Effects of riboflavin on boric acid toxicity

Functionalized Porous Aromatic Frameworks as High-Performance Adsorbents for the Rapid Removal of Boric Acid from Water

This study demonstrates that functionalized, highly porous polymers are promising for the adsorptive capture of boric acid, a neutral contaminant that is difficult to remove from seawater using conventional reverse osmosis membranes. Appending N-methyl-d-glucamine (NMDG) to the pore walls of high-surface-area porous aromatic frameworks (PAFs) yields the adsorbents PAF-1-NMDG and P2-NMDG in a simple two-step synthesis. The boron-selective PAFs demonstrate adsorption capacities that are up to 70% higher than those of a commercial boron-selective resin, Amberlite IRA743, and markedly faster adsorption rates, owing to their higher NMDG loadings and greater porosities relative to the resin. Remarkably, PAF-1-NMDG is able to reduce the boron concentration in synthetic seawater from 2.91 to <0.5 ppm in less than 3 min at an adsorbent loading of only 0.3 mg mL^-1 . The boron adsorption rate constants of both frameworks, determined via a pseudo-second-order rate model, represent the highest values reported in the literature-in most cases orders of magnitude higher than those of other boron-selective adsorbents. The frameworks can also be readily regenerated via mild acid/base treatment and maintain constant boron adsorption capacities for at least 10 regeneration cycles. These results highlight the numerous advantages of PAFs over traditional porous polymers in water treatment applications.

6 Final Report on the Safety Assessment of Sodium Borate and Boric Acid

Sodium Borate and Boric Acid are used in cosmetics as preservatives, antiseptics, water softeners, pH adjusters, emulsifiers, neutralizes, stabilizers, buffers, or viscosifiers.

Investigators have reported that Sodium Borate and Boric Acid are poorly absorbed through intact skin; however, both compounds are absorbed through abraded, denuded, or burned skin. In a 90-day dermal toxicity study, Boric Acid (25-200 mg/kg/day) was nonirritating and nontoxic when applied to the intact skin of rabbits. Sodium Borate and Boric Acid were relatively nontoxic when tested orally in animals.

A 5% Sodium Borate in water solution was mildly or moderately irritating to the skin of rabbits and guinea pigs, and practically nonirritating when instilled in rabbits' eyes. Acute studies indicated that, at 10% in water, Boric Acid was mildly or moderately irritating to the skin of rabbits and guinea pigs.

Sodium Borate or Boric Acid in the diet of rabbits and rats caused growth retardation. Doses of up to 1.06 g/kg/day Sodium Borate in the diet of male rats exerted toxic effects on the gonads as well as infertility.

Boric Acid was nonmutagenic in the Ames test. Boric Acid induced reduced eye phenocopies and lumpy chromosomal inclusions in Drosophila melano-gaster. Limited carcinogenic and teratogenic studies did not indicate a statistically significant effect.

In clinical studies, cosmetic formulations containing up to 3.2% Sodium Borate were nonirritating to moderately irritating and nonsensitizing when applied to human skin. Formulations containing up to 2.4% Boric Acid were moderately irritating and practically nonirritating. Photopatch testing of formulations containing 1.1% or 1.7% Sodium Borate were negative.

Based on the increased absorption of Boric Acid by damaged skin as compared to intact skin, as well as the testicular atrophy observed in experimental animals, the Panel concluded that Sodium Borate and Boric Acid, in concentrations ≤ 5%, are safe as cosmetic ingredients when used as currently recommended; however, cosmetic formulations containing free Sodium Borate or Boric Acid at this concentration should not be used on infant or injured skin.

General, reproductive, developmental, and endocrine toxicity of boronated compounds

Boric acid and inorganic borates are abundant in nature. They are widely used in industrial, agricultural, cosmetic, and numerous smaller applications. These compounds are toxic to all species tested at high doses, but they are not carcinogenic or mutagenic. The major toxicities are reproductive and developmental. Testicular effects occurred at approximately 26 mg boron equivalents/kg body weight (bw)/d (26 mg boron equivalent (BE)/kg bw/d). New data on endocrine toxicity includes altered follicle stimulating hormone and testosterone within 14 d of treatment. Because these hormonal changes may be secondary effects of testicular toxicity, borates are not suspect as endocrine disrupters. The most sensitive of all the endpoints are prenatal growth and morphologic development in the rat; these changes occurred at a dose of 12.9 mg BE/kg bw/d. The no observed adverse effect level for rat fetal development was 9.6 mg/kg BE. Considering the estimated human exposure levels and a safety factor of 30, humans are not at significant risk of reproductive failure due to borates from environmental sources. The margin of exposure is estimated at 72 for males and 129 for females. Thus, the likelihood of human toxicity caused by boric acid and inorganic borates from exposure during normal activities is remote.

