Reduction of the phenolic components in olive-mill wastewater by an enzymatic treatment and its impact on durum wheat (Triticum durum Desf.) germinability

Olive-mill wastewater (OMW), an effluent of olive oil extraction process, is annually produced in huge amounts in olive growing areas. An interesting option for its disposal is the spreading on agricultural land, provided that phytotoxic effects are neutralized. The objective of the present investigation was to evaluate the potential of an enzyme-based treatment in removing OMW phytotoxicity. To this aim, germinability experiments on durum wheat (Triticum durum Desf. cv. Duilio) were conducted in the presence of different dilutions of raw or enzyme-treated OMW. OMW treatment with laccase resulted in a 65% and 86% reduction in total phenols and ortho-diphenols respectively, due their polymerization as revealed by size-exclusion chromatography. Raw OMW exerted a significant concentration-dependent inhibition on the germinability of durum wheat seeds which was evident up to a dilution rate of 1:8. When the effluent was treated with a fungal laccase, germinability was increased by 57% at a 1:8 dilution and by 94% at a 1:2 dilution, as compared to the same dilutions using untreated OMW. The treatment with laccase also decreased the mean germination time by about 1 day as compared to untreated controls. These results show that germinability inhibition due to OMW can be reduced effectively using fungal laccase, suggesting that phenols are the main determinants of its phytotoxicity.     

Reusing ethyl acetate and aqueous exhausted fractions of dry olive mill residue by saprobe fungi

Some saprobe fungi (Phlebia radiata, Trametes versicolor, Coriolopsis rigida, Pycnoporus cinnabarinus, Fomes sclerodermus or Pleurotus pulmonarius) were able to bioconvert the ethyl acetate fraction (DEAF) and the corresponding aqueous exhausted fraction (EAF) of dry olive mill residue (DOR), reducing their phytotoxicity on Lepidium sativum seeds. Large amount of hydroxytyrosol together with other eight monomeric phenols were found in the native DEAF fraction, which represents a good source of antioxidants. P. radiata, T. versicolor and F. sclerodermus caused an effective phytotoxicity reduction of EAF in the concentration range of 25-3 gl(-1). In particular, in the range between 12.5 and 3 gl(-1), the EAF samples inoculated with P. radiata and F. sclerodermus surprisingly stimulated the germinability of L. sativum, suggesting their use as a potential biofertilizer. This is the first report which showed the bioconversion of the above fractions in shorter time with respect to the previous findings concerning DOR. The possible implications of laccase in the decrease of DEAF and EAF phytotoxicity was also discussed.     

利用干法半干法烟气脱硫灰热分解钾长石的实验研究

探讨了目前干法半干法脱硫灰综合利用当中存在的诸多问题.提出了利用该类灰渣热分解钾长石矿,生产以钾、钙、硅和镁为主的土壤营养调节剂.并对最佳的物料配比、焙烧条件和助剂的种类及含量进行了实验研究,利用广州恒运集团公司产出的脱硫灰,在1 050℃下焙烧2 h,使烧成物在酸性条件下最大可溶K2O达6.49%、有效CaO达32.28%、SiO2达13.83%、MgO达1.68%.烧成物料的PH值为9.6,是一种安全、适用于偏酸性土壤使用的复合元素土壤营养调节剂.     

Vinegar residue compost as a growth substrate enhances cucumber resistance against the Fusarium wilt pathogen Fusarium oxysporum by regulating physiological and biochemical responses

Environmental Science and Pollution Research - Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. cucumerinum (FOC) is the most severe soil-borne disease attacking cucumber. To assess the...     

Effect of culturing temperatures on cadmium phytotoxicity alleviation by biochar

Biochar produced from rice straw at 400 °C (RS400) was prepared to determine its alleviating effect on Cd phytotoxicity to wheat seedlings under different cultivation temperatures and pH. A hydroponic system (pH 4.3) and a loam soil slurry system were designed to respectively simulate acidic and neutral soil condition, and cultivation at increasing temperatures (20, 25, and 30 °C) were performed to evaluate the greenhouse effect. The root and shoot elongation and the Cd concentration in root and solution were measured; furthermore, batch experiments for Cd adsorption were undertaken. An increasing inhibition of the root by Cd addition was observed at increasing temperatures. The inhibition rate was 50.50 and 20.80% in hydroponic system and slurry system at 25 °C, respectively; however, the corresponding inhibition rates of root were significantly decreased to 25.5 and 3.5% with addition of RS400. This is mainly attributed to the reduction of Cd migration into the roots by RS400, which decreased Cd bioavailability. The mechanism behind the reduced Cd bioavailability is attributed to the Cd adsorption and the strong buffering capacity of acidity by RS400. Therefore, biochar could be a potential amendment for the remediation of Cd-contaminated soil even at increasing culturing temperatures.

