Considerations of an air-quality standard to protect terrestrial vegetation from acidic precipitation
Studies on the effects of acidic precipitation which is here defined as wet or frozen deposition with a hydrogen ion concentration greater than 2.5 ..mu..eq 1/sup -1/, are reviewed. At the present time there is an inadequate amount of information that shows decreases in crop growth except for one field study. Most studies with plants (crops and forests) are inadequate for standard setting because they are not conducted in the field with adequate randomization of plots coupled with rigorous statistical analyses. Although visible injury to foliage has been documented in a variety of greenhouse studies, no experimental evidence demonstrates loss of field crop value or reduction in plant productivity due to visible foliar injury. Acidic precipitation can contribute nutrients to vegetation and could also influence leaching rates of nutrients from vegetation. Although these processes occur, there are no data that show changes in nutrient levels in foliage that relate to crop or natural ecosystem productivity. Experimental results show that fertilization of ferns is inhibited by current levels of acidic precipitation in the northeastern United States. However, the overall impacts of inhibited fertilization on perpetuation of the species or ecosystem productivity have not been evaluated. Simulated acidic precipitation has been shown to effect plant pathogens in greenhouse and field experiments. Simulated acidic precipitation inhibited pathogen activities under some circumstances and promoted pathogen activities under other circumstances. No conclusion can be drawn about the effects of current levels of precipitation acidity on plant pathogen-host interactions. From these data it must be concluded that research on the effects of acidic precipitation on terrestrial vegetation is too meager to draw any conclusions with regard to an air quality standard.
- Research Organization:
- Manhattan Coll., New York (USA). Lab. for Plant Morphogenesis; Brookhaven National Lab., Upton, NY (USA)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 6566539
- Report Number(s):
- BNL-29097; CONF-810131-1
- Resource Relation:
- Conference: California symposium on acid precipitation, San Francisco, CA, USA, 13 Jan 1981
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACID RAIN
BIOLOGICAL EFFECTS
CROPS
INJURIES
LEACHING
LEAVES
NUTRIENTS
PATHOGENS
PLANTS
PRODUCTIVITY
REPRODUCTION
ATMOSPHERIC PRECIPITATIONS
DISSOLUTION
RAIN
SEPARATION PROCESSES
560303* - Chemicals Metabolism & Toxicology- Plants- (-1987)