Effect of olive-processing technology on the utilization of olive mill pomace as a soil amendment.

In the Mediterranean basin, the treatment and disposal of olive mill pomace (OMP) remain a salient environmental issue for the olive oil-producing industry. This study assesses the effects of olive-processing technology (three-phase and two-phase systems) on the potential use of OMP as a soil amendment. Samples from 12 Croatian olive mills were analyzed for their total phenolic content (TPC), residual oil fraction, and elemental concentration. The samples were profiled using Fourier transform infrared spectroscopy (FT-IR) and structurally characterized using scanning electron microscopy-energy-dispersive X-ray spectroscopy (EDS). Compared to three-phase samples, two-phase OMP was more acidic (pH 4.5 vs. 5.0), with a higher TPC (3835 vs. 1576 mg/kg fresh weight), oil content (11.7% vs. 7.5% d.w., where d.w. is dry weight), electrical conductivity (EC, 5.1 vs. 3.0 mS/cm), and levels of calcium (Ca, 1.34 vs. 1.20 g/kg d.w.) and copper (Cu, 10.4 vs. 7.0 mg/kg d.w.). Similar values of carbon/nitrogen (C/N; 61 vs. 72), N (10 vs. 8.1 g/kg d.w.), phosphorus (1040 vs. 691 mg/kg d.w.), and potassium (K, 13.7 vs. 8.1 g/kg d.w.) were observed. The amounts of chromium, copper, nickel, and zinc were below EC limits in both cases. The EDS mapping revealed that Ca was concentrated at sharp-edged OMP particles while K was evenly distributed, suggesting that pelletized OMP compost is preferable for amending soil to obtain a homogeneous distribution of nutrients. It was also possible to distinguish between OMPs based on oil and lignin absorption bands in their FT-IR spectra. According to the obtained results, composting is recommended for both types of OMP to produce a safe product for amendment purposes.

Micro-analytical Evidence of Copper-Based Pigment and Fungal Contamination of Medieval Mural Paintings in Beram, Croatia.

The aim of the present study was to map the painting materials, degradation processes, and biological features present on the mural painting in the church of St. Mary in Beram (Croatia) to study their possible interaction and produce information helping the preservation of this valuable painting. The research was conducted on micro samples of painting materials taken from different sites along the painting and the characterization of the present fungal species was carried out. The painting samples, together with observable patinas and degradation products, were studied by optical microscopy (OM), scanning electron microscopy, energy-dispersive spectroscopy (SEM/EDS), Fourier-Transform Infrared spectroscopy, and powder X-ray diffraction. Fungal diversity was studied using cultivation methods followed by OM and SEM analyses in addition to molecular analysis. The results contribute to the characterization of the original painting materials, successively added materials and occurred interventions, to the understanding of degradation progressions and fungal biotransformation processes. A mineral, cumengite, a copper-based pigment extremely rarely used in art, was found. Its occurrence together with barium sulfate, gypsum, and calcium oxalate possibly produced by microbiological activity was studied and information was added regarding the composition of painting materials in St. Mary church mural cycle.