Antibacterial and antimutagenic activitiy of extracts and essential oil from (Tunisian) Pistacia lentiscus

Aqueous and flavonoid-enriched extract as well as essential oil (EO) obtained from leaves of Pistacia lentiscus were assessed for antibacterial and antimutagenic activities. Antibacterial activity of different extracts and EO were evaluated against six bacterial strains. A marked inhibitory effect was observed against Salmonella typhimurium, whereas lower activity was observed against Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enteritidis. EO showed significant inhibitory effects against Salmonella typhimurium, Salmonella enteritidis and Staphylococcus aureus. The antimutagenic activity of the different extracts against Aflatoxin B₁ (AFB₁) and sodium azide was demonstrated with the Salmonella typhymurium assay. The number of revertants per plate decreased significantly when the plant extracts were added to the assay system using Salmonella typhimurium TA100, TA98 and TA1535.     

Supramolecular complex formation,a possible antigenotoxic mechanism of glucomannan against aflatoxin B1

Abstract

Glucomannan is a highly branched polysaccharide with glycosidic linkages, constituted of mannoses and glucoses. In recent years, its usefulness due to its immunological, antioxidant and antimutagenic activity has been recognized. The aim of the study was to determine the antigenotoxic ability of glucomannan extracted from Candida utilis orally administered (100–700?mg/kg) to mice, which subsequently received 1?mg/kg aflatoxin B₁. Hepatocytes obtained from these animals 4–16?h post administration were examined by means of the comet assay. The antigenotoxic effect was found to be higher than that observed in previous studies with α-mannan and β-D-glucan isolated from Saccharomyces cerevisiae., In order to explore the possibility of formation of a supramolecular complex between glucomannan and aflatoxin B₁, both compounds were co-crystallized, their melting points determined, and the complex analyzed through ultraviolet spectroscopy. The spectroscopy data suggest that the protective effect of glucomannan is related to the formation of a supramolecular complex between the two compounds.     

Role of carbonic anhydrase in the supply of inorganic carbon to the giant clam—zooxanthellate symbiosis

The mechanism whereby inorganic carbon (C_i) is acquired by the symbiotic association between the giant clam (Tridacna derasa) and zooxanthellae (Symbiodinium sp.) has been investigated. C_i in the haemolymph of the clam is in equilibrium with the surrounding sea water. The photosynthesis rate exhibited by the intact clam varies as a function of the C_i concentration in the clam haemolymph. The gill tissue contains high carbonic anhydrase activity which may be important in adjusting the C_i equilibrium between haemolymph and sea water. Zooxanthellae (Symbiodinium sp.) isolated from the clam mantle prefer CO₂ to HCO ₃ ^- as a source of inorganic carbon. The zooxanthellae have low levels of carbonic anhydrase on the external surface of the cell; however, mantle extracts display high carbonic anhydrase activity. Carbonic anhydrase is absent from the mantle of aposymbiotic clams (T. gigas), indicating that this enzyme may be essential to the symbiosis. The enzyme is probably associated with the zooxanthellae tubes in the mantle. The results indicate that carbonic anhydrase plays an important role in the supply of carbon dioxide within the clam symbiosis.     

城市污水厂污泥倾倒对海洋生物的毒性研究

以广州市和佛山市的5个城市污水处理厂的污泥为实验对象,选取费氏弧菌、蒙古裸腹溞、卤虫、裸项栉鰕虎鱼仔鱼4种不同营养级的海洋生物为受试对象,结合化学分析方法,研究广州区域周边污水污泥浸出液的生物毒性效应。结果显示各污水污泥浸出液的毒性均较大,且浸出液的Cu污染浓度较高;广州市污水污泥对4种受试生物的毒性效应要高于佛山市。从污泥毒性对受试生物的选择性方面分析,发现卤虫筛分能力强且灵敏度高,而费氏弧菌则相关性好且方法简捷。研究结果为反映城市污泥的生物毒性强度和选择合适毒性评价受试生物提供基础数据。     

