---

Fish tank or swimming granuloma caused by Mycobacterium marinum is an opportunist pathogen commonly found in aquatic environments. We present a 16 year-old boy with frequent exposure to aquarium water who had several nodules (sprotrichoid forms) on his right hand. Pervious studies showed that fish tank granuloma is a rare skin infection (0.27 per 100,000 population in one year). However, taking proper history and considering the patient’s signs and symptoms could be helpful in diagnosis and treatment.

---

Background and purpose: Polycyclic aromatic compounds (PAHs) are considered as priority organic compounds pollutants worldwide due to their high toxicity. Presence of oil wells has made petroleum hydrocarbon as one of the sources of pollution in the Caspian Sea. These are the pollutants of soil and water which are very dangerous and lethal for the aquatic ecosystem. The purpose of this study was to determine the 16PAHs (as oil pollution) in the sediments and two commercial fish in the Caspian Sea. Materials and methods: In this study, 32 sediment samples were collected from 8 stations at eight transects at 10 meter depth during four seasons. Also, 34 samples of Liza saliens (n=17) and Rutilus frisii kutum (n=17) were taken from the south of Caspian Sea. The samples were extracted using Soxhlet execrator with organic solvents and then analyzed using GC-FID (Shimadzu-14 A) instruments. Results: Concentration of 16PAHs in sediment in most stations was lower than critical level (NOAA standard). Applying different PAHs ratios, it was found that PAHs originated predominantly from the pyrogenic source either from the combustion of grass, wood and coal (majority of the samples) or from petroleum combustion (harbor area). The mean concentration of PAHs in Liza. s and R. frisii kutum were observed 2460 ± 60 and 2710 ± 56 µg/kg dw, respectively and 990 ± 33 µg/kg dw for sediment. In general, concentrations of PAHs in edible tissue of two species were higher than their corresponding sediment concentrations reflecting their great bioavailability (242-3880 µg/kg dw). The highest concentrations were observed in some ports of the southern Caspian Sea (Anzali, Nowshahr, and Amirabad), probably due to intensive shipping activities. Conclusion: The distribution pattern of PAHs was similar for fish and sediments, particularly for sediments characterized by high contamination level, and they were dominated by the high molecular weight PAHs (4-6-rings) which have high ecological risks.

---

Background and purpose: Cold-smoking is one of the most common ways to increase the shelf life of fish during storage. Materials and methods: This study aimed to extract and measure the polycyclic aromatic hydrocarbon (PAH) carcinogens, using high-pressure liquid chromatography (HPLC)-mass, fatty acids profile, nutritional value, and bacterial community in three widely-used species of smoked fishes [Rutilus frisii (Kutum), Liza aurata, and Hypophthalmichthys molitri] of Caspian Sea, Iran. Results: Amounts of high molecular weight (HMW)-PAHs, as indicator of carcinogenic components in smoke, showed concentrations of 0.100, 0.039 and 0.033 µg/kg in smoked Hypophthalmichthys molitrix, Liza aurata and Rutilus frisii, respectively (P < 0.05). The concentration of Benzo[a]Pyrene was calculated in Hypophthalmichthys molitrix and Rutilus frisii 0.001, and in Liza aurata 0.004 µg/kg (P < 0.05). The amounts of ω-3 in Hypophthalmichthys molitrix, Liza aurata and Rutilus frisii were 15.79%, 11.18% and 8.74%, respectively (P < 0.05). The Poleyen index amounts (EPA+DHA/C16) were 0.30% in, 0.13% and 0.14% in Hypophthalmichthys molitrix, Liza aurata and Rutilus frisii, respectively (P < 0.05). High correlation was considered between amounts of lipids and PAHs (R2 = 0.56). Number of anaerobic bacteria in smoked Hypophthalmichthys molitrix, Liza aurata and Rutilus frisii was 5.26, 5.15 and 5.18 log ufc/g, respectively and amounts of total coliform (TC) was recorded 5.21, 5.23 and 5.20 in them, respectively (P < 0.05). Conclusion: Contents of PAHs, quality indexes and bacterial community were at the accepted ranges and the suitable unsaturated fatty acids (UFA) and Polyen index were considerable in studied fish.

