Mosses make way to higher altitudes

Toxic heavy metals in valley air recorded through moss

Bishnu Prasad Aryal
Kathmandu, August 22

Climate change has not only forced the animal to migrate to upper parts but it has also compelled the plants to migrate to high lands. Three species of moss earlier available in low land are now found at the periphery of the Kathmandu valley and even in upper parts.

“In my recent study, I recorded three species of low land moss found in high lands,” said moss researcher Nirmala Pradhan, who is doing PhD on low land mosses. “Adverse climate change has caused dryness and decline in photosynthesis process and its productivity,” she added.

These species are Funaria, Physcomitrium and Bryum pseudotriquestrum. “Funaria is sub-tropical species available at 1,000m, which is now found in temperate Kathmandu,” said Pradhan. “While Physcomitrium (bowl moss) is available at 300m can also be seen around Kathmandu.”

Pradhan said, low land species of Bryum is available now on the altitude from 2,900m to 6,000. “Birds, insects and wind help disperse the spurs from one place to another,” she said.

There are 21,000 species of non-flowering moist plant Moss in the world. Among them, 1,150 including 31 endemic species are available in Nepal. Four of them are endangered. Moss, a non-flowering plant, is very useful in anti-biotic production, decoration, controlling soil erosion, pollution indicator, medicine in wounds and cracks, fuel, shoes factory, food for birds and animals, using as shock absorber and nursery bed, and religious ceremonies.

Another researcher Kumudini Shakya, whose PhD research just completed in bio-monitoring air-borne heavy metals accumulated in moss in Kathmandu Valley, said that the results of the metal pollution in the valley are dreadful. “This is the first experiment in Nepal. Moss is proved more effective than lichen, which was experimented earlier, to oversee the accumulation of air-borne heavy metals,” she said.

The research was carried out in three areas—ring road, inside ring road and outside ring road-- testing in two categories of clean and polluted zones. Species of Thuirdium, Tasyphyllum and Giraldii mosses were tested in clean areas while Brachythecium, erythrodontium julaceum and Faerronia matsumurae were examined in polluted areas.

“The heavy metals were highly accumulated in all of the species except in Giraldii moss,” said Shakya. “The metals were examined in heavy traffic areas such as Ratnapark, Chabahil, Putalisadak, Lagankhel and Kalanki.” She said. “Lead, Cadmium, Chromium, silver, mercury, uranium, copper, zink, cobalt, manganese and nickel were high in the valley air.”

These are very toxic and harmful to both human beings and plants, she said. The scientific gravity of these metals should not be more than 4.5gm/c³ in the air. “However, the measurements of the Lead, Cadmium and Chromium were recorded very high,” she added. “The measurement in lead is 3.45-83mg/kg moss, cadmium .01-2.25mg/kg and chromium 2.5-70.5mg/kg.”

The health impacts of heavy metals are headache, fatigue, anemia, chronic obstructive pulmonary diseases, which can cause cancer, lung cancer and respiratory diseases. “These are increasing in the valley day by day,” Shakya warned.

Pradhan said that the use and conservation of mosses are neglected here. “It must be fully utilized to trace environmental hazard affecting human health,” she added.