Leaf choice by crustaceans in a mangrove forest in Queensland

The feeding behaviour of leaf eating crustaceans feeding on leaves shed by Avicennia marina, Bruguiera gymnorhiza and Rhizophora stylosa in the mangrove forest at Myora Springs, Queensland, Australia was studied between 1980 and 1984. Individual Sesarma erythrodactyla (carapace >9 mm long), one of the most abundant species of crabs in the forest, processed approximately half a leaf from any of the three species of mangroves in 24 h under laboratory conditions. of the amount of leaf material processed, 20% was lost from the mandibles due to sloppy feeding, 68% was egested as faeces and 12% converted into crab biomass. Crabs processed more leaf material at 30°C than at 20°C. S. erythrodactyla preferred leaves of A. marina to those of the other two species, probably because leaves of A. marina have a lower tannin and a higher nitrogen content. Of the other two species, B. gymnorhiza was preferred to R. stylosa. Among leaves of R. stylosa, S. erythrodactyla exerts a strong preference for aged rather than freshly fallen, and for thick rather than thin leaves. The mesofauna (carapace length <9.0 mm) which processed dead mangrove leaves comprised juveniles of S. erythrodactyla, the crab Ilyograpsus paludicola, the isopod Exosphaeroma alata and the amphipods Orchestia sp. and Melita sp. These species processed between 0.2 and 24.7 mg dry wt of a leaf per individual over a period of 4 d. Of this, 72 to 85% was egested as faeces. The significance of leaf eating crabs to nutrient cycling in mangrove forests is discussed. I conclude that leaf processing by crustaceans shortens the time span between leaf fall and consumption of leaf material by organisms. This may have the effect of conserving leaf biomass inside the mangrove forest.     

Aerobic nitrogenase activity measured as acetylene reduction in the marine non-heterocystous cyanobacterium Trichodesmium spp. grown under artificial conditions

Aerobic nitrogenase activity in the marine non-heterocystous cyanobacterium Trichodesmium spp. NIBB 1067, isolated off the Izu Peninsula, Japan in 1983 and grown under artificial conditions, was assayed by the acetylene reduction method. This strain exhibited acetylene reduction activity under aerobic conditions when cells had been grown in the medium free of combined nitrogen. Activity was markedly enhanced by light, and dependent on the growth phase being higher during the exponential growth phase and lower during the late linear and stationary growth phases. Since typical colony formation occurred during the last growth phase, the present results contradict the idea that N₂-fixation depends on colony formation. The photosynthesis inhibitor DCMU at 10^-6 M inhibited light-dependent acetylene reduction completely. Acetylene reduction by Trichodesmium spp. was tolerant of O₂ as strongly as that in the heterocystous cyanobacteria. Even at a partial pressure of oxygen (p_{O 2}) of 3 atm, the activity still remained as high as half of the maximum. It was almost under anaerobic conditions. Maximum activity was obtained at pO₂ of ca. 0.1 atm.     

In situ pumping activities of tropical Demospongiae

Studies employing Scuba techniques were carried out on populations of 3 species of tropical demosponges to determine in situ patterns of water-pumping activity. Short-term changes in individual activity of deep-water species (15 to 55 m) were determined from continuous recordings of exhalant current velocities. Long-term changes were determined by repeated measurements of oscular velocity and oscular area. Mycale sp. was found to maintain constant levels of pumping activity in both short and long-term studies. Verongia gigantea underwent periodic cessations of activity averaging 42 min, at random intervals of approximately 19 h. Cessations were asynchronous throughout the population and inherent in origin. Long-term activity variations appeared to be cyclic, but were explainable by environmental events. Shallow-water populations of Tethya crypta exhibited a synchronized diurnal cycle of contraction and dilation, probably tied to the diurnal cycle of illumination. A longer term (average 15.8 days) cycle of activity-inactivity, also involving contraction and dilation, was asynchronous throughout the population during the calm season. Each individual maintained a fairly uniform cyclic period ranging from 9 to 21 days. Changes of T. crypta activity were probably due to changes in flagellar activity. With the onset of the stormy season, the activity of all members of the population was brought into synchrony by the effects of approximately biweekly storms. The behavior of Verongia archeri, Agelas sp., and other species indicates that constant activity (e.g. Mycale sp.) may be restricted to thin-walled species working at low pressures and velocities. Activity patterns are consistent within species, but variable in higher taxa. Behavioral activity patterns of sponges must be taken into account in ecological and physiological studies of these animals.     

