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Solid waste production has increased in recent years. Many studies have shown that generated leachate from solid waste contains a high concentration of heavy metals. Their removal efficiency from leachate was investigated in aerobic suspended and attached growth systems in lab-scale within 72 hours of aeration. All of the materials used were analytical grade (Merck). Maximum efficiency of the attached growth system in removal of BOD 5 and COD was, respectively, 80% and 78.28%. Maximum removal efficiency for both attached and suspended growth was related to lead, and minimum removal efficiency was related to vanadium for the attached growth, and cadmium for suspended growth. Heavy metals removal efficiencies in attached growth from max to min were lead, iron, manganese, cobalt, zinc, mercury, magnesium, copper, chromium, nickel, cadmium, and vanadium, respectively; and the removal efficiencies for suspended growth from max to min were lead, manganese, iron, zinc, copper, magnesium, cobalt, mercury, chromium, nickel, vanadium, and cadmium, respectively. Generally it can be concluded that both systems are suitable for young leachate treatment, but to satisfy environmental discharge standards post treatment will be necessary.

In this article, the data of heavy metals phytoremediation efficiency were provided. The Azolla was collected from the lake around the Rasht city and washed in tap water, then weighed (0.2, 0.4 and 0.8 g), and kept for 15 days in the 100 ml disposable container in the presence 5, 10 and 25 mg/L of lead, nickel and cadmium ions. The samples were stored in polyethylene containers for analysis of the metal concentration with ICP-OES. According to the results, removal efficiency was increased from 40% to 70% at 10 days along with the increasing of the biomass from 2.0 to 8.0 g. The removal efficiency of Ni (II), Cd (II), and Pb (II) were increased by increasing the contact time up to 10 days. The removal efficiency decreased by increasing of the metals concentration from 5 to 25 mg/L. The highest removal efficiency was observed at heavy metals concentrations of 5 mg/L and contact time of 10 days. Results showed that Azolla had a high potential for the removal of heavy metals from water resources and it can be used in phytoremediation of heavy metals in environmental refinement projects.

Background and Objective: Exposure to formaldehyde has adverse effects on health both acutely and over the long term (e.g., carcinogenicity). The substance is widely used in pathology and histology departments. This study focused on cancer risk of formaldehyde in pathology department of five hospitals in Rasht. Materials and Methods: Sampling and determination of formaldehyde in pathology department were carried out based on the NIOSH method of 3500. The working condition and working environment were investigated and a semi quantitative risk assessment were used to health risk assessment of formaldehyde and The individual lifetime cancer probability, which is defined as the increase in the probability of developing cancer during continuous exposure to an air pollutant were used to assess health risks with formaldehyde. Results: The results showed that the exposure level of all subjects were higher than the Occupational Exposure Limit for 8 hours exposure time of formaldehyde. However, in the five occupational groups, the highest weekly exposure index was observed for the Lab Technicians (0.664 ppm) at Hospital no. 5, which could have been due to more daily working hours at this sampling site and a lack of adequate ventilation. The formaldehyde concentration was in the 0.0192 to 0.326 ppm ranges for five hospital pathology departments. The cancer risk ranged from 9.52×10-5 to 1.53×10-3 , and it was greater than the WHO acceptable cancer risk level.Conclusions: The results of the risk assessments can be used for managing the chemical exposure of allocated resources for defining control actions. This process plays an important role in reducing the level of exposure to formaldehyde in pathology departments.