of whole chloragocytes, which helps earthworms to tolerate high metal concentration at least to a certain point (Langdon et al. 2001). The histopathological changes in
earthworm tissues are the major characteristics of heavy metal contamination and
were reported by various toxicities. Babić et al. (2016) showed blunting and
feathering of intestinal epithelium and disorganization of chloragocytes with mild
granulation of chloragocytes followed with severe necrosis in earthworms exposed
to sewage sludge. Popović et al. (2015) reported that industrial wastewater contains
abundance of inorganic compounds, xenobiotics, and organic contaminants that
produce significant histopathological alterations in earthworms. Bangarusamy
et al. (2014) reported various histopathological changes such as villous atrophy,
necrosis, and enteritis with cellular infiltration in the intestine of earthworms.
Esaivani et al. (2015) observed extensive alterations in the intestinal tract of the
earthworms exposed to inorganic fertilizer and pesticides. The chloragogenous
tissue showed clear changes as cells lose their structural integrity. The epithelial
lining showed fusion of intestinal villi that lead to the reduction of absorption area of
nutrients from food. The chemical fertilizer-exposed earthworms showed disintegration of nuclei and enlargement of epithelial lining.
P. hysterophorus showed detrimental effects on the intestine of earthworm. The
earthworm’s growth, cocoon production, and antioxidant enzymes were in low level
with P. hysterophorus treatment. During the management and risk assessment of
parthenium, it was reported that this weed induces oxidative stress, and due to this,
the earthworms adapt the morphometric characteristics of tissue including the
epidermis as well as intestine of earthworm.
15.3 Conclusion
Various environmental wastes showed bioaccumulation of heavy metals in the
tissues of earthworms, induced oxidative stress, and caused alterations in
histomorphology of intestine as well as in antioxidant status of the organism along
with the growth and fecundity of earthworms. Still the wonderworm Eisenia fetida
was able to convert various toxic waste, that is, P. hysterophorus, into a useful
manure. The appropriate concentration of P. hysterophorus in cow dung is an
essential factor for the survival of earthworms without causing any harm so that it
should be converted into effective manure. Thus, these organisms can be used on
large scale to convert various environmental wastes into useful product. But some
measures and precautions should be taken to protect these organisms from the ill
effects of toxic environmental pollutants. It is also recommended that field trials
should be conducted on different crops before using P. hysterophorus-mixed
vermicompost in agricultural fields.
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H. Kaur et al.
earthworm tissues are the major characteristics of heavy metal contamination and
were reported by various toxicities. Babić et al. (2016) showed blunting and
feathering of intestinal epithelium and disorganization of chloragocytes with mild
granulation of chloragocytes followed with severe necrosis in earthworms exposed
to sewage sludge. Popović et al. (2015) reported that industrial wastewater contains
abundance of inorganic compounds, xenobiotics, and organic contaminants that
produce significant histopathological alterations in earthworms. Bangarusamy
et al. (2014) reported various histopathological changes such as villous atrophy,
necrosis, and enteritis with cellular infiltration in the intestine of earthworms.
Esaivani et al. (2015) observed extensive alterations in the intestinal tract of the
earthworms exposed to inorganic fertilizer and pesticides. The chloragogenous
tissue showed clear changes as cells lose their structural integrity. The epithelial
lining showed fusion of intestinal villi that lead to the reduction of absorption area of
nutrients from food. The chemical fertilizer-exposed earthworms showed disintegration of nuclei and enlargement of epithelial lining.
P. hysterophorus showed detrimental effects on the intestine of earthworm. The
earthworm’s growth, cocoon production, and antioxidant enzymes were in low level
with P. hysterophorus treatment. During the management and risk assessment of
parthenium, it was reported that this weed induces oxidative stress, and due to this,
the earthworms adapt the morphometric characteristics of tissue including the
epidermis as well as intestine of earthworm.
15.3 Conclusion
Various environmental wastes showed bioaccumulation of heavy metals in the
tissues of earthworms, induced oxidative stress, and caused alterations in
histomorphology of intestine as well as in antioxidant status of the organism along
with the growth and fecundity of earthworms. Still the wonderworm Eisenia fetida
was able to convert various toxic waste, that is, P. hysterophorus, into a useful
manure. The appropriate concentration of P. hysterophorus in cow dung is an
essential factor for the survival of earthworms without causing any harm so that it
should be converted into effective manure. Thus, these organisms can be used on
large scale to convert various environmental wastes into useful product. But some
measures and precautions should be taken to protect these organisms from the ill
effects of toxic environmental pollutants. It is also recommended that field trials
should be conducted on different crops before using P. hysterophorus-mixed
vermicompost in agricultural fields.
260
H. Kaur et al.