8273

• UCREFRP Catalog Number: 8273
• Author: U.S. Bureau of Reclamation, U.S. Fish and Wildlife Service, U.S. Geological Survey and U.S. Bureau of Indian Affairs.
• Title: Guidelines for Interpretation of the Biological Effects of Selected Constituents in Biota, Water, and Sediment.
• USFW Year: 1998.
• USFW - Doc Type: \
• Copyright Material: NO

National Irrigation Water Quality Program Guidelines

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mechanism of boron toxicity in animals is not
fully understood. It is not known whether
boric acid, the borate ion, or some other boron
complex is the toxic boron compound (Maier
and Knight 1991). Boric acid and the borate
ion exhibit remarkable stability in natural
aquatic systems, and any boron that is not
taken up by plants and/ or animals will tend
to accumulate and remain bioavailable over
extended periods of time (Perry et al. 1994).

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Boron compounds enter the North American
environment at an estimated rate of
32,000 tons annually, primarily from laundry
products, irrigation drain water, fertilizers and
other agricultural chemicals, coal combustion,
and mining and processing (Eisler 1990).
Boron compounds also are used as fire
retardants and leather-tanning compounds
and have even been used in rocket fuels.
Elemental boron is frequently used for
neutron absorption in nuclear reactors, and
sodium borohydride is used by the pulp and
paper industry in the production of the
whitening agent sodium dithionite (Thurston
et a!. 1979). The United States supplies about
70 percent of the global boron demand.

Summary of Effects

Plants in general are far more sensitive than
animals to boron toxicity, and there is a large
literature base documenting boron's effects on
plants, especially crop plants. The exact

Considering the paucity of data on boron
toxicity, effect levels can be predicted only
tentatively at this time. These tentative
predictions are listed in table 6.

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Study Approaches

The majority of papers reviewed for this
report were laboratory studies dealing with
boron effects on plants and birds. Most of
the plant literature concerned toxicity or

Table G.-Predicted boron effect levels

Level of Toxicity
Medium No effect concern threshold Explanation
Water (mg/L) 0.5 0.5-10 10 For crops and aquatic plants (Perry et al. 1994)
6 6-13 13 For aquatic invertebrates (NOAEL and LOAEL
for Daphnia magna)
5 5-25 25 For fish (viz., catfish and trout embryos; Birge
and Black 1977; Perry et al. 1994)
<200 For amphibians (LC100 for leopard frog
embryos)
Bird eggs (mg/kg fw) 13 13-20 20 Smith and Anders (1989), Stanley et al. (1996);
20 = EC10 for viability of mallard eggs
Waterfowl diet >30 LOAEL for mallards; impaired growth of
(mglkg) ducklings
Mammal diet >80 LOAEL for rodents; decreased fetal body
(mg/kg bw/day) weight

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