---

Background and purpose: The release of metals due to different natural and human activities, bioaccumulation, biological inseparability and toxicity, even in low densities, have caused serious threat to living creatures and human. This study evaluated the concentration of heavy metals including lead, cadmium, zinc and copper in edible tissues of Caspian Kutum (Rutilus frisii kutum) in Miankaleh International Wetland and the health risk resulted from consumption of this fish. Material and Methods: During fishing season, 20 White fishes were collected from Miankaleh International Wetland with the permission of Environmental Protection organization. The densities of heavy metals in skin and muscles were determined using atomic absorption (Scientific Equipment GBS). Data was analyzed using SPSS V.16. Results: The mean densities of lead, cadmium, zinc and copper in the skin were 3.4, 0.48, 40.55, and 3.3, respectively and 2.1, 0.39, 16.52, 4.5 microgram per gram of the wet weight in muscle tissues, respectively. A significant difference was seen in the concentration of heavy metals between the skin and the muscle tissue (p<0.01). The observed EDI and EWI were found lower than the guidelines recommended by WHO and FAO. Conclusion: According to this study the concentration of zinc and copper in whitefish were lower than the standard levels, so its consumption is not a threat to the health of consumers. However, the levels of cadmium and lead in edible tissues of whitefish were found higher than international levels. Hence, the pollutants of Miankaleh wetland (i.e. industrial and agricultural wastewater) should be highly controlled.

---

Background and purpose: Mercury contamination is still a threat to the environmental and public health in both developed and developing countries. The aim of this study was to determine the total and organic mercury content in the muscle of goldfish (Carassius aurathus gibelio) obtained from the east and west of Anzali Wetland. We also assessed the health risks involved in consumption of this fish. Materials and methods: Twenty goldfish were collected from the east and west of Anzali Wetland. Total mercury concentrations were determined using Advanced Mercury Analyzer (AMA 254), and organic mercury concentrations in the muscle were also determined by AMA 254 following acid digestion and extraction with toluene. Results: Total mercury and organic mercury concentrations in the muscles tissue of goldfish collected from the east of Anzali wetland were significantly higher (106.97±56.92 ng/g ww and 88.00±45.41 ng/g ww) than those obtained from west of the wetland (45.50±16.88 ng/g ww and 40.62±14.32 ng/g ww). Also, significant positive correlations were found between concentrations of total and organic mercury and the amount of lipid. Conclusion: The mean concentrations of total mercury in all fish samples did not exceed the maximum level recommended by the World Health Organization for human consumption (0.5 mg g-1 ww). However, the maximum number of allowable consumption of fish per month in east and west of the wetland for children were found 3 and 5, respectively and for adults these allowable numbers were 13 and 25, respectively.

---

Background and purpose: Pesticides are used in agriculture to increase crop production. Organophosphate pesticides are used more than other pesticides since they are inexpensive and more influential on a wide range of pests. Fish containing pesticides have significant human health consequences. In this study, three types of most consumed fish in the Caspian Sea were evaluated for Diazinon organophosphate levels.

Materials and methods: Twenty seven samples of three species of fish (Rutilus frisii kutum, Cyprinus carpio, leaping mullet) were randomly collected from three stations in central coast of Caspian Sea. The samples were digested and extracted and Diazinon residues were extracted. Diazinon concentrations were determined using a Gas chromatography (GC-MS) method. All results were statistically analyzed using One-way analysis of variance (ANOVA) and t-test. Then Tukey-post test was applied to compare the pesticide residues levels in the samples.

