| toxicity summary | IDENTIFICATION AND USE: Sodium carbonate is a grayish-white powder of lumps containing up to 99% sodium carbonate. Sodium carbonate is used for the production of glass, soaps and detergents and other chemicals and it also used by the 'metals and mining' industry and the 'pulp and paper' industry. Sodium carbonate is not only used by industry but is also used by consumers. It may be used directly in solutions of sodium carbonate for soaking of clothes, dishwashing, floor washing and for degreasing operations but it is also present in a large number of consumer products like cosmetics, soaps, scouring powders, soaking and washing powders. Sodium carbonate is also a food additive. HUMAN STUDIES: Aqueous solutions are strongly alkaline, concentrated solutions tend to produce local necrosis of mucous membranes. An aqueous solution, 50% weight/volume, of sodium carbonate was applied to the intact and abraded skin of human volunteers. The sites were examined at 4, 24, and 48 hr and scored for erythema, edema, and corrosion. The solution produced no erythema and edema. The human skin showed tissue destruction at the abraded sites. Ingestion of large quantities may produce corrosion of GI tract, vomiting, diarrhea, circulatory collapse, death. Dusts of vapors of sodium carbonate may cause irritation of mucous membranes with subsequent coughing and shortness of breath. It is a primary irritant at concentrations below 15% and caustic at concentrations above approximately 15% depending on contact time, areas of exposure, and other factors. ANIMAL STUDIES: An aqueous solution, 50% weight/volume, of sodium carbonate was applied to the intact and abraded skins of rabbits, guinea pigs. The sites were examined at 4, 24, and 48 hr and scored for erythema, edema, and corrosion. The solution produced no erythema and edema. The rabbit skin showed tissue destruction at the abraded sites. Dry, powdered sodium carbonate, as 25% to 75% of a mixture with dry sodium sulfate, applied to eyes of rabbits and monkeys in a systematic study was judged "corrosive" or "harmful" to both species, whether or not followed by irrigation at two minutes after application. However, most monkey eyes exposed to 50% mixture showed little or no persistent injury 21 days after exposure. A repeated dose inhalation study was conducted in male rats exposed to a 2% aqueous sodium carbonate aerosol for 4 hr/day, 5 days/week for 3.5 months. Pulmonary ascorbic acid levels were decreased. Deviations in lungs were found in control and experimental animals but only experimental animals displayed hyperplasia and desquamination of bronchiolar epithelium, and perivascular edema. Other pulmonary changes included thickening of alveolar walls, hyperemia and lymphoid infiltration but these changes were also observed in about 50% of the controls. Aqueous solutions of sodium carbonate were administered daily via oral intubation to pregnant mice at doses ranging from 3.4 to 340 mg/kg bw during days 6-15 of gestation. The test substance produced no unwanted effects. Similar negative results were reported for rats and rabbits for daily doses from 2.45-245 mg/kg bw and 1.79-179 mg/kg bw, respectively. An in vitro mutagenicity test with bacteria was negative. ECOTOXICITY STUDIES: Sodium carbonate at 10 mg/L, reduced oxygen consumption in Caspian Sea shrimp in all of the observation periods, except days 3 and 10, when it was higher than the control. At 100 mg/L, oxygen consumption was higher during 1st 5 days and thereafter reduced gradually. Sodium carbonate is naturally occurring and commonly found in soil and water in the environment suggesting that releasing low levels of sodium carbonate would not be expected to adversely effect wildlife or water resources. |
