Background As modern industry and agriculture experience swift growth, the issue of environmental pollution is escalating at an alarming rate. Vast quantities of heavy metal contaminants are being released into the rivers and lakes, leading to a stark decline in water quality. Consequently, aquatic products tainted with heavy metals are making their way into the food chain, posing potential risks to human health. In recent years, crayfish (Procambarus clarkii) has emerged as a popular aquatic commodity, with both cultivation and consumption on the rise. As a result, the focus on the food safety of P. clarkii has intensified, commanding greater scrutiny and attention.

Objective The aim of the study was to find out the content characteristics of heavy metal elements in P. clarkii cultured in Dongting Lake area and evaluate its edible safety and selenium-rich development potential.

Methods In the study region, a total of 60 farms’ samples of P. clarkii were gathered for analysis. The concentrations of heavy metals within both the head (comprising visceral mass and carapace) and the body (encompassing abdominal muscles and exoskeleton) of these P. clarkii were assessed using inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectroscopy (AFS), respectively. This comprehensive approach aimed to delineate the distributional patterns of heavy metal content in P. clarkii, assess its implications on food safety, and appraise the potential for selenium bioaccumulation.

Results The concentrations of heavy metals in P. clarkii sampled from the eastern fringe of Dongting Lake exhibited a gradient of zinc surpassing copper followed by other trace elements. Notably, detrimental heavy metals like arsenic, chromium, cadmium, and lead predominantly accumulated in the non-consumable head regions of P. clarkii, whereas essential nutrients such as selenium, copper, and zinc were found in higher quantities within the edible portions. Selenium levels varied between 0.130 mg·kg⁻¹ and 0.950 mg·kg⁻¹, meeting the criteria for selenium-enriched foods, with a 100% occurrence rate of selenium richness. Exceedance of standards was observed in shrimp samples for lead (at a rate of 16.67%) and arsenic (at a rate of 3.33%). Safety assessments indicated moderate contamination of lead in the studied population of P. clarkii, alongside slight contamination of arsenic, hydrargyrum, and cadmium; however, the tolerable intake assessment of these heavy metals suggested that adult consumption of P. clarkii remained within safe limits. Comparative and correlational analyses with sedimentary heavy metal contents led to an initial inference that the residual levels of cadmium and arsenic in P. clarkii cultivated along the eastern margin of Dongting Lake could potentially be linked to the sedimentary heavy metal pollution within the aquaculture pond environments.

Conclusion The edible risk of P. clarkii cultured in the eastern edge of Dongting Lake is still in the safe range, and the Se content in P. clarkii reached 100% of the selenium-rich level, which can provide higher economic value for P. clarkii.

Significance The above conclusions clarify the food safety and selenium-rich potential of P. clarkii cultured in the eastern edge of Dongting Lake, which can provide a reference for the development of P. clarkii culture industry and the brand construction of characteristic selenium-rich P. clarkii in this region.