Amy E. Landis’s research while affiliated with Colorado School of Mines and other places

Plastics are one of the most widely consumed materials around the world, and its impact on our ecosystems is undeniable. Initiatives to reduce plastic waste have gained momentum in recent years, but the focus areas of such initiatives do not always align with significant positive impacts. This presentation demonstrates a material flow analysis (MFA) aimed at quantifying the global flow of plastics, from production to end of life, ultimately identifying where plastic reduction efforts can be most impactful. On a global scale, specific data on plastic production and material flow is lacking, so calculations relied heavily on data published in the United Nations' Mapping Global Plastics Report, based on the year 2015. The MFA was conducted with emphasis on end of life and flows lost to the environment, including macro‐ and microplastics. Across the global MFA, results show packaging was the largest individual industry consumer of plastics. Categories designated as “other” should be investigated further due to their substantial presence in the material flow. Plastics lost to the environment made up about 2% of the total mass, but that 2% equated to over 8 million metric tons. These lost plastics stem from various sources, making the issue difficult to tackle, but addressing this loss is important, nonetheless. Reducing demand for plastic production through decreased use is an obvious approach to minimizing waste and pollution, and this study provides insight about which plastics pose the greatest threat while also identifying current data gaps, ultimately guiding where future efforts should be focused.

Greenhouse gas emission reduction is often cited as a reason for high energy density, next-generation battery development. As lithium-O 2 battery research has progressed, researchers have examined the potential of many novel materials in the drive to reduce parasitic reactions and increase capacity. While the field has made great strides towards producing more reliable batteries, there has been little verification that lithium-O 2 batteries will reduce net environmental impacts. This paper examines how material selection ultimately impacts lithium-O 2 battery environmental impacts. Given that researchers should not wait until lithium-O 2 batteries reach commercialization to assess their environmental impact, this paper describes how to incorporate LCA as an integral part of the battery design process. Furthermore, it provides impact factors of many relevant materials to increase the ease of LCA for the field. Graphic abstract

Improving phosphorus (P) management is important for both ecosystem protection and avoiding mineable P scarcity. In order to inform the development of impactful solutions to both of these issues, we assessed the potential of several specific management strategies to reduce demand for new mined P in fertilizers and supplements for livestock, thereby reducing net P inputs to land. The strategies assessed were variable rate fertilizer (VRF) application, improvements to P digestibility for livestock, efficient utilization of manure and wastewater treatment (WWT) P, and elimination of avoidable domestic food waste. The potential of these strategies to reduce net anthropogenic P inputs was assessed at the county level for the coterminous US using the commodity-specific net anthropogenic phosphorus and nitrogen inputs (CSNAPNI) model. The largest contributions toward eliminating NAPI in the US can come from efficient manure utilization either at national (30 to 50% NAPI reduction) or county-level (21 to 30% NAPI reduction). However, widespread adoption of VRF (10 to 41% NAPI reduction), and all other strategies considered (5% or greater NAPI reductions each) could make significant contributions. In combinations of strategies that included VRF or P digestibility improvements, negative feedbacks occurred. VRF reduced demand for fertilizer, thereby reducing the potential for efficient manure and WWT P utilization at the county-level. P digestibility improvements in poultry and swine diets reduced the expected production of recoverable manure P by 36%, decreasing the total manure P that could be used to replace mined P fertilizer. However, P digestibility improvements also reduced county-level excess manure P by 25%. Prior studies have focused on quantifying P inputs or the potential of in-situ best management practices (BMPs) to reduce losses to water, but strategies to reduce P inputs are understudied.

Guar gum, the main product of the guar crop, is used widely in the USA as an emulsifier in the food industry and as fracturing fluid additive in the oil and gas industry. The USA is the number one global importer of guar, and interest has grown to domestically cultivate guar in the USA. Guar is an annual desert legume native to India and Pakistan. The goal of this study was to evaluate the environmental sustainability of growing guar in the USA via a life cycle analysis (LCA). The LCA helps identify the information gap for US agriculture and guide future field studies to optimize guar cultivation in the USA. This study concluded that in terms of environmental sustainability, irrigation, harvesting, and P-fertilization methods offer the most opportunity for improved guar agricultural sustainability. This is promising because one of guar’s prominent characteristics is its high water use efficiency and ability to grow in marginal soils. Lowering irrigation and water use can be implemented with simple management practice changes such as optimizing irrigation. In addition, this study shows that there is an opportunity for field trials to optimize fertilizer application rates to achieve the greatest yields. This study also found a knowledge gap with respect to carbon soil fluxes and field emissions of nitrogen and phosphorus from guar agriculture. As the USA considers adopting guar agriculture in the southwest, through research collaborations such as the USDA Sustainable Bioeconomy of Arid Regions Center of Excellence, it will be critical to evaluate irrigation to achieve maximum yields (e.g., drip, flood, sprinkler) and fill fertilizer and emissions knowledge gaps. Graphical abstract

Environmental or ecological footprints provide a measure of demands on the earth's resources and originally referred to human demands. Many organizations have established guidelines for performing detailed Life Cycle Assessment (LCAs), including the Environmental Protection Agency, the Society for Environmental Toxicology and Chemistry, and the American National Standards Institute. LCAs would provide useful environmental information about poly(lactic acid) (PLA). One of the assumed environmental benefits of biopolymers is their reduction in the amount of fossil fuels and subsequent greenhouse gas emissions compared to their petroleum‐derived polymer counterparts. The environmental performance of PLA has primarily been evaluated from the cradle to gate based on greenhouse gas emissions, nonrenewable energy use, and water use. Agricultural management strategies can be employed to reduce water quality degradation resulting from corn production. Improving upon energy consumption throughout the life cycle of PLA can minimize its environmental footprint.

One approach to address both the environmental and scarcity issues that occur with phosphorus (P) losses from human systems is to improve understanding of the P demands of bio‐based products. Most P demand in the United States is driven by production of crops for animal feed and mineral P feed supplements for animals. In this research, we used the Commodity‐Specific Net Anthropogenic Phosphorus and Nitrogen Inputs (CSNAPNI) model to (1) assess the contributions of individual feed products such as corn, soy, and mineral P supplements to the embodied P of animal products and (2) estimate net anthropogenic phosphorus inputs (NAPIs) for the contiguous United States for two animal P‐intake scenarios. Results show that P supplements may contribute up to 30% of embodied P in pork and dairy products, up to 60% in chicken, and up to 75% in turkey. Other major contributors to animal product‐embodied P are grains, which are responsible for around 60% of embodied P in pork and dairy products, at least 30% in chicken, and at least 20% in turkey products. Results also show that animal P intake is such a significant driver of anthropogenic phosphorus that a reduction of animal P intake by 25% could reduce NAPI to the contiguous United States by 30%. Considering promising research on methods to improve digestibility of both mineral P supplements and grain P in animal diets, these results are encouraging.