reduction and ammonium oxidation in the planted bed, as compared to the unplanted control. A high tolerance of plants towards sulphide toxicity was observed, which might be due to the detoxification of sulphide by oxygen released by the roots. However, during the period of 2009-2010, the nitrification was negatively impacted by the sulphide production as the reduction in the removal of ammonium from 75% to 42% (with inflow concentration of 55 mg/L) correlated with the increasing mean annual sulphide concentrations. The effect of the detoxification of sulphide and the immobilization of phosphate by the application of the iron-rich soil matrix in the initial years was proven; however, the life-span of this effect should not only be taken into consideration in further design but also in scientific studies.

Temporal variations in natural attenuation of chlorinated aliphatic hydrocarbons in eutrophic river sediments impacted by a contaminated groundwater plume

Chlorinated aliphatic hydrocarbons (CAHs) often discharge into rivers as contaminated groundwater baseflow. Biotransformation, sorption and dilution of CAHs in the impacted river sediments have been reported to reduce discharge, but the effect of temporal variations in environmental conditions on the occurrence and extent of those processes in river sediments is largely unknown. We monitored the reduction of CAH discharge into the Zenne River during a 21-month period. Despite a relatively stable influx of CAHs from the groundwater, the total reduction in CAH discharge from 120 to 20 cm depth in the river sediments, on average 74 ± 21%, showed moderate to large temporal variations, depending on the riverbed location. High organic carbon and anaerobic conditions in the river sediments allowed microbial reductive dechlorination of both chlorinated ethenes and chlorinated ethanes. δ(13)C values of the CAHs showed that this biotransformation was remarkably stable over time, despite fluctuating pore water temperatures. Daughter products of the CAHs, however, were not detected in stoichiometric amounts and suggested the co-occurrence of a physical process reducing the concentrations of CAHs in the riverbed. This process was the main process causing temporal variations in natural attenuation of the CAHs and was most likely dilution by surface water-mixing. However, higher spatial resolution monitoring of flow transients in the riverbed is required to prove dilution contributions due to dynamic surface water-groundwater flow exchanges. δ(13)C values and a site-specific isotope enrichment factor for reductive dechlorination of the main groundwater pollutant vinyl chloride (VC) allowed assessment of changes over time in the extent of both biotransformation and dilution of VC for different scenarios in which those processes either occurred consecutively or simultaneously between 120 and 20 cm depth in the riverbed. The extent of reductive dechlorination of VC ranged from 27 to 89% and differed spatially but was remarkably stable over time, whereas the extent of VC reduction by dilution ranged from 6 to 94%, showed large temporal variations, and was often the main process contributing to the reduction of VC discharge into the river.

Enzymatic conversion of ε-hexachlorocyclohexane and a heptachlorocyclohexane isomer, two neglected components of technical hexachlorocyclohexane

α-, β, γ-, and δ-Hexachlorocyclohexane (HCH), the four major isomers of technical HCH, are susceptible to biotic transformations, whereby only α- and γ-HCH undergo complete mineralization. Nevertheless, LinA and LinB catalyzing HCl elimination and hydrolytic dehalogenations, respectively, as initial steps in the mineralization also convert β- and δ-HCH to a variety of mainly hydroxylated metabolites. In this study, we describe the isolation of two minor components of technical HCH, ε-HCH, and heptachlorocyclohexane (HeCH), and we present data on enzymatic transformations of both compounds by two dehydrochlorinases (LinA1 and LinA2) and a haloalkane dehalogenase (LinB) from Sphingobium indicum B90A. In contrast to reactions with α-, γ-, and δ-HCH, both LinA enzymes converted ε-HCH to a mixture of 1,2,4-, 1,2,3-, and 1,3,5-trichlorobenzenes without the accumulation of pentachlorocyclohexene as intermediate. Furthermore, both LinA enzymes were able to convert HeCH to a mixture of 1,2,3,4- and 1,2,3,5-tetrachlorobenzene. LinB hydroxylated ε-HCH to pentachlorocyclohexanol and tetrachlorocyclohexane-1,4-diol, whereas hexachlorocyclohexanol was the sole product when HeCH was incubated with LinB. The data clearly indicate that various metabolites are formed from minor components of technical HCH mixtures. Such metabolites will contribute to the overall toxic potential of HCH contaminations and may constitute serious, yet unknown environmental risks and must not be neglected in proper risk assessments.

