Determination of mercury in some freshwater fish species from Chahrmahal va Bakhtyari Province, Iran and potential limits for human consumption

A systematic review of the concentration of potentially toxic elements in fish from the Persian Gulf: A health risk assessment study

Fish as a critical food source is responsible for supplying nearly 20% of the average per capita animal protein for 3.2 billion people worldwide. However, oral exposure to potentially toxic elements (PTE) such as mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As) through marine fish consumption can cause health risks in consumers. This study aimed to collect information among databases (2000-2020), including ScienceDirect, PubMed, SCOPUS, EMBASE, and Google Scholar, regarding the concentration of PTEs in different types of fish from the Persian Gulf. In this regard, thirty articles containing 266 samples were included in the current systematic review. In addition, the non-carcinogenic risk caused by ingestion of PTEs via consumption of fish was calculated. The average PTE concentrations in fish muscles were presented in the following order: As (0.37 mg/kg ww) > Pb (0.20 mg/kg ww) > Cd (0.17 mg/kg ww) > Hg (0.13 mg/kg ww). However, the mean concentration of PTEs was below the defined level by the World Health Organization, and the findings revealed that the calculated average daily dose (ADD) for Cd and Pb in Iranian children and adult consumers was lower than the reference dose (RfD), whereas the ADD of Hg was higher than the RfD for children consumers. The total target hazard quotient for Iranian and children consumers was >1. The excess lifetime cancer risk values for Pb were safe, unlike those for Cd, which were in an unsafe range (>10^-4) for consumers.

A novel electrochemical biosensor for ultrasensitive Hg2+ detection via a triple signal amplification strategy

We developed a novel electrochemical biosensor for ultrasensitive Hg2+ detection via a triple signal amplification strategy of a DNA dual cycle, organic-inorganic hybrid nanoflowers (Cu3(PO4)2 HNFs) and gold nanoparticle (AuNP) probe. The DNA dual cycle was triggered by exonuclease III (Exo III) in the presence of Hg2+, and Cu3(PO4)2 HNFs were synthesized as an AuNP probe carrier. The electrochemical biosensor displayed high stability, high sensitivity and excellent specificity, which was improved by up to seven orders of magnitude compared to the World Health Organization (WHO) allowed Hg2+ levels in drinking water. This signal amplification strategy could be easily modified and extended to detect other hazardous heavy metals and nucleic acids.

Mercury concentration in muscle, bellyfat and liver from Oreochromis niloticus and Lates niloticus consumed in Lake Albert fishing communities in Uganda

Without surveillance studies on mercury (Hg) levels in predominant fish species and parts eaten in a fishing community, the FAO/WHO guidelines might be surpassed, hence health risk. A monitoring study in a developing country with 29 Oreochromis niloticus (Nile tilapia) and 34 Lates niloticus (Nile perch) from landing sites provided muscle, bellyfat and liver samples for Mercury detection using Inductive Couple Plasma-optical emission spectroscopy. The study shows that fish eaten in the fishing community are small with fewer risks from mercury. Tilapia accumulated more mercury in muscle and liver than Nile perch. Fish consumed has mercury levels higher than FAO/WHO guidelines, and the bellyfat of Nile perch bioaccumulated more mercury than Tilapia. Based on the above, it is clear that some fish species should not be eaten by the vulnerable groups due to levels of Hg found in the muscle and bellyfat. This research will serve as a base for future studies, sensitization campaigns and policy design on mercury uptake through fish in fishing communities of developing countries.

Recent Developments in the Speciation and Determination of Mercury Using Various Analytical Techniques

This paper reviews the speciation and determination of mercury by various analytical techniques such as atomic absorption spectrometry, voltammetry, inductively coupled plasma techniques, spectrophotometry, spectrofluorometry, high performance liquid chromatography, and gas chromatography. Approximately 126 research papers on the speciation and determination of mercury by various analytical techniques published in international journals since 2013 are reviewed.

Fluorescent graphene quantum dot nanoprobes for the sensitive and selective detection of mercury ions

Graphene quantum dots were prepared by ultrasonic route and served as a highly selective water-soluble probe for sensing of Hg(2+). The fluorescence emission spectrum of graphene quantum dots was at about 430nm. In the presence of Hg(2+), the fluorescence of the quantum dots significantly quenched. And the fluorescence intensity gradually decreased with the increasing concentration of Hg(2+). The change of fluorescence intensity is directly proportional to the concentration of Hg(2+). Under optimum conditions, the linear range for the detection of Hg(2+) was 8.0×10(-7) to 9×10(-6)M with a detection limit of 1.0×10(-7)M. In addition, the preliminary mechanism of fluorescence quenching was discussed in the paper. The constructed sensor with high sensitivity and selectivity, simple, rapid properties makes it valuable for further application.

Mercury contamination in Khramulia (Capoeta capoeta) from the Cheshme Kile and Zarrin Gol Rivers in Iran and human health risk assessment

Total mercury concentrations were determined in muscle tissue of Khramulia (Capoeta capoeta) captured in the Cheshme Kile and Zarrin Gol Rivers, Iran. In Cheshme Kile River, 49 fish samples were collected. The mean total mercury concentration in the muscles of C. capoeta from this area was 249 ng g(-1) dw. In Zarrin Gol River, where 62 fish samples were collected, the total mercury in muscles averaged 164 ng g(-1) dw. A significant difference was found between means of mercury in the rivers (p < 0.001). All samples from the two rivers had mean mercury concentrations below the maximum allowable limits for mercury set by the Food and Agriculture Organization, World Health Organization, Standardization Administration of China and Environmental Protection Agency. The results of this study indicate that the values of hazard target quotient and estimated weekly intake are low and represent a negligible risk for human health.