Search

The last year of a National Science Foundation (NSF) funded scholarship program was used to provide pseudo-formal peer mentoring activities to engineering, mathematics, and science undergraduates. A one-credit class was used to afford time for peer mentors and mentees to interact. During the fall semester, seniors augmented each week's topics with personal experiences as to how they used the skill/topic that they had learned in their freshmen class in a future sophomore, junior or senior level course or on their co-op assignment. The last 10 min of every class were used for the seniors and freshmen to have an informal discussion. During the spring semester, the seniors served as an additional technical resource for the freshmen as they completed their class project. All participants found the one-credit class, project and peer mentoring activities beneficial to their education and would highly recommend the experience to incoming students.

A unique undergraduate team that spans five different engineering disciplines, chemistry, biology, and mathematics was formed. The team was formed to promote cross-disciplinary learning, to improve retention, and to prepare the students for the kind of problems they will face in their careers. This paper describes the variety of activities used over 2 years to tie the team together, as well as afford opportunities to develop team-building skills. The activities described highlight the critical elements of a faculty leader whose own work is interdisciplinary, correct balance of disciplines in the team, and sufficient time for team development. The use of external feedback was essential for all activities. Clearly defined goals and hard deadlines were critical for the completion of individual activities, as well as developing a healthy team environment. Although the student cohort has learned from the activities, more time is needed to assess whether the students have become a fully efficient team. Furthermore, an additional cohort would be needed to assess whether the approach was able to assist with student's interest in STEM and their desire to help other people.

Elevated heavy metal soils and water contamination have been shown to impose toxic effects on plants, animals, and human health. The extent of toxicity depends on the nature of the metals, soil and aquatic system characteristics, and the complex interactions between metals and the environment. Recent studies have shown that metal-microbe interactions may be effective for the remediation of contaminated media. This study investigated the effectiveness of an isolated rhizosphere bacterial consortium for treating an aqueous solution containing 600 mg/L of Cd, Cr, and Ni. The consortium was resistant to the metal toxicity as evidenced by an increase of population density of more than 6 x [10.sup.11] cfu/mL. The microbial activity facilitated a reduction in aqueous metal concentration with a metal precipitation selectivity of Cr [much greater than] Cd > Ni. CE Database keywords: Heavy metals; Water pollution; Soil pollution.

It is well documented that excess phosphorus in source waters is a major contributor to harmful algal bloom formation. While there are many approaches to controlling algal populations in reservoirs, including a variety of phosphorus reduction approaches (e.g., sequestration of legacy phosphorus with alum or clay products), addressing physical phosphorus loading upstream is considered less often. Water treatment residuals (WTR) containing alum, a common waste product of conventional surface water treatment, have been shown to retain the ability to capture phosphorus even after the WTR 'sludge' is formed and removed from the sedimentation process. This research designed and tested a refillable, reusable in-stream phosphorus cartridge system which beneficially reutilizes WTR 'sludge' to sequester instream phosphorus and remove it from the water when spent media is replaced. This reduces in-stream phosphorus entering into the reservoir without permanently adding additional materials to the waterbody and provides measurable results as to the amount of phosphorus removed. The ten sampling events during the first year's field assessment indicated that the gates removed a total of 556.31 g of reactive phosphorus (PO43−) and it is anticipated that the actual phosphorous removal was even greater. Other watershed managers can implement the same approach using their own WTR to capture in-stream phosphorus. [ABSTRACT FROM AUTHOR]

Excess phosphorous in waterways is known to be a cause of harmful algal blooms. This research evaluated if baking water treatment residuals (WTRs) would increase the number of adsorption sites, thereby increasing the WTRs ability to adsorb phosphorous. Initial 24-h sorption studies determined optimal baking temperatures of 175°C for alum based-WTR (Al-WTR) and 150°C for Al-WTR amended with power activated carbon (PAC) (PAC-WTR). Adsorption-desorption isotherm studies for baked Al-WTR (175°C) and PAC-WTR (150°C) found that there was a net desorption of phosphorous when distilled water was used as the background solution. When surface water was used, baked Al-WTR adsorbed more phosphorous at 5°C while baked PAC-WTR adsorbed more at 20°C. Continuous flow column tests were also conducted and found a sorption capacity of 7.91 mg PO4 g−1 WTR for baked Al-WTR that was less than as-is and 16.21 mg PO4 per kg-WTR, which was 83% better than its as-is counterpart. An analysis of all experiments found that as-is WTR performed better (p<0.05) than baked WTR and would be the recommended reuse of the water treatment plant's WTR for the adsorption of phosphorous. [ABSTRACT FROM AUTHOR]

