Characteristics and risk assessment of sewage sludge from urban wastewater treatment plants in Shaanxi Province, China.

In this study, an investigation of important properties, including moisture content, pH, plant nutrients, organic matter, mineral oil, and the contents of heavy metals (HMs) in sewage sludge (SS) collected from 32 urban treatment plants in Shaanxi Province, China, was carried out. The test results showed that the pH and the moisture, organic matter, total nitrogen (TN), total phosphorus (TP), and mineral oil contents of the SS varied over different rainfall periods, and most of the indicators met the standard criteria for SS agricultural reuse in China. Principal component analysis (PCA) and correlation analysis indicated that the pollutant characteristics of the SS depended on time span and geographical distribution. The mean contents of Pb, Cd, Cu, Zn, Ni, Cr, Hg, and As in SS were 3.95, 16.38, 5.43, 7.70, 1.31, 1.53, 32.77, and 1.40 times higher than the soil background values, respectively. Speciation analysis showed that the forms of HMs in the SS were significantly different. Assessments based on the geoaccumulation index (Igeo), Nemerow integrated pollution index (NIPI), and potential ecological risk index (RI) suggested that HM pollution risk levels were either uncontaminated or moderately contaminated in some regions and that SS recycled for agricultural applications carried a low risk. In conclusion, certain potential ecological risks exist for SS agricultural utilization in Shaanxi Province, and it is necessary to reduce the HM content before SS resource utilization for land application.

Release of Interleukin-1ß evaluation among mineral oil mist-exposed workers.

Exposure to aerosols has been found to be linked to respiratory impairment. Although the effects of both indoor and outdoor exposures to particulates have been extensively reported, exposures to mists are less studied. Herein, we reported a survey of mineral oil mist toxicity in an occupational exposure scenario. For the purpose of this study, 65 lathe workers of the metal processing industry, as mineral oil mist-exposed population, were studied. Thereafter, the participants' age, smoking habits and work experience were matched with those of the control workers (n = 65) who were not occupationally exposed to mist. Thereafter, air samples were evaluated from the breathing zone of the workers using NIOSH method 5026. Plasma Interleukin-1ß as a pro-inflammatory indicator was assessed in all the studied subjects. Mean ± standard deviation of mineral oil mist time-weighted average exposure in lathe workers was 7.10± 3.49 mg/m3. IL-1ß cytokine levels were significantly higher in the lathe groups compared to the control group. The mean level of Interleukin-1ß in the control subjects (2922 pg/L) was selected as the cut-off point of the inflammation effect. Based on this pro-inflammatory point, the results of monitoring showed that 60% of the exposed were affected. A Spearman correlation was also found between mineral oil mist exposure and inflammation in the affected subjects. Our findings highlighted the immunological potential of mineral oil mist in occupational exposure. Overall, the results of this study suggested that Interleukin-1ß evaluation in mineral oil mist exposure could be considered as both an acute and chronic inflammation marker.

Evolution of hyphenated techniques for mineral oil analysis in food.

The occurrence of mineral oil in food is known since the early 1990s, and it was discovered by chance in one of the first applications using the hyphenated LC-GC system. Since then, the relationship between hyphenated techniques and mineral oil analysis has been tightly interrelated and successful. This review aims to show and explain how this mutual interaction has driven the development of the hyphenated techniques on one side and has supported the increase of knowledge on the other, supporting the complex task of mineral oil determination in food. The paper presents the background of the mineral oil problem in food (a brief history of its finding, toxicology, and occurrence), moving then toward the analytical determination. The development of different hyphenated techniques in relation to mineral oil determination is discussed, focusing mainly on 2D techniques, such as LC-GC. The necessity of additional dimensions, such as LC-LC-GC and comprehensive approaches, such as GC × GC and LC × GC, is also discussed. Finally, the role of the hyphenation with MS is presented.

Tolerance of Impatiens balsamina L., and Crotalaria retusa L. to grow on soil contaminated by used lubricating oil: A comparative study.