Chlorinated englerins with selective inhibition of renal cancer cell growth

The chlorinated englerins (3-9) were isolated from Phyllanthus engleri and shown to selectively inhibit the growth of renal cancer cells. The compounds were shown to be extraction artifacts produced by exposure to chloroform decomposition products during their isolation. The most active compound, 3, was synthesized from englerin A (1).

Effect of carbon sources on the removal of 1,1,2-trichloroethane and 1,1,2,2-tetrachloroethane in UASB reactor

The effect of two carbon sources namely sodium acetate and ethanol was studied in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors for the removal of chlorinated ethanes i.e., 1,1,2-Trichloroethane (TCA) and 1,1,2,2-Tetrachloroethane (TeCA) contained in the simulated wastewaters. The Hydraulic Retention Time (HRT) was maintained as 24 hours in all the reactors. The granular biomass in the test reactors R2 and R3 were acclimated to 40 mg/L of TCA and 20 mg/L of TeCA, respectively. The effluent TCA and TeCA concentrations were 0.03 mg/L and 0.18 mg/L, respectively, at the end of acclimation phase. Sodium acetate and ethanol both were found to be suitable as the primary substrates in the biodegradation of TCA and TeCA. However, lower concentrations of the toxic pollutants (TCA and TeCA) were obtained in the effluents with the use of sodium acetate. The COD removal efficiency in the test reactors (R2 and R3) varied in the range of 95 % to 98.2 % accompanied by the formation of 1,2-Dichloroethane (DCA) as the major intermediate.

[Fixed-bed adsorption characteristics of chlorinated hydrocarbon vapors onto hydrophobic hypercrosslinked polymeric resin]

The dynamic adsorption of trichloroethylene (TCE), 1,2-dichloroethane (DCE) and trichloromethane (TCM) vapors onto hydrophobic hypercrosslinked polymeric resin (LC-1) were investigated using the fixed-bed adsorption method. The results indicated that the breakthrough time decreased and the height of mass transfer zone increased with the elevated initial concentration, gas flow rate and adsorption temperature. The gas flow rate had the wost significant influence on breakthrough time and height of mass transfer zone among the three factors. In addition, a simple semi-empirical mathematic model developed by Yoon and Nelson was applied to investigate the breakthrough behavior, and all correlation coefficients R2 were greater than 0.994.

Modifying metal nanoparticle placement on carbon supports using an aerosol-based process, with application to the environmental remediation of chlorinated hydrocarbons

A facile aerosol-based process (ABP) is developed to vary the placement of iron nanoparticles on the external surface of carbon microspheres or within the interior. This is accomplished through the competitive mechanisms of sucrose carbonization and the precipitation of soluble iron salts, in an aerosol droplet passing through a high temperature heating zone. At lower aerosolization temperatures, carbonization occurs first leading to iron salt precipitation on the external surface, while at higher temperatures interior placement occurs through concurrent iron salt precipitation and sucrose carbonization. The resulting composites are highly conducive to the reductive dechlorination of compounds such as trichloroethylene (TCE) as the carbon support is a strong adsorbent, and zerovalent iron effectively reduces TCE to innocuous gases such as ethane. Since both iron and carbon are widely used catalysts and catalyst supports, the simple process of modifying iron placement has significant potential applications in heterogeneous catalysis.

Synthesis of 5-chloro-8-hydroxy-6-methoxy-3-pentylisocoumarin

The synthesis of title isocoumarin, the 5-chloro analog of naturally occurring 7-chloro-8-hydroxy-6-methoxy-3-pentylisocoumarin, isolated from Tessmannia densiflora is described. Chlorination of ethyl 2-(2-ethoxy-2-oxoethyl)-4,6-dimethoxybenzoate (2) afforded 3-chloro ester (3) followed by hydrolysis to furnish the 2-(carboxymethyl)-3-chloro-4,6-dimethoxybenzoic acid (4) that was converted to corresponding anhydride (5). Condensation of the latter with hexanoyl chloride in the presence of tetramethylguanidine and triethyl amine afforded 5-chloro-6,8-dimethoxy-3-pentylisocoumarin (6) which upon regioselective demethylation yielded the title isocoumarin (1).