Results: Diazinon was found detected in all samples. The leaping mullet samples collected from Babolsar and Khazarabad stations showed higher levels of Diazinon (55.25±48.03, 55.17±52.5 µg/kg, respectively) compared to others. ANOVA did not show any significant difference between all three types of fish in concentration of diazinon (P=0.33).

Conclusion: In this study, Diazinon was found at a high level in all samples (115.78 µ µg/kg) in leaping mullet sample from Babolsar region. However, it was not more than acceptable level determined by WHO (0.01 mg/kg). Hence, the three investigated species fish are considered to be safe for human consumption.

---

Background and purpose: There is an increasing interest towards consumption of aquatic products, therefore, the health of aqua ecosystems is highly important. Heavy metal pollution in fish is a global concern due to its bioaccumulation potential, toxicity and persistence in food chain. This study investigated the concentration of heavy metals (cadmium, lead, chromium, copper, and zinc) in the gill, liver, and muscle tissue of Cyprinus carpio, Capoeta trutta, and Ctenopharyngodon idella in Gharasou River, Kermanshah province, Iran.

Materials and methods: Sampling was done in Gharasou River and the gill, liver, and muscle tissues were prepared. The concentrations of heavy metals were measured using an ICP.

Results: The average concentrations of Cd, Pb, Cr, Cu, and Zn in the muscle tissue of Cyprinus carpio and Capoeta trutta were 0.001 and 0.001, 0.016 and 0.008, 0.14 and 0.14, 0.53 and 0.33, and 0.51 and 0.51 µg/g wet weight, respectively. The metals with highest and lowest concentrations were zinc and cadmium that were found in different tissues of the fishes, respectively. The accumulation of metals in the tissues of liver and gills was found to be higher than that in the muscles. Moreover, the Hazard Quotients (HQ) index of all heavy metals was than 1.

Conclusion: The concentrations of heavy metals were lower than the levels permitted by World Health Organization, hence, the fish species studied are considered healthy to use.

---

Background and purpose: Southern area of the Caspian Sea is an important resource of seafood products in Iran. One of the major factors affecting the health of seafood consumers is lead (Pb), due to its wide distribution and bio-accumulative property. In this study, all the studies, conducted during 2003-2016 on the amount of lead in white, mullet, and carp fish at the southeastern coast of the Caspian Sea were assessed.

Materials and methods: This meta-analysis used the data on 1242 muscle tissues of Rutilus frisii kutum, Liza auratus, Liza saliens, and Cyprinus carpio collected from the southern coast of the Caspian Sea. The level of lead concentration in samples was obtained from recently published articles in valid scientific journals. Then, dietary consumption risk and consumption limit of these fishes were assessed.

Results: In this study, mean concentrations of lead in fish muscle tissues were higher compared to levels accepted by various various national. However, daily and weekly absorption of this element through fish consumption was lower than the dose permitted by the Food and Agriculture Organization/World Health Organization. It was found that 0.23, 0.43, and 0.28 kg/day of Caspian white fish, mullet, and carp for adults, and 0.048, 0.09, and 0.58 kg/day of the these fishes can be consumed by children, respectively, without any non-carcinogenic effects.

Conclusion: According to the results of this study, a great difference was observed between various studies in terms of the reported effect factor. While publication bias was notable, it seems that the current amount of consumption of the evaluated fish has led to no serious health risks in consumers.

---

Background and purpose: Fish is an important source of protein for human and is an important part of the diet, so, studying the concentration of heavy metals in commercial fish could be helpful in evaluating the risk of fish consumption.
Materials and methods: A total of 60 fish samples from four different species including anchovy, white, perch, and trout was randomly collected in fall 2016 from Rast Fish Market. After sample preparation and microwave digestion, the amount of heavy metals were determined by inductively coupled plasma optical emission spectrometer (ICP-OES). The US Environmental Protection Agency's (EPA) method was used to estimate the health risks associated with exposure to heavy metals in fish samples.
Results: The highest concentrations of heavy metals included mercury in whitefish (1.29 ± 0.23 μg/g), lead in whitefish (4.54 ± 0.75 μg/g), cadmium in salmon (0.07 ± 0.01 μg/g), arsenic in whitefish (1.36± 0.15 μg/g), nickel in whitefish (0.61 ± 0.07 μg/g), tin in whitefish (0.63 ± 0.05 μg/g), and chromium in fish perch (1.52 ± 0.04 μg/g). Non-cancer risk for all heavy metals in all the species was less than 1.
Conclusion: The concentration of metals in species studied was in acceptable level, indicating no risk of toxicity. According to current results, fish consumption does not lead to adverse health effects.
 