Screening of plant species with an ability to grow on contaminated soil is the most critical step in the planning of a phytoremediation program. While flourishing growth of Impatiens balsamina L. and Crotalaria retusa L. has been observed in areas adjacent to automobile service stations in Sri Lanka, no systematic study of their tolerance to used lubricating oil (ULO) contaminated soil has been carried out. Therefore, the aim of the present study was to investigate the comparative responses of I. balsamina L. and C. retusa L. to soil contaminated with ULO. Both species exhibited 100% seed germination in soils treated with 1%-5% w/w ULO. After 120 h exposure, root lengths and biomass of germinated seedlings of both species were significantly (p < 0.05) reduced in all treatments above 3% w/w ULO. The measured growth parameters of plants following 90 d exposure to 0.5-3% w/w ULO, indicated significant (p < 0.05) negative effects on I. balsamina and C. retusa at >1% w/w and >2% w/w ULO, respectively. There were no significant effects on chlorophyll content or root anatomy of either species under any treatments. Therefore, we concluded that I. balsamina can tolerate up to 1% of ULO and C. retusa up to 2% w/w ULO without displaying any negative effects. Comparatively higher biodegradation of ULO in the rhizosphere, root nodule formation, increases in root length and root hair density are all possible strategies for the exhibited higher tolerance of C. retusa. Therefore, the overall results indicate that C. retusa has the greater potential to be used in phytoremediation of ULO contaminated soils. The findings of the present study will be beneficial in planning phytoremediation program for ULO contaminated soil.

Physicochemical characteristics of oil-based cuttings from pretreatment in shale gas well sites.

Understanding the physicochemical characteristics of oil-based cuttings (OBCs) is an important foundation for subsequent treatment and management. The macro- and microscopic properties of white oil-based cuttings (WOBCs) and diesel-based cuttings (DBCs) after the different pretreatment steps have been assessed using scanning electron microscopy. The organic and inorganic compositions of OBCs have been analyzed using X-ray diffraction, Fourier-transform infrared spectrometry, and gas chromatography-mass spectrometry. Inorganic matter (SiO2, BaSO4, and CaCO3), alkanes, aromatic compounds, and water were the main components of OBCs. The organic content (26.14%) and alkane content of the WOBCs were higher than that of the DBCs, whereas for the inorganic content (70.87%), the reverse was true. The macro- and micromorphologies of OBCs were quite different because their oil and water contents were different. The oil contents of OBCs decreased in the order A1 (14.64%) > A3 (12.67%) > A2 (11.06%) and B1 (9.19%) > B3 (8.94%) > B2 (4.66%); the water contents decreased in the order A1 (2.99%) > A3 (2.19%) > A2 (1.09%) and B1 (2.30%) > B3 (1.87%) > B2 (1.09%). Moreover, a skid-mounted treatment technology for OBCs was proposed. The results can be a scientific guidance for the treatment and management of OBCs.

Mineral oil residues in soil and apple under temperate conditions of Kashmir, India.

The study was undertaken to ascertain the persistence of Orchol-13, a mineral oil used against insect pests of horticultural fruit crops in soil and apple following the dormant and summer applications of 2 and 0.75% respectively. Soil samples were collected during dormant, while as both soil and apple samples were collected during summer season. Samples were collected at 0, 1, 3, and 5 days post treatment in both the seasons. Average recoveries of paraffinic constituents (which constitute about 60% of mineral oils by composition) from soil and apple at 1 µg ml-1 spiking level were found to be 74.18 and 76.81% respectively. The final quantification of paraffinic constituents was performed on gas chromatograph equipped with flame ionization detector (GC-FID). No paraffinic constituents of mineral oil could be detected in soil and apple at 0 day post treatment in both the seasons.

Improved microwave-assisted saponification to reduce the variability of MOAH determination in edible oils.

BACKGROUND: Mineral oil aromatic hydrocarbon (MOAH) analysis in foods is a major analytical challenge. Quantification is associated with a high uncertainty. The sources of uncertainty are multiple, but the major one is related to data interpretation and integration, which is partially derived from insufficiently efficient sample preparation. Recently, an updated ISO method for the analysis of mineral oil in fats and oils and a standard operating procedure for infant formula analysis have been published. Both methods reported significantly different (up to 1.25) distributions of the internal standards used for quantification (i.e., tri-tert-butyl benzene (TBB) and 2-methyl naphthalene (2-MN)) over the different solvent phases used in the saponification step. RESULTS: In this work, a microwave-assisted saponification and extraction method was optimized for MOAH analysis to solve the problem related to the MOAH internal standards partition. The paper examines the impact of the solvent mixture used, the concentration of KOH on the partition of TBB and 2-MN, and the effect of the matrix and the washing step to extract the unsaponifiable fraction containing the mineral oils. SIGNIFICANCE: The optimized procedure achieved a TBB/2-MN ratio of 1.05 ± 0.01 tested in five different fats and oils, namely, sunflower, rapeseed, coconut, palm, and extra virgin olive oils. The method can significantly contribute to reducing the uncertainty of the MOAH quantification when saponification is applied.