Comparison of two sample preparation methods for analysis of organochlorine pesticides residues in fish muscle

The aim of this study was to compare recoveries of organochlorine pesticides (heptachlor, α-HCH, β-HCH, γ-HCH, op'-DDD, pp'-DDD, pp'-DDE, op'-DDT, pp'-DDT) from fish muscle dried by two alternative methods: (i) grinding with anhydrous sodium sulphate and (ii) freeze drying. Pesticide residues content was determined by gas chromatography-mass spectrometry (GS-MS) method. For four pesticides (γ-HCH, α-HCH, heptachlor and pp;-DDD) in four of five fish species, higher recoveries were obtained from the freeze-dried samples. For five remaining pesticides, correlations between fish species and drying method were not found. The results of this study do not clearly indicate which drying method caused lower losses of analytes. Recoveries from the freeze-dried samples ranged from 69.9 to 117.6 %, while recoveries from the samples ground with sodium sulphate varied from 64.4 to 126.7 %. Either of the methods gave satisfactory recoveries and they both can be used interchangeably.

Organochlorine pesticides in ambient air in selected urban and rural residential areas in the Philippines derived from passive samplers with polyurethane disks

The passive sampler with PUF disk was applied to investigate the types and concentrations of organochlorine pesticides (OCPs) in ambient air in three urban and rural residential areas simultaneously at different weather conditions in the Philippines. The concentrations of OCPs derived from the passive samplers indicated clear distinctions in the predominance of certain types and amounts of OCPs in air at different sampling sites and periods of sampling. Chlordanes were detected in concentrations ranging from 218 to 2,324 pg/m³ in the urban residential sites in all the sampling periods, indicating the possible use of these pesticides as termiticides in houses. Endosulfans were detected in two rural sites at 491 pg/m³ and 904 pg/m³ during one sampling period; indicating the possible use of the pesticide in the farm areas at that period.

Chlorinated and diepoxy withanolides from Withania somnifera and their cytotoxic effects against human lung cancer cell line

Phytochemical studies on the aerial parts of Withania somnifera L. Dunal. (Solanaceae) led to the isolation of a chlorinated steroidal lactone (27-acetoxy-4β,6α-dihydroxy-5β-chloro-1-oxowitha-2,24-dienolide), a diepoxy withanolide (5β,6β,14α,15α-diepoxy-4β,27-dihydroxy-1-oxowitha-2,24-dienolide), and withaferin A. Their structures were elucidated by using spectroscopic techniques. All three compounds exhibited a growth inhibition and cytotoxic activity against human lung cancer cell line (NCI-H460), with withaferin A being the most potent (GI(50)=0.18 μg/mL and LC(50)=0.45 μg/mL) among three compounds tested.

Fate of pesticides in the arid subtropics, Botswana, Southern Africa

Despite a history of pesticide usage, few data exist on their concentrations in air and soil of Southern Africa. To add to the understanding of the processes controlling the fate of organic contaminants in arid regions, the levels, spatial trends, and seasonal variability of pesticides were studied in air and soil from Botswana. XAD resin-based passive air samplers (PAS) were deployed at 15 sites across the country from May 2006 to May 2007. Soil samples were collected from the vicinity of nine of the PAS sampling sites. In addition, 27 24-h high-volume air samples were collected in Maun, at the southeastern edge of the Okavango Delta, every two weeks for one year. Levels of pesticides in PAS were low, with α-endosulfan and lindane being most abundant. Concentrations in soils were extremely low and only soils with high organic carbon contained notable amounts of dieldrin and traces of other pesticides. In particular, air and soil from the Okavango Delta had very low levels even though the area had repeatedly been sprayed with DDT and endosulfan in the past. Air samples from Eastern Botswana, where the majority of the population lives, contained higher levels. Higher air concentrations of α-endosulfan occurred during summer and higher HCB levels occurred in winter. This seasonality was related with neither minor seasonal changes in temperature nor hydrological seasonal events such as the rainy season or the flooding of the Okavango Delta. Thus, the observed spatial and seasonal patterns are more likely related to pesticide usage pattern than to environmental factors or historical use. High temperature and low organic matter content limit the uptake capacity of most subtropical soils for pesticides. No evidence was found that sorption to dry mineral matter plays a major role. Arid soils in subtropical regions are therefore neither a major reservoir of organic contaminants nor do they constitute a significant long-term source of pesticides to the atmosphere.

