Freshwater

Ozone :: Freshwater

Effects and Implications

Submerged plants and other species are not anticipated to be directly affected by ozone pollution. Emergent vegetation associated with freshwater habitats may be vulnerable but evidence for freshwater species is lacking.

Diatoms

Description: 

 

The relationship between acidity and the species composition of diatoms has been recognised for many decades (e.g. Hustedt 1937-39; Nygaard 1956). They serve as good indicators to changes in environmental parameters such as pH and nutrient availability. They also have short generation times and the community composition reacts relatively quickly to changes in the environmental conditions.

Zinc :: all ecosystems

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). 

Vanadium :: all ecosystems

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).

Platinum group :: all ecosystems

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). 

Mercury :: freshwater ecosystems

Key Concerns

Mercury is toxic to aquatic organisms (WHO 1989). A 28d-EC50 for vegetation damage to the Canadian pondweed (Elodea Canadensis) exposed to mercuric chloride was 7.4 mg/l, with a 50% inhibition of photosynthesis reported following exposure to 0.8 mg/l for 24 hours (Brown and Rattigan 1979). A 14d-EC50 for vegetation damage to duckweed (Lemna minor) was 1.0 mg/l (Brown and Rattigan 1979).

Manganese :: all ecosystems

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).

Copper :: all ecosystems

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.

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