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Vol. 21 No. 3 - July 2015

Syngonium podophyllum 'Maza Red', as Indoor Phytomonitor

By: Seemaa Ghate*

Indoor pollution is defined as “The presence into air indoors the physical, chemical and biological contaminants not normally present in outdoor air of high quality system” The factors of pollution are confined indoors where the ventilation is generally poor. The individual spends almost all of 24 hours in the building (80-90%), breathing approximately 22.000 times.

The sources of Indoor air pollutants include asbestos, pesticides, fibers from clothing, curtains, carpets, insulation, etc., fungi and bacteria, human coughs, sneezes, sweat, etc., tobacco smoke, ozone, chemicals from detergents, solvents, and cleaning fluids, etc.  Different types of Indoor Pollutants and their sources are: D.Trans-Elthrin and CO – mosquito repellents, paradichlorobenzene and napthalene – room freshners, paints, NO2 and CO – smoke in the kitchen, alcohol and acetone - cosmetics, formaldehyde - grocery bags, paper towels, paints, floor coverings, air freshners ,xylene - computer and video screens, ammonia - cleaning products, trichloroethelene – perfumes.

In today's world people spend more than 90% of their time inside their houses or office places, where levels of a dozen common organic pollutants can be two to five times higher than outside. Indoor pollution is now considered by many experts to be one of the major threats to human health. In early 1950s Dr T. G. Randolf became one of the first medical doctors to associate indoor pollution with allergies and other chronic illness. The US Environmental Protection Agency (EPA) currently ranks indoor pollution as one of the top five threats to public health. While researching on the problem of Indoor pollutants it was thought to test known phytomonitor against indoor pollutants released from some household sources.

In this article, the efficacy of Syngoniumodophyllum as phytomonitor has been reported against indoor pollution caused by mosquito coil that is generally burnt in the houses as mosquito repellant.

Mosquito coil is mosquito-repelling incense, usually shaped into a spiral, and typically made from a dried paste of pyrethrum powder. A typical mosquito coil can measure around 15 cm in diameter and lasts up to 8 hours. Mosquito coils are widely used in Asia, Africa, and South America. Smoke emitted from one mosquito repellant coil is equivalent to those of 100 cigarettes, thus causing harm to a large number of people in India. D-Trans Allthrines from Mosquito coil is dangerous to health. The main site of action of the pyrethroids is the sodium channel, which is kept open for long periods of time, causing prolonged sodium current to flow, leading to hyper-excitation of the nervous system. Synthetic pyrethroids, e.g. allethrin cause subnormal or super-normal excitability.

Eco-friendly approach for controlling Indoor Pollution: Phytoremediation

Growing plants in the indoor as well as outdoor environment is widely accepted as a means of retaining our connection with the nature. Because green plants not only beautify the place along with other uses but they improve the air which is the very essence of our lives. Green plants even have capacity to relieve stress. They form a surface capable of absorbing air pollutants. It is a proven fact that plants effectively reduce the concentration of pollutants in the indoor as well as outdoor environment. Phytoremediation is the direct use of living green plants for in situ (in-place or on-site) risk reduction for contaminated environment. Phytoremediation warrants consideration for cleaning up environments at which there are relatively low concentrations of contaminants. Phytoremediation technologies represent active processes that are designed and implemented to control and eliminate contamination.

Monitor chosen : Syngonium podophyllum'Maza Red'

Syngonium podophyllum 'Maza Red' is the most commonly cultivated species of genus Syngonium, being used as a houseplant since the late 19th century. It is also called as Arrowhead plant. The monitor was chosen due to its easy growth in all types of mediums tested in the laboratory. Plant requires less maintenance, it is fast growing and their lamina is broad to show injury symptoms. Leaves are alternate, three-lobed and arrow-shaped, up to 30cm long, 2-8cm wide. Juvenile leaves are entire with silvery-white veins or centre, bounded by green. Mature leaves are dark green and segmented into three leaflets, the central leaflet being the longest. Roots are profusely well developed to absorb nutrients from the medium.

Research

Factors important in the selection of phytoremediation as a technique, were decided. The factors such as selection of plants for remediation, local growing conditions, easy availability and inexpensive nutrients, location and type of contaminants to be treated, were studied. The study illustrated how those factors can be potential advantages (or limitations) in the selection of phytomonitor for the indoor environment. The research also illustrated the field applications of phytoremonitor at the selected sites to get the social response so that a tone, appropriate for audiences who have only a limited technical background is set.

Several common houseplants are studied, with which practically everyone is familiar, has seen them in the office or in the house, on a co-worker's desk, or for sale in the nursery.  Each plant is studied for its suitable substratum for growth, growth factors and sensitivity to indoor pollution. Finally a system is set with selected indoor plants which are considered as air quality monitors.