     

Co-substrate-mediated utilization of high concentration of phenol by Aspergillus niger FP7 and reduction of its phytotoxicity on Vigna radiata L.

Environmental Science and Pollution Research - Phenol and its derivatives behave as mutagens, teratogens and carcinogens inducing adverse physiological effects and are considered environmental...     

Uptake of oxytetracycline and its phytotoxicity to alfalfa (Medicago sativa L.)

A series of experiments were conducted in a hydroponic system to investigate the uptake of oxytetracycline (OTC) and its toxicity to alfalfa (Medicago sativa L.). OTC inhibited alfalfa shoot and root growth by up to 61% and 85%, respectively. The kinetics of OTC uptake could be well described by Michaelis-Menten equation with Vmax of 2.25 micromol g-1 fresh weight h-1, and Km of 0.036 mM. The uptake of OTC by alfalfa was strongly inhibited by the metabolic inhibitor, 2,4-DNP (2,4-dinitrophenol), at pH 3.5 and 6.0, but not by the aquaporin competitors, glycerol and Ag+. OTC uptake, however, was significantly inhibited by Hg2+, suggesting that the inhibition of influx was due to general cellular stress rather than the specific action of Hg2+ on aquaporins. Results from the present study suggested that OTC uptake into alfalfa is an energy-dependent process.     

Dephenolization and detoxification of olive-mill wastewater (OMW) by purified biotic and abiotic oxidative catalysts

The capability of two oxidative catalysts, a laccase from Rhus vernicifera and birnessite, a manganese oxide, in the dephenolization and detoxification of two olive-mill wastewater (OMW) samples, C1 and C2, differing for complexity and composition, was evaluated. OMW phenolic extracts (EC1 and EC2) and mono-substrate solutions of phenols mostly present in OMW samples were also tested. Birnessite was more effective than laccase in removing the phenolic content from mono-substrate solutions (more than 70% of each initial phenolic concentration) and of either OMW samples or EC1 and EC2 extracts. For instance, 60% of the total phenolic content of EC1 was removed after 48-h treatment with 5 mg mL(-1) birnessite and the efficiency was lower as greater was the complexity of the OMW sample (only 17% removal from EC2 over the same time span). Phytotoxicity tests with Lepidium sativum and Lycopersicon esculentum seeds and antibacterial toxicity tests with Bacillus megaterium were performed on crude OMW samples and their extract and exhausted fractions before and after the catalytic treatment. Results demonstrated that (a) monomeric phenols were certainly but not exclusively responsible of OMW phytotoxicity, whereas their removal led to a quite complete elimination of the toxicity toward bacterial growth; (b) other components not removable by the oxidative catalysts very likely contribute to OMW phytotoxicity; and (c) the choice of the vegetal species to use in toxicity tests might be crucial for correct and easily interpretable results. Overall the results provided useful information on the possible use of oxidative catalysts for the efficient treatment of complex aqueous wastes such as those deriving from olive industry.     

Comparative phytotoxicity of Rac-metolachlor and S-metolachlor on rice seedlings

The toxicity of Rac-metolachlor and S-metolachlor on rice (IIYou92, Oryza sativa L.) seedlings was determined and compared in a hydroponics experiment. The elongation of shoot, main root, and the number of lateral roots were inhibited in both Rac- and S-metolachlor treatments. The 96 h- IC50 of Rac- and S-metolachlor were 12.32 and 9.44 μM for shoot, and 4.69 and 1.75 μM for root, respectively. The content of chlorophyll a, chlorophyll b and total chlorophyll of leaf treated by Rac-metolachlor was higher than that treated by S-metolachlor. The activities of superoxide dismutase, peroxidase, cytochrome P450 2E1, glutathione S-transferase, and the content of glutathione increased after herbicide exposure, and the activities or the content was higher in the S-metolachlor treatment than in the exposure to Rac-metolachlor. Ultrastructural studies revealed that Rac- and S-metolachlor had adverse effects on leaf cells, and S-metolachlor treatment caused higher damage.     

