The environmental behaviour of polychlorinated phenols and its relevance to cork forest ecosystems: a review

Pentachlorophenol (PCP) has been used as a herbicide, biocide and preservative worldwide since the 1930s and as a result, extensive and prolonged contamination exists. The environmental impact increases when its many degradation products are taken into consideration. A number of chloroanisols and their related chlorophenols have been found in cork slabs collected from Portuguese oak tree forests before stopper manufacturing, and contamination by PCP and polychlorinated anisole (PCA) has been detected in Canadian forests. It is suggested that the use of polychlorinated phenols, in particular PCP, is thought to be a cause of the cork taint problem in wine, a major socio-economic impact not only for industry but on sensitive and highly biodiverse ecosystems. It also highlights particular issues relating to the regional regulation of potentially toxic chemicals and global economics world wide. To fully understand the impact of contamination sources, the mechanisms responsible for the fate and transport of PCP and its degradation products and assessment of their environmental behaviour is required. This review looks at the current state of knowledge of soil sorption, fate and bioavailability and identifies the challenges of degradation product identification and the contradictory evidence from field and laboratory observations. The need for a systematic evaluation of PCP contamination in relation to cork forest ecosystems and transfer of PCP between trophic levels is emphasised by discrepancies in bioaccumulation and toxicity. This is essential to enable long term management of not only transboundary contaminants, but also the sustainable management of socially and economically important forest ecosystems.     

Dechlorination of pentachlorophenol in supercritical carbon dioxide with zero-valent palladium-magnesium bimetallic mixture

A stream of substrate pentachlorophenol [PCP, 5 mg min(-1) in water-methanol (1 + 4, v/v)] was merged with 1.5 ml min(-1) of supercritical carbon dioxide (scCO2) and delivered to a reactor column (25 cm x 1 cm) of zero-valent palladium-magnesium mixture. The resulting dechlorinations, although very efficient, were not quantitative. For continuous operation at 400 degrees C for 6 h, phenol was the principal product, with lesser quantities of methylated products and only traces of chlorinated products (principally monochlorinated species). PCP deoxygenation was not observed and ring methylation was decreased relative to analogous reactions in hydroxylic organic solvent. With time, the reactor column slowly lost dechlorination activity. Reducing the loading of Pd0 on Mg0 from 2% to 1% (w/w) apparently did not change the course of the reaction; however, the dechlorination capacity was decreased correspondingly. None the less, over 6 h or 5 h of continued operation, the dechlorination efficiency was 0.995 for the 2% (w/w) loading of Pd0 on Mg0 and 0.984 for the 1% (w/w) loading.     

A new system to bioassay pesticides present in the surface microlayer using floating propagules of an aero-aquatic hyphomycetous fungus Pseu doaegerita matsushimae

The surface microlayer often contains pesticides at levels which may be more than one hundred thousand times those sampled in the remainder of the water column. Standard bioassay systems cannot asses these pesticides since no system yet devised has made use of organisms inhabiting the surface microlayer. Using floating propagules of Pseudoaegerita matsushimae, an aeroaquatic hyphomycetous fungus, a bioassay system was devised in which the percentage germinations of such propagules after exposure to various levels of pesticides were plotted to produce a dosegermination scale onto which subsequent data could be fitted. The following pesticides and pesticide mixtures were used: PCP; DDT; Methoxychlor; Bis(tributyl)tin Oxide; Malathion; Captan; 1 part PCP/1 part DDT; 2 parts PCP/1 part DDT; 3 parts PCP/1 part DDT; 2 parts DDT/1 part PCP; 3 parts DDT/1 part PCP; 1 part PCP/1 part Methoxychlor; 2 parts PCP/1 part Methoxychlor; 3 parts PCP/1 part Methoxychlor; 2 parts Methoxychlor/1 part PCP; 3 parts Methoxychlor/1 part PCP. The bioassay system revealed increased sensitivity to pesticides and pesticide mixtures which affected respiratory metabolism. Some pesticide mixtures were more effective in inhibiting germination than their individual components while others appeared much less toxic to the propagules than their unassisted components.     

Analysis of HO-PCBs and PCP in blood plasma from individuals with high PCB exposure living on the Chukotka Peninsula in the Russian Arctic

A trace analytical method is presented for the analysis of hydroxylated polychlorinated biphenyl metabolites (HO-PCBs) and pentachlorophenol (PCP) in human plasma. The described methodology is a modification of a previously validated method used for PCB and organochlorine pesticide analysis. The modified method enables the combined analysis of phenolic and neutral halogenated compounds. A tandem Florisil column is used for separating the HO-PCBs and PCP from the neutral fraction, instead of the more common chemical partitioning. In the same step the neutral fraction is purified for GC analysis. The extraction of the HO-PCBs and PCP was found to be highly dependent on sufficient acidification of the sample and the polarity of the extracting solvent. Analysis of plasma samples gave recovery rates for (13)C(6)-PCP and (13)C(12)-4-HO-CB 187 of 64 and 72%, respectively. The limit of detection ranged between 2-20 pg g(-1) plasma for the HO-PCBs and 5 pg g(-1) plasma for PCP. No matrix interferences were observed in the chromatograms. In plasma samples (n = 15) from the native Chukchi people in Uelen (Russian Arctic), a population with high PCB exposure, the median ratio of sum HO-PCBs to sum PCBs was as high as 0.4 and the sum HO-PCBs and PCBs were significantly correlated (r(2) > 0.7, p < 0.01). The median sum HO-PCBs (10 congeners) was 5920 pg g(-1) plasma with 4-HO-CB 107 as the dominating congener (median: 1670 pg g(-1) plasma). The median PCP level was measured at 642 pg g(-1) plasma.     