Experimental Design and Technology used

The selection of Known Indoor Plants such as Syngonium (Syngonium podophyllum 'Maza Red), Green spider plant (Chlorphytum comosum), Chinese evergreen (Aglonema commutatum), Peperomia (Peperomia meridiana), Ficus (Ficus benjamina) was done. Amongst these selected plants Syngonium podophyllum 'Maza Red' was selected to test its ability to remove some poisonous gases. A vacuum dessicator with temperature and humidity control was used to understand the ability of Syngonium podophyllum 'Maza Red', to be used as phytoindicator for poisonous gases released from different household source like mosquito coils. exposure experiments with all five selected plants was done. Three sets were exposed. 

Monitoring was based on the visible injury, PII and GLC analysis. Extract of the leaves of the plants exposed were analysed on G LC. Response of the selected plants at two different sites, where these pollutants are used, was recorded. The response is compared with the exposure experiments.

Results

Syngonium podophyllum 'Maza Red' proved most effective in absorbing poisonous gases released from mosquito coil, amongst all selected plants. It did not show any visible injury when exposed for 4 hours to gases released from a mosquito coil. Different parameters used were number of leaves exposed, number of leaves affected, visible injury to the leaves, colour of the leaves. When exposed to gases released from a mosquito coil for four hours, the PII value calculated was zero. When Syngonium podophyllum 'Maza Red' was exposed to gases released from a mosquito coil for four hours and analyzed on GLC, it was observed that new compounds were absorbed by the plant as compared to the control. New peaks of compounds were seen at RT 7.268, 15.750, 16.880. The new peaks may be the indicative of the poisonous gases absorbed by the plant. But further confirmation on GCMS is required.

Possible applications for human health

Burning mosquito coils indoors generates smoke that can control mosquitoes effectively. This practice is currently used in numerous households due to the fear of different severe diseases like chickenguniya, dengue, malaria etc. Pollutant concentrations resulting from burning mosquito coils could substantially exceed health-based air quality standards or guidelines. Burning one mosquito coil would release the same amount of PM2.5 mass as burning 75-137 cigarettes. The emission of formaldehyde from burning one coil can be as high as that released from burning 51 cigarettes.

Unlike cigarettes, mosquito coils do not contain tobacco but harmful chemicals are released from burning them used in many bug sprays. These are formaldehyde, octachlorodipropyl ether and bischloromethyl ether. The active ingredient in mosquito coils is Pyrethroid insecticides, used in many bug sprays mostly harmless to humans, but can irritate the skin and eyes. Some people are allergic to them too.

Formaldehyde is a colourless, flammable and strong smelling gas. Inhaling it could cause watery eyes, throat discomfort, coughing, wheezing, nausea and skin irritation. Also, it can cause nasal or sinus cancer and even leukaemia Formaldehyde is not an ingredient of mosquito coils but a by-product of burning them. 

The research done with the help of Syngonium podophyllum 'Maza Red' may prove promising where use of mosquito repellent is unavoidable. Instead of affecting our health due to poisonous gases from mosquito repellents use of such indoor phytomonitor may be advised. It is already researched that two to three 8-10" plants in 6-8” diameter container for every 100 square feet of floor space can do the job.

Conclusion

Syngonium podophyllum 'Maza Red' is best suited to absorb gases released from mosquito coil and so, it can  effectively act as a phytomonitor. This conclusion is based on its ability to grow in easily available nutrient medium, visible injury, PII and GLC analysis. Our preliminary research indicates that the identification of specific plants for Visual Injury Symptoms of pollutants is possible. It is also encouraging that GLC analysis further confirmed some of our findings. Future research is still needed for advancing phytoremediation as a technology. This includes studying how to screen and harvest plants, choosing an assortment of plants for particular pollutants of concern, understanding mechanisms for nutrient and heavy metal removal, and ideal environments for maximum plant uptake etc.

Growing one or two house plants on the desk at the office may not completely protect a person from indoor pollution.  There are many reasons people keep plants around though.  Unrelated studies have shown they have the power to lift people's spirits.  Phytoremediation may work effectively on indoor pollution when implemented on a large scale.  In future it might be common to have a garden or small forest inside the house but at the present time a compromise between phytoremediation and conventional methods works best and satisfies both public acceptance and scientific criticism.

 

*Women Scientist, D.S.T., New Delhi, India, Know How Foundation, Alisha homes, Amchi colony, Bavdhan, Pune – 411021. India. shamu995@rediffmail.com


This article has been reproduced from the archives of EnviroNews - Newsletter of ISEB India.


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