Reduced activity of alkaline phosphatase due to host–guest interactions with humic superstructures

Nuclear Magnetic Resonance (NMR) spectroscopy was applied to directly study the interactions between the alkaline phosphatase enzyme (AP) and two different humic acids from a volcanic soil (HA-V) and a Lignite deposit (HA-L). Addition of humic matter to enzyme solutions caused signals broadening in ¹H-NMR spectra, and progressive decrease and increase of enzyme relaxation (T₁ and T₂) and correlation (τ_C) times, respectively. Spectroscopic changes were explained with formation of ever larger weakly-bound humic–enzyme complexes, whose translational and rotational motion was increasingly restricted. NMR diffusion experiments also showed that the AP diffusive properties were progressively reduced with formation of large humic–enzyme complexes. The more hydrophobic HA-L affected spectral changes more than the more hydrophilic HA-V. ¹H-NMR spectra also showed the effect of progressively greater humic–enzyme complexes on the hydrolysis of an enzyme substrate, the 4-nitrophenyl phosphate disodium salt hexahydrate (p-NPP). While AP catalysis concomitantly decreased NMR signals of p-NPP and increased those of nitrophenol, addition of humic matter progressively and significantly slowed down the rate of change for these signals. In agreement with the observed spectral changes, the AP catalytic activity was more largely inhibited by HA-L than by HA-V. Contrary to previous studies, in which humic–enzyme interactions were only indirectly assumed from changes in spectrophotometric behavior of enzyme substrates, the direct measurements of AP behavior by NMR spectroscopy indicated that humic materials formed weakly-bound host–guest complexes with alkaline phosphatase, and the enzyme catalytic activity was thereby significantly inhibited. These results suggest that the role of extracellular enzymes in soils may be considerably reduced when they come in contact with organic matter dissolved in the soil solution.     

Polychlorobiphenyls and other organochlorine compounds in human follicular fluid

Based on observations in animals, there is an increasing evidence that a number of persistent organochlorine pollutants can alter the endocrine homeostasis, this resulting in toxic effects in particular in the developing organism. However, the role of these chemicals in determining endocrine-related diseases in humans, and possibly a decrease of fertility, is still controversial. Exposure data concerning the human reproductive system are essential for risk assessment. Based on this, the occurrence in follicular fluid of polychlorobiphenyls (PCBs), 2,3,7,8-chlorosubstituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane (p,p'-DDT) and its metabolites, and hexachlorobenzene (HCB) was investigated. With respect to PCBs, the sum of the three most abundant congeners (PCBs 138, 153 and 180) was 1230 ng/g, lipid basis (0.37 ng/g, wet weight). Congener distribution profile overlapped what is usually observed in other human tissues, as blood and milk. PCDDs, PCDFs, p,p'-DDT and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethane (p,p'-DDD) were below their determination limits. 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE) and HCB were detected in concentrations respectively in the order of 700 and 70 ng/g, lipid basis (approximately 0.2 and approximately 0.02 ng/g, wet weight).     

Evaluation of the sustainability of swine manure fertilization in orchard through Ecological Footprint Analysis: results from a case study in Italy

Ecological Footprint Analysis (EFA) is an environmental accounting system, in physical unit, able to quantify the total amount of ecosystem resources required by a region or by a production process. This methodology is both scientifically robust and widely diffused for territorial and productive analysis. The application of EFA to agricultural systems are still uncommon and examples in the fruit sector rare.In this work a detailed application of EFA to an experimental trial in a commercial nectarine orchard in Piedmont (Italy) is presented. The field trial is focused on the evaluation of agronomical benefit of various kinds of swine manure for fertilizing orchards. Four productive systems were established from 2008: liquid slurry (LS), covered slurry (CS), solid fraction (SF), mineral nutrition (MN). All the environmental impacts of the four systems were quantified both directly on field and with extrapolations from farmer knowledge. As previous studies suggested, we considered not only the one-year field operations, but also the whole lifetime of the orchard. The environmental costs of each system are presented and related to each other on the basis of their relative footprint value.Results highlight almost the same ecological footprint for the three manure fertilized systems (LS, CS and SF) with average of 0.96 gha t⁻¹) and the highest ecological footprint can be found in the MN system (1.14 gha t⁻¹). Interesting remarks can be done comparing the contributions to the ecological footprint of the field operations related to fertilization in the four systems. In the manure fertilized systems the fertilizer contribution goes from 0.9% to 1.2% of the total ecological footprint; but in the MN system the fertilizer contribution is 6.6% of the total ecological footprint. Results support the hypothesis that internal recycle and connections among different systems increasingly resulted in high system benefit and sustainability.     