Experiments were conducted to compare the effect of citric acid (CA) on metal uptake in Phragmites australis cultured in artificial acid mine drainage (AMD) contaminated soil or aqueous solutions. When the chelator CA was present, it appeared to reduce metal plaque (i.e. Mn and Fe) formation around the roots systems of reeds; while simultaneously increasing the metal accumulation in both belowground and aboveground tissues of reeds cultured in AMD contaminated soil or solutions. Compared to soils, the effect of CA to decrease Mn and Fe plaque and enhance Mn and Fe uptake in solutions was more pronounced. In general, the more CA that was added, the more Mn and Fe accumulated in the reeds, especially the underground tissues of reeds. However, the effects of CA on Al accumulation in reeds grown in AMD soil and solutions were different. CA decreased Al plaque formation and increased Al uptake in reeds cultured in AMD contaminated soil but had no influence on Al levels in reeds grown in AMD solutions. CA could be effective at enhancing the phytoremediation of metals from AMD contaminated sites, depending on the metal levels, types of metals and the characteristics of contaminated media. [ABSTRACT FROM AUTHOR]

Abstract: Phragmites australis (common reed) is often used to treat acid mine drainage (AMD) sites contaminated with high concentrations of heavy metals and low pH. This study investigated the effects of different levels (low 0.34 g/L, middle 17.86 g/L and high 33.62 g/L) of the biodegradable chelator citric acid (CA) on pH change, metal (i.e. Fe, Al and Mn) accumulation and translocation in reeds cultured in aqueous AMD contaminated media for 4 and 12 weeks. The results indicated that CA inhibited further deceases in AMD pH as well as increased Fe and Mn accumulation in both belowground and above ground tissues of reeds. As expected, increasing CA dosage and treatment time increased metal accumulation in plants. By 12 weeks, 0.18 ± 0.01 mg Mn/g, 56.78 ± 7.63 mg Fe/g and 0.60 ± 0.01 mg Al/g were accumulated in roots; while 0.06 ± 0.01 mg Mn/g; 6.38 ± 0.06 mg Fe/g; and 0.19 ± 0.01 mg Al/g were sequestered in stems of reeds treated with 33.62 g/L CA. Further research is needed to study the application of CA to enhance the phytoremediation efficiency of AMD contaminated field. [ABSTRACT FROM AUTHOR]

Phragmites australishas been used to treat acid mine drainage (AMD)-contaminated soil. However, the mechanism about metal translocation in reeds was not widely reported. This study investigated metal (Fe, Al, and Mn) storage location in reeds grown in five different sampling sites of an AMD field. As expected, the more metals in soil, the more metals entered the belowground organs of plants. Reeds grown in soils with the highest levels of metals accumulated 0.16 ± 0.04 mg/g Mn, 16.29 ± 4.15 mg/g Fe, and 1.31 ± 0.22 mg/g Al in roots. Most of the iron was sequestered in the roots, while Al was transferred to the shoots. Histological staining found that most of the iron was sequestered in the exodermis, while Al extended the endodermis of roots. Al even entered the stele of roots grown in soil with higher Al levels. The epidermis, cortex, and central cylinder of rhizomes were the main tissues for Fe and Al storage. The more metals in rhizomes, the stronger intensity of the staining was observed around the vascular systems of rhizomes. No structural difference was observed among reeds collected from different sites. Further studies may be needed to enhance the transfer of metals in reeds and increase the phytoremediation efficiency. [ABSTRACT FROM PUBLISHER]