Enhancing General Chemistry Labs to Construct Engaging, Colorful Experiments

General Chemistry I (CHEM 121) sets the foundation for the chemistry education of Valparaiso students; therefore, it is critical that the CHEM 121 lecture and laboratory courses provide rich learning experiences that are meaningful, focused and both academically and visually engaging. In this project, two new or significantly revised laboratory experiments were incorporated into the curriculum during the Spring 2018 semester for the first time: 1) The Limiting Reagent in Action: Determining the Formula of a Precipitate and 2) The Analysis of Microplastic Pollution in Local Soil. The common goal of both labs were to increase student understanding of challenging general chemistry concepts by enhancing student engagement. In the case of Experiment 1, this was accomplished by improving the visual appeal of the reactions employed; in the case of Experiment 2, this was accomplished by directly connecting course material to study real-world pollution problems facing NW Indiana. Results of this experimentation and its impact on student learning in CHEM 121 are described

Defective Gut Function in \u3cem\u3eDrop-Dead\u3c/em\u3e Mutant \u3cem\u3eDrosophila\u3c/em\u3e

Mutation of the gene drop-dead (drd ) causes adult Drosophila to die within 2 weeks of eclosion and is associated with reduced rates of defecation and increased volumes of crop contents. In the current study, we demonstrate that flies carrying the strong allele drdlwf display a reduction in the transfer of ingested food from the crop to the midgut, as measured both as a change in the steady-state distribution of food within the gut and also in the rates of crop emptying and midgut filling following a single meal. Mutant flies have abnormal triglyceride (TG) and glycogen stores over the first 4 days post-eclosion, consistent with their inability to move food into the midgut for digestion and nutrient absorption. However, the lifespan of mutants was dependent upon food presence and quality, suggesting that at least some individual flies were able to digest some food. Finally, spontaneous motility of the crop was abnormal in drdlwf flies, with the crops of mutant flies contracting significantly more rapidly than those of heterozygous controls. We therefore hypothesize that mutation of drd causes a structural or regulatory defect that inhibits the entry of food into the midgut

Investigations into the Reactivity of Microplastics in Water

Microplastics, plastic pieces less than 5 mm in size, are a significant part of the plastic pollution in surface waters. Given the massive, global extent of this pollution, it is important to understand the chemical reactivity of microplastics in water. This study used radiation chemistry techniques to explore the transformations of plastics in water. Adsorption experiments were also conducted with microplastics and other model water contaminants. When water mixtures are exposed to gamma radiation, radicals that are prominent in nature, namely the hydroxyl radicals (●OH), are created. The reported irradiation experiments were done to simulate stagnant waters. Water mixtures containing either polyethylene (PE) or polyethylene terephthalate (PET) in closed containers were exposed to different irradiation dose rates and doses. Caffeine, dodecane, and benzophenone, commonly occurring pollutants, were used as model compounds in microplastics adsorption experiments. Infrared and Raman spectroscopies, along with GC-MS and LC-MS, were the main techniques used to assess the changes to the microplastics. A few compounds, such as dodecane and 2-dodecanone, were detected in the water/PE mixtures after exposure to the radicals. The surface chemistry of the microplastics was mostly unchanged, even after high doses of irradiation. Adsorption experiments showed that caffeine does not adsorb to PE or PET, dodecane strongly adsorbs to PE, and benzophenone partly adsorbs. The natural ●OH-mediated breakdown of caffeine was not affected by the presence of PE. Even though benzophenone adsorbs to PE, the degradation rate of benzophenone in solution did not change in the presence of PE microplastics

Quantifying and Analyzing Synthetic Microfiber Pollution in Great Lakes Sediment near Cladophora Mats

