A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts

Mercury is transported globally in the atmosphere mostly in gaseous elemental form (GEM, Hg0 gas), but still few worldwide studies taking into account different and contrasted environmental settings are available in a single publication. This work presents and discusses data from Argentina, Bolivia, Bosnia and Herzegovina, Brazil, Chile, China, Croatia, Finland, Italy, Russia, South Africa, Spain, Slovenia and Venezuela. We classified the information in four groups: (1) mining districts where this contaminant poses or has posed a risk for human populations and/or ecosystems; (2) cities, where the concentration ofatmospheric mercury could be higher than normal due to the burning of fossil fuels and industrial activities; (3) areas with natural emissions from volcanoes; and (4) pristine areas where no anthropogenic influence was apparent. All the surveys were performed using portable LUMEX RA-915 series atomic absorption spectrometers. The results for cities fall within a low GEM concentration range that rarely exceeds 30 ng m-3, that is, 6.6 times lower than the restrictive ATSDR threshold (200 ng m-3) for chronic exposure to this pollutant. We also observed this behavior in the former mercury mining districts, where few data were above 200 ng m-3.We noted that high concentrations of GEM are localized phenomena that fade away in short distances. However, this does not imply that they do not pose a risk for those working in close proximity to the source. This is the case of the artisanal gold miners that heat the Au–Hg amalgam to vaporize mercury. In this respect, while GEM can be truly regarded as a hazard, because of possible physical–chemical transformations into other species, it is only under these localized conditions, implying exposure to high GEM concentrations, which it becomes a direct risk for humans.Grants CGL2009-13171 and CTM2012-33918 from the Spanish Ministry of Economy and Competitiveness and PII1I09-0142- 4389 from theCastilla-LaMancha (Spain)RegionalGovernment.Published713-7346A. Monitoraggio ambientale, sicurezza e territorioJCR Journalrestricte

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

Pedochemical evolution and trace elements availability to plants in ophiolitic soils

SCI. TOT. ENVIR

Pedochemical evolution and trace elements availability to plants in ophiolitic soils

SCI. TOT. ENVIR

Pedochemical evolution and trace elements availability to plants in ophiolitic soils

SCI. TOT. ENVIR

Fluid geochemistry and geothermometry in the unexploited geothermal field of the Vicano-Cimino volcanic district (central Italy)

The Vicano–Cimino Volcanic District (VCVD) is related to the post-orogenic magmatic activity of the peri- Tyrrhenian sector of Central Italy. The chemical and isotopic compositions of 333 water discharges and 25 gas emissions indicate the occurrence of two main sources: 1) cold Ca-HCO3 to Ca(Na, K)-HCO3 type waters from relatively shallow aquifers hosted in volcanic and sedimentary formations; and 2) thermal Ca-SO4(HCO3) type waters located in a deep CO2-pressurized reservoir, hosted in carbonate–evaporite rocks and separated from the shallow aquifers by thick sequences of low-permeability formations. Carbon dioxide is mainly produced by thermal metamorphic decarbonation within the deepest and hottest parts of the carbonate–evaporite reservoir (δ13C–CO2 from−3.1 to+2.2‰vs. VPDB), likely affected by a mantle-rooted CO2. ReleaseofCO2-rich gases from the deep aquifer into the overlying shallow aquifers produces high-CO2 springs and bubbling pools. The spatial distribution of thermal waters and CO2-rich cold discharges is strongly controlled by fractures and faults located in correspondencewith buried structural highs. Stable isotopes (δD and δ18O) suggest thatmeteoric water feeds both the shallowand deep reservoirs. The relatively lowR/Ra values (0.27–1.19) indicate that He ismainly deriving from a crustal source, with minor component from the mantle affected by crustal contamination related to the subduction of the Adriatic plate. Consistently, relatively high N2/Ar and N2/3He ratios and positive δ15N–N2 values (from0.91 to 5.7‰vs. air) characterize the VCVD gas discharges, suggesting the occurrence of a significant “excess” nitrogen. Isotopic compositions of CH4 (δ13C–CH4 and δD–CH4 values from−28.9 to−22.1‰vs. VPDB and from −176 to −138‰ vs. VSMOW, respectively), and composition of light alkanes are indicative of prevalent thermogenic CH4, although the occurrence of abiogenic CH4 production cannot be excluded. The δ34S–H2S values (from+9.3 to+11.4‰vs. VCDT) are consistentwith the hypothesis of H2S production fromthermogenic reduction of Triassic anhydrites. Gas geothermometry in the H2O–H2–Ar–H2S system suggests that the VCVD gases equilibrated in a liquid phase at redox conditions controlled by interactions of fluids with the local mineral assemblage at temperatures lower (b200 °C) than that andmeasured in deep (N2000 m) geothermalwells. This confirms that secondary processes, i.e. steam condensation, gas dissolution in shallow aquifers, re-equilibration at lower temperature, and microbial activity, significantly affect the chemistry of the uprising fluids. Thermal water chemistry supports the occurrence in this area of an anomalous heat flowthat, coupledwith the recent demographic growth, makes this site suitable for direct and indirect exploitation of the geothermal resource, in agreement with the preliminary surveys carried out in the 1970's–1990's for geothermal exploration purposes

