Comparative Quantification of the Negative Impact of Pesticide Use in an Agricultural Region of Mexico

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Manuscript title: Identification of the environmental impact of agrochemicals used in agriculture

 

The manuscript describes the identification and estimation of environmental and socioeconomic impact of various agricultural pesticides. I find this subject and the approach the authors used to be very interesting. The Introduction is well written, giving all necessary information about the subject in question and setting a well-defined aim of the study. The Materials and methods are very detailed. The Results section is extensive, but not hard to read. Discussion nicely follows the results and connects them to pertinent data. The Conclusion is in accordance with the results.  Overall the manuscript is well written and I would also suggest proofreading to eliminate typos.

Minor points and questions:

1) “The continued use of agrochemicals in Valle de Arista, SLP, Mexico, has generated loss of effectiveness of molecules and impacts on public health and the environment.”

I do understand what is written but it seems a little clumsy in English, maybe rewrite it and instead of molecules use active substances.

2) I like that the authors highlight the lack of education in the application of chemical pesticides, but this is also important for biological control. Without much interference in the Introduction, add a sentence or two about integrated pest management.

3) When first mentioning “aging of pesticides” please explain what it refers to.

4) The equations should be numbered!

5) Table 3 is a little hard to follow, decreasing the font size might help to keep everything in line. Furthermore, under “Workers” are two categories, “Appy” and “Collect” for which I could not find an explanation?

6) Probably a direct translation, but the title “Estimation of the environmental impact of chemical synthesis inputs” does not reflect the content, maybe pesticide inputs?

7) I recommend the authors to check whether some of the references are bilingual or at least have English titles and to add them if they do.

Author Response

Please see the attachment 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors present a study that aims to quantify the negative impact of pesticide use in the valley/basin of Arista in Mexico, a region with intense agriculture based on artificial irrigation. The authors conclude that the fungizde carbendazim and the insecticide pymetrozine are the active ingredients with the highest socio-environmental cost, primarily impacting the consumer, workers and aquatic life.

The manuscript is well written and only minor problems were detected with English language.

The graphics shown, except for figure one appear to be screenshots of rather low image quality.

Figure one shows points 4 and 5 in flowchart that have not been addressed in the manuscript.

First I would like to state that, in my opinion, it is, in principle, a very good idea to quantify the socioeconomic impact of agricultural pesticides and to make their overall impact on nature and society more visible and comparable. Despite my sympathy and agreement for the intentions of the authors, I found the manuscript not easy to understand.

 

It starts with the title “Identification of the environmental impact of agrochemicals used in agriculture” which does not describe the content of the manuscript, because environmental impact of agrochemicals was not directly investigated in this study. A more precise title would be: “Comparative quantification of the (estimated) negative impact of pesticides use in the Valle de Arista, Mexico.”

The term “negative impact” would be justified, because the authors did not consider the (monetarian) benefits of pesticide use i.e. the costs of not using them.

The authors state that their investigation is mainly based on the Environmental Impact Quotient (EIQ) and the Environmental Accounting System for Pesticides. If I understand correctly, the EIQ has been suggested by Cornell scientists to easily quantify the environmental impact of pesticides, by simply considering the active ingredients and applied quantities.

The value of interest is then the “EIQ field use rating (EIQ FUR)“ that is calculated with the formula:

“EIQ Field Use Rating (EIQ FUR) = EIQ x % Active Ingredient x Rate”.

The authors used a different form to calculate field rate, described in the form of: EIFF = EIQ ∗ q ∗ d ∗ n. The description: “d = amount of commercial products applied in the field” can be misunderstood as number of other pesticides applied. I assume the correct description is “Amount of pesticide applied per application in kg.” How was the % of active ingredient determined?

The Gower similarity index was used to identify groups of producers with specific production traits. However, splitting base of only 40 producers into 13 groups does not appear to be necessarily representative for the whole valley. Moreover, the most interesting question of pesticide (i.e. active ingredients) use was not included and therefore the whole analysis is rather supplementary.

Finally, the authors used the “estimated average cost of negative externalities from pesticide” and applied a purchasing power parity (PPP) for Mexico. This is certainly correct in the context but has general consequences. It is understood, that the monetarian value in USD is rather a common value for the impact of the pesticides. By applying a PPP it is however implied that the impact is lower in Mexico than in the US. While it is clear that the costs may be lower in Mexico, the consequence is that human health and environmental health are valued differently in US and Mexico, which is a general problem of the indicator USD. This should at least be discussed by the authors.

There are several wordings in the text which should be reconsidered by the authors:

line 20 “agri-inputs dealers”

line 41: “increased presence of pests and diseases (of plants?)”

line 43,57: aging (decay, decomposition?)

line 90: No intervention has been applied. The authors indicate a descriptive study in lines 71-75.

line 179: What is the meaning of: “ Aquifers Aquatic life Birds Bees Beneficial insects”

line 252: Please explain “summing a ≤51% of the variance. “

line 290: “was USD $15.60 per hectare (and year).”

line 318: Please explain: “Regarding low-impact agricultural practices, a limited presence of biological and ethological control was identified”

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript explores the significant and urgent issue of quantifying the environmental and socio-economic impacts of intensive agricultural practices in the Valle de Arista region of Mexico. The authors take an integrated approach by combining the EIQ methodology with a pesticide environmental accounting system, providing valuable scientific insights for developing sustainable farming strategies.

However, a detailed examination of the work revealed a number of significant methodological and substantive shortcomings that require serious revision.

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The sample size of N=40 raises questions. No justification is given for this specific number. Why was 40 chosen? What is the total number of farmers in the region? Was a power analysis conducted to determine the appropriate sample size? For the purpose of multivariate statistics, such as PCA and the Gower's coefficient, a sample size of 40 is considered very small and may result in unstable and non-reproducible findings.

Why does the conclusion state that the impact is generally low and medium (line 272), when the data in Table 4 clearly shows that many farmers have a high total impact per hectare? Could you please reconcile the conclusion with the data presented?

Table 4. Please provide descriptive statistics (mean, standard deviation, minimum, maximum) for the total EIFF per hectare for all farmers and separately for each pesticide group.

Table 5 summarizes the impacts of crops. However, these numbers (251, 217, and 165) are not directly comparable because they have not been normalized by area. Tomatoes have the largest area (80 hectares), so they have the highest overall impact. To make a more accurate comparison of impact intensities, you need to calculate the average EIFF per hectare for each crop.

The entire paragraph (the paragraphs starting with "Regarding the socioeconomic impact..." and "This study arose from..." Lines 359, 340) simply repeats the "Methods" section instead of discussing the results. This is unnecessary and takes up valuable space in the "Discussion" section. Therefore, it would be better to delete these paragraphs and instead discuss how the Leach and Mumford method was useful for your specific case and what limitations were revealed when applying it to Mexico.

The conclusions state (Lines 395-396): "Carbendazim and Pymetrozine are active ingredients with the highest socioeconomic cost...". However, according to Table 6, Pymetrozine has the lowest externality cost (3.32 USD/ha), while Carbendazim has the highest (46.84 USD/ha). Is there a mistake here?

Figure 5 looks quite unusual. It doesn't seem to be a graph, but more like a screenshot or even a photo of a PC screen. The sizes of the data points in bars don't match the data on the X-axis.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

I have no special comments.