Evaluation of the antimutagenic and antiradical potentials of extracts from the tubers of (Tunisian) Cyperus rotundus

The mutagenic potential of aqueous, total oligomers flavonoids (TOF), ethyl acetate and methanol extracts from tubers of Cyperus rotundus L. was assessed using Ames Salmonella tester strains TA98 and TA100, and SOS chromotest strain Escherichia coli PQ37 with and without metabolic activation (S9). None of the different extracts produced a mutagenic effect. Likewise, the antimutagenicity of the same extracts was tested using the “Ames test” and the “SOS chromotest”. Our results showed that C. rotundus extracts possess antimutagenic effects against S. typhimurium TA98 and TA100 strains towards the mutagen aflatoxin B1 (AFB1), similar to E. coli PQ37 strain against AFB1 and Nifuroxazide mutagens using the SOS chromotest assay. A free radical scavenging test was used in order to explore the antioxidant capacity of the extracts obtained from the tubers of C. rotundus. TOF, ethyl acetate and methanol extracts showed an important free radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazine (DPPH) free radical. These extracts showed an IC50 value of respectively 5, 20 and 65?µg?mL^?1. The beneficial effects of TOF, ethyl acetate and methanol extracts of C. rotundus were assessed by antioxidant and antimutagenic activities.     

Molt cycle alterations in behavior,feeding and diel rhythms of a decapod crustacean,the spiny lobster Panulirus argus

The crustacean molt cycle manifests extensive behavioral changes in addition to physiological and integumentary modifications. The paucity of quantitative studies led us to characterize molt stage dependent alterations in rhythmic locomotor, feeding, and agonistic behavior of subadult spiny lobster Panulirus argus held grouped and solitarily in simulated natural conditions. Non-disruptively determined molt stages were defined as proportions of intermolt duration. Significant nocturnal rhythmicity persisted through the full molt cycle, though daily form varied as a function of activity level and molt stage. A distinct early evening peak signaled initiation of foraging and walking behavior. Thereafter, rhythm amplitude either declined progressively (low activity: unimodal pattern), remained high (high activity: nocturnal plateau), or exhibited a secondary early morning peak (intermediate activity: bimodal and polymodal patterns). Activity ceased at or immediately prior to sunrise. Ecdysis was predominantly nocturnal, probably reflecting species specific spatiotemporal movement patterns and social behavior. A selective advantage of nocturnal ecdysis was postulated concerning avoidance of cannibalism and diurnal predators. Locomotor activity and feeding rates were not equivalent through the molt cycle, though both peaked in stages B₂-C₁. Locomotor activity remained high in metecdysis, decreased sharply at proecdysis initiation (D₀), reaching lowest levels in D₁-D₃, then increased in D₃ through B₁. Activity dropped steeply at ecdysis, though lobsters were capable of intense and coordinated activity. Feeding decreased slowly through metecdysis after the B₂-C₁ maximum, then increased temporarily in C₄ and D₀, indicating heightened feeding motivation. This contrasts with the locomotor activity decrease at proecdysis. Food consumption declined rapidly in D₁ and D₂ and ceased at the D₂-D₃ transition. Feeding resumed in B₁ or B₂, intensifying to maximum in late B₂. Feeding remained relatively constant within stages, whereas locomotor activity varied greatly, though both correlated with metabolic needs. Grouped and solitary lobsters displayed similar patterns of foraging and walking, equivalent to those of locomotor activity and feeding of solitary individuals. Frequency of agonistic interactions (not aggression per se) remained relatively constant through the cycle, peaking in metecdysis, though the highest relative proportion occurred near ecdysis. Lobsters then were submissive and avoided physical contact with conspecifics. Clearly, locomotor activity, feeding, and social behavior of P. argus are not simply determined. Indeed, behavior is distinctly phase coordinated with varying metabolic requirements dependent on the proximity to ecdysis and ecological pressures.     

镉对单环刺螠非特异性免疫及组织蓄积的影响

为探究镉(Cd)对海洋动物的毒性效应,考察了不同质量浓度(0.005、0.05和0.5 mg·L~(-1)) Cd处理对单环刺螠相关免疫生理指标及主要组织中Cd蓄积量的影响。结果表明:Cd胁迫下,血细胞密度(density of hemocyte, DHC)先升后降再升,酚氧化酶(phenoloxidase, PO)活力先升后降,溶菌酶(lysozyme, LSZ)活力先降后升再降,至处理96 h,处理组DHC均显著高于对照组(P0.05),总蛋白含量变化不显著;除低浓度胁迫组(0.005 mg·L~(-1))PO活力与对照组相近外,其他处理组的PO和LSZ活力均显著低于对照组(P0.05)。超氧化物歧化酶(superoxide dismutase, SOD)活力和丙二醛(malondialdehyde, MDA)含量总体呈上升趋势,过氧化氢(H_2O_2)含量先升后降再升,至胁迫96 h,各处理组SOD活力、MDA和H_2O_2含量均显著高于对照组(P0.05)。总之,Cd胁迫对单环刺螠非特异性免疫影响显著,Cd的短期胁迫可刺激DHC、PO和LSZ升高,免疫力增强,而高浓度Cd的胁迫时间较长会造成机体解毒能力下降,持续刺激机体产生过氧化反应,MDA含量升高,可作为单环刺螠在Cd长期胁迫下的免疫检测指标。不同胁迫浓度组单环刺螠肌肉和消化道中的Cd含量随胁迫时间均呈上升趋势,且存在显著的时间-剂量-效应关系(P0.05),其蓄积量水平为:消化道肌肉,具有组织特异性。     

