No description available.

This research investigated the effects of waterborne zinc (Zn) on the interactions between guppies, Poecilia reticulata (Peters), and Gyrodactylus turnbulli Harris, 1986, a monogenean parasite of its skin and fins. The first objective was to determine if sublethal concentrations of waterborne Zn (up to 240 mug/L added to artificial freshwater) exerted a concentration-dependent effect on the population dynamics of Gyrodactylus on isolated guppies. Whereas survival of uninfected fish was unaffected, mortality of infected fish increased linearly with increasing Zn concentration. In addition, the improved parasite population growth at concentrations up to 120 mug Zn/I suggested either that the elevated Zn promotes survival and/or reproduction of the parasite, or impairs host defense mechanisms. Analysis of lifetime survival and reproduction of individual parasites on and off the fish revealed Zn toxicity to the parasite as survival of detached parasites decreased linearly with increasing Zn concentration and parasite survival on the host was also lower at the highest Zn concentrations. Also, all morphological parameters decreased linearly in response both to increasing concentration and duration of exposure to waterborne Zn. The guppy epidermis responded rapidly to both infection and waterborne Zn, and the cumulative effects of these combined stressors were synergistic for epidermal thickness and mucous cell numbers, but antagonistic in terms of mucin composition. Both Zn and infection induced mucous production, but at elevated Zn concentrations and/or at high parasite burdens, the capacity for continued mucous production was apparently exceeded. I hypothesize that this condition is favorable for parasite survival because of the impaired host response; but unfavorable for host survival because of the high numbers of pathogenic parasites and the inability to control entry of Zn into host tissues. In conclusion, sublethal concentrations of waterborne Zn are more detrimental to the infected host than to the parasite.

Phytoextraction is an innovative method that can be implemented to remove lead (Pb), cadmium (Cd), and zinc (Zn) from contaminated soil. A two-year field and growth chamber study was conducted to determine the effectiveness of several soil amendments in the phytoextraction or stabilization of Pb, Cd and Zn. Field plots were established at the Memorial Drive Dump site (Muncie, IN). Amendments included composted municipal solid waste (MSW) (25 Mg/ha), dried sewage sludge (SS) (25 Mg/ha), citric acid (2 mmol/kg soil), ethylenediaminetetraacetic acid (EDTA) (2 mmol/kg soil), and a control. A mixed grass crop was capable of survival and growth in the contaminated soil; in contrast, Helianthus annuus (sunflower) and Ambrosia artemisiifolia (ragweed) failed to become established. Soil Pb and Zn occurred primarily in the carbonate, organic-bound and residual forms (23.1%, 31.8%, and 44.4%, Pb, respectively and 11.4%, 26.5%, and 60.2% Zn, respectively). Soil Cd occurred primarily in the soluble, carbonate, and residual forms (21.8%, 21.3%, and 27.4%, respectively). In a growth chamber leaching study, soil Pb was most rapidly leached from the 0.1 M EDTA treatment (51.7 mg Pb over 200 pore volumes); the 0.001M resulted in the lowest leaching. Soil Pb was most rapidly leached using 0.1 M HEDTA (52.1 mg Pb over 200 pore volumes). The 0.001 M HEDTA rate resulted in lowest Pb leaching. Addition of an NPK solution resulted in minimal Pb leached. The MSW and dried sludge treatments resulted in the greatest dry matter production on the plots. Dry matter production was significantly (p >0.05) higher in the MSW (1.09 MT/ha) and SS (95 MT/ha) treatments. Addition of EDTA, citric acid and MSW significantly (p < 0.05) increased the amount of Cd uptake into plant tissue. The study also demonstrated the ability of vegetation to establish and grow on toxic soil and to uptake Pb, Cd, and Zn. / Department of Natural Resources and Environmental Management

No description available.

Copper and zinc are heavy metals commonly present in highway stormwater runoff. Discharge of these metals to surface waters inhabited by sensitive aquatic species including threatened and endangered salmonids has necessitated the need for improved treatment techniques. Although copper is of the greater toxicological concern, zinc is often present at concentrations several times higher than copper and may compete with copper during adsorptive treatment processes. In the current study, the ability biogenic fish-bone based alternative adsorbent, Apatite II™, for copper and zinc removal from synthetic stormwater runoff was evaluated. Batch experiments were employed to examine equilibrium removal and rapid small scale column tests (RSSCT) were used to simulate dynamic operation in continuous systems. In both batch and continuous systems, the release of phosphate and calcium were observed, and Apatite II™ achieved high removal efficiencies. The removal of copper and zinc was likely due to a combination of processes including adsorption, ion exchange and precipitation. Precipitation played a dominant role in copper removal and the release of phosphate and pH buffering appear to drive this process. While precipitation was also quite important for zinc removal, adsorptive removal also played a role. The findings from the current study provide a general understanding of the performance of copper and zinc removal from stormwater runoff using Apatite II™. / Graduation date: 2012