Please identify the top strengths (up to 3) of the Rolsky and Kelkar (2021) paper

1 - This paper presents an impressive integrated model of emissions, fate, and environmental emission of polyvinylalcohol via the effluent of WWTPs.
2 - The model is simple in design and this is in itself a major positive achievement. Related to this, a key strength of the model described in the paper is that it can also be applied to other chemicals of emerging concern.
3 - The key research needs are clearly presented.

1. The most important strength of the article is the integration of multiple sources of data to generate a seemingly coherent conclusion about the discharge of polyvinyl alcohol into the environment through wastewater discharges. Data were collated from published results of research one the rates of PVA degradation through various wastewater treatment processes, and these results were complemented with information gleaned from a limited survey of households in the United States to estimate PVA loading into wastewater streams. Finally, information from 'typical' discharges of treated effluent and sludge was used to generate approximate proportions released into each compartment. Such studies require a wide range of methodologies, and the authors are to be commended for the research approach.

2. A second strength of the article is the section on modeling of water use and wastewater generation in the United States. The model is not too sophisticated and it is explained through equations, and the assumptions are mostly well described.

3. The third strength of the article is the use of Figures to complement the text. The Figures contain pertinent information such that readers who may not be experts on each of the various methods used can visualize how the integrative research approach worked together to generate the conclusions in the final figure about modeled usage and emissions of PVA into various applications.

1. Estimates the possible environmental release of PVA from laundry and detergent pods in the USA
2. Clearly outlines the basis of the estimate (although variance estimates are not well explained; see weakness 2)

1) A thorough review of the use, purchasing patterns and mass flow of PVA from consumption into wastewater and its likely fate across different untreated or WWTP treatment processes.
2) Establishment of first model of PVA fate through literature review of likely degradation and coupling to a WWTP mass balance model
3) Extrapolation of results across the US, by relying on GIS data.

Conceptual model

1. All stages of the WWTP are evaluated separately for their ability to degrade, remove, and disperse PVA. Although the authors could have included a more thorough assessment of AOPs, the approach is robust and very informative. I would welcome such an approach for any kind of (modelled) assessment of WWTP removal efficiency.

- Survey generating information for the estimation of PVA used by domestic users in the USA.
- Literature review of works studying PVA degradation in WWTPs.
- Attempts to summarize the fate of PVA in wastewater in the USA, including treated and untreated flows, and the fate of PVA in a WWTP, including fractions in effluent and sludge.

1. Rolsky and Kelkar (2021) has provided qualitative, quantitative, and spatial analysis to estimate the emissions of PVA resulting from domestic use of LDPs in US.

2. The authors provided a comprehensive literature review on removal of PVA in WWTPs, and the amount of waste water treated in USA.

3. The authors compiled the amount of treated of untreated water and the degree of PVA degradation in the treated waste water, and visualised the environmental emissions of PVA in every USA states.