Nitrogen Oxides :: Arable
[See also: Nitrogen deposition :: Improved Grassland]
Key Concerns
Symptoms of zinc toxicity in plants include reduced root growth, and inhibition of various physiological processes including transpiration, respiration and photosynthesis. Stunted growth, leaf epinasty and chlorosis of younger leaves are characteristic of zinc toxicity (WHO 2001). Reduced yield, and chlorosis have been reported in various crop species, including fescues, blue grass, barley, soybean, lettuce and cyperus grown in soil with high zinc concentrations (Chaney 1993).
Key Concerns
Vanadium can be toxic to plants, inducing iron-deficiency chlorosis and trace element nutrition, by reducing the levels of managanese, copper, calcium and phosphorous. These effects have been found in plants exposed either via hydroponic solutions or soil. The concentration of vanadium in soil which causes toxic effects in plants may range from 10 to 1300 mg/kg, depending on the plant species, the form of vanadium and the soil type (WHO 1988; WHO 2001).
Key Concerns
There is a paucity of data regarding effects of airborne platinum group metals on ecosystems. However toxic effects, including inhibited transpiration, and histopathology have been reported in plants exposed to high concentrations of either platinum or palladium salts following exposure in a nutrient solution (WHO 1991; WHO 2002).
Key Concerns
Symptoms of manganese toxicity to terrestrial plants vary widely between species. They include marginal chlorosis, necrotic lesions and distorted development of the leaves (Woolhouse 1983). In plants, manganese tends to accumulate in the shoots, rather than roots, resulting in symptoms occurring in the leaves (Loneragan 1988).
Key Concerns
Effects of lead on plants include reductions in growth, photosynthesis, mitosis and water adsorption (Eisler 1989).
Ecosystem specific infromation
Key Concerns
Copper is an essential element for all biota, therefore any adverse effects must be balanced against its essentiality. This means that for all organisms, there will be range of optimal copper concentrations. Exposure to copper concentrations outwith this range, will result in adverse effects, due to either copper deficiency, or copper toxicity.
Key concerns
Cobalt in soil is retained by oxides, such as iron and manganese oxide, crystalline materials including aluminosilicates and goethite, and natural organic substances found in soil. In clay soils, the adsorption may be due to ion exchange at the cationic sites on clay with either simple ionic cobalt or hydroloysed ionic species such as cobalt hydroxide (ATSDR 1992).
There is a paucity of data on the effects of cobalt on species indicative of terrestrial ecosystems.
Key concerns