Advanced separation of mineral oil aromatic hydrocarbons by number of aromatic rings using donor-acceptor-complex chromatography to extend on-line coupled liquid chromatography-gas chromatography.

An automated implementation for a subfractionation of mineral oil aromatic hydrocarbons (MOAH) into a mono-/di-aromatic fraction (MDAF) and a tri-/poly-aromatic fraction (TPAF) is presented, which is highly demanded by the European Food Safety Authority (EFSA) respecting the genotoxic and carcinogenic potential of MOAH. For this, donor-acceptor-complex chromatography (DACC) was used as a selective stationary phase to extend the conventional instrumental setup for the analysis of mineral oil hydrocarbons via on-line coupled liquid chromatography-gas chromatography-flame ionization detection (LC-GC-FID). A set of six new internal standards was introduced for the verification of the MOAH fractionation and a quantification of MDAF and TPAF, respectively. The automated DACC approach was applied to representative petrochemical references as well as to food samples, such as rice and infant formula, generally showing well conformity with results obtained by state-of-the-art analysis using two-dimensional GC (GCxGC). Relative deviations of DACC/LC-GC-FID compared to GCxGC-FID methods regarding the ≥ 3 ring MOAH content ranged between -50 and +6 % (median: -2 %, all samples, only values above limit of quantification). However, crucial deviations mainly result from "border-crossing" substances, e.g., dibenzothiophenes or partially hydrogenated MOAH. These substances can cause overestimations of ≥ 3 ring MOAH fraction during GCxGC analysis due to co-elution, which is mostly avoided using the DACC approach. Furthermore, the DACC approach can help to minimize underestimations of toxicologically relevant ≥ 3 ring MOAH caused by an unavoidable loss of MOAH during epoxidation, since natural olefins, such as terpenes, predominantly elute in MDAF, which was exemplarily shown for an olive oil and a terpene reference. The presented approach can be implemented easily in existing LC-GC-FID setup for an automated and advanced screening of MOAH to lower the need for elaborate GCxGC analysis also in routine environments.

Comparison of carrier gases for the separation and quantification of mineral oil hydrocarbon (MOH) fractions using online coupled high performance liquid chromatography-gas chromatography-flame ionisation detection.

On-line coupled high performance liquid chromatography-gas chromatography-flame ionisation detection (HPLC-GC-FID) was used to compare the effect of hydrogen, helium and nitrogen as carrier gases on the chromatographic characteristics for the quantification of mineral oil hydrocarbon (MOH) traces in food related matrices. After optimisation of chromatographic parameters nitrogen carrier gas exhibited characteristics equivalent to hydrogen and helium regarding requirements set by current guidelines and standardisation such as linear range, quantification limit and carry over. Though nitrogen expectedly led to greater peak widths, all required separations of standard compounds were sufficient and humps of saturated mineral oil hydrocarbons (MOSH) and aromatic mineral oil hydrocarbons (MOAH) were appropriate to enable quantitation similar to situations where hydrogen or helium had been used. Slightly increased peak widths of individual hump components did not affect shapes and widths of the MOSH and MOAH humps were not significantly affected by the use of nitrogen as carrier gas. Notably, nitrogen carrier gas led to less solvent peak tailing and smaller baseline offset. Overall, nitrogen may be regarded as viable alternative to hydrogen or helium and may even extend the range of quantifiable compounds to highly volatile hydrocarbon eluting directly after the solvent peak.

Comparison of two different multidimensional liquid-gas chromatography interfaces for determination of mineral oil saturated hydrocarbons in foodstuffs.

This investigation focused on direct comparison of two popular multidimensional liquid-gas chromatography (LC-GC) systems, the Y-interface (retention gap approach) and the syringe-based interface (programmed temperature vaporizer approach). Such transfer devices are structurally very different, and could potentially have a substantial effect on the outcome of a specific application. In this work the application was a topic of much current interest, determination of mineral oil saturated hydrocarbon (MOSH) contamination of a series of food products (rice, pasta, icing sugar, olive oil); the final results were then compared. The two LC-GC methods developed were validated for linearity over the calibration range, analyte discrimination, precision, accuracy, and limits of detection and quantification. No significant differences were found between the two approaches.

Optimization of sample clean-up for the determination of small amounts of MOSH and MOAH in edible oils - method DGF C-VI 22 (20).

