The interference of tetrachloromethane in the measurement of benzene in the air by a gas chromatography–photoionisation detector (GC-PID)

The European Union requires that benzene in the air is continuously measured due to its toxicity and widespread presence in the population nuclei, mainly motivated by vehicle emissions. The reference measuring technique is gas chromatography (GC). Automatic chromatographs used in monitoring stations must verify the operating conditions established in Standard EN 14662 part 3, which includes a type approval section with a number of tests that analysers must pass. Among these tests, the potential interference of a number of compounds is evaluated. The 2005 version of the mentioned standard requires the evaluation of the potential interference of tetrachloromethane (TCM). The 2015 version eliminates TCM as a potential interferent. Although most consumer uses of TCM have been banned, recent studies have measured significant concentrations of TCM in the air. In this paper, the potential interference of TCM in benzene measurements obtained with gas chromatography coupled to a photoionisation detector (GC-PID) has been investigated. Our study shows that the simultaneous presence of benzene and TCM causes a significant decrease in benzene readings. For TCM concentrations of 0.7&thinsp;µg&thinsp;m−3 (typical of urban areas) and 4.5&thinsp;µg&thinsp;m−3 (detected in the vicinity of landfills), the relative errors in benzene measurements were 34&thinsp;% and 70&thinsp;%, respectively, which are far too high compared to the maximum overall uncertainty allowed for benzene measurements (25&thinsp;%). Possible mechanisms to qualitatively and quantitatively explain the behaviour of the PID when measuring benzene with and without TCM have been proposed.</p

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Influence of sample temperature and environmental humidity on measurements of benzene in ambient air by transportable GC-PID

Calibration of in situ analysers of air pollutants is usually done with dry standards. In this paper, the influence of sample temperature and environmental humidity on benzene measurements by gas chromatography coupled with a photoionisation detector (GC-PID) is studied. Two reference gas mixtures (40 and 5 µg m−3 nominal concentration benzene in air) were subjected to two temperature cycles (20/5/20 °C and 20/35/20 °C) and measured with two identical GC-PIDs. The change in sample temperature did not produce any significant change in readings. Regarding ambient humidity, the chromatographs were calibrated for benzene with dry gases and subjected to measure reference standards with humidity (20 and 80 % at 20 °C). When measuring a concentration of 0.5 µg m−3 benzene in air, the levels of humidity tested did not produce any significant interference in measurements taken with any of the analysers. However, when measuring a concentration of 40 µg m−3, biases in measurements of 18 and 21 % for each respective analyser were obtained when the relative humidity of the sample was 80 % at 20 °C. Further tests were carried out to study the nature of this interference. Results show that humidity interference depends on both the amount fractions of water vapour and benzene. If benzene concentrations in an area are close to its annual limit value (5 µg m−3), biases of 2.2 % can be expected when the absolute humidity is 8.6 g cm−3 &ndash; corresponding to a relative humidity of 50 % at 20 °C. This can be accounted for in the uncertainty budget of measurements with no need for corrections. If benzene concentrations are above the annual limit value, biases become higher. Thus, in these cases, actions should be taken to reduce the humidity interference, as an underestimation of benzene concentrations may cause a mismanagement of air quality in these situations

Using saline reclaimed water on almond grown in Mediterranean conditions: Deficit irrigation strategies and salinity effects

The main objective of this study was to acquire agronomic knowledge about the effects of irrigation with saline reclaimed (RW) and desalinated DESERT (DW) water and different irrigation strategies: control full irrigation (FI) and regulated deficit irrigation (RDI) on leaf nutrients, tree growth and fruit quality and yield of almond trees in pots. Our results showed that RW had the highest concentration of some valuable agronomic nutrients such as N, but also of phytotoxic elements (Na and Cl). Na leaf concentration on RW treatments reached toxic levels, especially under RDI, and toxicity symptoms were shown. Regarding tree growth, cumulate trunk diameter on RW-RDI was significantly lower than on the control treatment and shoot growth was reduced from the beginning of the irrigation season in RW treatments. Maximum yield was reached on RW-FI, 18% higher than the control treatment. However, RDI strategies influenced negatively on yield, being 23% less in RW and 7% less in DW although water productivity was not significantly reduced by water stress. These findings manifest that the combination of RW and RDI can be a promising future practice for almond irrigation, but long-term studies to establish suitable management practices must be developed. © IWA Publishing 2019