Technical note: evaluation of extraction methodologies for the determination of an organochlorine pesticide residue in vegetation

Numerous extraction methodologies are used to quantify pesticide levels in vegetation. Sample availability, resource use, efficiency, time consumption, space allocation, and cost vary considerably among the commonly employed techniques. A study was conducted to compare the efficiency of microwave assisted extraction (MAE), blender homogenized extraction (BE), Soxhlet extraction (SE), the QuEChERS ("Quick, Easy, Cheap, Effective, Rugged, and Safe") method, and a simple oven assisted extraction (OAE), to recover p,p'-DDE from the tissues of Cucurbita pepo. A hot-solvent soak of stem or root tissues in a 2-propanol/hexane mixture, OAE yields recoveries that are statistically equivalent to the other procedures. The method recovered 1800 +/- 190 ng g(-1) and 8100 +/- 900 ng g(-1) (BCF = 87 +/- 9.7) p,p'-DDE from stem and root tissue, respectively. Recoveries for the other methods ranged from 1400-2200 ng g(-1) for the stems and 3600-7200 ng g(-1) for the roots. Statistical analyses for stem and root extraction indicate that there is no significant difference among the variances of each method. Given its simplicity, precision, and efficiency, OAE appears to be suitable for the extraction of an organic pollutant such as p,p'-DDE from plant tissues and for use in phytotechnology development and risk assessment.

Chlorinated iridoid glucosides from Veronica longifolia and their antioxidant activity

From Veronica longifolia were isolated three chlorinated iridoid glucosides, namely, asystasioside E (6) and its 6-O-esters 6a and 6b, named longifoliosides A and B, respectively. The structures of 6a and 6b were proved by analysis of their spectroscopic data and by conversion to the catalpol ester verproside (5a) or to catalpol (5), respectively. The configuration of the previously known vanilloyl analogue, urphoside B, was shown to be the 6β-epimer (6c) of the structure originally reported. Longifoliosides A (6a) and B (6b) were found to exhibit radical-scavenging activity against nitric oxide, superoxide, and 2,2-diphenyl-1-picrylhydrazyl radicals.

Bioavailability of organochlorine compounds in aqueous suspensions of fullerene: evaluated with medaka (Oryzias latipes) and negligible depletion solid-phase microextraction

The wide application of engineered nanomaterials, such as fullerene (C(60)), will inevitably lead to their release into the aqueous environment, which may alter the bioavailability of organic compounds to aquatic organisms. Negligible depletion solid-phase microextraction (nd-SPME) together with medaka (Oryzias latipes) bioaccumulation were used to study the effects of aqueous suspensions of fullerene (nC(60)) on the bioavailability of eight organochlorine compounds (OCCs) (logK(OW) 3.76-6.96). Freely dissolved concentrations of OCCs decreased by 11.5-88.4% at addition of 5mgL(-1)nC(60) as indicated by reduced equilibrium concentrations in the SPME fiber coating, the highest reduction being observed for the most hydrophobic OCCs. Medaka bioaccumulation study demonstrated that at the kinetic uptake regime, nC(60) significantly decreased the bioaccumulation of the high hydrophobic OCCs (logK(OW)>6), but slightly enhanced the bioaccumulation of the less hydrophobic OCCs (logK(OW)<6). The OCC concentrations in medaka (C(fish)) at the kinetic uptake regime linearly correlated with that in nd-SPME fiber (C(fiber)) without nC(60) (p=0.007-0.013, R(2)=0.666-0.723), but this correlation deteriorated with the presence of nC(60) (p=0.073-0.081, R(2)=0.423-0.440). These results suggest that in nC(60) the uptake mechanism of OCCs to medaka is different from that to nd-SPME fiber. While only the freely dissolved OCCs are available to nd-SPME fiber, both the freely dissolved and the nC(60) associated OCCs contributed to the accumulation of OCCs to medaka.