|
Wood products used in, over or around water, treated via the pressure-treating
process, as described by the American Wood Preservers Association,
should use only those preservative chemicals registered for specific
uses by the U.S. Environmental Protection Agency (EPA). These products
include Creosote, ACZA (Ammoniacal Copper Zinc Arsenate), ACA (Ammoniacal
Copper Arsenate), CCA (Chromated Copper Arsenate), Pentachlorophenol
(Penta), Copper Napthenate, and ACQ (Ammoniacal Copper Quat). Also
approved for placement are all untreated wood products, and other
natural, native or non-wood materials as applicable.
Treated
wood materials subject to these guidelines shall be produced in
compliance with the " Best Management Practices (BMPs) for the
Use of Treated Wood in Aquatic Environments" issued by the Western
Wood Preservers Institute (WWPI), dated July 1996 or as revised
and approved by IDEQ. Prior to placement of treated wood products
in, over or around waters of the state, the producer of the products
shall be required to assure compliance with the BMPs in the production
process, either by written verification or via third-party assurance
by WWPI or their designated agent. IDEQ understands that WWPI may
change or modify its BMP manual from time-to-time, and that the
changes made may be ones that IDEQ will approve. IDEQ requests copies
of the revised BMP manual in a form to facilitate comparison so
that changes may be approved. Until changes are approved by IDEQ,
the July 1996 manual or subsequent approved manual remains in effect.
Where proposals
call for placement of a significant volume of treated wood, as determined
by IDEQ, in, over, or around a small body of water with low flow
velocity, a site-specific risk assessment may be required. If unacceptably
high risks are predicted to water quality or the aquatic environment,
the use of the proposed product will be prohibited. An alternative
product may be allowed should the applicant prove to IDEQ that such
a product will not impair water quality or beneficial uses and otherwise
comply with Idaho Water Quality Standards.
Treated
wood should not be used where it comes into direct or indirect contact
with water used for human consumption without a waiver from IDEQ,
except for uses involving incidental contact such as docks and bridges.
The
installation of new materials as part of the maintenance of existing
structures shall use materials produced using BMPs (see 1 above).
Field
treating with preservatives over waters of Idaho shall be minimized.
Where, during construction, maintenance or inspection, application
of preservative chemicals is required in the field, the following
actions should be taken:
a.
Treat wood materials at least 75 feet from the water and/or above
the high-water mark to prevent spills, drips, and leaks from contaminating
surface water. Any spills, drips, and leaks of preservatives will
be collected to protect surface and ground water. Disposal of
excess and spilled preservatives shall be in accordance with applicable
rules.
b.
All personnel conducting the field treating are to be properly
trained and/or licensed to apply preservatives in accordance with
EPA label instructions for the preservative.
c.
Where treating wood materials over the water or below the high-water
mark is necessary, take appropriate precautions for collecting
drips or spills to assure that wood preserving chemicals are not
discharged or released into waters of the state.
Non-pressure
treatment of dried round wood products with Penta is a recognized
and legitimate use in, around, and over aquatic environments.
a. The
species of trees which may be treated and the specifications for
the wood preservatives are addressed in the 1996 American Wood
Preservers Association (AWPA) Book of Standards and Specifications
and should be used to ensure the safe use of Penta in aquatic
environments.
b. The
key to non-pressure, Penta-treated wood in and around water is
the responsible use of the product. Wood treated with Penta should
be used only where such protection is important and only in applications
such as poles, posts, rail ties, and outdoor structural timbers.
Penta-treated wood should not be used where it may come into direct
or indirect contact with drinking water for domestic use by humans
and animals. Penta-treated products may be used for incidental
contact with water such as fences, docks, and bridges, as stated
in the EPA approved Consumer Information Sheet. If there is a
question regarding the proper use of non-pressure, Penta treated
wood products, the local IDEQ regional office should be contacted
for clarification.
IDEQ
continues to have concerns about the potential risk to freshwater
aquatic organisms that may occur as a result of the woods treated
with Penta or Copper Napthenate coming into contact with freshwater.
The basis for IDEQ’s concern is the lack of scientific
studies documenting the risks to freshwater organisms and the environment.
|
