Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
This study evaluated mercury concentrations in five varieties of canned fish and in the hair of 243 residents from Port Moresby, Papua New Guinea, to assess mercury exposure via fish consumption. Specifically, it measured both organic and total mercury in the fish and human hair samples, correlating mercury exposure with dietary habits. The focus keyphrase, “mercury concentrations in canned and fresh fish,” is central to understanding human exposure risks in this context, especially for heavy metal certification programs concerned with safe consumption levels in environments where fish is a dietary staple. The study aimed to bridge a vital knowledge gap regarding mercury intake in populations with high reliance on fish protein.
Who was studied?
Two groups from Port Moresby were studied: 121 coastal residents and 122 non-coastal residents, primarily from lower-income areas. The coastal group had a mean age of 27 years, ranging from 3 to 75 years, while the non-coastal group had a mean age of 19 years, ranging from 2 to 59 years. Both groups provided detailed information on age, sex, weight, and weekly consumption of fresh and canned fish. Hair samples were analyzed for mercury content, and fish samples were purchased from various retail outlets over several months. The diverse population sample, including both coastal and non-coastal residents, provides a comprehensive overview of how mercury concentrations in canned and fresh fish translate to human exposure in a real-world setting.
Most important findings
| Critical Points | Details |
|---|---|
| Mercury in canned fish | Tuna had the highest mean total mercury (0.45 mg/kg), with 13 out of 38 cans exceeding the WHO recommended maximum of 0.5 mg/kg. Mackerel, the most consumed variety, had a mean of 0.17 mg/kg, with only one can exceeding the limit. Other varieties (salmon, sardine, pilchard) had significantly lower mercury levels. |
| Mercury in human hair | The overall mean total mercury concentration in hair was 2.1 mg/kg (range 0.15–14.4 mg/kg). The coastal group had significantly higher hair mercury (mean 2.6 mg/kg) compared to the non-coastal group (mean 1.7 mg/kg). The average ratio of organic to total mercury was 80%. Seven subjects (all coastal) exceeded 5 mg/kg, with three above 10 mg/kg. |
| Fish consumption and mercury correlation | Coastal residents consumed more fresh fish (mean 5.8 meals/week) and had higher hair mercury, but no significant correlation was found between fish consumption and hair mercury in this group. In non-coastal residents, a weak correlation existed between fresh fish consumption and hair mercury, but it accounted for only 3.6% of hair mercury variance. |
| Regulatory and health relevance | Most canned fish varieties, especially the most consumed (mackerel), were below international safety thresholds for mercury. Tuna, less commonly consumed by the local population, sometimes exceeded limits. Despite some individuals with elevated mercury, population-wide health effects are unlikely, but subclinical effects at lower exposure cannot be excluded. |
Key implications
Mercury concentrations in canned and fresh fish were mostly below international safety thresholds, yet certain tuna samples exceeded recommended limits, highlighting the need for regular monitoring. For heavy metal certification programs, mackerel’s low mercury content supports its safety, but occasional high levels in tuna stress the importance of product-specific testing and transparent labeling. Population exposure, as reflected in hair mercury concentrations, suggests minimal immediate health risks, though ongoing surveillance is essential to detect potential subclinical effects and protect vulnerable groups. These findings reinforce the critical role of targeted monitoring in heavy metal certification systems.
Citation
Kyle JH, Ghani N. Mercury concentrations in canned and fresh fish and its accumulation in a population of Port Moresby residents. Sci Total Environ. 1983;26:157–162.
Mercury (Hg) is a neurotoxic heavy metal found in various consumer products and environmental sources, making it a major public health concern. Its regulation is critical to protect vulnerable populations from long-term health effects, such as neurological impairment and cardiovascular disease. The HMTC program ensures that products meet the highest standards for mercury safety.