Effects of dietary boron supplementation on broilers

Two experiments were conducted with a total of 432 broiler chicks to investigate the influence of supplementing different amounts of boron to practical corn-soybean meal diets. The birds were housed in batteries and had free access to feed and water. In Experiment 1, 144 1-day-old broiler chicks were fed a basal diet supplemented with 0, 5, 40, 80, or 120 ppm boron for 21 days. Female body weight was not influenced by the dietary treatments. However, males supplemented with 5 ppm boron were heavier and their tibias resisted more load than the control birds. Overall feed conversion was not influenced by boron. In Experiment 2, 288 1-day-old broiler chicks were fed a basal diet supplemented with 0, 60, 120, 240, or 300 ppm boron for 22 days. Male and female body weights of the 300-ppm group were lower than those of the control birds. Percentage tibia ash was highest with 300 ppm boron. No significant differences were found in intestinal tract weight (grams of intestine per 100 g body weight) among treatments. Boron concentration in the breast muscle and liver increased as dietary concentration of boron increased. Data collected in these two experiments indicated that consumption of diets containing up to 240 ppm boron from hatch to 21 days of age was not detrimental to broiler performance. Data were not conclusive on the need for supplemental boron in broiler diets based on corn and soybean meal.

A fatal case of acute boric acid poisoning

A 77 year-old male mistakenly ingested an estimated 30 g of boric acid as a single oral dose to stop hiccups. On admission, he had vomiting, diarrhea, and hiccups. Laboratory data was diagnostic of acute renal failure. Hemodialysis and charcoal hemoperfusion were performed in series. The serum concentration of boric acid was reduced by the therapy, but the patient died due to cardiac insufficiency. Acute boric acid poisoning resulting from a single oral dose in adults has rarely been reported. Our case is the fourth fatal case in adults since the 1920s following a single, acute ingestion of boric acid.

Tissue disposition of boron in male Fischer rats

Boric acid (H3BO3), an inorganic acid with widespread commercial use and consumer exposure, impairs fertility in male rodents at dose levels lower than those required to cause other adverse effects. Previous studies found a testicular lesion in adult Fischer rats fed 9000 ppm boric acid (1575 ppm boron) and slightly reduced basal serum testosterone levels. A CNS-mediated hormonal component to this lesion was suggested. Detailed data on the tissue disposition of boron in the rat, including accessory sex organs and the brain, are lacking. This study examined the tissue disposition of boron in reproductive, accessory sex organs, and other selected tissues in adult male Fischer rats fed 9000 ppm boric acid to determine if selective accumulation of boron in reproductive tissues, accessory sex organs, and/or the brain might correlate with and explain the apparent selective testicular toxicity. Adult male Fischer rats were fed 9000 ppm boric acid for up to 7 days. Animals were killed at 1, 2, 3, 4, and 7 days after the start of exposure. Plasma and excised tissues were heat-digested in acid and analyzed for boron by inductively coupled argon plasma emission spectrometry (ICAP). With the exception of adrenal glands, control boron levels in all tissues examined were below 4 micrograms/g. There was a rapid increase in plasma and tissue boron 1 day after the start of exposure (range 2- to 20-fold), with the exception of adipose tissue. With the exception of bone and adipose tissue, all soft tissues examined, including the testis, epididymis, accessory sex organs, hypothalamus, and rest of brain, appeared to reach steady-state boron levels (range 12-30 micrograms/g) by 3-4 days. Bone boron levels continued to increase up to the termination at 7 days (40-50 micrograms/g by Day 7). Bone attained the greatest concentration of boron (2- to 3-fold over plasma levels) while levels in adipose tissue were 20% of plasma levels during the 7-day exposure period. All other tissues appeared to show no appreciable accumulation of boron over plasma levels. The data suggest that neither the apparent selective testicular toxicity nor the slight CNS hormonal effect associated with boric acid exposure can be explained on the basis of selective accumulation of boron in the testis or brain/hypothalamus, respectively. Thus, the testicular toxicity is likely the result of certain biological processes that are unique to the testis and which are targets of boron exposure.

Combined boric acid and cinchocaine chloride poisoning in a 12-month-old infant: evaluation of haemodialysis

A mixture containing 3 g of boric acid and 300 mg of cinchocaine chloride prescribed due to painful dental protrusion was accidentally ingested by a 12-month-old girl. She developed violent vomiting and coughing. Irritability, tremor, seizures and a delirious reaction. She was treated with diazepam, intubated, sedated and ventilated. Her diuresis was stimulated with furosemide and fluid. Within the first 24 h she was treated with haemodialysis twice on femoral catheters. Her renal function was unaffected. In two days she fully recovered. The maximum measured levels of boric acid and cinchocaine chloride approximately 6 h after ingestion were 26 micrograms/ml and 71 ng/ml respectively. The plasma half-life of boric acid was 7.0 h and decreased to 3.6 and 4.4 h during the two haemodialyses. The total body clearance of boric acid increased correspondingly from 21 ml/min to 41 and 34 ml/min. The in vitro clearance of boric acid of the dialyser was later determined to be 18 ml/min. It is concluded that haemodialysis is valuable in the treatment of boric acid intoxication because it increases the elimination of the drug even in patients without any sign of renal toxicity.

Boric acid poisoning

The skin manifestations associated with boric acid intoxication are particularly striking. We present a case report of a 44-year-old black woman who, following a suicide attempt, demonstrated the classic features of acute boric acid poisoning. She developed generalized erythema creating a "boiled lobster" appearance with massive areas of desquamation. A discussion of the history of the use of boric acid by the medical profession follows the patient presentation.