Methods for determining MOSH and MOAH in edible oils showed major problems with interlaboratory comparability of analytical results, especially in the lower concentration range below 10 mg/kg. However, a method with improved sensitivity and reproducibility is urgently needed to obtain a valid data basis for minimization efforts. To cope this problem a new method was created in 2020. The method was established as the standard method DGF C-VI 22 (20) of the German Society for Fat Science e.V. (DGF). For the development of this method different sample epoxidation approaches have been performed, evaluated and improved. Additionally, a saponification, a decision tree for sample preparation, an upstream clean-up column and a system suitability test were introduced. The focus was on reliability and interlaboratory comparability over all edible oil matrices up to a LOQ of 1 mg/kg. The optimized method was validated in terms of trueness and precision in a collaborative trail with 11 laboratories. The achieved recovery rates of 89-105% MOSH and 70-105% MOAH met the JRC requirements. Method and validation results were obtained with HorRat values between 1.3 and 1.8 for MOSH and MOAH.

Investigation of the effect of refining on the presence of targeted mineral oil aromatic hydrocarbons in coconut oil.

The goal of this work was to investigate the impact of refining on coconut oil particularly on the most toxicologically relevant fraction of the mineral oil aromatic hydrocarbon (MOAH) contamination, namely the fraction composed by the three to seven aromatic rings. A fully integrated platform consisting of a liquid chromatography (LC), a comprehensive multidimensional gas chromatography (GC) (LC-GC × GC) and flame ionization detector (FID) was used to obtained a more detailed characterization of the MOAH sub-classes distribution. The revised EN pr 16995:2017-08 official method was used for preparing the samples, both with and without the auxiliary epoxidation step. Crude coconut oil was spiked with different MOAH standards, namely naphthalenes, alkylated naphthalenes, benzo(a)pyrene, and its alkylated homologues. Refining was modelled by deodorization at 230 °C, stripping with 10 kg/h of steam under 1 mbar vacuum for 3 h. Complete removal of the naphthalenes and reduction of more than 98.8% of the benzo(a)pyrenes was observed. Epoxidation had a significant impact on the MOAH fraction with more than three rings, but with a high dependency on the sample matrix, being significantly less evident in the refined samples than in the crude ones.

Review on chromatographic and specific detection methodologies for unravelling the complexity of MOAH in foods.

Contamination of foods with mineral oil hydrocarbons, particularly mineral oil aromatic hydrocarbons (MOAH), can potentially pose a health hazard to consumers. However, identifying toxic substances among the many thousands of compounds comprising mineral oils in food samples is a difficult analytical challenge. According to the European Food Safety Authority, there is a lack of concentration and structural data about mineral oil hydrocarbons in foods, and therefore it is not clear to what extent consumers in Europe might be exposed to toxic levels of MOAH. The current gold standard method for determination of mineral oil hydrocarbons is online high-performance liquid chromatography (LC)-gas chromatography (GC) with flame ionization detection, which quantifies total saturated/aromatic content, but gives no qualitative information. The objective of this review is to explore the future prospects in mineral oil hydrocarbon determination and MOAH characterization in foods. To that end, peer reviewed literature was explored, particularly from the viewpoint of a methodology for detailed characterization of the MOAH fraction that can aid toxicological assessment. The literature clearly shows that there is much to be gained from the orthogonality power of multidimensional chromatographic separations and mass spectrometric (MS) detection. Comprehensive two-dimensional GC coupled to MS, preceded by pre-fractionations of MOAH by LC is suggested to be the most promising approach for further research. In addition, the strengths and weaknesses of a number of other, alternative approaches, both for qualitative and quantitative analysis, are discussed.

Optimization and validation of microwave assisted saponification (MAS) followed by epoxidation for high-sensitivity determination of mineral oil aromatic hydrocarbons (MOAH) in extra virgin olive oil.

A rapid and solvent-saving method, based on microwave-assisted saponification (MAS) followed by epoxidation and on-line liquid chromatography (LC) - gas chromatography (GC) - flame ionization detection (FID), was optimized and validated for high-sensitivity MOAH determination in extra virgin olive oils. Quantitative recoveries and good repeatability were obtained even at concentrations of added mineral oils close to the LOQ (0.5 mg/kg for the total hump, 0.2 mg/kg for each single C-fraction). The validated method, also applied for MOSH determination (C-fraction LOQ: 0.5 mg/kg), was used to analyse 18 extra virgin olive oils from the Italian market or oil mills, and 10 additional samples extracted in the laboratory (with an Abencor apparatus) from hand-picked olives. The former resulted contaminated with variable amounts of MOSH and MOAH (on average 19.0 mg/kg and 2.5 mg/kg, respectively), while the latter showed no detectable MOAH, and low and rather constant MOSH (generally below 2.0 mg/kg).

Screening for mineral oil hydrocarbons in vegetable oils by silver ion-planar solid phase extraction.

The analysis of mineral oil hydrocarbons in vegetable oils is challenging especially regarding the analysis of mineral oil aromatic hydrocarbons (MOAH) since native terpenes like squalene or ß-carotene are usually extracted along with the MOAH fraction and interfere their detection. When applying a recently developed screening method for the analysis of mineral oil saturated hydrocarbons (MOSH) and MOAH in paper and cardboard by planar solid phase extraction (pSPE) to vegetable oils, native terpenes expectably interfered with MOAH analysis. Thus, an adaption of pSPE employing silver ions, named silver ion-planar solid phase extraction (Ag-pSPE), was developed in this study. Impregnation of thin-layers with silver nitrate (AgNO3) was found to be very successful in retaining squalene and ß-carotene. MOAH analysis of vegetable oils after saponification showed good repeatability (relative standard deviation (%RSD) <10%) and recoveries of 73.4-112.4% at a spiking level of 4.5 mg/kg (n = 4). For MOSH analysis, a simple solid phase extraction (SPE) clean-up with aluminum oxide removed native n-alkanes prior to Ag-pSPE. Recoveries for MOSH were 55.3-84.5% with %RSD <11% at a spiking level of 45.5 mg/kg (n = 4). Limits of decision and quantitation were at 7.2 and 22.2 ng/zone for MOSH and 1.1 and 3.4 ng/zone for MOAH, respectively, which corresponded to the recently introduced pSPE method, thus showing that analytes were not affected by the impregnation of HPTLC plates with AgNO3. The method comparison with LC-GC showed similar results for MOSH, while the amounts for MOAH determined by Ag-pSPE were higher.

High sensitivity determination of mineral oils and olefin oligomers in cocoa powder and related packaging: Method validation and market survey.

Mineral oil saturated (MOSH) and aromatic hydrocarbons (MOAH) and related hydrocarbons of synthetic origin are both packaging and processing contaminants of health concerns. The purpose of this work was to validate a method for their rapid and high-sensitivity determination in cocoa powder, using it to monitor the presence of these contaminants in products purchased in Italy and North Macedonia. Relevant primary and secondary packaging was also analyzed. Method performance was good (average recovery 74-106 %, with RSD ≤13 %). In addition to pre-existing contamination, oligomeric polyolefin hydrocarbons (POH) from primary plastic packaging and MOSH/MOAH from recycled cardboard secondary packaging were found in many samples. Total MOSH/POH ranged from 1.2 to 69.2 mg/kg (on average 20.9 mg/kg), exceeding the German benchmark levels of 9 mg/kg in half of the samples from Italy and in all those from Northern Macedonia. Most of the samples had MOAH >0.5 mg/kg.

Quantification and characterization of mineral oil in fish feed by liquid chromatography-gas chromatography-flame ionization detector and liquid chromatography-comprehensive multidimensional gas chromatography-time-of-flight mass spectrometer/flame ionization detector.

Mineral oil is an ubiquitous food contaminant potentially toxic. It is generally divided into aromatic hydrocarbons (MOAH) and saturated hydrocarbons (MOSH). These compounds are currently under investigation by the European Union to determine their occurrence and their toxicity before legislating on the matter. Although the discussion mainly focuses on food, animal feed can indirectly contribute to human exposure to such a contaminant. In this study, seven commercial feeds were analyzed. The analyses were carried out in two different Universities (Udine-IT and Liège-BE), performing the same sample preparation protocol: microwave-assisted saponification and extraction followed by epoxidation for the MOAH fraction. The final determination was performed by hyphenated liquid-gas chromatography (LC-GC) and LC coupled to comprehensive multidimensional gas chromatography (LC-GC × GC) with parallel detection, namely flame ionization detector (FID) and time-of-flight mass spectrometer (ToFMS). The results obtained by the two laboratories were generally in good agreement. The results obtained by LC-GC × GC-ToFMS/FID platform provided consistent results, with the advantages of more robust data interpretation that can compensate for problems occurring during purification. Moreover, the coupling of enhanced separation obtained by GC × GC and the MS information allowed for a more in-depth characterization of the contamination.

Automated workflow utilizing saponification and improved epoxidation for the sensitive determination of mineral oil saturated and aromatic hydrocarbons in edible oils and fats.

Refined edible oils and fats are known to contain olefins resisting the typical epoxidation used for the sample preparation of mineral oil saturated and aromatic hydrocarbons (MOSH and MOAH). These olefins can be misinterpreted as MOAH and are therefore an important reason for inconsistent results between laboratories. Collaborative trials confirm this assumption for low MOAH contents near the quantitation limits regularly. In the scope of this work, a new epoxidation approach was developed. Persistent olefins in refined oils could be successfully epoxidized with performic acid. The reaction kinetics was investigated using model substances for biogenic olefins and MOAH. It was rationalized why certain olefins resist epoxidation and which MOAH can potentially get lost. A prominent peak cluster in the MOAH fraction of refined palm oils could be identified by means of GC-MS and explained why it cannot be epoxidized. Based upon this, an automated and streamlined workflow for sample preparation and analysis was composed tackling major problems identified in previously published methods. Optimized and miniaturized saponification, extraction, epoxidation, and enrichment paired with online LC-GC-FID led to a robust method that was tested and validated for edible oils and fats (RSDR < 7% for MOSH and MOAH at values of 14.9 and 2.1 mg/kg, respectively). Due to increased sample amount and minimized blank values, quantitation limits below 1 mg/kg for MOSH and MOAH were achieved. The trueness of the method was verified by analyzing collaborative trial samples.

On-Line HP(LC)-GC-FID Determination of Hydrocarbon Contaminants in Fresh and Packaged Fish and Fish Products.

BACKGROUND: Fish products can be contaminated with mineral oil hydrocarbons (MOH), mainly as a result of environmental contamination (wild fish) or contaminated feeds (farmed fish). Packaged products may also be contaminated with polyolefin oligomeric hydrocarbons (POH), which, depending on the packaging, storage condition, matrix composition, and fat content, may migrate relatively easily from the packaging to the food. OBJECTIVE: A rapid, solvent-sparing method for determining hydrocarbon contaminants in fish products was developed, validated, and applied to farmed and wild fish products (both fresh and packaged samples, stored under different conditions). METHOD: Microwave-assisted saponification (MAS) was used in combination with on-line LC-GC-flame ionization detection (FID). RESULTS: The proposed method showed quantitative recovery, good repeatability, and high sensitivity. Farmed salmon had variable mineral oil saturated hydrocarbon contamination (from 0.5 to 4.3 mg/kg), accompanied by mineral oil aromatic hydrocarbons (maximum 1.4 mg/kg), while wild salmons had no detectable contamination. Samples of one farmed salmon and a swordfish, both sliced and packed under vacuum, resulted contaminated with POH migrated from the packaging. POH migration was also evident in a ready-to-eat meal. CONCLUSIONS: The proposed method showed good performance characteristics in terms of recovery, repeatability, and LOQ. Fatty fish products are more prone to contamination with hydrocarbon contaminants. HIGHLIGHTS: MAS allows for rapid and efficient sample preparation. An LC-GC-FID method for MOH/POH determination in fish products was validated. Fish products may be contaminated with variable amounts of hydrocarbon contaminants.

A review on the requirements for environmentally friendly insulating oils used in high-voltage equipment under the eco design framework.

The advancements in electricity production and distribution, as well as the growing consumption of electrical energy, have made electrical equipment a vital part of the technological infrastructure. On the other hand, the necessity for environmentally safe and sustainable solutions is another requirement for electrical transformers, the same as for every technology and equipment nowadays. In this aspect, the main challenges in electrical transformers are the reduction in power losses, the use of construction materials with minimum environmental impact, and the elongation of their service life. All three challenges are related to the insulating oils that are used in the transformers which are exclusively mineral based and are products of crude oil. Mineral oils can almost be fully recyclable and can be regenerated with satisfactory results. However, they are not biodegradable, they are flammable, and they may present toxic properties for both humans and the environment. Bio-based lubricants are fully recyclable and can be regenerated, they have none of the hazardous properties of mineral oils, and are fully biodegradable. Furthermore, they are considered a sustainable solution, since they are not fossil-based but products of cultivation and the supplies can be considered indefinite. This paper tries to present an assessment of the environmental impact of vegetable-based insulating oils for electrical transformers, in the wider view of sustainability global efforts, considering additional environmental impact compared with the already used in related works. The assessment is executed for the whole life cycle of two product groups of transformers, as determined by the EU Eco Design Directive 2009/125/EC and the EU Regulation 548/2014 on eco design of requirements on transformers.