Evaluation of the tailings basins pollution potential

Tailings basins within mining areas may represent potential sources of environmental contamination for soil and underground water. In fact, the disposed muds are typically characterized by high concentration of heavy metals and other possibly dangerous compounds. The tailings basins built in Europe before the legal implementation of the EU Directive on the landfill of waste (Directive 99/31) were not provided with impermeable barriers. In such conditions, during the initial period of the basin life the liquid phase in the disposed residue filtrates throughout the solid phase under a unit vertical hydraulic gradient, reaching the soil underneath; afterword, when the accumulated mud forms an impermeable layer at the bottom of the basin, the same mud, under the load of the superimposed new strata, consolidates, ejecting liquids throughout the bottom. The article discusses the implementation criterion aimed at evaluating the conformity of old tailing basin to the new regulation on landfill of waste and a method for the calculation of the rate of polluted liquids released through the bottom of a tailing basin during its operative life and after its closure

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

Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03). CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

The unique landfill site and the mine void backfilling as solutions for the environmental safety of the abandoned mine areas

abandoned mining districts of Sardinia in which contaminated materials both from mining excavations and mineral processing plants are accumulated. Remediation solutions based on the relocation of the materials in new and engineered dumps or on materials treatment are not appropriate due to the huge volume of the deposits (the whole amount has been estimated in 70 Mm3). It appears particularly workable the use of a small number of the compromised major sites as “accumulation centres” in which materials from the other smaller abandoned areas of the same district, can be placed. This strategy has important advantages related to some typical elements of the mining areas i.e. the presence of tailing basins, often having significant surface extension, and the existence of mining voids both on the surface and underground. The use of these surfaces and volumes as “accumulation centres” introduces important technical matters referred mainly to the need of ensuring pollutants containment, to the embankments stability and to the safety condition of surface and underground voids during and after backfilling operations. The paper discuss the issues related to the selection criteria of the sites to be used as “accumulation centre” and proposes some technical solutions aimed at obtaining their permanent and global safety conditions

An innovative way for the construction of PRB’s

The concept of permeable reactive barriers (PRB) is being considered with increasing interest for polluted groundwater remediation, as an alternative to conventional physical barriers. The construction of a PRB using the excavation/backfill concept is generally difficult and expensive. A new approach to the problem examines the application of high-pressure water jets for the creation of this kind of barriers. The papers deals with the research activity being carried out at DIGITA’s Waterjet Laboratories and the results obtained during a study aimed at evaluating the volumes of soil involved in the process as a function of the operating parameters. Then the envisaged technology for the construction of reactive barriers or curtains is described. In conclusion some considerations concerning the industrial application and the economic feasibility of the method are reported