 

---

Background and purpose: Heavy metals are among the pollutants that can cause destructive and fatal effects on marine organisms, including fish, in aquatic environments. This study aimed to determine and compare the concentration of heavy metals in the edible tissue of highly consumed farmed fishes (trout and carp) and marine fishes (carp, mullet, and whitefish) in Mazandaran province, Iran.
Materials and methods: In this study, 10 farmed fishes of Rainbow trout and Carp and 20 marine fishes of Carp, Leaping mullet, and Rutilus kutum were purchased from several cities of Mazandaran province, including Sari, Farahabad, Babolsar, Fereydoun Kanar, and Mahmoud Abad from the fishmongers market in two seasons (spring and summer). In this study, the edible tissues were completely separated and homogenized by a meat grinder; then, the freeze-dried tissues were analyzed by an ICP-MS to identify heavy metal contents.
Results: The average length and weight of the sampled marine fish species were 33.05±6.24 cm and 354.65±230.54 gr, respectively. Also, the length and weight of the farmed fish species were 33.45±10.30 cm and 586.45±501.32 gr, respectively. The results showed that the average concentration of most heavy metals in both farmed and marine species was within the permissible ranges, and only the average amount of zinc and manganese in both groups was reported higher than the maximum allowed permissible ranges. Spearman's statistical analysis showed no significant relationship between the metal concentration and the fish's length and weight (P<0.05, n=30 and rs=-0.219).
Conclusion: This study revealed that although the concentrations of studied elements in sampled farmed and marine fishes were within the permissible range compared to Food and Drug Administration (FDA), World Health Organization (WHO), and Food and Agriculture Organization (FAO) standards, the average concentrations of Mn and Zn were higher than the mentioned standards.
 

---

Background and purpose: Depression is one of the mental illnesses that affects a significant number of people. The zebrafish model has been proposed as a new tool for research on depression and other neurological disorders. The aim of this study was to investigate various aspects of the effects of antidepressant drugs, expand the scope of information derived from the Unpredictable Chronic Stress (UCS) protocol, and enhance understanding of the characteristics of zebrafish.
Materials and methods: In this experimental study, a total of 384 adult short-finned zebrafish housed in 24 aquariums were used. The zebrafish were divided into two main groups: a control group (without stressors) and the UCS group. Within each group, the fish were further divided into four subgroups: control, diazepam (120 μg/L), sertraline (10 μg/L), and a combination of diazepam+ sertraline. Behavioral tests were conducted using the Novel Tank Test. Fish movements were recorded for six minutes and analyzed using EthoVision software. Biochemical tests were performed by measuring cortisol levels.
Results: When the two drugs were used in combination, a significant decrease in the total distance traveled (from 37 to 18 meters), a significant increase in the time spent at the surface of the tank (from 55 to 154 seconds), and a significant increase in the number of trips to the surface (from 18 to 85 trips) were observed. Diazepam and sertraline also significantly reduced cortisol levels, from 1 ng/g tissue to 0.64 ng/g tissue and from 1 ng/g tissue to 0.15 ng/g tissue, respectively.
Conclusion: This study reinforces the use of zebrafish as a model organism for investigating the behavioral and physiological effects of stress. Furthermore, the findings demonstrate that the combination of sertraline and diazepam may be effective in mitigating the progression of depression.