Human health risk assessment of arsenic and trace metals in atmospheric dust of Arak industrial area, Iran.

In order to investigate concentrations, variability, sources, and human health risk of trace elements, 38 atmospheric dust samples were collected around Arak industrial area. The average concentrations of Cd~Zn, As, and Pb were 3.3, 2.5, and 2.4 times higher than the corresponding geochemical background, respectively, while concentrations of Co, Cu, Ni, and Hg were lower. Based on geo-accumulation index (Igeo), trace elements were classified between practically uncontaminated to moderate contaminated levels. The potential risk (RI) map showed that about 86% of the study area for all trace elements was in the moderate risk class. According to the results of positive matrix factorization (PMF) model, four factors were extracted for trace elements, including industrial sources, natural sources, mining, and transportation, that contributed about 30, 27, 26, and 17% to pollution of the area, respectively. The carcinogenic risks for inhalation exposure to Cd, As, Ni, and Co were lower than the permissible risk limit than the EPA recommend (10-6), indicating an acceptable level of risk. Results of the health risk evaluation indicated that the non-carcinogenic health risk (i.e., hazard quotient, HQ) for children and adults decrease following: As > Pb > Ni > Zn > Cd > Cu > Co > Hg. When excluding As, the hazard index (HI) was lower than the safe level (HI < 1) for all the trace elements, whereas HQ values of As for children and adults were 17.1 and 1.6, respectively, indicating a potential risk for children. In sum, several remedial actions to eliminate or to reduce the dust pollution are urgently required in the industrial area of Arak.

Pollution assessment and spatial distribution of trace elements in soils of Arak industrial area, Iran: Implications for human health.

Emerging industrial hubs have resulted in soil and dust pollution by trace elements, being a potential source and pathway for human exposure to nearby cities. The aim of this study was to determine the spatial distribution, levels, sources and health risk assessment of metals and arsenic in soils of Arak industrial area, Iran. A total of 235 topsoil (0-5 cm) samples were collected from the vicinity of Arak, and the concentrations of As, Zn, Ni, Pb, Cu and Cd were 152, 104, 93, 38, 14 and 1.2 mg kg-1, respectively, and exceeded the background values, with the exception of Cu. Values of pollution indexes revealed that most of the soils are especially enriched by As and Cd. Multivariate statistical analysis showed that Pb and Zn originated from common anthropogenic sources related to industrialization and mining, whereas Cu and Ni are probably associated with geological sources. Cd was mainly derived from the input of agricultural and industrial activities, and As should be attributed to residues in mining. Spatial risk maps showed the high risk of trace elements pollution in the order of As (100%) > Cd (62%) > Ni (12%) > Pb (5%) > Zn (4%) > Cu (0%). The results of the noncarcinogenic risk assessment showed that chronic daily intake in children and adults for ingestion pathway was higher than for dermal contact and inhalation. Values of hazard index (HI) for trace elements were below the safe level (HI ≤ 1), indicating that no noncarcinogenic risk threaten children and adults. Likewise, the total carcinogenic risk of Cd in both groups is less than the EPA threshold (1 × 10-6), indicating a low carcinogenic risk, however As (1 × 10-6 to 1 × 10-4) indicates an acceptable risk.

Estimation of soil specific surface area using some mechanical properties of soil by artificial neural networks.

Soil specific surface area (SSA) is an important property of soil. Depending on the measurement techniques, determination of the SSA is costly and time consuming. Hence, a limited number of studies have been conducted to predict the SSA from the soil variables. In this study, the soil samples were taken from the literature. Fractal parameters (FP) were calculated by the model of Bird et al. (European Journal of Soil Science 51, 55-63, 2000) used as the input variables to predict the SSA. Some studies have been carried out on the prediction capability of the different parameters using the artificial neural networks (ANNs). The ANNs were further used and 20 models were developed to investigate the value of input variables to predict the SSA. The results showed that the PTF13 (RMSE = 0.13) and PTF18 (RMSE = 0.13) with the input variables of particle-size distribution and Atterberg limits revealed better performance than the other PTFs (in the training step). It is because of the fact that free swelling index (FSI) and Atterberg limits were closely correlated to the soil clay mineralogy as one of the important factors controlling the SSA. In general, this results demonstrated that the PTF9 with the variables of sand, clay, plastic limit (PL), liquid limit (LL), and FSI showed the best (RMSE = 0.37) results in the estimation of the SSA. In conclusion, there was not a strong correlation between the soil mechanical properties and SSA but also ANNs were a suitable method to predict the SSA from the soil variables.

Modified approach to vaginal hysterectomy without initial colpotomy.

PURPOSE OF REVIEW: To evaluate the surgical technique and outcomes of women undergoing the modified approach to vaginal hysterectomy at Harbor-University of California, Los Angeles Medical Center from 2000 to 2011. A retrospective chart review was performed of all vaginal hysterectomy cases performed using the modified technique. RECENT FINDINGS: There is much evidence in favor of the safety of vaginal hysterectomy over other modes of hysterectomy, such as the lower overall incidence of vaginal cuff dehiscence, shorter hospital stays and faster recovery from surgery. The traditional method of performing vaginal hysterectomy involves early anterior or posterior colpotomy. At times, this may be difficult secondary to a flush cervix, distorted anatomy, and adhesions from prior surgeries or infection. At our teaching institution, however, we have adopted a different technique, initially developed by Dr. Reza Mohajer who is one of our faculty members and co-author of this article, that facilitates ligation of uterine vessels without initial attempt at colpotomy. This enables Ob/Gyn residents to safely and successfully perform vaginal hysterectomies despite large uterine size, nulliparity, flush cervix and previous pelvic surgery. SUMMARY: Modified approach to difficult vaginal hysterectomy facilitates performance of vaginal hysterectomy without need for initial anterior or posterior colpotomy.

The status of lead and cadmium in soils of high prevalenct gastrointestinal cancer region of Isfahan.

BACKGROUND: Cadmium and lead compounds are classified as human carcinogens by several regulatory agencies. Twenty five percent of all cancer-related deaths are attributed to gastrointestinal cancers (GI Ca). We investigated the levels of 2 different heavy metals (Cd and Pb) in the soils of the Lenjanat region, Isfahan province, Central Iran where intensive agriculture is surrounded by different industries like steel and cement-making factories and mining and gastrointestinal cancers are very common in this province. MATERIALS AND METHODS: Two hundred topsoil samples (0-20 cm depth) were collected from agricultural and non-agricultural soils of the region and were analyzed for heavy metals. The metal contents were determined by flame atomic absorption spectrometry. RESULTS: The findings of this study showed that frequency of gastrointestinal cancers in the study area have been increased in the recent years. Results of soil samples in this region showed that the mean concentration of Pb and Cd were more than 16 and 1 mg kg(-1), respectively. The total Cd concentration in most of the samples exceeded the suggested Swiss thresholds (0.8 mg kg(-1)) but the mean value of Pb concentration in soil was less than the threshold of 50 mg kg(-1) set by Swiss Federal Office of Environmental, Forest and Landscape. Compared to the threshold values for heavy metals (Cd and Pb) in soils, data showed that the studied fields were contaminated especially by Cd. CONCLUSION: High heavy metals content in the soils seems to play an important etiological role in the carcinogenesis. Excessive accumulation of heavy metals in agricultural soils may not only result in soil contamination, but also lead to elevated heavy metal uptake by crops, and thus affect food quality and safety. Thus, analyzing heavy metals content in crops, water and dust could provide us a better insight to solve the problem.