Detecting ozone and demonstrating its phytotoxicity in forested areas of Poland: a pilot study

Ambient concentrations of ozone (O(3)) were measured and O(3) phytotoxicity to tobacco (Nicotiana tabacum L.) was demonstrated in several forest locations in Poland during a pilot study from July-October, 1991. At southern and central locations in Poland, the 24-hour average O(3) concentrations measured with a UV absorption photometer were in the range of 32-55 ppb, and the corresponding 1-hour maxima in the range of 39-83 ppb. At these locations longer period (four to fifteen days) average concentrations were determined using O(3) passive samplers (DGA, Inc.) and were reaching 60 ppb, while at Bialowieza in eastern Poland O(3) concentrations averaged less than 40 ppb. In Szarow, near the Niepolomice Forest in southern Poland, 1-hour O(3) maxima estimated from the data obtained using passive samplers were about 105 ppb in early September. At several locations in southern and central Poland, extensive O(3) injury was determined on O(3)-sensitive Bel W-3 tobacco plants; such injury did not occur in the Bialowieza Forest of eastern Poland. The results of this pilot study indicate that O(3) is present at phytotoxic levels in southern and central Poland.     

微量金属元素及其配合物对厨余垃圾甲烷发酵的影响

生物可利用的微量金属元素不仅能够保证污染物以最大的速率转化,而且还可以使某些特殊的转化得以发生,并提高微生物对有毒污染物质的耐受能力。在研究厨余垃圾总固体浓度(total solid, TS)、接种量和C/N比对厨余垃圾厌氧发酵影响的基础上,重点探讨微量金属元素钴及其配合物丝氨酸对厨余垃圾厌氧发酵甲烷产量及关键酶含量的影响。结果表明,当TS为0.5%、接种污泥量为100 mL/L和C/N比为20∶1时,厨余垃圾厌氧发酵的甲烷产率较高,为367 mL/g COD;添加2 μmol/L的微量金属元素钴-配合物丝氨酸时,甲烷产率则提高到432 mL/g COD,相应地,辅酶M的含量由空白实验的41.21 μmol/g VSS提高到54.64 μmol/g VSS,辅酶F₄₂₀的含量由0.31 μmol/g VSS提高到0.48 μmol/g VSS。     

阿特拉津在水环境中的残留及其毒理效应研究进展

阿特拉津是中国及世界上广泛使用的一种除草剂,目前已存在于某些地区的湖泊和地下水中,并对生态环境和人类饮用水源造成潜在威胁.介绍了阿特拉津的应用概况,综述了阿特拉津在水环境中的残留状况及其对生物的生理生化毒性和遗传毒性研究进展.并在此基础上,提出应加强阿特拉津对生物的"三致"(致癌、致畸、致突变)作用、生殖毒性、蓄积毒性和毒性作用机制的研究,以及阿特拉津与其他污染物对生物的联合毒性作用和毒性作用机制的研究.     

Evaluation of fluoranthene phytotoxicity in pea plants by Hill reaction and chlorophyll fluorescence

The effect of both increased concentrations (0.01 and 1 mg l(-1)) of fluoranthene (FLT) and the duration of exposure (18 and 25 days) on the growth and photosynthetic processes in pea plants (Pisum sativum L., cv. Garde) was investigated. FLT concentration in roots and shoot of pea plants was also determined. The obtained results demonstrated that the higher concentration of FLT (1 mg l(-1)) significantly inhibited the growth of the pea plants after 25 days of the application, also affected the content of photosynthetic pigments (chlorophyll a, b and carotenoids), and the primary photochemical processes of photosynthesis. In chlorophyll fluorescence parameters, the significant increase of F(0) values and the decrease of F(V)/F(M) and Phi(II) values was recorded. The Hill reaction of isolated chloroplasts of pea plants was significantly inhibited after 25 days by presence of FLT (0.01 and 1 mg l(-1)) in nutrient solution, while after 18 days no significant response of Hill reaction activity was recorded. The fluoranthene content in roots and shoot of pea plants increased with increasing FLT concentration in the environment and the substantial accumulation of FLT was observed in the roots.     

