The Social Sciences Division website has a useful section on their microsite for staff and students, giving information and links about fieldwork, including advice on ethics approval and risk assessments.  They have also issued various documents for supervisors and those undertaking fieldwork (the links take you to documents on the Division's website):

Check sheet for fieldwork supervisors / Practical guidance for fieldwork supervisors on Health and Safety and Risk Assessment

Safe interviewing guidelines

Vicarious trauma fact sheet

Fieldwork experiences case studies

Anyone undertaking fieldwork must complete a Risk Assessment template and attach it to their on-line Travel and Fieldwork Insurance application