Different Suitability of Olive Cultivars Resistant to Xylella fastidiosa to the Super-Intensive Planting System

Until today, only Leccino and Fs-17 (=Favolosa®) olive cultivars proved resistant to Xylella fastidiosa subsp. pauca (Xfp) due to a low presence of bacteria in the xylem. Integrated disease management in olive growing areas threatened by the spread of Xfp is crucial to overcoming the environmental, economic and social crisis. Since the EU Decision allows for the plantation of resistant olive cultivars in infected areas, there is a need to define a suitable plantation system for these cultivars. The adoption of new planting systems, such as intensive and super-intensive (SHD), could compensate for the economic losses and restore the olive agroecosystem. The aim is to ascertain the suitability of the available Xfp-resistant cultivars to SHD planting systems that demonstrate the best economic and environmental sustainability. Hence, a five-year study was established in an experimental SHD olive orchard (Southern Italy) in order to analyse the main vegetative and productive traits of Leccino and Fs-17, together with four other Italian cultivars (Cipressino, Coratina, Frantoio and Urano), compared with the well-adapted cultivars to SHD orchards (Arbequina and Arbosana), by means of the von Bertalanffy function. The results indicated that cv. Fs-17 showed sufficient suitability for SHD planting systems, giving the best-accumulated yield despite some canopy growth limitations, whereas cv. Leccino did not show satisfactory results in terms of both vegetative and yield parameters, confirming its suitability for intensive planting systems. These results are useful for optimizing integrated resistance management in Xfp-infected areas by planting resistant host plants

Plant and soil microbial community responses to different water management strategies in an almond crop

Climate change is one of the main challenges facing the agricultural sector as it strives to meet global food needs. In arid and semiarid areas, the scarcity of water imposes the use of alternative sources - such as reclaimed water (RW) or desalinated water (DW) - and of deficit irrigation strategies, such as regulated deficit irrigation (RDI), in order to maintain productivity. The impact of both alternative water sources and RDI strategies on soil microbial communities in conjunction with the crop response has been little studied, and far less in fruit trees. Here, we evaluated the effects of the irrigation water quantity (RDI or the optimal water amount) and quality (DW or saline RW) on: i) the biomass, composition, and activity of the soil microbial community, and ii) the plant agro-physiological response at the level of the water status, nutrients, vegetative growth, and yield of almond trees. The DW-RDI treatment had a lower vegetative growth than the rest, reducing the nutrient requirements and increasing the contents of organic carbon and nitrogen in soil. This coincided with a significant increase in the bacterial biomass and enzyme activities in soil, as well as with a decrease in plant nutrient use efficiencies and yield. Irrigation with RW increased the fungal biomass. When there were no water restrictions (RW-FI), none of the plant agro-physiological parameters were affected; when RDI was applied (RW-RDI), the highest soil sodicity was reached and vegetative growth and yield were negatively affected, although the plant nutrient use efficiencies did not decrease as much as with DW-RDI. In addition, the plant nutrient use efficiencies were negatively correlated with the soil enzyme activities. These results improve our knowledge of the functioning of plant-soil interactions in Mediterranean crops subjected to different irrigation strategies

Ripening Indices, Olive Yield and Oil Quality in Response to Irrigation With Saline Reclaimed Water and Deficit Strategies

