Background: Remaining of crude oil in storage tanks usually lead to accumulation of oily sludge at the bottom of the tank which should be treated and disposed of in a suitable manner. In this research the feasibility of chemical oxidation with H2O2 and Fenton's reagent for removal of total petroleum hydrocarbons (TPH) from composted storage tank sludges was investigated.

Materials and Methods: The sludge was mixed with immature compost at various sludge to compost ratios including 1:2, 1:4, 1:6, 1:8 and 1:10 and composted for 82 days. Then, hydrogen peroxide and Fenton’s reagent were added to the composted mixture in six concentrations including 2%, 5%, 10%, 15%, 20% and 30% w w-1 for a period of 24 and 48 hr.

Results: TPH removal in composting reactors with the ratios of 1:2, 1:4, 1:6, 1:8 and 1:10 were 66.59, 73.19, 74.81, 80.20 and 79.91 percent, respectively. The mean TPH removal of 1:8 composted mixtures with 2%, 5%, 10%, 15%, 20% and 30% of oxidant concentrations were 1, 5.09, 19.37, 28.16, 34.37 and 38.05 percent, respectively. The highest removal efficiency was achieved in stepwise addition to the sludge. As well, increasing oxidation time from 24 to 48 hr had a little effect on TPH removal increase and the removal efficiencies of H2O2 and Fenton were nearly similar.

Conclusion: Chemical oxidation with hydrogen peroxide and Fenton as a post-treatment step is an acceptable process in TPH removal from bottom sludge of storage tanks.

Background: As dental solid waste are among the most important environmental pollutants due to its high contents of toxic and hazardous agents, suitable treatment and management of it are of great importance. The objective of this study was to quantity & quality analyses of dental solid waste and associated management practices in the general dentistry offices in the city of Arak.

Materials and Methods: 15 samples of solid waste were taken from the 5 selected general dentistry offices, classified into 66 components and 4 fractions, and then the quantity & quality characteristics were evaluated. Management practices of the solid waste were also investigated by using a questionnaire.

Results: According to the results, per capita and the average generation rate of each dentistry office were 66.71 g/day-patient and 1340.45 g/day, respectively. Potential infectious, domestic-type, chemical & pharmaceutical, and toxic wastes consisted of 54.25%, 35.14%, 8.19%, and 2.14% of the waste generated, respectively. 10 components including latex gloves, nylon & plastic, saliva & blood-contaminated kleenex, paper & cardboard, used ampoules, saliva ejector tubes, gypsum, food waste, saliva & blood-contaminated dental rolls, and nylon gloves were responsible for more than 80% of the total waste generated, respectively.

Conclusion: Each fraction of dental solid waste (toxic, chemical & pharmaceutical, potential infectious and domestic-type wastes) should be separately collected and disposed of according to the related criteria.

Abstract

Background: Human exposure to air pollution is associated with an increased risk of diseases such as heart failure, asthma and cancer. It has been suggested that oxidative stress is involved in air pollution-induced disorders. Recently, γ-glutamyltransferase (GGT) is known as a marker of oxidative stress. This study was aimed to evaluate the effect of exposure to outdoor air pollution on enzyme activity of GGT and also usage of GGT serum level as a marker for studying of harmful effects of air pollution in the resident with high air pollution level.

Materials and Methods: In this analytical cross-sectional study, 110 healthy adult men, never-smoking, who worked in an area with high air pollution and 90 men who worked in an area with low air pollution, as control group, were enrolled. All subjects were in the age range of 25-45 years with minimum work history of three years. The GGT activity in the serum samples was determined using a spectrophotometric method.

Results: Our results showed that the serum levels of GGT in the subjects in the areas with high air pollution (33.92 ± 1.61 U/L) did not differ significantly with those of control region (33.62 ± 1.74 U/L).

Conclusion: Overall, this study did not support the hypothesis that GGT enzyme could be considered as an oxidative stress marker following exposure to outdoor air pollution. Further studies with a larger sample sizes and also trials in other areas are required to confirm these results.