Watermelon

Overview

This ingredient stub was created during the FDA FY2018-FY2020 Total Diet Study element-results ingest so future source ingests have a stable destination for this food matrix. FDA reports this item as TDS Food 81, “Watermelon, raw/frozen.” FY2018-FY2020 TDS Elements Analytical Results

Why this commodity accumulates heavy metals

Watermelon is a cucurbit fruit with a high water content (approximately 92 percent by weight) and a large physical volume. Both characteristics limit heavy metal accumulation on a per-gram basis: metals taken up from soil by the root system are distributed across a large mass of dilute fruit tissue. The thick outer rind provides an additional physical barrier that restricts metal translocation into the edible flesh. Watermelon is therefore among the lower-risk food matrices on the wiki for most heavy metals. The FDA TDS FY2018-FY2020 data (n=27) consistently show zero or near-zero values for Pb, Cd, Cr, and tHg across the full distribution, with only Ni (reaching 79 ppb at maximum), tAs (reaching 6.8 ppb at maximum), and Cd (reaching 2.6 ppb at maximum) showing any non-zero observations at the upper tail (FY2018-FY2020 TDS Elements Analytical Results). The Ni signal is consistent with low-level background Ni in cucurbit crops. The tAs signal at trace levels is not unexpected for fruit grown on soils with any background arsenic. Root-level uptake from contaminated soils is the operative pathway for all detected metals; there is no aquatic bioaccumulation or manufacturing-related metal pathway for fresh watermelon.

Heavy metal contamination profile

Per-analyte snapshot derived from the machine-readable contamination_profile in the frontmatter above. data gap indicates the literature has been reviewed for this commodity-analyte combination and no usable occurrence data was found (a finding, not a placeholder). The Key sources column shows the top 2-3 contributing sources by year and sample size, with numbered wikilink aliases.

Analyte	Coverage	Typical (ppb)	Confidence	Key sources
Pb	n=2	0	low	1, 2
Cd	n=2	0–1.4	low	1, 2
iAs	data gap	—	—	—
tAs	n=2	0–3.8	low	1, 2
tHg	n=2	0	low	1
Ni	n=2	0–52	low	1
Al	data gap	—	—	—
Cr	n=2	0	low	1, 2
Sn	data gap	—	—	—
U	n=2	0	low	—

FDA TDS FY2018-FY2020 Evidence

The normalized row-level data for this TDS food is stored in data/evidence/fda_tds_fy2018_2020_element_results_samples.csv, with per-food/per-analyte summaries in data/evidence/fda_tds_fy2018_2020_summary_by_food_analyte.csv. Concentrations are retained as FDA reported them, with the reporting-limit column preserved separately; reported zeroes are not rewritten as <LOD unless a source explicitly says to do so. FY2018-FY2020 TDS Elements Analytical Results

Routing

This node is linked from the ingredient index and the FDA TDS source routing table.

Contamination Profile State

Per-analyte state — populated, in progress, or declared data gap — is carried authoritatively in the machine-readable contamination_profile frontmatter and the contamination-profile table above. Ingredient-level values belong here; finished-product values belong on the relevant product-category page.

FDA TDS FY2018-FY2020 Occurrence Values

FDA Total Diet Study FY2018-FY2020 reports prepared/composite-food concentration distributions for this ingredient as TDS food “Watermelon, raw/frozen” (FY2018-FY2020 TDS Elements Analytical Results). Values are in ppb-equivalent on the basis FDA reported. The full sample-level data are stored in data/evidence/fda_tds_fy2018_2020_element_results_samples.csv; per-analyte distributions in data/evidence/fda_tds_fy2018_2020_summary_by_food_analyte.csv. These distributions count as one source under Persistent Wiki Ingest Rule synthesis discipline; numerical values stay in body scratch until a second independent source is integrated.

Metal	n	max	Schema
Cd	27	2.6	in profile
Cr	27	0	in profile
Ni	27	79	in profile
Pb	27	0	in profile
U	27	0	in profile
tAs	27	6.8	in profile
tHg	27	0	in profile

Ranges by source, region, and variety

FDA TDS FY2018-FY2020 data (n=27) show that the vast majority of watermelon samples are at or below detection limits for all analytes (FY2018-FY2020 TDS Elements Analytical Results). Where detectable, Ni reached a maximum of 79 ppb, tAs a maximum of 6.8 ppb, and Cd a maximum of 2.6 ppb. These distributions suggest that elevated values are rare events, likely associated with specific growing conditions rather than being characteristic of the commodity category as a whole. No geographic or varietal breakdown for watermelon heavy metals is available in the current corpus.

Processing effects

Fresh watermelon consumed raw undergoes no processing steps that alter metal concentrations. Watermelon juice and watermelon-based beverages produced by pressing and filtering concentrate metals in proportion to water reduction only minimally, as the high initial water content of the fruit means that juice yield is high and solid residue is low. Freezing (the form in the TDS description “Watermelon, raw/frozen”) does not alter metal concentrations. No cooking or thermal processing is conventionally applied to watermelon in its primary use as a fresh fruit.

Ingredient-derivative risk

Watermelon is used primarily as a fresh fruit. Processed derivatives include watermelon juice, watermelon extract (used in beverages and supplements), watermelon rind pickles, and freeze-dried watermelon powder. The rind carries a different metal profile than the flesh because it is the outer structural tissue closest to the soil interface; rind-specific metal data are not in the current corpus. Freeze-dried watermelon powder concentrates metals proportionally to water removal but the low initial metal content of the flesh means concentrations remain low even after dehydration.