Cairns 2009 Workshop: Day 2

Sessions Three & Four: Curation Materials and Techniques, Integrated Pest Management

Presenter: Tharron Bloomfield

Preventive Conservation

  • is the main focus to ensure long term preservation of collections.
  • Preventive Conservation Workplan.
  • Temperature and Rel Hum. Lower temps mean longer life. Lower temps mean greater running costs. High level, low level and fluctuation issues. RH is more of a concern that temp when it comes to managing pests. Low RH leads to more brittle and fragile collections.
  • Literature indicates that mould will grow at 65% or above if this level is maintained for 3 days. Another factor is air flow though as this can help prevent the mould growth. Best conditions for maintaining a collection of mixed materials (organic, paper) 18-22°C and RH of 50-55%.
  • Moved from eradication of insects with chemicals towards management of insects through procedures - cultural practices (monitoring, housekeeping, quarantine). Integrated Pest Management.
  • Treat the 'vault' or collection room as a secured storage area and freeze anything which leaves.
  • Building exterior, especially light sources, should be designed to avoid attracting insects during the night which may then enter building.
  • Freezer. Check actual temperatures with a data logger. Also check the freeze-defrost cycle as there core temperature may not be maintained lon enough, and freezing may not be rapid enough.
  • Anoxic Treatments (Lack of oxygen). In DNA there was a plan to move carpological collections from collection room to office space because of storage space issues. Needed a different method of storage outside the controlled environment. Carpological specimens in bottles, bags, loose in netting, plastic bags heat sealed. Decided on a single method of heat sealed bags into which is placed an Ageless sachet (Oxygen scavenger/absorber - iron particles and sea salt). Ageless sachets have an exothermic reaction that absorbs oxygen from the environment. Within the sealed plastic bags they remove all oxygen and thereby kill any insects present. Cryovac bags ensure there is no air exchange, and if an oxygen indicator tablet is included then the seal can be monitored.
    • Using Ageless instructions handout
    • Different sized Ageless sachets depending on item size, different sized cryovac bags/pockets, heat sealer, oxygen indicator tablets
    • Be set up to do a whole production run, very inefficient to do one at a time.
    • Issue of spiny items piercing bags. Could make some kind of box or protective cover to prevent bags being pierced.
    • Initial set up costs high, but becuase the collection is rarely accessed the maintenance costs are low, and ongoing periodic monitoring.
    • Not required if carpological collection is maintained in a controlled environment.
    • additional support supplied to specimen by adding a square piece of acid free cardboard
  • Environmental Monitoring
    • Introduce program to measure and record temp and humidity levels. Good features include digital display, alarm (including sms, call), handheld shuttle with a USB port to collect data if many units in building.
    • Psychrometer most accurate measurement tool
    • Three reasons for monitoring - routine (data logger, thermo-hydrograph), diagnostic (know or suspect an issue and monitor to verify/check), performance (confirm behaviour of Building Management System).
    • All institutions should be monitoring even if conditions are 'perfect', sometimes other institutions will require this before sending a loan (in the museum world).

Archival

  • 'Archival' doesn't have a legal definition unless it has an ISO standard, and is often more of a marketing term
  • Sometimes the word is only used to indicate pH of 7.0 or above (acid free)
  • Spend most resources on archival products that are in direct contact with the item.
  • In a constant low temperature environment the acid reaction is less of a problem. Once the chemical acid reaction has occurred in paper products and other items (e.g. 10-15 yrs) the effects on collection item are passed and therefore for example the remounting of specimens is not such a priority. Ongoing deterioration of the paper and labels could be a problem and therefore remounting/labelling may still be required.
  • A4 copy paper. Most paper is pH neutral. Permanent paper (ISO), normal copy paper, archival paper.
  • Fragment packets - polyropylene, paper. Celophane is not archival, preference is to use polypropylene. Often attach paper packet to sheet and then enclose bag. May place whole sheet into a bag if the specimen is falling apart.

Permanent inks

  • mostly in the dark, low luxhours
  • Uniball Mitsubishi permanent ink
  • Artline 200
  • Staedtler Lumocolor for polypropylene bags

Some local management issues

  • Freezing of collections for routine pest management - possible waste of staff time and resources if there is a more widespread infestation which would simply lead to re-infestation post-freezing.
  • No food on desks, no living material in herbarium
  • Always treat specimens (e.g. freezing) and don't rely on assurance of sender/owner.
  • Foxing - metal impurities in the paper from manufacturing oxidises over time which causes large brown blotches and breaks down the paper over time. Requires remounting.
  • To hold a specimen of cannabis need to have a specific permit. May not loan specimens between herbaria.
  • Detecting psocids. BRI (Alan Bolin) recommends placing a fresh mushroom on paper out as bait overnight. The next next morning if psocids are present they may be obvious on the paper and mushrooms.
  • BRI (Alan Bolin) questioned the policy adopted by some herbaria of not freezing algae specimens, see reasoning for not freezing in a post on the ALGAE-L listserv. Psocids have been found in BRI algae collections, plus the possibility of insects in loan packaging. BRI does freeze.

Mounting techniques

  • Sticky tape 3M - polyester tape with acrylic glue
  • gummed paper tape
  • dental floss nylon and teflon
  • pva glue (pH neutral)
  • linen thread

Jeremy and 3M tape

  • 3M Tape. Product code for tape used in CANB and NE no longer being made because 3M could no longer guarantee the archival properties that were being claimed. Possibly testing was not done to back up claims. No deterioration observed on tape used in herbaria to date. Single-sided acid free tape will no longer be made by 3M and alternatives need to be found once stocks run out.
  • Pigment Ink. If out of direct sunlight presumed to be stable. Have the archival properties been tested.
  • Belinda Pellow - experience at SYD indicates that polyester tape used since the 1970s is still holding up well.

Fumigation

  • PERTH- recent outbreak of insects. Use Methyl Bromide to fumigate. Holes in ceiling may be linked to insect outbreaks. This year tried new fumigation PROFUME but not very effective as heavier than air and didn't fumigate space well - fans used to circulate air. When fans on fumigant leaked out and concentration couldn't be maintained. Every room had insects that survived fumigation. If don't fumigate experience is that the base level of insects is higher over winter and spring outbreak is greater. Fumigate at Easter every second year is sufficient, but when fumigation was at Christmas then fumigation was required every year.
  • Alex Roach - Heritage Collections consultant for pest fumigation.
  • NO true fumigant alternative to methyl bromide, emphasising the importance of integrated pest management.
  • Some evidence from Japan to suggest that methyl bromide has changed DNA of fungal specimens. OpenURL
  • All staff are responsible for integrated pest management, MEL do Mortein domestic bombs themselves using the attached procedure, other institutions have external contractors to conduct application of chemicals.

Items to watch out for that attract pests

  • eco-friendly natural cellulose foam beads
  • soup sachets
  • food in field store room e.g. tea bags
  • rat bait (rat sac) attracts tobacco beetle

Permanent Poisons

  • Mercuric chloride - may deteriorate over time but BRI testing indicates that is still viable after many years.

Recommendations (some of them)

  1. Annual CHAH Curatorial standard
  2. Calculate approximate costs per item of the Ageless sealed cryovac bags
  3. National archival standards for herbaria - ABRS/CHAH initiative. e.g. Environmental control standards that need to be met/demonstrated before a loan will be sent
  4. Risk Management - documents from Tharron to be uploaded
  5. Book - Urban Pest Management in Australia, 5th Edition Gerozisis, John / Hadlington, Phillip / Staunton Ion

-- Main.FrankZich - 2009-09-14

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