Degradation of pentachlorophenol in a contaminated soil suspension using hybrid catalysts prepared via urea�Cformaldehyde polycondensation between iron(III)-tetrakis(p-hydroxyphenyl)porphyrin and humic acid

Hybrid catalysts were synthesized by attaching iron(III)-tetrakis(p-hydroxyphenyl)porphyrin (FeTPP(OH)₄) to humic acid (HA) via urea–formaldehyde polycondensation. FTIR spectra of the prepared catalysts indicated that the catalysts prepared via urea–formaldehyde polycondensation contained cross-links between the phenolic groups of FeTPP(OH)₄ and HA, which contains aliphatic amine functional groups. The prepared catalysts were examined for their ability to catalyze the oxidative degradation of pentachlorophenol (PCP) in a contaminated soil suspension. The levels of PCP degradation and dechlorination for the hybrid catalysts were significantly higher than those for the non-modified catalyst, FeTPP(OH)₄.     

Evaluation of the larvicidal efficacy of extracts from three plants and their synergistic action with propoxur against larvae of the filarial vector Culex quinquefasciatus (Say)

Petroleum ether extracts of Piper longum, Curcuma aromatica, and Ocimum basilicum were tested for their larvicidal activity against Culex quinquefasciatus, a filarial vector using WHO standard procedures. Among the three plants, extract of P. longum was found to be highly effective with LC₅₀ and LC₉₀ being 0.89 and 1.49 ppm, respectively. C. aromatica also showed significant larvicidal activity with LC₅₀ and LC₉₀ being 11.41 and 17.36 ppm, respectively. The LC₅₀ and LC₉₀ for O. baslicum were 76.67 and 200.56 ppm, respectively. Propoxur, a carbamate was also studied for its larvicidal activity, which showed LC₅₀ to be 0.09 ppm and LC₉₀ to be 0.16 ppm. Synergistic studies of all three plant extracts with propoxur revealed P. longum as a more efficient synergist with synergistic factor (SF) of 4.13 for LC₅₀ value and 1.68 for LC₉₀. Both C. aromatica and O. basilicum exhibited antagonistic activity at their respective LC₉₀ values with propoxur. At 1 : 1 ratio of the phytoextracts and propoxur, P. longum and C. aromatica showed synergism whereas O. basilicum displayed additive effect. Thus, P. longum was found to be a better larvicidal and synergistic agent at all tested ratios. Evidence indicates that mixed formulations of phytoextracts with insecticides might reduce the concentration of the chemicals to be applied for vector control.     

Chitobiase activity in the epidermis and hepatopancreas of the fiddler crab Uca pugilator during the molting cycle

The activity of chitobiase, also known as N-acetyl-β-glucosaminidase, in the epidermis and hepatopancreas of the fiddler crab Uca pugilator (Bosc, 1802), during the molting cycle, was investigated. A pH optimum of 5 to 6 was found for the enzymatic activity in both the epidermis and hepatopancreas. The temperature optimum for epidermal and hepatopancreatic chitobiase activities was 50 to 60 °C. The K _m values for epidermal and hepatopancreatic chitobiase activities at 19 °C were 0.190 ± 0.027 and 0.203 ± 0.016 mM 4-methylumbelliferyl-N-acetyl-β-glucosaminide, respectively. Hepatopancreatic chitobiase activity was significantly higher than epidermal enzymatic activity in all the molt cycle stages tested except Postmolt Stage A-B. Chitobiase activity varied significantly during the molting cycle, with the epidermal enzymatic activity in Premolt Stage D_3–4 significantly higher than in Stage C (intermolt) and Premolt Stage D₀, whereas hepatopancreatic chitobiase activity in Premolt Stage D_3–4 was significantly higher than in all other molt stages tested. The patterns of chitobiase activity in the epidermis and hepatopancreas correlate well with the hemolymph titer of ecdysteroids in U. pugilator during the molting cycle; this suggests that chitobiase activity in both tissues is regulated at least in part by the steroid molting hormones. Received: 6 May 1998 / Accepted: 12 September 1998     