The 70% worldwide surface of olive orchards is irrigated. The evaluation of non-conventional water resources and water-saving techniques has gained importance during the last decades in arid and semiarid environments. This study evaluated the effects of irrigation with two water sources: low-cost water DEsalination and SEnsoR Technology (DESERT) desalinated water (DW) ECw ∼1 dS m-1) and reclaimed water (RW) (ECw ∼ 3 dS m-1) combined with two irrigation strategies: full irrigation (FI) (100% of ETc) and regulated deficit irrigation (RDI, 50% of ETc) on fruit yield, ripening indices, and oil yield and quality of olive trees cv Arbosana planted in Mediterranean conditions. Our results showed that RW without water restrictions increased the fruit yield by 35% due to a slight increase in the fruit weight and, mainly, to a greater fruit set than the control trees; although this did not result in a higher oil yield (g tree-1) since the oil content per fruit dry weight was reduced. The RDI strategy did not decrease the fruit yield despite the fact that olive weight tended to decrease, and it increased the oil yield by ∼14.5%. The combination of both stresses (RW and RDI) neither decreased the fruit yield; however, it significantly reduced oil yield (25% less in 2018) since oil content per fruit dry weight was strongly reduced (40%) compared to control trees. Both RDI treatments, regardless water source, determined acidity levels in olive paste lower than in FI treatments; however, it reduced oil extractability and fatty yield. The finding about oil quality indicated that olive exposure to RW, regardless of the water amount, decreased oil quality mainly due to the reduction of oleic acid and the increase of C18:2/C18:3 ratio and peroxides; on the contrary, both RW and RDI improved the total polyphenols. In all cases, the parameters met the legislation. In short, with appropriate management, RW and RDI have great potential to manage oil olive production; nevertheless, studies subjected to long-term use of these techniques should be experienced to ensure the sustainability of oil yields and quality

Physiological responses of almond trees under regulated deficit irrigation using saline and desalinated reclaimed water

Regulated deficit irrigation (RDI) strategy using reclaimed water (RW) is becoming a common procedure in some Mediterranean regions. Full and regulated deficit irrigation were combined with desalinated (ECw 1 dS m−1) and saline (ECw 3 dS m−1) reclaimed water to irrigate young potted almond trees over a 3-year period. The full irrigation treatments received 130% of the crop evapotranspiration (ETc) and the RDI treatments received 80% of ETc during the kernel filling. Trunk diameter decreased in both RDI treatments at the end of the experimental period, although this response was more marked in the trees irrigated with saline RW. There were negative relationships between shoot growth and leaf Na+ and Cl+ contents in the saline treated trees, in which the accumulation of salts in leaves was associated with osmotic adjustment, which was responsible for maintaining midday leaf turgor. Plant water status, measured by the leaf and water potential, decreased in almond exposed to water deficit or irrigated with saline RW, indicating a slight dehydration in these plants due to the difficulty in water uptake from the substrate. Trees subjected to both deficit irrigation treatments showed lower stomatal conductance values than full irrigated treatments during the RDI period. However, at the end of experimental period, the lowest Pn values were found in plants irrigated with saline RW, especially in trees irrigated with saline RW combined with RDI strategy, verifying the relevance of duration of exposure to the stress. Saline and desalinated RW can be successfully used for irrigating almond trees, which might be of great economic and competitive significance for agriculture, but further research focused on a longer term should be carried out since detrimental effects might appear. Deficit irrigation combined with saline RW in P. dulcis is not recommended since it intensifies the negative effects of water and salt stress applied individually

Shared and Differential Retinal Responses against Optic Nerve Injury and Ocular Hypertension

Glaucoma, one of the leading causes of blindness worldwide, affects primarily retinal ganglion cells (RGCs) and their axons. The pathophysiology of glaucoma is not fully understood, but it is currently believed that damage to RGC axons at the optic nerve head plays a major role. Rodent models to study glaucoma include those that mimic either ocular hypertension or optic nerve injury. Here we review the anatomical loss of the general population of RGCs (that express Brn3a; Brn3a+RGCs) and of the intrinsically photosensitive RGCs (that express melanopsin; m+RGCs) after chronic (LP-OHT) or acute (A-OHT) ocular hypertension and after complete intraorbital optic nerve transection (ONT) or crush (ONC). Our studies show that all of these insults trigger RGC death. Compared to Brn3a+RGCs, m+RGCs are more resilient to ONT, ONC, and A-OHT but not to LP-OHT. There are differences in the course of RGC loss both between these RGC types and among injuries. An important difference between the damage caused by ocular hypertension or optic nerve injury appears in the outer retina. Both axotomy and LP-OHT induce selective loss of RGCs but LP-OHT also induces a protracted loss of cone photoreceptors. This review outlines our current understanding of the anatomical changes occurring in rodent models of glaucoma and discusses the advantages of each one and their translational value