FIGURE 22 Continued

CHRONIC (>365 Days)

1,000

043m

03Sr O40rO41r 042r

Ow045d

Key

r Rat

■ LD50 I Minimal risk level for

m Mouse

• LOAEL for serious effects (animals) j, e,tects otber man cancer

d Dog

3 LOAEL for less serious effects (animals)

O NOAEL (animals)

A LOAEL for serious effects (humans)

A LOAEL for less serious effects (humans)

The number next to each point corresponds to entries in Table 2-2,

Gastrointestinal Effects. Ingestion of boron in humans can cause gastrointestinal effects. Nausea, persistent vomiting, diarrhea, and colicky abdominal pain in infants were associated with acute ingestion of a total of 184 mg boron/kg/day or greater (based on 1.9 kg body weight) as boric acid which was accidently incorporated in infant formula (Wong et al. 1964). Vomiting was the only sign of boron toxicity in two adult females who had ingested 241 mg boron/kg/day as boric acid in a fungicide and 895 mg boron/kg of a boric acid-containing insecticide in a suicide attempt. The subjects were hospitalized for 24-96 hours and did not develop further symptoms following release (Linden et al. 1986).

Hematological Effects. Two male and three female dogs fed 44 mg boron/kg/day as borax had decreased packed cell volume and hemoglobin values. Erythrocyte count, total and differential leucocyte counts were comparable to control levels (Weir and Fisher 1972).

Hepatic Effects. Case reports in humans suggest that the liver is susceptible to boron toxicity at high dose levels (Wong et al. 1964). Jaundice has been reported, and there were mild alterations at histological examination in infants who ingested 505 or 765 mg boron/kg/day as boric acid (accidentally incorporated in infant formula) for 3-5 days (Wong et al. 1964). In the same incident, congestion and fatty changes were observed, and there was parenchymatous degeneration in newborn infants who ingested 505 or 765 mg boron/kg as boric acid for 3-5 days (Wong et al. 1964).

In rats given approximately 20.8 mg boron/kg/day as borax in drinking water, NADPH-cytochrome C reductase activity and cytochrome b5 content decreased in the liver microsomal fraction after 10 and 14 weeks (Settimi et al. 1982). There was also a reduction in the cytochrome P-450 concentration detected at 14 weeks (Settimi et al. 1982).

Renal Effects. Human case reports involving high accidental ingestion levels show that boron can cause injury to the kidney. Degenerative changes in parenchymal cells with oliguria and albuminuria have been demonstrated in two newborn infants after ingestion of 505 and 765 mg boron/kg/day as boric acid in an evaporated milk formula over a period of 3-5 days (Wong et al. 1964).

Dermal/Ocular Effects. Skin effects can occur following ingestion of boron (as boric acid) in humans. Extensive exfoliative dermatitis began in infants as an erythema involving palms, soles, and buttocks. It eventually became generalized with subsequent bulbous formation, massive desquamation, and sloughing (Wong et al. 1964). These changes were associated with ingestion of 505 mg boron/kg/day; however, skin lesions were lacking following ingestion of 765 mg boron/kg/day. Similarly, extensive erythema with desquamation was observed in an adult who ingested boric acid powder (Schillinger et al. 1982). The exact amount ingested was not stated. However, 14 g (equivalent to 22.5 mg boron/kg based on 109 kg body weight) was measured as missing from a container from which the patient admitted consuming half its contents.

In animals, rats fed 88 and 263 mg boron/kg/day as borax or boric acid had inflamed eyes and skin desquamations on the paws and tails (Weir and Fisher 1972).

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