Biomass fuel combustion and health.

Biomass fuels (wood, agricultural waste, and dung) are used by about half the world's population as a major, often the only, source of domestic energy for cooking and heating. The smoke emissions from these fuels are an important source of indoor air pollution, especially in rural communities in developing countries. These emissions contain important pollutants that adversely affect health-such as suspended particulate matter and polycyclic organic matter which includes a number of known carcinogens, such as benzo[a]pyrene, as well as gaseous pollutants like carbon monoxide and formaldehyde.Exposure to large amounts of smoke may present a health risk that is of a similar order of magnitude to the risk from tobacco smoke. The effects on health arising from exposure to air pollution are reviewed, based on what has been reported in the literature so far. Further and more detailed information on exposures and on the epidemiological aspects is urgently required.The persons most frequently affected are women who do the cooking for households in rural villages; they suffer from impaired health due to prolonged and repeated contact with these harmful pollutants. When they are pregnant, the developing fetus may also be exposed and this leads to the risk of excess deaths. In the developing countries, exposure to biomass fuel emissions is probably one of the most important occupational health hazards for women. A conservatively estimated 300-400 million people worldwide, mostly in the rural areas of developing countries, are affected by these problems.

Crosslinked agarose encapsulated sorbents resistant to steam sterilization. Preparation and mechanical properties.

The application of agarose in hemoperfusion is hampered by the lack of a suitable sterilization method. A technique has been developed for the crosslinking of agarose encapsulated sorbents by the reaction with 1,3-dichloro-2-propanol (DCP) under strong alkaline conditions. A twofold molar excess of DCP with respect to agarose and an equimolar amount of sodium hydroxide at a concentration of 0.3 mol/L with a reaction time of 1-4 h at 50 degrees C are found to be the optimal conditions. The compressive strength of crosslinked beads is increased by a factor of 4. Agarose capsules are found to degrade by the influence of gamma radiation, but are resistant to steam sterilization at 134 degrees C during at least 30 min when crosslinked.

Problems in treating experimentally induced acute hepatic failure by hemoperfusion or cross circulation.

Acute hepatic failure was induced in rats by galactosamine injection intraperitoneally (1 gm per kg). Twenty-four hours later rats were treated by hemoperfusion (HP) over encapsulated sorbents: cellulose acetate-coated charcoal, polyelectrolyte-coated XAD4, a combination of both, or cross circulation with a healthy donor. Compared with control treatment (prevention of hypoglycemia by glucose infusion), the survival rate was not improved by HP or cross circulation: controls 19% vs. treated animals 0 to 17%. Extension of duration or increased frequency of HP gave the same survival rates. Computer simulation based on zero-order introduction of a possible toxin into a two-compartment model shows that HP up to 5 hr per day is not able to clear the body effectively from the assumed toxin if its partition coefficient exceeds a value of 50.

Coating membranes for a sorbent-based artificial liver: adsorption characteristics.

Techniques are described for the coating of sorbents to be used in an artificial liver support system based on mixed sorbent bed hemoperfusion. Activated charcoal has been coated with cellulose acetate (CA) by solvent evaporation. With Amberlite XAD-4, the Wurster technique was used for coating with CA. XAD-4 has also been coated with a synthetic polyelectrolyte with anticoagulant activity by adsorption and fixation by gamma radiation-induced crosslinking. Activated charcoal, XAD-4, and a cation exchange resin, all in powdered form, were encapsulated in agarose gel beads. Adsorption characteristics onto the sorbents are described. The results are in agreement with a theoretical model presented. In general, adsorption onto XAD-4 is limited by film diffusion. With activated charcoal, pore diffusion limitation is generally observed. Blood compatibility is improved by coating.

In vitro adsorption of oxalic acid and glyoxylic acid onto activated charcoal, resins and hydrous zirconium oxide.

Patients suffering from primary hyperoxaluria show elevated plasma concentrations of oxalic acid and glyoxylic acid. The in vitro adsorption of these compounds into activated charcoal, a series of neutral and ion exchange resins and onto hydrous zirconium oxide has been investigated. Hydrous zirconium oxide was the most effective sorbent studied for the removal of both oxalic acid and glyoxylic acid. In batch experiments, the zirconium oxide was capable of binding 5.5 mu mol oxalic acid and 8 mu mol glyoxylic acid per gram sorbent using 0.5 gram sorbent and 50 ml of solutions with initial concentrations of 100 mu mol . L-1 and an ionic composition resembling that of plasma. Recirculation of 2 L of the same solutions through 12 gram of a mixture of hydrous zirconium oxide and alumina for 6 hours at a flow rate of 12 ml . min-1, resulted in a final concentration of 70 mu mol . L-1 of oxalic acid and 50 mu mol . L-/ of glyoxylic acid.

Rapid assessment of air, water, and land pollution sources.

A procedure is outlined to make a rapid across-the-board estimate of the quantities of air, water and land pollution in a given region or country. Such inventories, though not as detailed as one would eventually need, provide a first integrated view of the magnitude and quantity of pollution and can contribute to effective and comprehensive pollution control planning.