Environmental Engineering Reference
In-Depth Information
carbendazim, glyphosate, and dimethoate on E. fetida and found a significant reduction in
the earthworm growth in a dose-dependent manner. According to Van Gestel et al. (1992),
parathion affects the growth of Eisenia andrei . Booth et al. (2000b) studied the effects of
two organophosphates, chlorpyrifos and diazinon, while Mosleh et al. (2003a) investigated
the toxicity of aldicarb, cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl
in the earthworm Aporrectodea caliginosa and observed a reduction in growth rate in all
pesticide-treated worms. Mosleh et al. (2002, 2003b) studied the effects of endosulfan and
aldicarb on Lumbricus terrestris and have suggested growth rate as an important biomarker
for contamination by endosulfan and aldicarb. Zhou et al. (2007) assessed and found that
chlorpyrifos had an adverse effect on growth in earthworms exposed to 5 mg/kg chlorpy-
rifos after eight weeks. Some studies have shown that the growth of earthworms appeared
to be more severely affected at the juvenile stage.
Toxicity of avermectins to soil invertebrates in soil and in feces from recently treated
sheep was studied. Abamectin was more toxic than doramectin. In soil, earthworms
( Eisenia andrei ) were most affected with LC 50 s of 18 and 228 mg/kg dry soil, respectively,
while LC 50 s were 67-111 and >300 mg/kg for springtails ( Folsomia candida ), isopods ( Porcellio
scaber ), and enchytraeids ( Enchytraeus crypticus ), respectively. EC 50 s for the effect on repro-
duction of springtails and enchytraeids were 13 and 38 mg/kg, respectively, for abamectin,
and 42 and 170 mg/kg, respectively, for doramectin. For earthworms, NOEC was 10 and
8.4 mg/kg for abamectin and doramectin effects, respectively, on body weight. Earthworm
reproduction was not affected. This study indicates a potential risk of avermectins for soil
invertebrates colonizing feces from recently treated sheep (Lucija et al. 2008). Malathion
affects the reproduction as well as morphology of Eisenia foetida. It also causes skin rupture
(Reddy and Rao 2008).
Bharati and Subba Rao (1986) observed that the sublethal concentrations of phosphami-
don, monocrotophos, and dichlorvos reduce carbohydrate and glycogen content and increase
phosphorylase “a” and “b” activity in the muscle and blood of the earthworm, Lampito mauritii
(Kingberg). Fenitrothion produces similar effects on carbohydrate metabolism of the body
wall muscle of Octochaetona pattoni (Varadaraj 1986). Reddy et al. (1983) have noted an increase
in the blood sugar level under fenitrothion treatment. Although persistence of insecticides in
soil and their effects on density of nontarget organisms is minimal at a normal agricultural
dose, the effect is obvious at population metabolism with changes in physiological and bio-
chemical responses.
Soils that contain significant copper residues have been observed to have few earth-
worms (Van Rhee 1967; Van Zwieten et al. 2004), reduced surface activity (fewer castings
visible at the soil surface), and greater litter build-up (Ma 1984). Copper has been shown
to reduce the burrowing activity of earthworms, which in turn led to increased soil bulk
density in a vineyard (Eijsackers et al. 2005). Likewise, Gaw et al. (2003) described the
lack of pesticide breakdown in soils where copper was a co-contaminant. There is clear
evidence that soil organisms and thus soil functions can be affected by pesticides. At sites
in a study on avocado orchards in northern NSW (New South Wales) (Merrington et al.
2002), an absence of earthworms in areas of copper contamination was accompanied by
a thick layer of organic matter (ca. 10-30 cm deep) that was clearly stratified on the soil
surface, with little evidence of breakdown and incorporation into the subsurface layers.
This phenomenon is not seen in other subtropical horticultural systems where copper
fungicides are not used. A strong correlation has been observed between the soil-copper
concentration and the level of copper in earthworm tissues (Ma et al. 1983). It has been
noted that earthworms exhibit chronic toxic responses at relatively low concentrations of
copper (<4-16 mg/kg) (Helling et al. 2000). The enchytraeid worm Cognettia sphagnetorum
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