Sampling Population:
- A critical step for the identification of possible local pollution of methylmercury
is the selection of population in which residents' hair is collected for
mercury analysis.
- Population to be surveyed should contain frequent consumers of fish/shellfish
that is caught in suspected methylmercury polluted water area.
Note: Almost exposure to methylmercury occurs entirely from a single dietary
category - fish, shellfish and marine mammal such as whales.
Explanation to Participants:
- The aim of hair collection and mercury analysis should be provided to participants
orally or by other appropriate manners.
Note: The hair samples collected will be processed properly for chemical analysis.
Methylmercury is found to contaminate in fishes and other marine creatures
at trace concentrations through an aquatic food web. Methylmercury is readily
absorbed from the digestive tract after ingestion of the contaminated foods
such as fishes, and thereafter concentrates in hair. This is the reason
we use hair samples for the estimation of methylmercury exposure of individuals.
The hair sample will never be used for any purpose other than the mercury
analysis.
- The agreement of the participant on the collection of hair is the prerequisite
for the sampling. Information provided to the participant should contain
that the disagreement with the donation of his/her hair does not result
in any disadvantage for him/her at all.
- The name of the participant who agrees to the hair collection and the date
of the agreement and/or the date of sampling should be recorded as the
individual data for the agreed participant. The additional individual data
recorded should contain identification (ID) number, sex, age (or date of
birth), and sampling site.
Note: The written agreement by the participant is not necessarily requirement
for the hair sample collection following the ethical guideline of The Research
Ethical Board of National Institute for Minamata Disease (NIMD) by which
this research project has been approved in advance.
Note: The application of local ethical guideline and the requirement of recommendation
by local ethical board should be considered if necessary.
Collection of Hair Samples:
- Cut scrap hairs with scissors at close site to hair root. A minimum amount
requirement is twenty strands of hair each with about10 cm in a length.
The shorter the length is, the more strands are required. If longer hair
strand is available, a proximal portion of hair strand (a hair root side)
with about 10 cm in a length may be kept by removal of excessive distal
hair strand (a hair tip side) after cutting out of the entire hair strands.
Note: A proximal portion of hair (a hair root side) is suitable rather than
a distal part (a hair tip side) for the analysis in the aim of estimation
for methylmercury exposure. The reason is that the contents of methylmercury
might decrease during growth of hair under certain conditions including
treatment with artificial hair waving.
- Put the collected hair sample into envelope on which the identification
(ID) number of the participant is indicated. Use one envelope for one participant.
Sending the Collected Hair Samples:
- Collect and store hair samples until the number of participants exceeds
50 individuals, and thereafter send the samples with list of participants.
The number of participants is not more than 100 for each sampling site.
- The list of participants should include identification (ID) number, sex,
age, date of sampling, and sampling site. Name of participants and their
address are omitted from the list that is sent to National Institute for
Minamata Disease (NIMD).
Note: Personal information, including name and address, that can be used for
identification of individual participant should be protected from free
access. It should be under a strict control by specific administrator.
The personal information might be necessary in certain cases, for example,
a feed back of the analysis results to local community.
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