Growth rate and carbon affinity ofUlva lactuca under controlled levels of carbon,pH and oxygen

We examined the growth rate (µ) ofUlva lactuca L. (collected from Roskilde Fjord, Denmark in 1987) at different levels of dissolved inorganic carbon (DIC), pH and oxygen in two culture facilities. Growth was faster in Facility A (µ _max ca 0.3 d^–1) than in B (µ _max ca 0.2 d^–1), probably because of more efficient stirring and higher light intensity. The growth-DIC response curve exhibited low half-saturation constant (K _1/2) values (0.35 mM DIC in A, 0.55 mM in B) and growth rates close toµ _max at natural seawater concentration of 2 mM DIC. Growth rate showed a low sensitivity to oxygen over a wide range of DIC and oxygen concentrations. Collectively, the results demonstrated an efficient mechanism for DIC use, unaffected by acclimatization to DIC concentrations between 0.2 and 3 mM. The growth rate decreased little between pH 7.5 and 9 at 2 mM DIC, but steeply above pH 9 approaching zero just above pH 10. The decline of growth at high pH may result from direct pH effects on cell pH, reduced HCO ₃ ^- availability and impaired operation of the carbon uptake process. The growth responses ofU. lactuca to DIC, pH and oxygen resembled those observed in previous short-term photosynthetic experiments. This similarity is probably due to the fast growth ofU. lactuca which means that photosynthetic products are rapidly converted into cell growth. Based on the culture experiments we argue that field plants ofU. lactuca not exposed to stagnant water and DIC depletion are likely to be limited in growth by environmental factors other than DIC (e.g. light and nutrients). Dense mats ofU. lactuca, however, may show reduced growth as a result of DIC depletion, high pH and self-shading.     

Feeding habits of pasiphaeid shrimps close to the bottom on the Western Mediterranean slope

The composition of the diet and daily cicle of predatory activity of pasiphaeid shrimps in the Northwestern Mediterranean were established; special attention was focussed on nocturnal feeding habits close to the bottom. Daily activity in both species was studied in two continuous 24-h sampling periods. Samples were obtained using bottom trawls between 1988 and 1990. Both species fed on benthic prey items at night. The nocturnal diet of Pasiphaea multidentata consisted of gammarid amphipods, isopods (Cirolana borealis) and macruran decapods (Calocaris macandreae). Nocturnal feeding activity was carried out only by large specimens (cephalothorax length >28 mm), which stayed close to the bottom during the nighttime. In contrast, the specimens collected during the daytime exhibited highly digested remains of pelagic prey (hyperiids, fishes, euphausiids, chaetognaths) ingested as a result of predatory higher activity in the water column the night before. The feeding strategy of P. sivado was parallel to that of P. multidentata. At night large specimens were located near the bottom and fed on suprabenthic gammarid amphipods. This nocturnal feeding activity by both these mesopelagic pasiphaeid species furnishes evidence of energy transfer from the benthos to the planktonic system in bathyal communities. Changes were observed in the diet of P. multidentata with depth. Crustaceans made up a larger share of the diet of P. multidentata on the lower slope than on the upper middle slope, probably because of changes undergone by bathyal communities with increasing depth. The feeding rate was higher in the submarine canyons, where the diet is also more specialised. Dietary overlap between the two pasiphaeids was very low, due to the different size range of prey exploited.     

Toxicity of endosulfan on growth,photosynthesis, and nitrogenase activity in two species of Nostoc (Nostoc muscorum and Nostoc calcicola)

Treatments of the cyanobacteria Nostoc muscorum and Nostoc calcicola with the insecticide endosulfan (5, 10, and 20?µg?mL^?1) inhibited growth, photosynthetic pigments, photosynthetic, and nitrogenase activities. The sensitivity of N. muscorum to endosulfan was higher than that of N. calcicola. The toxic effect of endosulfan was more pronounced on phycocyanin; however, a considerable reduction in chlorophyll a and carotenoids was also noticed. ¹⁴C-fixation appeared to be more sensitive to the insecticide than photosynthetic oxygen evolution. Endosulfan caused strong inhibition of photosystem (PS) II activity whereas PS I was least affected. The inhibition of PS II activity was partially restored by electron donors (DPC, NH₂OH, and MnCl₂) at low dose of endosulfan. Nitrogenase activity was significantly suppressed in both species by the endosulfan at high dose (20?µg?mL^?1). On the basis of our comparative analysis, N. calcicola was found to be endosulfan resistant and can be used in paddy fields for better productivity under pesticide stress.     

