Microelements, Fatty Acid Profile, and Selected Biomarkers in Grass Carp (Ctenopharyngodon idella) Muscle Tissue: Seasonal Variations and Health Risk Assessment

Overview

Kovacik et al. measured 16 microelements plus total mercury in dorsal muscle of 36 grass carp (Ctenopharyngodon idella) harvested from a university experimental pond in Kolinany, Slovakia during summer (n=18) and autumn (n=18) seasons. The pond is adjacent to intensive agricultural activity and connected to a wastewater treatment plant. All metals were measured by ICP-OES (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Se, Sr, Zn); total mercury was measured separately by CV-AAS. Cadmium and cobalt were below the limit of quantification in all samples; arsenic was below LOQ in more than 88% of samples; lead was below LOQ in more than 66% of samples; selenium was below LOQ in approximately 50% of samples. The overall elemental ranking was Fe > Zn > Al > Sr > Ba > Ni > Se > Cr > Cu > Mn > Pb > As > Li > Hg. Total hazard quotient (TTHQ) ranged 0.27–0.76, below 1 in all individuals; mercury and nickel jointly accounted for 49% of the TTHQ and were identified as the elements of most concern.

Key numbers

All concentrations are in mg/kg wet weight (mean ± SD; n=18 per season).

ICP-OES LOD (µg/L): Al 0.20, As 1.50, Cd 0.05, Cr 0.15, Cu 0.30, Fe 0.10, Ni 0.30, Pb 0.80; CV-AAS tHg detection limit 1.5 ng/kg.

TTHQ range: 0.27–0.76 (THQ < 1 for all individuals). Main contributors to TTHQ: Hg + Ni = 49%.

Methods (brief)

ICP-OES (Agilent ICP OES 720) after closed-vessel microwave acid digestion (HNO3/H2O2). CV-AAS (AMA-254; Altec) for total Hg by direct solid analysis. Certified reference materials ERM CE278K, ERM-BB184, BCR-274 for QA; recoveries 89–99%. All As reported is total arsenic (ICP-OES, no speciation); iAs/tAs split not available.

Implications

Certification: Grass carp from this Slovak agricultural pond show Cd and Co below LOQ in all samples; tHg (0.012–0.053 mg/kg) is well below EU/Codex limits for fish (0.5 mg/kg). Ni (up to ~6 mg/kg in autumn) is the primary metal of concern alongside Hg. No EU MRL exceedances are reported, but the Ni concentrations are notable given the agricultural context.

Courses: Illustrates how freshwater fish grown near wastewater treatment plants and intensive agriculture can accumulate Ni and Al; seasonal variation (higher in autumn) is ecologically significant.

App: Provides baseline ranges for multiple metals in freshwater fish (grass carp, SK); Cd and As confirmed at or below detection in this species/location.

Wiki pages updated on ingest

• Nickel
• Mercury
• Freshwater Fish
• Seafood

Update history

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