Microfiber pollution is ubiquitous in aquatic environments. Synthetic microfibers, a major class of microplastics, such as polyester, rayon, acrylic, and nylon, are present in clothing and other textile items, and are now viewed as contaminants of emerging concern. Routine laundering of synthetic fabrics has contributed to massive microfiber contamination in surface waters. In addition to its presence in water and sediment, previous microfiber research by our group showed that Great Lakes Cladophora, a common macroalgae, entangles and adsorbs microfibers in much greater amounts. This research aims to assess the role of the lake sediment below and near Cladophora mats in the fate of these microplastics. To determine if this sediment traps synthetic microfibers, research was conducted with sediment samples collected by the United States Geological Survey (USGS). Samples were cleaned using a ZnCl2 solution for density separation, which suspends most microfibers from the heavier sediment. All samples were then subjected to an advanced oxidation technique, which generates hydroxyl radicals that decompose most natural organic materials, including natural fibers. Microscopic analysis was implemented to quantify synthetic microfibers. The early analyses indicate that the lake sediment does not have entanglement or adsorbent properties. Due to the ubiquitousness of microfibers, method blanks were implemented to determine the amount of microfiber contamination introduced in the lab and suggest some work is still needed to reduce external contamination. A range of 0 to 12 microfibers (Av = 7) have been found in the samples per average dry weight of 32.152 g

Enhancing General Chemistry Labs to Construct Engaging, Colorful Experiments

General Chemistry I (CHEM 121) sets the foundation for the chemistry education of Valparaiso students; therefore, it is critical that the CHEM 121 lecture and laboratory courses provide rich learning experiences that are meaningful, focused and both academically and visually engaging. In this project, two new or significantly revised laboratory experiments were incorporated into the curriculum during the Spring 2018 semester for the first time: 1) The Limiting Reagent in Action: Determining the Formula of a Precipitate and 2) The Analysis of Microplastic Pollution in Local Soil. The common goal of both labs were to increase student understanding of challenging general chemistry concepts by enhancing student engagement. In the case of Experiment 1, this was accomplished by improving the visual appeal of the reactions employed; in the case of Experiment 2, this was accomplished by directly connecting course material to study real-world pollution problems facing NW Indiana. Results of this experimentation and its impact on student learning in CHEM 121 are described

Air Pollution in the Valparaiso Area

Volatile Organic Compounds (VOC’s) and particulate matter (PM) have been serious air pollution concerns around the world, particularly where industries and high volume traffic is present. These pollutants have been shown to have a negative effect on most living organisms, which is why they are regulated in many countries. To determine the air quality in the Valparaiso area, an experimental plan was conducted to determine the amount and type of these pollutants in the air. One of the project goals was to measure and compare indoor vs outdoor pollution. Another was to observe and assess weather effects on outdoor air pollution. Various locations around Valparaiso University campus and in the surrounding geographical area were chosen to analyze VOCs and PM. VOC testing was conducted using a solid phase microextraction fiber (SPME) to passively collect air pollutants. For PM, a MIE pDR-1500 active personal particulate monitor was used to actively draw in air and measure the concentration of particulate matter. A filter paper was used in the personal particulate monitor to collect the actual particulates. The instrument was run with both no filter, to determine total PM, and an adapter to select for PM 2.5 microns or lower. The SPME fibers were analyzed using a gas chromatographer - mass spectrometer (GCMS) to help determine the volatile or semi-volatile compounds present in the air. The collected data shows many differences between indoor and outdoor air

The effect of polypropylene on the formation of byssal threads produced by Dreissena polymorpha (zebra mussels)

The presence of microfibers and microplastics in the environment is an ever-growing ecological concern. Accumulation of microplastics (plastic particles smaller than 5 mm) in aquatic environments and the subsequent exposure of these particles to organisms have been shown to have negative effects on aquatic biota. As an invasive, filter-feeding bivalve found across Indiana freshwater ecosystems, the zebra mussel (Dreissena polymorpha) serves as a good model organism for studying microplastics’ effects on physiological and behavioral functions of affected organisms. We have studied the impacts of microplastic exposure on a freshwater mollusk, the zebra mussel. We collected zebra mussels from Stone Lake, Indiana, in late fall of 2019. Individual zebra mussels were exposed to polypropylene rope fibers (concentration of rope fibers in the environment of one zebra mussel was ~400 microfibers per L) for 24-hour trials and assessed the effects by production of byssal threads, which are produced by the zebra mussel for anchorage and in response to predation threats. Results from a comparison between unexposed control mussels (n=70) and mussels exposed to rope fibers (n=70) revealed no significant difference in motility nor the number of byssal threads produced. Despite using microplastic concentrations that were higher than that found in the Great Lakes, a 24 hour exposure time may still not have been enough to significantly impact the animals. Continued research on the attachment strength of Dreissena polymorpha exposed to rope fibers will provide clearer evidence of any direct effect of these microplastics on the ecologically important mussel species

What is with all the plastic garbage everywhere and where does it go?

