Effects of acidic deposition and other energy emissions on wildlife: a compendium

Energy emissions, including acidic depositions, pose potential problems for wildlife populations. Historical and recent events show both direct, acute effects and indirect, chronic effects from a variety of airborne pollutants. Information on effects of selected gaseous and particulate energy emissions on domestic animals and livestock and on wildlife is compared. Our understanding of wildlife effects can be improved by the evaluation of veterinary toxicological information and research on the ecological equivalents of domestic and laboratory animals.

Exposure to toxic agents: the heme biosynthetic pathway and hemoproteins as indicator

The heme biosynthetic pathway is closely controlled by levels of the end product of the pathway, namely, heme, and porphyrins are normally formed in only trace amounts. When control mechanisms are disturbed by xenobiotics, porphyrins accumulate and serve as a signal of the interaction between a xenobiotic and the heme biosynthetic pathway. For example, an increase in erythrocyte protoporphyrin is a useful measurement for early detection of exposure to lead and porphyrinuria was an early manifestation of a hexachlorobenzene-induced porphyria in Turkey. In recent years a variety of additional xenobiotics has been shown to interact with the heme biosynthetic pathway, namely, halogenated aromatic hydrocarbons, pesticides, sulfides, and a variety of metals. Moreover, different xenobiotics (e.g., dihydropyridines and compounds containing unsaturated carbon-carbon bonds) interact with the prosthetic heme of cytochrome P-450 forming novel N-alkylporphyrins.

Exposure to hydrogen sulfide, mercaptans and sulfur dioxide in pulp industry

An hygienic survey for hydrogen sulfide, methyl mercaptan and its derivatives and sulfur dioxide in kraft mills and in sulfite mills revealed concentrations varying from 0 to 20 ppm hydrogen sulfide, 0 to 15 ppm methyl mercaptan and comparable amounts of dimethyl sulfide with dimethyl disulfide up to 1.5 ppm. The greatest emissions were detected at chip chutes and evaporation vacuum pumps. Batch operations yielded clearly higher sulfur dioxide concentrations (up to 20 ppm) as compared to a continuous ammonia-base digester. Furthermore, there was a strong correlation with the season in the sulfite mills where higher concentrations were found in the winter when natural ventilation was poorer. As to the health effects, the exposed workers complained of headaches and a decrease in concentration capacity more often than matched controls. The number of sick leaves was greater in the exposed workers than among the controls.

A critical review of the literature on hydrogen sulfide toxicity

The information available on the biological activity of hydrogen sulfide has been examined for present status of critical results pertaining to the toxicity of hydrogen sulfide. This review of the literature is intended as an evaluative report rather than an annotated bibliography of all the source material examined on hydrogen sulfide. The information was selected as it might relate to potential toxic effects of hydrogen sulfide to man and summarized, noting information gaps that may require further investigation. Several recommendations are listed for possible consideration for either toxicological research or additional short- and long-term tests. Two bibliographies have been provided to assist in locating references considered in this report: (1) literature examined but not cited and (2) reference citations. The majority of the references in the first bibliography were considered peripheral information and less appropriate for inclusion in this report.

Physiological and biochemical effects of acute exposure of fish to hydrogen sulfide

1. Exposure of channel catfish to 0.5 mg/l H2S at 20 degrees C resulted in hyperpnea, followed by apnea, and finally respiratory arrest. 2. Catfish brain cytochrome oxidase activity was inhibited in vitro 18% by 10(-7) M H2S, 64% by 10(-6) M H2S, and 100% by 10(-4) M H2S. 3. When channel catfish were exposed to 0.1 mg/l H2S at 20 degrees C for 30 min, the cytochrome oxidase activity of the brain was inhibited 40% and that of the gill was inhibited 74%, while blood lactate rose from 11.6 to 38.1 mg/100 ml. 4. Catfish with nitrite-induced methemoglobinemia showed less inhibition of brain and gill cytochrome oxidase when exposed to hydrogen sulfide than did control fish. 5. Sulfide-inhibited brain cytochrome oxidase recovered from a 50% inhibition to control levels in channel catfish after 6 hr in freshwater at 10 degrees C. 6. Management practices are recommended which may help the commercial fish farmer alleviate the problem of the toxicity of sulfide to fish during harvest operations.

Acute and subchronic toxicity studies of rats exposed to vapors of methyl mercaptan and other reduced-sulfur compounds

Acute inhalation experiments were conducted to determine 24-h LC50 values for adult Sprague-Dawley rats of both sexes exposed to vapors of methyl mercaptan and other reduced-S compounds for 4 h periods. Using calculated gas concentrations, the following LC50 value for each gas and combination was determined: metyhl mercaptan, 675 ppm; dimethyl sulfide, 40,250 ppm; dimethyl disulfide, 805 ppm; hydrogen sulfide, 444 ppm; and an equimolar mixture of methyl mercaptan, dimethyl sulfide, and dimethyl disulfide, 550 ppm. The effects of body and tissue weights, gross metabolic performance, O2 consumption, systolic blood pressure, various blood parameters, and intestinal transit time associated with 3-mo exposures of young adult male rats to chemically verified concentrations of 2, 17, and 57 ppm methyl mercaptan vapor are summarized in this report. No mortality was experienced by any group. Histopathological findings were essentially nil except for microscopic suggestions of liver damage. The most readily apparent phenomenon was the decrease in body weight. Average values of terminal body weights for all exposed groups were lower than that for the sham control group. This difference was significant in the 57 ppm group and followed a statistically significant dose-related trend.

Veterinary aspects of salmonid fish farming: husbandry

A knowledge of environmental requirements is important in order to obtain good growth and health when farming salmonid fish. Biological requirements are discussed, including water quality parameters and nutritional aspects. The main techniques used for farming salmonids are described together with the annual cycle of operations undertaken on a commercial trout farm.