Total airborne Hg as well as black particles (soot) were monitored in a number of clean air areas in Sweden. For some of the sampling sites, back trajectories for air movements at 850 mb were provided by the Norwegian Meteorological Institute. It is shown that the total Hg in air may be divided into two fractions. The most important one may be considered to be a background and is probably the result of re-emission of Hg by the ground and by natural water. The other fraction is highly dependent on wind direction in the same way as black particles. This fraction seems to be of anthropogenic origin.

Chrome tannery sludge applied to agricultural land may have benefits in terms of added N for crop growth. An experiment was designed to compare tannery waste with commercial N fertilizer and investigate the potential of the waste as an alternative or supplement to commercial fertilizer. Soils with 38% and 7% orggganic C and N content of 1.3% and 0.2% respectively, were amended with lime, commercial N fertilizer, or tannery sludge containing 1.6% Cr. A portion of the tannery waste was supplemented with additional Cr('3+) salt before adding to the soils. The amended soils were analyzed for total Cr, ammonium acetate extractable Cr, selected nutrient and trace element concentrations. The tannery sludge increased soil pH, total Cr and N, S, Ca, P, Mg, and Na concentrations. DTPA extractable Cr increased only when Cr('3+) salt was added, but soil pH decreased markedly. Electroconductivity of the soils increased with the waste application rate and, at the highest rate of Cr('3+) salt addition, far exceeded values recommended for successful crop production. The acidic, high salt conditions complicated interpretation of the Cr('3+) salt addition results. Tannery sludge may be applied to agricultural land as a fertilizer amendment without adversely affecting soil chemical properties. The amount and frequency of application should be determined by (1) total and available N, (2) total salt content, (3) total and available Cr, and (4) soil organic matter.

Soil samples were collected to a depth of 0 to 10 cm from several sites near a secondary Pb smelter during the summer of 1976 in order to determine heavy metal concentrations of soil and enumerate soil microorganisms and earthworms. Chemical analyses indicated that abnormally high concentrations of Pb, As, Cd, and Cu decreased with increasing distance from the source and population counts of bacteria, actinomyces, fungi, nematodes and earthworms increased with increasing distance from the smelter. The negative correlation coefficients between bacteria, actinomyces, fungi, and nematodes and the level of Pb, As, Cd, and Cu in the soil were statistically significant. The microflora of the contaminated soil was altered and the marked quantitative reduction or elimination of organisms were attributable to heavy metal pollution emission from the secondary Pb smelter.

An important consequence of acidification is the mobilization of Al from the edaphic to the aquatic environment. Elevated Al levels in acidic waters may be toxic to fish. Eggs, larvae, and postlarvae of white suckers (Catostomus commersoni) and brook trout (Salvelinus fontinalis) were exposed in laboratory bioassays to pH levels 4.2 to 5.6 and inorganic Al concentrations of 0 to 0.5 mg/l. Aluminium toxicity varied with both pH and life history stage. At low pH levels (4.2 to 4.8), the presence of Al (up to 0.2 mg/l for white suckers; 0.5 mg/l for brook trout) was beneficial to egg survival through the eyed stage. In contrast, Al concentrations of 0.1 mg/l (for white suckers) or 0.2 mg/l (for brook trout) and greater resulted in measurable reductions in survival and growth of larvae and postlarvae at all pH levels (4.2 to 5.6). Aluminium was most toxic in over-saturated solutions at pH levels 5.2 to 5.4. The simultaneous increase in Al concentration with elevated acidity must be considered to accurately assess the potential effect of acidification of surface waters on survival of fish populations.

Occurrence and distribution of organochlorine pesticides in the water of Lake Mariut, a brackish coastal Egyptian lake suffering from pollution, and their accumulation in the common fish Tilapia were studied. The major pesticides detected in the lake water were lindane, p, p'-DDE, o, p'-DDT, and p, p'-DDT. These compounds, except o, p'-DDT, were detected in the fish samples in exceedingly higher concentrations compared with those found in the lake water.

This paper describes the areal distribution of fecal coliform densities within the stream system of the South Platte River basin in Colorado. Low densities, e.g., 0 to 99 fecal coliforms per 100 ml, were found in mountain streams, while higher densities, e.g., 10000 to 100000 and above were found in plains streams. About 49% of the plains stations and 3% of the mountain stations were not in compliance with the Colorado secondary contact recreation standard of 2000 fecal coliforms per 100 ml. The higher fecal coliform densities were associated with discharges from wastewater treatment plants. This is significant from a public health standpoint since the tainted waters are spread throughout the South Platte basin to irrigated lands via streams, canals, and reservoirs. Because of current federal and state policy encouraging land treatment and reuse, such practice should be reviewed with respect to compliance with proposed fecal coliform standards, and whether such standards should be adopted.

Numerous field and laboratory studies have shown measurable effects of soil acidification on soil processes and yet there is no indication to date that forest production is being affected even in heavily impacted areas. A discussion of possible reasons for this apparent contradiction is presented along with results of two computer simulations of possible responses to acid rain induced changes in (a) N availability and (b) soil organic matter decomposition rate. The first simulation shows a direct relationship between N availability and forest production. The second indicates the possibility for a more complex response with changes in total soil organic matter more than compensating for changes in decomposition rate and producing an inverse relationship between decomposition rate and N availability.

The combined effect of Ca and pH on fish and fisheries is considered for both laboratory and field studies. It can be seen that at concentrations less than 100 mu-eq/l, Ca can exert a significant influence on survival times of fish, and similarly in the field, the number of fishless lakes and the number of fish species found in lakes are less dependent on H('+) concentration at low concentrations of Ca than at high Ca levels. The limited historical field data available suggest that alongside any increase there may have been in surface water acidity, Ca concentrations have also increased, and the latter may have offset to some extent the deleterious biological effects of this increased acidity. Nevertheless, details of seasonal and spatial variations in these important water quality factors will need to be considered before a full understanding of the response to acidity of a fishery can be reached.

Long range transport of episodic concentrationns of 0(,3) into the Appalachian Mountains of Virginia was recorded in the summer season of 1979 and 1980. Continuous monitoring of 0(,3) indicated monthly averages of 0.05 ppm 0(,3) and several periods averaged approx. 0.08 ppm 0(,3). Open-top chambers were used to test the effect of ambient doses of the pollutant on the growth of 8 planted forest tree species native to the area. Height growth was suppressed for all species at the end of the second growing season when grown in open plots (no chamber) and ambient chambers compared to those grown in charcoal-filtered air supplies chambers. Height growth trends of open ambient chamber filtered air chamber were consistent. Virginia pine and green ash were significantly taller (p

Equations describing particle transport to surfaces by diffusion, interception, impaction, and sedimentation have been used to preduct dry deposition onto five wild grass canopies. Detailed measurements of plant height and spacing, width of stems, leaves, and inflorescences, and wind data collected within and above each canopy have been applied as model input data. The resulting curves of deposition velocity versus particle diameter have then been used with size distribution data from the literature for Pb and sulfate to predict overall dry deposition. Results of these calculations suggest a wide range of dry deposition velocities of 0.05 to 1 cm/s for these species, the variation resulting from differences in surface structure and size distribution characteristics. At least 40% of the mass deposition of lead and sulfate results from the largest 10% of the airborne material.