Coal Conversion Technologies: Some Health and Environmental Effects

Several technologies to convert coal to liquid and gaseous fuels are being developed in the United States, some with support from the Department of Energy. Substitution of these technologies for those currently being used will produce different health and environmental hazards. In this article, selected health and environmental effects of four coal conversion and four existing technologies are compared. For each technology, the emission estimates for complete fuel cycles, including all steps in fuel use from extraction to the end use of space and water heating by electricity or direct combustion, were prepared by means of the Brookhaven Energy System Network Simulator model. Quantitative occupational health and safety estimates are presented for the extraction, transportation, distribution, processing, and conversion activities associated with each technology; also included are some public health damage estimates arising from fuel transportation and air pollution impacts. Qualitative estimates of health damage due to polycyclic organic matter and reduced sulfur are discussed. In general, energy inefficiencies, environmental residuals, and hence implied environmental effects and health damage increase in the order: (i) direct combustion of natural gas and oil, (ii) direct combustion of synthetic gas and oil, (iii) central-station electric power produced from synthetic gas, (iv) central-station electric power produced from coal, and (v) central-station electric power produced by the combustion of synthetic liquid fuels. The compliance and conflict of these technologies with the amendments of the Clean Air Act and other legislation are discussed.

Biochemical significance of the hard and soft acids and bases principle

The hard and soft acids and bases (HSAB) principle, which states that hard acids bind preferentially to hard bases and soft acids to soft bases, may serve to assess specific chemico-biological interactions. As living systems are composed mainly of "hard" elements, molecular events taking place within the cell are dominated by "hard-hard interactions". On this premise, it becomes likely that extraneous "soft" agents are particularly injurious to life. In the HSAB context a selected number of variegated phenomena are briefly discussed qualitatively; these include biocidal actions, heavy metal poisoning, chemical carcinogenesis, some enzymic reactions, and nucleic acid complexations. Although the HSAB principle cannot be used as a tool for mechanistic explanations of biochemical processes, it may provide clues to likely target molecules and the loci of action.

Enzymatic repair of UV-irradiated DNA in vitro

Excision repair of UV-damaged Bacillus subtilis transforming DNA has been carried out by a sequential enzyme system in vitro. Incision adjacent to the pyrimidine dimer in the DNA strand by correndonuclease II-initiated excision of the damage by the 5' in equilibrium 3'-directed exonuclease of the Micrococcus luteus DNA polymerase. Reinsertion of nucleotides into the gap in the strand by the DNA polymerase at 10 degrees C terminated in a single-strand break which was sealed by a polynucleotide ligase, thereby repairing the DNA strand. This restored biological activity to damaged DNA up to doses resulting in 60% inactivation of transforming activity. At higher doses, less repair was achieved, due to the development of double-strand breaks during the in vitro incision and excision steps.

Poly(inosinic acid)-poly(cytidylic acid) inhibition of DNA synthesis in synchronized HeLa cells

Inhibition by double-stranded polyribonucleotides of DNA synthesis in synchronized HeLa cultures is dose- and time-dependent. Inhibition by poly(I.C) primarily affected late G(1) and early S phases of the cell cycle. Single-stranded polynucleotides, native calf-thymus DNA, and yeast RNA had no effect. Radioautography showed that after 2-hr exposure the synthetic polyribonucleotides were predominantly inside the nucleus. The results extend the spectrum of action of double-stranded RNA.

Observations of cattle, goats and pigs after administration of synthetic interferon inducers and subsequent exposure to foot and mouth disease virus

Polyriboinosinic-polyribocytidylic acid (poly [rI.rC]) was administered intravenously to 11 cattle and 13 goats in doses of 0.25 to 4.0, and 1.0 to 5.0 mg/kg, respectively. Subsequent exposure of these and untreated control animals to foot and mouth disease virus (FMDV) failed to demonstrate any differences in either the course or severity of the disease. Serum interferon was detected in cattle one hour after the intravenous administration of poly (rI.rC). Six pigs given 4, 20, or 100 mg/kg of itaconic-acrylic acid copolymer (IAA, HMW) intraperitoneally reacted clinically the same as six untreated control pigs after contact exposure to FMDV. Three pigs given 50, 100, or 200 mg/kg of divinyl ether-maleic anhydride copolymer (DVE/MA, pyran) intraperitoneally similarly failed to show any difference in clinical reaction from three untreated control pigs after intranasal instillation of FMDV. Three pigs given 100, 200 or 400 mg/kg of DVE/MA intraperitoneally developed rapid diffuse peritonitis causing the death of one in 48 hours.

Multiple factors in leukaemogenesis

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Antiviral activity and side effects of polyriboinosinic-cytidylic acid complexes as affected by molecular size

The decrease of the molecular size of poly(I.C) to less than 10(6) decreases its ability to induce interferon, protect mice against virus, or enhance the immune response. Immune adjuvant activity appeared more sensitive to molecular weight than the other protective activities. The composition of the complex-the molecular size of the individual homopolymers when one was large and the other small-did not affect antiviral activity; the activity of a complex made from large poly(I) and small poly(C) was similar to one made from small poly(I) and large poly(C). Molecular size of the complex did not profoundly alter the side effects of poly(I.C). At 2 mg/kg, none of the complexes markedly altered phagocytic function. Only the largest complex sensitized the mouse to endotoxin. However, all of the complexes studied profoundly inhibited drug metabolism by the liver microsomal enzymes between 24 and 72 hr after their inoculation. Decreasing the molecular weight did not alter this inhibition.

Role of adrenal cortical function in toxicity of polyriboinosinic-polyribocytidylic acid and its component homopolymers

Adrenalectomized rats are 1000 times more sensitive to lethal effects of the double-stranded complex polyriboinosinic.polyribocytidylic acid than intact rats. They are protected from such lethal effects by corticosterone. The complex can rapidly induce diffuse, severe necrosis of villous epithelium in small intestine without damage in crypts. Injection of the individual homopolymers, polyriboinosinic acid and polyribocytidylic acid, separately but in rapid succession is at least as lethal as injection of the complex.

Secondary structures of DNA

The X-ray diffraction patterns of DNA do not support a four-stranded helical structure.

Inhibition of herpes simplex virus by synthetic double-stranded RNA (polyriboadenylic and polyribouridylic acids and polyriboinosinic and polyribocytidylic acids)

Two-stranded polyriboadenylic and polyribouridylic acids and polyriboinosinic and polyribocytidylic acids protect against herpes simplex virus-induced cytopathogenicity in HEp 2 cultures, systemic herpes simplex virus infection in mice, and herpes simplex virus-induced keratoconjunctivitis in rabbits.

Foot-and-mouth disease virus inhibition induced in mice by synthetic double-stranded RNA (polyriboinosinic and polyribocytidylic acids)

Synthetic 2-stranded RNA-a helical complex formed by duplexing homopolymers of polyriboinosinic and polyribocytidylic acids (poly I:C)-induced host resistance to foot-and-mouth disease virus when microgram quantities were injected into mice. There was a graded response as shown by titrations of polynucleotide complex or virus. Protection was effective for >48 hours after a single injection of polynucleotide complex. Survival and serum interferon titers were directly related.