An analysis of the impact of the Sudbury smelters on wet and dry deposition in OntariO

Meteorological analyses of acidic deposition data were undertaken to quantify the effect of Sudbury emissions on precipitation quality and air quality in Ontario during the period 1980–1983 with particular emphasis on the Sudbury smelter shutdown period (July 1982–March 1983). The techniques used included air parcel trajectories and detailed meteorological analysis.Results indicate that the contribution of the Sudbury smelters to sulphate wet deposition in central and southern Ontario was small—less than 12 % of the wet deposition at the study sites. The smelter contribution to sulphur dry deposition was greater—possibly as high as 47 % of the total at Kapuskasing, and up to about 20–30% of the total in central Ontario, with a smaller contribution (less than 5 %) to the southwest and west of Sudbury. These percentages apply to the smelter emission rate in the early 1980s, i.e. about 0.9 million metric tons of SO₂ per year.     

Saprobe fungi decreased the sensitivity to the toxic effect of dry olive mill residue on arbuscular mycorrhizal plants

We studied the influence of olive mill dry residue (DOR) treated with saprobe fungi on growth of tomato and alfalfa colonized by Glomus deserticola. The application of 25g kg(-1) of dry DOR to soil decreased the shoot and root dry weight of tomato and alfalfa. Plants were more sensitive to the toxicity of DOR when colonized with the arbuscular mycorrhizal (AM) fungi. The sensitivity of both plants to the toxicity of DOR differed according to whether they were colonized by G. deserticola or by indigenous AM fungi. The phytotoxicity of DOR towards tomato and alfalfa was decreased by incubation the residue before planting with saprobe fungi for 20wk. The beneficial effects of AM fungi on plant growth added with DOR incubated with saprobe fungi depend of the type of the plant and AM fungi. The contribution of AM fungi to the beneficial effect of DOR incubated with saprobe fungi varied according to the type of the plant and AM fungi. G. deserticola increased the shoot and root dry weight of plants when they were grown in the presence of DOR incubated with saprobe fungi for 20wk. The beneficial effect of saprobe fungi on the dry weight and the level of AM mycorrhization of plants seem to be related to the decrease caused by these fungi in the phenol concentration in DOR. However, the toxicity of DOR due to substances other than phenols can not be ignored. The use of certain saprobe and AM fungi allows the possibility of using DOR as an organic fertilizer.     

Application of remote sensing for assessment of change in vegetation cover and the subsequent impact on climatic variables

Environmental Science and Pollution Research - The impacts of vegetation cover changes (VCCs) and land use land cover changes (LULCCs) on climate variabilities need to be addressed while...     

农药残留的酶联免疫检测技术研究进展

简要介绍了农药残留的酶联免疫分析的技术原理，关键技术环节，综述了国内外的酶联免疫测定农药残留的研究动态，并展望了此技术的发展及应用前景。     

Pesticide residue removal in classic domestic processing of tomato and its effects on product quality

This study was undertaken to evaluate the effectiveness of several household practices (washing with water or acidic, alkaline, and oxidizing solutions, and peeling) in minimizing pesticide residue contamination of tomatoes, as well as the impact on the quality of the treated fruit. Tests were performed using two systemic fungicides (azoxystrobin and difenoconazole) and one contact fungicide (chlorothalonil). Solid-liquid extraction with low temperature partition (SLE/LTP) and liquid-liquid extraction with low temperature partition (LLE/LTP) were used to prepare the samples for pesticides determination by gas chromatography. Washing the tomatoes with water removed approximately 44% of chlorothalonil, 26% of difenoconazole, and 17% of azoxystrobin. Sodium bicarbonate (5%) and acetic acid (5%) solutions were more efficient, removing between 32 and 83% of the residues, while peeling removed from 68 to 88% of the pesticides. The washing solutions altered some fruit quality parameters, including acidity and chroma, and also caused weight loss. Acetic acid (0.15 and 5%) and hypochlorite (1%) solutions had the greatest effect on these parameters.