Integrated use of chemical and geophysical monitoring to study the diesel oil biodegradation in microcosms with different operative conditions

This study aimed to monitor the aerobic bioremediation of diesel oil-contaminated soil by measuring: a) the CO₂ production; 2) the fluorescein production; 3) the residual diesel oil concentration. Moreover, the complex dielectric permittivity was monitored through an open-ended coaxial cable. Several microcosms were prepared, changing the water content (u% = 8-15% by weight), the carbon to nitrogen ratio (C/N = 20-450), and the soil amount (200 and 800 g of dry soil). The cumulative CO₂ and fluorescein production showed similar trends, but different values since these two parameters reflect different features of the biological process occurring within each microcosm. The diesel oil removal efficiency depended on the microcosm characteristics. After 84 days, in the microcosms with 200 g of dry soil, the highest removal efficiency was achieved with a water content of 8% by weight and C/N = 120, while in the microcosms with 800 g of dry soil the best result was achieved with the water content equal to 12% by weight and C/N = 100. In the tested soil, the bioremediation process is efficient if the water content is in the range 8-12% by weight, and C/N is in the range 100-180; under these operative conditions, the diesel oil removal efficiency was about 65-70% after 84 days. The dielectric permittivity was monitored in microcosms with 200 g of dry soil. The open-ended coaxial cable detected significant variations of both the real and the imaginary component of the dielectric permittivity during the bioremediation process, due to the physical and chemical changes that occurred within the microcosms.

Bioremediation of Agricultural Soils Polluted with Pesticides: A Review

Pesticides are chemical compounds used to eliminate pests; among them, herbicides are compounds particularly toxic to weeds, and this property is exploited to protect the crops from unwanted plants. Pesticides are used to protect and maximize the yield and quality of crops. The excessive use of these chemicals and their persistence in the environment have generated serious problems, namely pollution of soil, water, and, to a lower extent, air, causing harmful effects to the ecosystem and along the food chain. About soil pollution, the residual concentration of pesticides is often over the limits allowed by the regulations. Where this occurs, the challenge is to reduce the amount of these chemicals and obtain agricultural soils suitable for growing ecofriendly crops. The microbial metabolism of indigenous microorganisms can be exploited for degradation since bioremediation is an ecofriendly, cost-effective, rather efficient method compared to the physical and chemical ones. Several biodegradation techniques are available, based on bacterial, fungal, or enzymatic degradation. The removal efficiencies of these processes depend on the type of pollutant and the chemical and physical conditions of the soil. The regulation on the use of pesticides is strictly connected to their environmental impacts. Nowadays, every country can adopt regulations to restrict the consumption of pesticides, prohibit the most harmful ones, and define the admissible concentrations in the soil. However, this variability implies that each country has a different perception of the toxicology of these compounds, inducing different market values of the grown crops. This review aims to give a picture of the bioremediation of soils polluted with commercial pesticides, considering the features that characterize the main and most used ones, namely their classification and their toxicity, together with some elements of legislation into force around the world.

Extrathoracic and intrathoracic airway responsiveness in sinusitis

BACKGROUND

Asthma associated with sinusitis is supposed to be sustained by bronchoconstrictive reflexes originating in extrathoracic airway (EA) receptors.

OBJECTIVE

The study was designed to evaluate the relationship between EA responsiveness and bronchial responsiveness in sinusitis.

METHODS

We performed histamine inhalation challenge in 106 patients with chronic sinusitis, during disease exacerbation and after treatment with antimicrobials and nasal flunisolide (100 micrograms daily) for 2 weeks. Forced expiratory volume in 1 second (FEV1) and maximal mid-inspiratory flow (MIF50) were the respective indexes of bronchial and EA narrowing; the histamine concentrations causing a 20% fall in FEV1 (PC20) and 25% drop in MIF50 (PC25MIF50) were used as thresholds of bronchial and EA responsiveness. Thresholds of 8 mg/ml or less were assumed to indicate bronchial hyperresponsiveness (B-HR) or EA hyperresponsiveness (EA-HR).

RESULTS

During sinusitis exacerbation 76 patients had EA-HR, which in 46 was associated with B-HR. The values of PC20 were closely related with those of PC25MIF50 (p < 0.001). EA-HR and B-HR were strongly associated with pharyngitis. After treatment, mean PC25MIF50 and PC20 were significantly increased (p < 0.001). The improvement of PC25MIF50 was closely related to that of PC20 (p < 0.001) and to the decrease in neutrophils in nasal lavage (p < 0.05). EA-HR reversed in 58 patients and improved in 10; B-HR reversed in 29 and improved in 12.

CONCLUSIONS

Our findings suggest that in sinusitis, B-HR may be sustained by constrictive reflexes originating in pharyngeal receptors, made hypersensitive by seeding of the inflammatory process.

Respiratory symptoms, lung function tests, airway responsiveness, and bronchoalveolar lymphocyte subsets in B-chronic lymphocytic leukemia

A respiratory questionnaire was completed and spirometry, tests for lung volumes, diffusion capacity for CO, and methacholine bronchial challenge were performed in 24 outpatients with B-chronic lymphocytic leukemia (B-CLL), aged 44-79, presenting in different stages of their disease. In 10 patients, bronchoalveolar lavage (BAL) fluid was also obtained. Ten of twenty-four patients had symptoms consistent with chronic bronchitis, unrelated both to smoking history and to the clinical stage. Abnormal values (< 2 SD) were found in 4 patients for total lung capacity (TLC), in 9 for vital capacity (VC), 8 for forced expiratory volume in 1 sec (FEV1), 11 for MEF50, 15 for MEF25 and in 7 for diffusing capacity for carbon monoxide. Seven of nineteen patients had PD20FEV1 at less than 1,600 micrograms of methacholine chloride. There was a significantly negative correlation between white blood cell count and VC (r = 0.41, P < 0.05). A positive correlation was found between PD20FEV1 and FEV1/VC (r = 0.61, P < 0.01). The mean and SEM for BAL cells/ml was 463 (71.8) x 10(3). No leukemic cells but a marked increase in T lymphocytes (32.5 +/- 7.8%) were found in BAL fluid. There were significantly negative correlations between the number of BAL CD3+ T lymphocytes and PD20FEV1 (r = 0.61, P < 0.05), and between the number of BAL CD8+ T lymphocytes and PD20FEV1 (r = 0.84, P < 0.01). In conclusion, patients with B-CLL have a high prevalence of respiratory symptoms, small airway dysfunction and CD8 "alveolitis" related to airway responsiveness; despite the well-known lung interstitial lymphocyte infiltration in B-CLL, leukemic cells are not found in BAL fluid.