Monitoring and Risk Assessment of Pesticide Residues in Fishery Products Using GC-MS/MS in South Korea.

The aim of this study was to assess the risk of pesticide contamination in aquaculture and its impact on fishery products. We conducted an assessment of 300 samples collected from nine regions in South Korea, including various types of seafood, such as freshwater fish, marine fish, crustaceans, and shellfish. Pesticide residues in seafood were analyzed using GC-MS/MS after sample preparation using a modified QuEChERS method, revealing the presence of eight pesticides (4,4'-DDE, 4,4'-DDT, boscalid, isoprothiolane, oxadiazon, pendimethalin, thifluzamide, and trifluralin) across seven fish species (carp, far eastern catfish, crucian carp, eel, Chinese muddy loach, mirror carp, and sea bass). Following the grouping of DDE with DDT, a risk assessment of fishery products was conducted. After the estimated daily intake (EDI) of fish was calculated and compared with the acceptable daily intake (ADI), the health risk index (HI, %ADI) of the detected pesticides was evaluated and found to be 1.07% or lower. The results suggest that the consumption of domestically farmed fish products in South Korea poses minimal health risks associated with pesticide residues.

Determination of 57 pesticide residues in fishery products by GC tandem mass spectrometry combined with QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction.

An analytical method using GC-MS/MS combined with quick, easy, cheap, effective, rugged, and safe extraction was developed to determine 57 pesticides in fishery products. The limits of detection and quantification (LOD and LOQ, respectively) of the analytical method ranged between 0.91 and 2.12 ng/g wet mass and 3 and 7 ng/g wet mass, respectively. Moreover, the linearity of the calibration curves was acceptable (R2 > 0.99). The relative pesticide recoveries ranged between 53.87 and 127.2%, and reproducibility ranged between 0.25 and 10.87%. The pesticide residues in brown seaweed, eel, flatfish, shrimp, and abalone samples were analyzed using the developed analytical method, and the results indicate that most samples were not contaminated by the 57 target pesticides, except low levels (< 10 ng/g) of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene, alachlor, ametryn, isoprothiolane, and prometryn in several samples.

Distribution and antimicrobial resistance of Vibrio parahaemolyticus isolated from fish and shrimp aquaculture farms along the Korean coast.

The present study investigated the distribution and antimicrobial susceptibility patterns of Vibrio parahaemolyticus in water samples and aquatic animals (fish and shrimp) from major aquaculture farms along the Korean coast in 2018. V. parahaemolyticus is the most common pathogen causing seafood-borne illness. The strain was detected in 34.7% of all samples tested, and was detected at higher levels during summer to autumn when the water temperature is higher. Although more than 90.0% of V. parahaemolyticus isolates were sensitive to 13 of the 15 antimicrobials tested, which is useful for treating V. parahaemolyticus infectious disease, the isolates exhibited higher resistance to two antibiotics (colistin and ampicillin), which should be excluded as treatment options for these infections. Koreans typically enjoy consuming raw seafood. To reduce the potential human health risk of raw seafood consumption, the prevalence and antimicrobial resistance of V. parahaemolyticus in aquaculture environments should be continuously valuated.

Dieckol Ameliorates Aß Production via PI3K/Akt/GSK-3ß Regulated APP Processing in SweAPP N2a Cell.

The proteolytic processing of amyloid precursor protein (APP) by ß-secretase (BACE1) and γ-secretase releases amyloid-ß peptide (Aß), which deposits in amyloid plaques and contributes to the initial causative events of Alzheimer's disease (AD). In the present study, the regulatory mechanism of APP processing of three phlorotannins was elucidated in Swedish mutant APP overexpressed N2a (SweAPP N2a) cells. Among the tested compounds, dieckol exhibited the highest inhibitory effect on both intra- and extracellular Aß accumulation. In addition, dieckol regulated the APP processing enzymes, such as α-secretase (ADAM10), ß-secretase, and γ-secretase, presenilin-1 (PS1), and their proteolytic products, sAPPα and sAPPß, implying that the compound acts on both the amyloidogenic and non-amyloidogenic pathways. In addition, dieckol increased the phosphorylation of protein kinase B (Akt) at Ser473 and GSK-3ß at Ser9, suggesting dieckol induced the activation of Akt, which phosphorylated GSK-3ß. The specific phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 triggered GSK-3ß activation and Aß expression. In addition, co-treatment with LY294002 noticeably blocked the effect of dieckol on Aß production, demonstrating that dieckol promoted the PI3K/Akt signaling pathway, which in turn inactivated GSK-3ß, resulting in the reduction in Aß levels.

Total and Methyl Mercury Concentrations in Antarctic Toothfish (Dissostichus mawsoni): Health Risk Assessment.

The concentrations of total mercury (THg) in different organs of the Antarctic toothfish (Dissostichus mawsoni) collected from CCAMLR research blocks in Subarea 88.3 and Division 58.4.1 off the coast of Antarctica were determined. The results revealed THg concentrations of 0.165 ± 0.095 mg/kg (0.023-0.454 mg/kg, wet weight) in the Antarctic toothfish. In muscle, methyl mercury (MeHg) accounted for approximately 40% of the THg. In a comparison analysis, muscle and liver tended to bioaccumulate the highest levels of THg, and both THg and MeHg contents showed correlations with fish length and weight. Compared with international guidelines, fish contained 2.5-6.4% and 4.0-10.3% of the provisional tolerable weekly intake for THg recommended by the Joint FAO/WHO Expert Committee on Food Additives and the tolerable weekly intake for MeHg proposed by the European Food Safety Authority, respectively. These results suggest that consumption of the Antarctic toothfish presents no health risk to humans.

Contents and risk assessment of heavy metals in marine invertebrates from Korean coastal fish markets.

The concentrations of the heavy metals cadmium (Cd), mercury (Hg), lead (Pb), chromium, silver, nickel, copper, and zinc in the edible portions of 105 marine invertebrates representing 16 mollusk and crustacean species were accurately determined to evaluate their hazard for human consumption. The samples were collected in 2011 from major fish markets on the coast of Korea and analyzed for Hg using a direct Hg analyzer and for other metals using inductively coupled plasma mass spectrometry. Estimated dietary exposure (EDE) was determined, and a risk assessment was made of the heavy metals to provide information concerning consumer safety. The Cd concentrations, which were the highest for the three hazardous metals (Cd, Hg, and Pb), were significantly higher (P < 0.05) in the bivalves and crabs than in the gastropods and cephalopods. However, the concentrations of these metals in all samples were within the regulatory limits set by Korea and other countries. The EDE was compared with the provisional tolerable daily intake (PTDI) adopted by the Joint FAO/WHO Expert Committee on Food Additives or the U.S. Environmental Protection Agency. The EDE of Cd, Hg, and Pb for each class of marine invertebrate were 0.07 to 2.64, 0.01 to 0.43, and 0.001 to 0.16% of the PTDI, respectively. The total EDE of Cd, Hg, and Pb for marine invertebrates accounted for 4.03, 0.96, and 0.21%, respectively, of the PTDI. The EDE of other metals in each class of marine invertebrate was less than 2% of the PTDI. The hazard index is a reasonable parameter for assessing the risk of heavy metal consumption associated with contaminated food. In the present study, the hazard index for all of the species was less than 1.0, which indicates that the intake of heavy metals from consumption of these marine invertebrates does not represent an appreciable hazard to humans.