Predatory feeding of two marine mysids

Predatory feeding of the marine mysids Mysidopsis bigelowi and Neomysis americana on several species of co-occurring copepods was examined in laboratory experiments. M. bigelowi exhibited a curvilinear functional response; there was a negative logarithmic relationship between prey density and clearance rates. N. americana also exhibited higher clearance rates at lower prey densities. Increased clearance rates at lower prey densities were probably due to increased swimming speed or reaction distance as hunger increased. This response occurred only when mysids could visually locate prey; in complete darkness clearance rates were significantly lower and independent of prey density. Feeding rates on different prey species were only partially dependent on prey size; prey movement patterns and escape behavior also strongly affected feeding rates. M. bigelowi showed active prey selection when offered a choice of different prey species. Estimates of predation rates of estuarine mysid populations indicate that they could have a significant effect on co-occurring copepod populations.     

Rapid assessment of metabolic activity in marine microalgae: application in ecotoxicological tests and evaluation of water quality

A new method for the assessment of the effects of several contaminants on marine microalgae,Tetraselmis suecica (Kyling) Butcher,Skeletonema costatum (Grev.) Cleve, andProrocentrum lima (Ehrenberg) Dodge was developed in 1990. The method is based on the measurement of cell esterase activity using a fluorimetric stain, fluorescein diacetate (FDA), selected from amongst three stains (FDA, Neutral Red, thiazolyl tetrazolium bromure) for its higher sensitivity. Biochemical (K _m,V _max) and physiological (growth, specific activity) aspects of the enzymatic activity as revealed by the FDA method are discussed. Different categories of compounds (weed-killers, insecticides, metals) and some water samples from Seine Bay were tested for their toxic effects on microalgae. Experiments were performed on microplates using a fluorimetric microplate reader. The various steps of the experiments and data-processing were controlled by software. Applications of the system to rapid ecotoxicological tests (determination of the IC₅₀, i.e., the concentration at which 50% inhibition of growth occurs) and to the assessment of environment quality by studying the toxic effect of water samples on microalgae are proposed.     

Nitrogen fixation (acetylene reduction) associated with the living coral Acropora variabilis

To estimate N₂-fixation, acetylene reduction assays were carried out on portions of the branches of the coral Acropora variabilis from the west coast of Malaysia. In some experiments, a sub-surface incubation apparatus was employed that was designed to keep the coral fragments near to their natural depth of occurrence. Other shipboard experiments used metabolic inhibitors to investigate the class of organism reducing acetylene. Stumps of coral gave the highest rates of activity, probably attributable to loosely associated cyanophytes. Coral tips also reduced acetylene at relatively high rates; reduction was enhanced in light by increased CO₂ concentration and decreased O₂ tensions indicative of photosynthetic bacteria. Algal material was not obvious on the tip surfaces and so the active organism was probably more integral to the coral structure than it was in the stumps. Maximum rates of acetylene reduction measured translated to 2.5 mg N₂ fixed per outcrop per day.     

Removal of pentachlorophenol from contaminated soil by catalytic oxidation with iron(III)-porphyrin complexes and potassium monopersulfate

Pentachlorophenol (PCP) in contaminated soil was removed by treatment with aqueous solutions of iron(III)-porphyrin complexes as catalysts and potassium monopersulfate (KHSO₅) as the oxygen donor. The contaminated soils were artificially prepared by spiking PCP to the kaolin and ando soils. Three types of iron(III)-porphyrin complexes, tetra(?p-sulfophenyl) porphineiron(III) (Fe(III)-TPPS), tetra(N-methyl-4-pyridil)porphineiron(III) (Fe(III)-TMPyP) and heme, were examined, and Fe(III)-TPPS was found to be the most effective for removing PCP. Although the sequential addition of KHSO₅ was examined, in an attempt to improve the efficiency of PCP removal, it was not effective. In a preliminary test of various aqueous solutions, the addition of humic acid (HA), with a lower degree of humification, led to a significant enhancement in PCP removal. When HA was added to the soil system, the percentages of PCP removal were increased by up to 10% compared to the absence of HA. Therefore, the addition of HA to the catalytic system was useful in enhancing PCP removal from contaminated soil.