Experimental analysis of selective laser sintering of polyamide powders: an energy perspective

This paper presents an analysis of Selective Laser Sintering (SLS) from an energy standpoint. Selective Laser Sintering (SLS) has a potential as an environmental benign alternative to traditional processes but only few authors deal with the process optimisation including energy aspects. In the present paper an analysis of the energetic aspect of SLS is proposed. In addition, with respect to the classical technological parameters (resolution, productivity) attention is paid to energetic elements (energetic productivity, laser parameters) showing how the perspective of a sensible development of such a kind of technology could be beneficial not only from a technological point of view, but also for energy saving in a lot of manufacturing fields. A polyamide powder is the material tested to acquire some characteristics data of the process. It is shown that the Volumetric Energy Intensity (VEI) of the process in optimal condition could be of the order of 0.2 J for each mm³ of material agglomerated.     

Theoretical interpretation of the adsorption of amoxicillin on activated carbon via physical model

Environmental Science and Pollution Research - The paper describes a theoretical analysis of the adsorption of amoxicillin (AMX) onto two activated carbons pyrolysed at either 600 or 700 °C...     

Increased levels of polychlorobiphenyls in Italian women with endometriosis

Endometriosis has been hypothesised to be linked to persistent and toxic organochlorinated chemicals. Dioxins and dioxin-like compounds have in particular been associated with the disease, mainly on the basis of experimental studies. Data in women are conflicting. A case-control study on 80 Italian nulliparous women of reproductive age was carried out to assess whether there is a correlation between the presence of endometriosis and blood levels of polychlorobiphenyls (PCBs), a family of ubiquitary environmental pollutants which comprises congeners with dioxin-like activity. Higher levels of PCBs were found in women with endometriosis. A mean cumulative value of 410 ng g(-1), lipid base, was found in cases versus the value of 250 ng g(-1) observed in the control group (odds ratio for upper tertile 4.0, CI 95% 1.3-13; p = 0.0003). PCB increase involved both dioxin-like (PCBs 105, 118, 156, and 167) and non-dioxin-like congeners (PCBs 101, 138, 153, 170, 180).     

Removal of cyanide by woody plants

Hydrogen cyanide is a high volume production chemical that causes severe environmental problems. The toxicity of potassium cyanide (KCN) to basket willow trees (Salix viminalis) was tested. In aqueous solution, 2 mg CN l(-1) as KCN depressed the transpiration after 72 h about 50%. Trees exposed to 0.4 mg CN l(-1) in aqueous solution showed initially a depression of transpiration, but recovered. Doses of 8 and 20 mg CN l(-1) in aqueous solution were quickly mortal to the trees. At the end of the test, almost all cyanide had disappeared from the solutions. Levels of cyanide in plants were related to the toxicity, with no elevated levels of cyanide in plants exposed to 0.4 mg CN l(-1). Willows grown in sand survived 423.5 h irrigation with 20 mg CN l(-1). Willows grown in sand irrigated with 50 mg CN l(-1) died within a few days. The roots of the surviving willows were able to consume about 10 mg CN kg fresh weight(-1)h(-1). Vascular plants possess the enzymes beta-cyanoalanine synthase and beta-cyanoalanine hydrolase, which convert free cyanide to the amino acid asparagine. The in vivo capacity of woody plants (willow, poplar, elder, rose, birch) to remove cyanide was evaluated. Tests were performed with detached leaves and roots in KCN solutions of different concentrations. The highest removal capacity was obtained for basket willow hybrids (Salix viminalis x schwerinii). The Michaelis-Menten kinetics was determined. Realistic values of the half-saturation constant, K(M), were between 0.6 and 1.7 mg CN l(-1); the maximum metabolic capacity, v(max), was around 9.3 mg CN kg fresh weight(-1)h(-1). The removal of cyanide by plants might be useful in phytoremediation and treatment of wastewater from gold mining.