Montejo-Custodio et al. 2026 - Landfill soil and water metals near mango agriculture

Montejo-Custodio and colleagues assessed soil, water, mineralogical, and hydrological indicators around a municipal solid-waste disposal site in Reforma de Pineda, Oaxaca, Mexico. This is in-scope supply-chain pathway and source-attribution evidence because it quantifies landfill-associated metals in environmental compartments adjacent to a mango cultivation plot and identifies runoff and groundwater transport pathways; it is not bottled mineral-water occurrence evidence.

Key numbers

Sampling included 13 soil samples at approximately 30 cm depth: 10 from the cultivated mango plot (P4-P13) and 3 from the landfill area (P3, T1, and T2). The study also collected three water samples: PV from residual water in the lower landfill area, PA from an artisanal well within the plot, and PM from a well in the urban zone.

The summary reports elevated V, Ba, Ni, Cr, and Pb in landfill soils, while Cd remained below detection limits. In the results section, the authors state that V, Ba, Ni, and Cr were detected in landfill soils (P3, T1, and T2) and in the lower agricultural plot (P13), while only V and Ba were observed in the upper plot (P12) at lower concentrations. Pb was detected only in the landfill area (T1 and T2), and Cd was below detection in all soil samples. The extracted text does not provide exact soil-metal concentration rows, so this page does not create a soil concentration table.

Table 2 reports metal concentrations in water, in mg/L:

The same table reports detection limits: Fe 0.988 mg/L, Cu 0.023 mg/L, Mn 0.001 mg/L, Zn 0.030 mg/L, V 0.001 mg/L, Ba 0.001 mg/L, Ni 0.001 mg/L, Pb 0.001 mg/L, Cr 0.001 mg/L, and Cd 0.015 mg/L.

The authors compare water results with Mexican NOM-127-SSA1-1994 maximum permissible limits for human-use and consumption water: Na < 200 mg/L, Ba < 0.70 mg/L, Cu < 2 mg/L, Cr < 0.05 mg/L, Fe < 0.30 mg/L, Mn < 0.15 mg/L, Pb < 0.025 mg/L, and Zn < 5 mg/L. They also cite NOM-001-SEMARNAT-2021 for Ni < 5 mg/L as the monthly-average discharge limit in rivers and streams.

The authors state that PA and PV exhibited concentrations above the cited MPL for Fe, Mn, V, and Pb, and for Cr in PV only. PM exceeded the cited MPL only for Fe. The water table’s Pb values, 0.001 mg/L in PA and 0.002 mg/L in PV, are below the cited 0.025 mg/L Pb MPL, so this statement is an internal source inconsistency; this page preserves the table values and records the inconsistency rather than changing the numbers.

The physical-soil results report landfill soils T1 and T2 with field capacity of 25-30%, compared with 31-36% for orchard soils P5, P6, P7, and P11. Landfill soils had very low organic matter, <0.5%, and moderately alkaline pH of 7.4-8.5, while mango-orchard soils had organic matter of 0.5-1.5% and were mostly moderately acidic.

Methods (brief)

The study combined soil, water, mineralogical, and hydrological assessment at a Reforma de Pineda, Oaxaca municipal landfill and an adjacent mango cultivation plot. Soil sampling used a targeted approach based on texture and slope. Physical and chemical soil analyses followed NOM-021-SEMARNAT-2000 protocols. Soil metals V, Ba, Ni, Pb, Cr, and Cd were measured by flame atomic absorption spectrophotometry following NMX-AA-051-SCFI-2001 and NOM-147-SEMARNAT/SSA1-2004. Water samples were also analyzed for K, Ca, Mg, Na, Fe, Cu, Mn, Zn, V, Ba, Ni, Pb, Cr, and Cd.

The study also used petrographic microscopy, X-ray diffraction, ANOVA-Tukey tests in R, and a two-dimensional rainfall-runoff numerical model using digital elevation models and National Meteorological Service rainfall data to identify runoff direction, recharge zones, and possible contaminant-transport pathways.

Implications

Certification: Do not use this source as bottled water, mineral water, mango, or finished-food occurrence. The source measures landfill-area environmental compartments and modeled transport conditions.

Courses: Useful source-attribution case showing how waste combustion, landfill leachate, soil hydrology, and adjacent agriculture can combine into a contamination pathway without a finished-product concentration table.

App: Context only. The source can inform environmental due diligence for agricultural sites near unmanaged landfills and groundwater pathways, not product scoring.

Wiki pages this source may touch

• irrigation-and-soil-amendments
• source-attribution-environmental-burden-apportionment
• soil-to-plant-transfer
• lead
• chromium
• cadmium
• vanadium
• barium
• nickel
• iron
• copper
• manganese
• zinc

Verification notes

Recovered from skip:not-food-occurrence under the 2026-06-10 inclusion-by-default rule. The old skip treated the paper as out of scope because it did not measure bottled or drinking mineral water. On reading, it is in-scope lane a3 supply-chain pathway and source-attribution evidence because it measures metals in landfill-adjacent water and soil compartments, names landfill waste and agricultural inputs as sources, and models runoff and groundwater pathways relevant to agricultural land.

Numbers were checked against the summary, methods, Table 1 physical-soil values, Table 2 water-metal values, the metals-in-soil-and-water discussion, the runoff-model discussion, and the conclusion in the extracted PDF text. Chromium is total Cr, not Cr-VI. Cadmium is included because it was measured and reported below detection in all soil and water samples. Products and ingredients are intentionally empty.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.