Fluid geochemistry and geothermometry in the unexploited geothermal field of the Vicano-Cimino volcanic district (central Italy)

The Vicano–Cimino Volcanic District (VCVD) is related to the post-orogenic magmatic activity of the peri- Tyrrhenian sector of Central Italy. The chemical and isotopic compositions of 333 water discharges and 25 gas emissions indicate the occurrence of two main sources: 1) cold Ca-HCO3 to Ca(Na, K)-HCO3 type waters from relatively shallow aquifers hosted in volcanic and sedimentary formations; and 2) thermal Ca-SO4(HCO3) type waters located in a deep CO2-pressurized reservoir, hosted in carbonate–evaporite rocks and separated from the shallow aquifers by thick sequences of low-permeability formations. Carbon dioxide is mainly produced by thermal metamorphic decarbonation within the deepest and hottest parts of the carbonate–evaporite reservoir (δ13C–CO2 from−3.1 to+2.2‰vs. VPDB), likely affected by a mantle-rooted CO2. ReleaseofCO2-rich gases from the deep aquifer into the overlying shallow aquifers produces high-CO2 springs and bubbling pools. The spatial distribution of thermal waters and CO2-rich cold discharges is strongly controlled by fractures and faults located in correspondencewith buried structural highs. Stable isotopes (δD and δ18O) suggest thatmeteoric water feeds both the shallowand deep reservoirs. The relatively lowR/Ra values (0.27–1.19) indicate that He ismainly deriving from a crustal source, with minor component from the mantle affected by crustal contamination related to the subduction of the Adriatic plate. Consistently, relatively high N2/Ar and N2/3He ratios and positive δ15N–N2 values (from0.91 to 5.7‰vs. air) characterize the VCVD gas discharges, suggesting the occurrence of a significant “excess” nitrogen. Isotopic compositions of CH4 (δ13C–CH4 and δD–CH4 values from−28.9 to−22.1‰vs. VPDB and from −176 to −138‰ vs. VSMOW, respectively), and composition of light alkanes are indicative of prevalent thermogenic CH4, although the occurrence of abiogenic CH4 production cannot be excluded. The δ34S–H2S values (from+9.3 to+11.4‰vs. VCDT) are consistentwith the hypothesis of H2S production fromthermogenic reduction of Triassic anhydrites. Gas geothermometry in the H2O–H2–Ar–H2S system suggests that the VCVD gases equilibrated in a liquid phase at redox conditions controlled by interactions of fluids with the local mineral assemblage at temperatures lower (b200 °C) than that andmeasured in deep (N2000 m) geothermalwells. This confirms that secondary processes, i.e. steam condensation, gas dissolution in shallow aquifers, re-equilibration at lower temperature, and microbial activity, significantly affect the chemistry of the uprising fluids. Thermal water chemistry supports the occurrence in this area of an anomalous heat flowthat, coupledwith the recent demographic growth, makes this site suitable for direct and indirect exploitation of the geothermal resource, in agreement with the preliminary surveys carried out in the 1970's–1990's for geothermal exploration purposes.Published96-1145A. Energia e georisorseJCR Journalrestricte