Littering determination

The absorption capacity of the litter determines the amount used, and also affects the functioning of hydraulic manure presses. The absorption capacity of litter depends on its initial moisture content. In the laboratory tests, peat had a much greater absorption capacity than other litters. 

Many studies have reported the effects of metals on general soil microbiological processes. Metals including cadmium, chromium, copper, lead, mercury, nickel, and zinc have been reported to inhibit many of the microbial processes listed above. Metal toxicity in the environment ultimately decreases litter decomposition, which can be measured by the rate of mass loss. Both copper (0.5 mg Cu g4 soil) and zinc (1.0 mg Zn g 1 soil) were shown to decrease the rate of decomposition of unpolluted Scots pine needle litter near a brass mill in Sweden.61 Duarte et al.63 also determined that copper and zinc toxicity reduced leaf decomposition rates and fungal reproduction. Other metals, such as cadmium, nickel, and lead, have also been reported to decrease litter decomposition.77... 

Dilly O, loemJ B, Vos A, Munch JC (2004) Bacterial diversity in agricultural soils during litter decomposition. Appl Environ Microbiol 70 468-474 Dizdaroglu M (1991) Chemical determination of free radical-induced damage to DNA. Free Radical Biol Med 10 225-242 Eaton RW, Ribbons DW (1982) Metabolism of dimethylphthalate by Micrococcus sp. strain 12B. JBacteriol 151 465-467... 

Females given diets containing 2, 60, 380, or 780 mg Pb/kg ration after giving birth to litters. Lead residues in whole young voles were determined for up to age 20 days... 

Timed-pregnant rats were dosed with l.Opg TCDD/kg on GD14. One day after birth, litters were cross-fostered to produce control, placental-only, lactational-only, and placental/lactational exposure groups. The DTH response to BSA was assessed in 5-month-old males. In these rats the severity of the suppression of the DTH response was related to the route of TCDD exposure (i.e., placental/lactational > lactational > placental), with suppression occurring only in the males receiving both placental and lactational exposure.128 In order to determine the lowest maternal dose of TCDD required to suppress the DTH response in pups, dams were dosed with 0.1,0.3, or l.Opg TCDD/kg on GD14 and the DTH response to BSA was evaluated in 4- and 14-month-old pups. In the males, suppression was observed at a maternal dose of O.lpg TCDD/kg at 14 months of age, while a maternal dose of 0.3pg TCDD/kg was required to cause suppression in... 

Not only is it difficult to detect effects on male fertility because of group-size considerations, effects on male fertility mediated by decreased sperm production are also difficult to detect because of the normally huge excess of sperm included in a rat ejaculate. Sperm production can be decreased by up to 90% without effect on fertility (either pregnancy rate or litter size) in the rat. This is not the case for men, so the sperm excess in the rat represents a serious flaw in the rat model (see Working, 1988). To address this deficiency and improve the sensitivity of the model, it is advisable to determine the effects of the test agent on testes weights, testicular spermatid counts, and histopathology of the testes (preferably plastic sections) in the male fertility study and/or the 14-week toxicity study. In some cases, these parameters may be more predictive of possible effects on male fertility in humans than the fertility rate in rats. 

Samples of manure were collected from the farms during both experimental periods. The samples were used for nutrient content determinations and for a pot experiment in which Italian rye grass was cultivated. The nutrient contents obtained were compared with the values for the farm in question during the use of different litters, and with the grouped means for the different litter manures. 

The process of forest litter decomposition is one of the key processes leading to the redistribution of Cs among the ecosystem components. It is affected by two major factors the rate of decomposition, which is dependent on the composition of the litter and the time since the introduction of Cs, which determines the level of decomposition of the uppermost, most heavily contaminated layer. The distribution of i Cs between the separate litter layers is important, since Of and Oh are critical for the roots of many undergrowth plant species (such as V. myrtillus, V. vitis-idaea, V. uUginosu and L. palustre ) and fungal saprotrophs (Clitocybe,... 

The main objectives in the present study were to (a) determine the phytotox1c1ty of knapweed litter, (b) test the inhibitory effect of knapweed seedlings on the growth of grass seedlings, and (c) determine the effect of knapweed on soil microbial respiration and soil phenol concentrations. 

Knapweed litter, collected from a severely infested site, was air-dried and ground to pass a 20-mesh screen. To determine the phytotoxicity of the litter, the ground material was applied to m plots on a pasture site in 1981 and on two rangeland sites in 1982. Sand (650 g) was combined with each knapweed treatment to produce an even dispersal of litter. The litter was applied in November and grass yields, estimated on a dry matter basis, were determined in the following June. 

The sex and body weight of each fetus should be determined. Each fetus should be examined for external alterations (7)... For rodents, approximately one-half of each litter should be prepared and examined for skeletal alterations. The remainder should be prepared and examined for soft tissue alterations (4). 

Historical control data is an essential component of the study directors toolbox for interpreting reproductive and developmental toxicity data. Scientific judgment and expertise should be used to determine if historical control data is needed for interpretation of study data, which historical control data is appropriate, and how it should be used to support interpretation of a finding. This tool can be a valuable addition to a comprehensive assessment of the study data, which includes determining whether a dose-response is present and whether any statistically significant findings occurred. Sound data interpretation requires that the litter, not the fetus or pup, be used as the experimental unit in developmental and reproductive toxicity studies. For continuous data (e.g., fetal weight). 

As part of an intermediate duration study, in which rats were exposed to 500 ppm isophorone in air, Dutertre-Catella (1976) mated exposed males with exposed females, control males with exposed females, exposed males with control females, and control males with control females after 3 months of exposure. Exposure of females continued throughout gestation, and they were allowed to deliver. No differences in pregnancy rate or litter size and no abnormalities in pups were found. The pups were not examined for internal malformations therefore, this study was inadequate to determine developmental effects of isophorone. 

---