Copper and zinc aging in soils for a decade: changes in metal extractability and phytotoxicity

2016 ◽  
Vol 13 (1) ◽  
pp. 160 ◽  
Author(s):  
Murray B. McBride ◽  
Meifang Cai

Environmental contextTrace metal toxicities to soils and plants depend on residence time in soils, a poorly understood phenomenon termed ‘aging’. Our research aimed to better understand long-term aging by measuring the solubility and toxicity of copper and zinc over a 10-year period after their addition to soils as soluble salts. We determined that, while metal solubility and toxicity did decrease in a decade, the highest levels of added metals (200 and 400mgkg–1) still had toxic effects on soybeans. AbstractTo assess long-term effects of field aging on Cu and Zn availability and phytotoxicity in soils, soils were spiked in the field using metal sulfate salts, and tested over 10 years for changes in total metals, salt-extractable (0.01M CaCl2) metals, Cu ion activity and phytoavailable metals using a soybean assay. Metal losses from the soils were generally small, with the coarse-textured (Arkport) soil having greater losses than the fine-textured (Hudson) soil. However, large reductions in salt-extractable metals occurred over the 10-year period, with most of this decline observed in the first several years following spiking. Copper ion activities decreased after 10 years of aging in all of the Cu-spiked soils, but remained high enough to be phytotoxic at metal loadings of 200 and 400mgkg–1. The soybean assay showed that Zn phytoavailability was significantly elevated in both soils at the loadings of 200 and 400mgkg–1 Zn. Higher plant tissue Cu was evident at additions of 200 and 400mgkg–1 Cu in the Arkport soil, but only at the 400mgkg–1 additions in the Hudson soil. Plant growth was significantly reduced at the 400mgkg–1 additions for both metals in both soils; growth inhibition at the 200mgkg–1 addition was also observed for both metals in both soils, but was not statistically significant for Zn. In summary, soils spiked with 200mgkg–1 (or more) of Cu or Zn salts express significant phytotoxicity after 10 years of field aging despite a shift of the metals into less labile forms.

Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.


Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.


2012 ◽  
Vol 43 (3) ◽  
pp. 42
Author(s):  
MITCHEL L. ZOLER
Keyword(s):  

VASA ◽  
2005 ◽  
Vol 34 (4) ◽  
pp. 243-249 ◽  
Author(s):  
Drinda ◽  
Neumann ◽  
Pöhlmann ◽  
Vogelsang ◽  
Stein ◽  
...  

Background: Prostanoids are used in the treatment of Raynaud’s phenomenon and acral perfusion disorders secondary to collagenosis. In subjective terms, intravenous administration of these agents produces success in more than 50% of patients. The therapeutic outcome of clinical administration of alprostadil or iloprost may vary from individual to individual. Patients and methods: The following variables were analysed in a cross-over study in 27 patients with collagenosis and Raynaud’s phenomenon: plasma viscosity and erythrocyte aggregation (rheological variables), partial pressure of oxygen and laser Doppler flowmetry in the finger region, and lymphocyte phenotyping and interleukin (IL) determinations (immunological variables). Results: Laser Doppler flowmetry revealed significant differences between patients with secondary Raynaud’s phenomenon and a control group of 25 healthy subjects. Laser Doppler readings did not change significantly as a result of the treatments. Therapy with iloprost produced a reduction in IL-1beta, L-selectin (CD 62 L) and IL-6. Conclusion: The change in immunological variables due to iloprost may explain the long-term effects of prostaglandins in the treatment of Raynaud’s phenomenon. From our results it is not possible to infer any preference for iloprost or alprostadil.


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