Natural processes such as volcanic activity, erosions and weathering contribute to the presence of mercury in the water, soil and the atmosphere. It enters the environment by both natural sources and human activities. Mercury (Hg) is a naturally-occurring element on the earth's crust. formulate health advice based on the measured and reported levels in commonly consumed fish species.Ģ.determine the ratio of MeHg to tHg in the different fish species, and.measure the levels of total mercury (tHg) and methylmercury (MeHg) in different fish species available for consumption in Hong Kong,.Inform customers the types of fish sold, served and used in fish products. For the high consumers among secondary school students, the estimated dietary exposure to methylmercury may exceed the PTWI and therefore their risk of adverse effects due to MeHg cannot be excluded. The amounts of MeHg relative to total mercury in different fish species varied considerably. Results of this study showed that most of the fish available in the Hong Kong market contained relatively low levels of tHg and MeHg, while a small proportion contained higher levels. However, the estimated dietary exposure for the high consumer (95th percentile exposure level) may exceed the PTWI (94% - 106% of PTWI). Together with data used for the risk assessment study "Dietary exposure to Mercury of Secondary School Students" in 2004, dietary exposure of secondary school students to methylmercury was estimated, and was below the PTWI for the average consumer (31-41% of PTWI). Mercury intake in an individual depends on the consumption amount as well as the mercury level in the food. The ratios of MeHg to tHg in the different fish species ranged from 0.46 to 0.99. Three samples of alfonsino (species: Beryx splendens) were found to contain tHg and MeHg at levels higher than 500 μg/kg (tHg: 609 – 1370 μg/kg MeHg: 509 – 1010 μg/kg). Two hundred and seventy-seven samples (99%) contained tHg and MeHg below 500 μg/kg. The range for tHg and MeHg of all samples were 3 – 1370 μg/kg and 3 - 1010 μg/kg, with the median of 63 μg/kg and 48 μg/kg respectively. All samples of whole fish were identified for their species by the Agriculture, Fisheries and Conservation Department (AFCD). Laboratory analysis was conducted by the Food Research Laboratory of the CFS. Total mercury and MeHg levels were analysed in 280 samples including 266 whole fish and 14 canned fish. Sampling was carried out from April to August 2007. Therefore, longer-living fish and fish at the top of the food chain such as large predatory fish tend to accumulate higher levels of mercury. The levels of tHg and MeHg in fish depend on their species, living environments, feeding patterns and ages. In 2003, the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) adopted a lower Provisional Tolerable Weekly Intake (PTWI) of 1.6 μg/kg bodyweight (bw) for MeHg. Concerns regarding MeHg in food are related to its potential to affect the nervous system, particularly in the developing foetus. It accumulates in the food chain particularly in fish mainly in the organic form as MeHg. Mercury is present widely in the environment from natural sources and human activities. On the basis of levels measured and reported in commonly consumed fish species health advice was formulated. The Centre for Food Safety (CFS) has conducted a study to measure the levels of total mercury (tHg) and methylmercury (MeHg), and the ratio of MeHg to tHg in different fish species available for consumption in Hong Kong. Mercury in Fish and Food Safety EXECUTIVE SUMMARY Acknowledgement is required if other parts of this publication are used.įood and Environmental Hygiene Department,Įmail: Table of Contents Executive Summary Under no circumstances should the research data contained herein be reproduced, reviewed, or abstracted in part or in whole, or in conjunction with other publications or research work unless a written permission is obtained from the Centre for Food Safety. This is a publication of the Centre for Food Safety of the Food and Environmental Hygiene Department of the Government of the Hong Kong Special Administrative Region.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |