Dilution of PAHs loadings of particulate matter in air, dust and rivers in urban areas: A comparative study (Tehran megacity, Iran and city of Tübingen, SW-Germany).

PAHs (polycyclic aromatic hydrocarbons) in urban areas are usually bound to particles. Concentrations are different in different compartments (airborne particles, street dust, suspended sediments in rivers and channels). This study follows concentrations of PAHs from particles in air to street dust and finally suspended sediments in the city of Tehran, Iran compared to Tübingen, Germany. Data sets are based on own investigations (PAHs on suspended sediments), or taken from literature studies (PAHs in street dust and airborne particles). Based on a cross-comparison of concentrations of PAHs on particles, and their congener distribution patterns, the occurrence, interrelation (exchange and mixing processes), as well as possible dilution processes among PAHs in the different particle classes are disentangled. Results show that for Tehran and Tübingen PAHs in airborne particles are very high (in the range of 500 mg kg-1). However, in street dust and suspended sediments PAHs concentrations on particles are around 100 times lower. Surprisingly concentrations in street dust and suspended sediments are 5 to 10 times lower in Tehran (average 0.5 mg kg-1) than in Tübingen (average 5 mg kg-1). Since it is unlikely that PAHs emissions are lower in the Tehran megacity, an effective dilution of the atmospheric signal by uncontaminated (background) particles is hypothesized. Uncontaminated particles may stem from wind erosion of bare surfaces, construction and sand mining sites or even dust from the desert areas, which are frequent in arid climate in Tehran.

Aliphatic hydrocarbons in urban runoff sediments: a case study from the megacity of Tehran, Iran.

Urban runoff is known as an important contributor to diffuse a wide range of pollutants to receiving environments. Hydrocarbons are common contaminants in runoff mainly transported coupled to suspended particles and sediments. The aim of the study was to investigate the distribution and sources of Aliphatics in the sediments of Tehran's runoff drainage network. Thirty surface sediment samples were collected along with three main sub-catchments of Tehran during April 2017. The concentrations of n-Alkanes (nC-11-nC-35) and isoprenoids were determined by GC-MS, and their possible emission sources were evaluated using the biomarkers and the diagnostic ratios. Total aliphatic hydrocarbon (n-alkanes + isoprenoids) concentrations were found in the range of 2.94 to114.7 mg.kg-1 dw with the total mean of 25.4 mg.kg-1 dw in the whole catchment. The significant concentrations of n-alkanes between n-C20 and n-C24 indicate the predominance of petrogenic origins at all stations. The CPI values range from 0.7 to 3, except the station C1S28 (CPI = 4.2). The CPI values were less than 1.6 at 70% of the stations which indicate the petrogenic nature of the aliphatic origins. Pr/Ph and LMW/HMW ratios ranged from 0.3 to 2.5 and 0.3 to 5.6 confirmed the petrogenic sources as the major origin of Aliphatics in urban runoff sediments. The ratios of n-C17/Pr and n-C18/Ph vary from 0.4 to 2.1 and 0.2 to 2.1, respectively which showed that petroleum contamination is mainly due to the degraded oil products with a lesser extent of fresh oil. Results revealed that the aliphatic hydrocarbons in the sediment samples were derived mainly from petrogenic sources such as leakage and spillage of fuels and petroleum derivatives with a relatively low contribution of biogenic sources. Vascular plants' waxes and microbial activities are identified as the most important biogenic sources of the samples. The mean concentrations of total organic carbon were 13.3,12 and14.7 mg.g-1 dw in the sub-catchments 1, 2, and 3, respectively. Pearson correlation test demonstrated a weak correlation between the concentrations of n-alkanes and TOC (P > 0.05) with a correlation coefficient of less than 0.54 for all the sub-catchments.

Severe abdominal distention due to ovarian cysts in a parrot fish (Paraneetroplus synspilus).

In autumn of 2019 a three years old female parrot fish was referred to the veterinary hospital for diagnosis and treatment. The prominent symptom was inappetence and a large mass or unilateral distention in the abdominal cavity. Ultrasonography and radiology imaging with contrast media were done to evaluate the abdominal cavity. According to presumptive diagnosis by imaging, the fluid-filled mass was aspirated by a sterile syringe. No bacteria or other microorganisms were seen in the fluid using microscopy and culturing of the fluid on trypticase soy agar. The parrot fish died after three days because of imbalance and inappetence. Two fluid-filled masses were seen in necropsy. The ovarian structure of the cyst was proved based on the anatomical position, histopathology, ultrasonography and radiology of the cyst tissue. It could be concluded that prompt diagnosis and therapy of ovarian cyst may be necessary for saving the life of the fish.

Matrix Solid-Phase Dispersion Based on Carbon Nanotube Coupled with Dispersive Liquid-Liquid Microextraction for Determination of Organochlorine Pesticides in Soil.

The presented article describes the methodology and results of investigating the capability of multi-walled carbon nanotube as sorbent in an efficient extraction method for determination of organochlorine pesticides, α-BHC, ß-BHC, γ-BHC, heptachlor, endrin, aldrin, 4,4'-DDD, 4,4'-DDE and 4,4'-DDT, in soil media. Matrix solid-phase dispersion was optimized for extraction from small amounts of soil samples and the resulting extracts were pre-concentrated using dispersive liquid-liquid microextraction. The most important experimental parameters of both extraction procedures were studied and the optimum conditions for simultaneous analysis of the target analytes were determined. In the final analysis procedure, a 0.20 g portion of dried soil sample was extracted by dichloromethane after being mixed with 0.020 g of carbon nanotube and 0.400 g of silica gel. Then, dispersive liquid-liquid extraction was used to pre-concentrate the extract before injecting the sample into the gas chromatographic system. The pre-concentration step showed to have up to 32 times of enrichment capability and the total procedure had reasonable sensitivity and reproducibility, with limit of detections <1.6 ng g-1 and relative standard deviation values below 8.1%, respectively. It was also demonstrated that the organic content of the soil can alter the extraction efficiency (70-105%), depending on both the amount of the organic matter and the individual analyte. Therefore, the importance of matrix spike samples, throughout the method validation procedure, was confirmed.

A case of conjoined twins (thoraco-omphalopygopagus tribrachius tetrapus) in lamb.

Nearly completed conjoined or fused symmetrical twins are generally called diplopagus. Sheep conjoined twins have been reported less than cow. An apparently female conjoined twin lambs was examined based on external and internal features. In radiology, two vertebral columns and two pairs of the ribs were seen. Only two heads and two necks were separated (thoraco-omphalopygopagus). There were three forelimbs (tribrachius), one of which grew on dorsal region as a notomelus. Teat buds of the monsters differed in number. Only one lamb had umbilicus, including one umbilical vein, and two umbilical arteries locating besides one urinary bladder. This lamb had also one uterus. Two-separated alimentary tracts were observed in a common abdomen. Common thorax and abdominal cavities were separated by a diaphragm. There were two esophageal hiatuses, and two caval foramina but only one aortic hiatus. Two pairs of lungs and two unequal and connected hearts in a common pericardium were observed. Abnormality of the circulatory system might have caused the death of the twins.