Pentachlorophenol in indoor environments. Does a single measurement of air and dust concentrations represent the contamination?

In order to be able to make a decision, as to whether a room or building has a health-endangering pentachlorophenol (PCP) concentration, usually the PCP concentrations in air and settled dust are measured. The variability of the PCP concentration in indoor air and dust was studied. Air and dust samples were taken from 75 rooms in 30 buildings with suspicion of application of PCP-containing wood preservatives. Sampling was repeated four times within 18 months. Thirty-six rooms were reconstructed within the study; 39 rooms had unchanged contamination status during the study. The four times repeated measurements of PCP concentrations in air and dust in these rooms showed large variations of the measured values. The variability of the results is to a large extent in the same range as the measured values. The observed relative standard deviation of the PCP concentrations in air and dust does not depend on the average PCP concentration detected in the individual rooms.     

毛细管柱气相色谱法测定水质五氯酚

用乙酸酐衍生，正己烷液一液萃取，毛细管柱气相色谱-电子捕获检测器对地表水、废水中五氯酚进行了测定，确定五氯酚浓度范围在5．0—500μg/L之间时，样品的测定精度、回收率及方法检出限均能满足要求。     

Entrapping of organic wastes by coordination clathrates

The feasibility of the Hofmann clathrates Ni(CN)₂(NH₃)·G(G=guest molecule) and the octahedral Werner-type complexes Ni(X)₂(L)₄ (X=NCS, NCO, CH₃CO₂, C₆H₅CO₂; L=Py, 4-Mepy) as a scavenger for organic substrates in a polluted aqueous or organic medium is dependent on the complex lability, thermal stability and reversibility in solvent trapping which can be conveniently studied by thermogravimetric means. Besides the parent monomeric octahedral complexes, all the thermal decompositional intermediates, namely, monomeric tetrahedral, dimeric octahedral and polymeric octahedral, are also potential scavengers for selected organic substances though they operate via a cycle of bond-making and bond-breaking processes.     

Reduction of pollutants in pulp paper mill effluent treated by PCP-degrading bacterial strains

Two PCP-degrading bacterial strains, Bacillus cereus (ITRC-S6) and Serratia marcescens (ITRC-S7) were used for the treatment of pulp and paper mill effluent at conditions; 1.0% glucose and 0.5% peptone at 30 +/- 1 degrees C at 120 rpm for 168 h of incubation. These two bacterial strains effectively reduced colour (45-52%), lignin (30-42%), BOD (40-70%), COD (50-60%), total phenol (32-40%) and PCP (85-90%) within 168 h of incubation. However, the highest reduction in colour (62%), lignin (54%), BOD (70%), COD (90%), total phenol (90%) and PCP (100%) was recorded by mixed culture treatment. The bacterial mechanism for the degradation of pulp and paper mill effluent may be explained by an increase in the cells biomass using added co-substrates resulting liberation of significant amount of chloride due to bacterial dechlorination of chlorolignins and chlorophenols this showed reduction in colour, lignin and toxicity in the effluent. Further, GC-MS analysis of ethyl acetate-extractable compounds from treated pulp paper mill effluent reinforces the bacterium capability for the degradation of lignin and pentachlorophenol, as many aromatic compounds such as 2-chlorophenol, 2, 4, 6-trichlorophenol and tetrachlorohydroquinone, 6-chlorohydroxyquinol and tetrachlorohydroquinone detected which were not present in the untreated effluent.     

Diurnal variations of abiotic parameters in a stream,recipient for drainage water in Ranstad,southwest Sweden

During 24 h, water samples were taken for determination of a number of key parameters in a water system containing high concentrations of FeII at circumneutral pH. None of the major constituents (Ca, Mg, Na, K and sulfate) showed diurnal variations, while dissolved oxygen and pH increased during the night. This increase could entirely be explained by the decrease in water temperature. However, the concentration of FeII slightly increased at constant concentration of total Fe during the night, opposite to earlier observations in other systems where the presence of FeII was shown to be controlled by photoreduction. Nocturnal peaks of FeII have also been observed in other systems with high iron concentrations, however, at acidic pH, but without obvious explanation. The mechanisms for this process therefore need further investigation.     

毛细管气相色谱法测定鳌江表层沉积物中五氯酚和六氯苯

建立了超声波萃取-醋酸酐原位衍生化-毛细管气相色谱同时测定鳌江表层沉积物中五氯酚和六氯苯的方法，优化了试验条件。方法线性范围为5μg／L-200μg／L，五氯酚和六氯苯的检出限均为0．5ng／g，沉积物标准物质的测定值符合质控要求，基质加标的平均回收率分别为77．7％和81．8％。