this study were: (1) to determine the range of MP 2% dust a.i. causing no mortality to
100% mortality of epigeic earthworm Eisenia fetida, (2) to assess the effects of acute
doses of MP 2% dust a.i. on the growth and survivability of epigeic earthworm
Eisenia fetida and (3) to assess the effects of chronic doses of MP 2% dust a.i. on the
growth, survivability and reproduction of epigeic earthworm Eisenia fetida in a
natural soil with septic tank sludge added as a feeding material.
20.2 Materials and Methods
20.2.1 Earthworms
Adult earthworms Eisenia fetida with well-developed clitellum (about 400 mg
average weight) were obtained from the vermiculture maintained in the Environmental Engineering Laboratory at Indian Institute of Technology (IIT) Patna, Bihar,
India. They were acclimatized in the test substrate (natural soil) for 24 h after
removing them from the synchronized culture in the laboratory. Earthworms were
properly rinsed and dried using a filter paper before measuring their initial weight.
20.2.2 Pesticide
Pesticide methyl parathion (MP) 2% dust belonging to the group of organophosphate
with 2% active ingredient (a.i.) was used for the purpose of the study. It was
purchased from a local agro-chemical shop at Bihta, Patna, Bihar, India as MP is a
widely used pesticide for agricultural purposes in India. MP is a highly toxic
chemical that has short-term and long-term repercussions on living matter. MP
mixed with tap water was in the form of a suspension and it was agitated properly
before applying the solution in the reactors.
20.2.3 Test Soil Preparation and Apparatus
The natural soil for the laboratory experiment was collected from the nearby
unconstructed areas of IIT Patna, Bihta campus which was earlier used as agricultural land. The use of natural soil from natural sites seems to be more effective in
representing a particular area than the artificial soils and other test and/or culture
soils like Organization for Economic Co-operation and Development (OECD)
standard soil, German standard soil Lufa, which are used for eco-toxicity test
(Fairbrother et al. 1999; Løkke and Van Gestel 1998). The soil was air-dried in a
hot air oven for 24 h maintained at a temperature 55 Æ 5
C. The air-dried sample
20 Effect of Methyl Parathion on the Growth and Reproduction of Eisenia. . .
353
100% mortality of epigeic earthworm Eisenia fetida, (2) to assess the effects of acute
doses of MP 2% dust a.i. on the growth and survivability of epigeic earthworm
Eisenia fetida and (3) to assess the effects of chronic doses of MP 2% dust a.i. on the
growth, survivability and reproduction of epigeic earthworm Eisenia fetida in a
natural soil with septic tank sludge added as a feeding material.
20.2 Materials and Methods
20.2.1 Earthworms
Adult earthworms Eisenia fetida with well-developed clitellum (about 400 mg
average weight) were obtained from the vermiculture maintained in the Environmental Engineering Laboratory at Indian Institute of Technology (IIT) Patna, Bihar,
India. They were acclimatized in the test substrate (natural soil) for 24 h after
removing them from the synchronized culture in the laboratory. Earthworms were
properly rinsed and dried using a filter paper before measuring their initial weight.
20.2.2 Pesticide
Pesticide methyl parathion (MP) 2% dust belonging to the group of organophosphate
with 2% active ingredient (a.i.) was used for the purpose of the study. It was
purchased from a local agro-chemical shop at Bihta, Patna, Bihar, India as MP is a
widely used pesticide for agricultural purposes in India. MP is a highly toxic
chemical that has short-term and long-term repercussions on living matter. MP
mixed with tap water was in the form of a suspension and it was agitated properly
before applying the solution in the reactors.
20.2.3 Test Soil Preparation and Apparatus
The natural soil for the laboratory experiment was collected from the nearby
unconstructed areas of IIT Patna, Bihta campus which was earlier used as agricultural land. The use of natural soil from natural sites seems to be more effective in
representing a particular area than the artificial soils and other test and/or culture
soils like Organization for Economic Co-operation and Development (OECD)
standard soil, German standard soil Lufa, which are used for eco-toxicity test
(Fairbrother et al. 1999; Løkke and Van Gestel 1998). The soil was air-dried in a
hot air oven for 24 h maintained at a temperature 55 Æ 5
C. The air-dried sample
20 Effect of Methyl Parathion on the Growth and Reproduction of Eisenia. . .
353