Despite countless efforts in recycling, awareness, and limited legislation, plastic pollution has continued to spiral out of control due to massive production/use and the inability to naturally decompose. Plastic pollution ends up accumulating in the environment in places like sediment and surface water. Unfortunately, another reservoir for plastic pollution is local compost, or decayed organic matter used for agricultural processes. A substantial amount of micro- and macro- plastics has been collected from both the local compost and along and around roads in Valparaiso. Plastic waste was collected at numerous roadside locations throughout the Salt Creek watershed in the Porter County area; it was quantified and classified by both recycling numbers and via infrared (IR) spectroscopy. Compost samples were collected and analyzed in the same manner, this time also accounting for microplastics. The compost was sieved with two and five micron sieves. A solution of zinc chloride (1.4 g/mL) was utilized to separate the microplastics via density separation. This was then further processed via H2O2/UV advanced oxidation to eliminate excessive organic matter and to isolate the microplastics and microfibers further. The results will identify the various types of plastics and their magnitude in the local environment, in both the local compost and throughout the Salt Creek watershed of Porter County, Indiana. These results can establish knowledge of how different types and sizes of plastics migrate throughout the environment, and provide citizens with ways to reduce the garbage

Investigation of a Local Plastic Pollution Incident and Presentation of a Potential Remediation Strategy

Microplastic (MP) pollution is ubiquitous in environments across the globe, since plastics are known to fragment into smaller pieces over time. Microplastics are contaminants of emerging concern and the full extent of their effects is unknown. In some areas, microplastics heavily contaminate surface waters and are susceptible to chemical weathering, which alters their properties. These pollutants have the potential to enter the trophic levels and disrupt biological systems, as well as serve as a vector for other environmental contaminants through adsorption. The increase in the input of MP pollution into the environment requires technical remediation strategies, as there is no natural mechanism for remediation of these pollutants. In Hammond, Indiana, the company that manufactures polyethylene (PE) portable toilets has released PE waste into the adjacent wetland. The current methods of remediation for the wetland involve using oil booms to contain the pollution. In this study, water and sediment samples were collected from the freshwater marsh and its adjoining lake that are contaminated with the PE shavings. Laboratory analyses of the samples indicate a pollution load of over 1000 MP per sample. Laboratory experiments were also conducted to investigate a potential means for plastic remediation using an agglomeration technique. The results of using different polymers, particle sizes, and chemical additives will be presented. This pollution incident exhibits the critical need for effective remediation strategies, as well as regulations that will protect the world’s surface waters

Air Pollution in the Valparaiso Area

Volatile Organic Compounds (VOC’s) and particulate matter (PM) have been serious air pollution concerns around the world, particularly where industries and high volume traffic is present. These pollutants have been shown to have a negative effect on most living organisms, which is why they are regulated in many countries. To determine the air quality in the Valparaiso area, an experimental plan was conducted to determine the amount and type of these pollutants in the air. One of the project goals was to measure and compare indoor vs outdoor pollution. Another was to observe and assess weather effects on outdoor air pollution. Various locations around Valparaiso University campus and in the surrounding geographical area were chosen to analyze VOCs and PM. VOC testing was conducted using a solid phase microextraction fiber (SPME) to passively collect air pollutants. For PM, a MIE pDR-1500 active personal particulate monitor was used to actively draw in air and measure the concentration of particulate matter. A filter paper was used in the personal particulate monitor to collect the actual particulates. The instrument was run with both no filter, to determine total PM, and an adapter to select for PM 2.5 microns or lower. The SPME fibers were analyzed using a gas chromatographer - mass spectrometer (GCMS) to help determine the volatile or semi-volatile compounds present in the air. The collected data shows many differences between indoor and outdoor air