Toxic effects of Lignite Fly ash During Vermicomposting on the growth and Reproduction of Earthworm Lampito Mauritii
G Manimegala, V Kavitha, S Sarojini, G Gunasekaran, R Ravichandran
G Manimegala, V Kavitha, S Sarojini, G Gunasekaran, R Ravichandran. Toxic effects of Lignite Fly ash During Vermicomposting on the growth and Reproduction of Earthworm Lampito Mauritii. The Internet Journal of Toxicology. 2008 Volume 7 Number 1.
Fly ash is a serious source of air pollution since it remains air borne for a long period of time and causes health hazards. Besides being a health hazard, fly ash degrades the environment, fly ash (FA) a waste material of national concern, arising out of lignite based thermal power plants was mixed with cashew leaf litter(CLl) and cow dung (CD) utilized for the present study. In the present study , the feed substrates were prepared on weight basis as control(C)- cow dung alone,T1-FA+CLl+CD (2:4:4), T2-FA+CLl+CD(3:3.5:3.5), T3-FA+CLl+CD(4:3:3), T4-FA+CLl+CD(5:2.5:2.5), T5-FA+CLl+CD(6:2:2). For each treatment 1 kg of feed substrate was taken in plastic troughs and 15 grams of
Fly ash is the portion of the combustion residue that enters the flue gas stream in power generating facilities and consists of many small, glass-like particles ranging in size from0.01 to 100 µm(1). Fly ash which contains silica, aluminum, oxides of iron, calcium, magnesium, arsenic, chromium, lead, zinc, nickel and other toxic metals is a by product of coal-fired power plants.
Most fly ash materials are disposed in landfills or slurry ponds. Land filling of fly ash may serve as a major source of environmental pollution through erosion and leaching of heavy metals (2). To prevent fly ash from being air borne, the dumping ground needs to be kept well at time. However in India where 150 million tones fly ash is produced annually, there is an urgent need to develop methods for use of fly ash, on a small scale as well as on large scale. Each new application has to be evaluated from the environmental point of view(3).Another use of fly ash is in agriculture since the hydroxide and carbonate salts give fly ash one of its principle beneficial chemical characteristics, the ability to neutralize acidity in soils(4). Fly ash amendment has been reported to modify soil pH, improve soil texture, and provide essential plant nutrients for increasing crop production(5).
Cashew nut (
The reproductive potential of earthworm was influenced by the quality and availability of food (8,9). Vermicomposting is an eco friendly and inexpensive
technology in which the earthworms are used as bioreactors to convert the organic materials into valuable compost. Bhattacharya and Chattopadhyay (10) found the survival of earthworms in three different ratios (1:1, 1:3 and 3:1) of cow dung and fly ash. Ananthakrisnasamy(11)also reported the survival of earthworms in three different ratios (1:1, 2:1 and 3:1) of cow dung and fly ash mixture. The fly ash was vermicomposted with cow dung and solubility of micronutrients was analysed (12).To the authors knowledge no studies have been made on the toxic role of fly ash on the growth and reproduction of indigenous anaecic earthworm. The main objective of the present study was (i) To find out the appropriate proportion of fly ash –leaf litter-cow dung for sustainable and efficient vermicomposting. (ii) To know the toxic role of fly ash on the growth and reproduction of earthworms in different fly ash mixtures.
Materials and methods
The FA was collected from a thermal power station I, Neyveli Lignite Cooperation, Neyveli. The fallen leaves (CLl) of cashew trees were collected from cashew fields around Neyveli, Tamil Nadu, India. The CD was collected from the dairy farm, Faculty of agriculture, Annamalai University.
The FA was thoroughly mixed with CLl and CD (w/w). All these mixtures were maintained at 60% moisture content. Six replicates were maintained in all the treatments. Treatment substrates were prepared in the following proportions on weight basis such as; T1-FA+CLl+CD (2:4:4), T2-FA+CLl+CD (3:3.5:3.5), T3-FA+CLl+CD (4:3:3), T4-FA+CLl+CD (5:2.5:2.5) and T5-FA+CLl+CD(6:2:2) CD alone was used as control(C). In each treatment one kg of mixture was added with 200 gram of clay loam soil (CLS) to prepare the substrate and it was precomposted for 30 days.
After 30 days 15.0 gram of adult clitellate
The growth and reproduction of
Biomass (gram) of earthworms in general increased in control and in all fly ash mixtures significantly(p<0.05), but the rate of biomass production decreased after 60th day (i.e 75th and 90th day). The overall rate of biomass production was maximum in T2 (27.6±1.51 gram) and the least growth was observed in T5 (16.5±1.37 gram) on 60th day.
The variation in the cocoon production is depicted in Table.2.The inoculated adult clitellate worms started to produce cocoon and they were observed on 15th day in C, T1, T2 and T3 but in T4 observed on 30th day and in T5 on 45th day. Among all the treatments the total number of cocoon was higher in T2 (108.9±1.76) than the other treatments; it was followed by T1, C, T3, T4 and T5 respectively. From the table significant (p<0.05) differences were found in the cocoon production
The numbers of hatchlings by the
T4 (41.8±1.48)> T5 (13.1±1.55).
The enhanced growth and reproduction of
The rate of biomass and reproduction of
The growth and reproduction of earthworms are highly influenced by the quality and availability of feed, various physiochemical parameters etc (14,15). Growth and reproduction in earthworms require OC, N and P (16) which is obtained from litter, grit and microbes (17, 18). The first step in the vermiculture is selection of suitable feed materials for earthworms. These can be nitrogen rich materials like cow dung, pig manure, poultry manure, etc or other organic material should be like leguminous agro waste(19).
According to Sarojini
In our observation, the maximum worm biomass and reproduction was observed in T2-FA+CLl+CD (3:3.5:3.5). It may be due to higher N content/ higher microbial content/ higher palatability for the growth of earthworms. Similarly, Gupta
Authors are thankful to the authorities of Annamalai University and Head, Department of Zoology, for providing necessary facilities to conduct the research.