Heavy metals in Collard greens

Quick read

Collard greens in the HMI library has 14 reported results for lead, cadmium, total arsenic, total mercury, nickel, chromium and uranium from 3 sources.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →}

Metals measured:
Lead, cadmium, total arsenic, total mercury, nickel and chromium and others, in 14 results from 3 sources.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →}
Main drivers:
Form, basis and where the collard greens was sampled; reporting limits decide how many results are non-detects.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →}
Practical framing:
Ask for lot results with a quantification limit well below the limit that applies in the destination market.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →}

Collard greens overview

Collard greens in the HMI library has 14 reported results for lead, cadmium, total arsenic, total mercury, nickel, chromium and uranium from 3 sources.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →} WHO GEMS/Food submissions reported lead in collard greens, as sold from 70 results in 1 reporting region, with subgroup medians below 7 µg/kg, mostly non-detects.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →} In the US Total Diet Study, collard greens, cooked had a median lead result below 4 µg/kg across 27 composites from 2017–2020.^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}

Spungen et al. 2024 reported lead at 2.7 µg/kg (mean) and cadmium at 27 µg/kg (mean) in collard greens, cooked from all samples.^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →}

For a buyer the practical points are the form bought, the basis a result is reported on, where the collard greens came from and the laboratory’s reporting limit. Testing finds contamination but does not remove it.

What counts as collard greens

This page covers collard greens in 2 forms kept separate in every comparison: collard greens, cooked (9 results) and collard greens, as sold (5 results).^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →}

Results stay on the basis each source reports: as sold or fresh weight, dry weight, or unstated. Dry-weight, as-sold and unstated results are never pooled, and no moisture conversion is applied.

Heavy metal contamination profile of collard greens

The table holds every extracted collard greens result: one row for each statistic a source reports for a form, group and metal, 14 rows in all, grouped by metal and form; percentiles, ranges and maxima for the same samples as a mean or median are shown on that row.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →} Monitoring medians are HMI calculations from individual submissions; non-detects remain intervals between zero and the reporting limit and are never read as zero.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}

3 rows can be rated against an HMI reference for the same form and basis, 0 rows have a direct same-study comparison, and the rest stay unrated with the reason recorded.

Comparison methods and scope

Each row is one statistic a source reports for one form of collard greens, group and metal; percentiles, ranges and maxima reported for the same samples as a mean or median are shown on that row. Different forms and preparation states are kept apart, and dry-weight results never share a reference with as-sold or fresh-weight results. Ratings place a result against an HMI reference built from monitoring results and ordinary-setting medians for the same form and basis. Same-study contrasts compare a contaminated or treated site with its control, targeted with random sampling, a prepared form with the unprocessed one, or one group of a study with the median of its other groups. Held rows failed a check against their own source and are shown but not compared.

About this table

Food formCollection scopeFindingComparisonEvidence

Collard greens findings from monitoring programmes, total diet studies and every extracted field, market and contaminated-site study, in µg/kg with each source’s form, basis, statistic and censoring retained.
Food form	Collection scope	Finding (µg/kg)

2 findings · 2 studies
Collard greens, cookedFDA Total Diet Study	6 collection regions2017–2020	median.
Collard greens, cookedSpungen et al. 2024	all samples2018–2020	mean.
3 findings · 1 study
Collard greens, as soldWHO GEMS/Food	PAHO2016	median.
Collard greens, as soldWHO GEMS/Food	PAHO2016	median.
Collard greens, as soldWHO GEMS/Food	PAHO2000–2017	median.

2 findings · 2 studies
Collard greens, cookedFDA Total Diet Study	6 collection regions2017–2020	median.
Collard greens, cookedSpungen et al. 2024	all samples2018–2020	mean.
1 finding · 1 study
Collard greens, as soldWHO GEMS/Food	PAHO2003–2017	median.

1 finding · 1 study
Collard greens, cookedFDA Total Diet Study	6 collection regions2017–2020	median.
1 finding · 1 study
Collard greens, as soldWHO GEMS/Food	EURO2022	median.

1 finding · 1 study
Collard greens, cookedFDA Total Diet Study	6 collection regions2017–2020	median.

1 finding · 1 study
Collard greens, cookedFDA Total Diet Study	6 collection regions2017–2020	median.

1 finding · 1 study
Collard greens, cookedFDA Total Diet Study	6 collection regions2017–2020	median.

1 finding · 1 study
Collard greens, cookedFDA Total Diet Study	6 collection regions2017–2020	median.

Shared dataset methods and interpretation

Source summaries retain their original statistic, material, basis and censoring. Each source drawer identifies methods and overlapping samples. No matched reference or pooled distribution is inferred.

HMI collard greens Pb reference · Collard greens, cooked

Reference and scope

HMI collard greens Pb reference · Collard greens, cooked. Collard greens, cooked; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	≤4	≤4	≤4
Alternative weighting	≤4	≤4	≤4

27 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
FDA Total Diet Study	27	100%

Methods

HMI pools subgroup medians for collard greens, cooked on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

FDA Total Diet Study is the only compatible sampling family for collard greens, cooked on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

FDA Total Diet Study

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-b65c51c9e880:65e806b80788

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens Pb reference · Collard greens, as sold

Reference and scope

HMI collard greens Pb reference · Collard greens, as sold. Collard greens, as sold; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	≤7	≤7	5.5–8 (bounded)
Alternative weighting	≤7	≤7	5.5–8 (bounded)

19 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
WHO GEMS/Food	19	100%

Methods

HMI pools subgroup medians for collard greens, as sold on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

WHO GEMS/Food is the only compatible sampling family for collard greens, as sold on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

WHO GEMS/Food

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-4ada02ee712f:0fd12c12945a

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens Cd reference · Collard greens, cooked

Reference and scope

HMI collard greens Cd reference · Collard greens, cooked. Collard greens, cooked; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	16	22	34
Alternative weighting	16	21	34

27 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
FDA Total Diet Study	27	100%

Methods

HMI pools subgroup medians for collard greens, cooked on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

FDA Total Diet Study is the only compatible sampling family for collard greens, cooked on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

FDA Total Diet Study

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-49f8aa81b8c9:49aeb242c266

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens Cd reference · Collard greens, as sold

Reference and scope

HMI collard greens Cd reference · Collard greens, as sold. Collard greens, as sold; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	26	27	30.5
Alternative weighting	26	27	30.5

15 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
WHO GEMS/Food	15	100%

Methods

HMI pools subgroup medians for collard greens, as sold on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

WHO GEMS/Food is the only compatible sampling family for collard greens, as sold on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

WHO GEMS/Food

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-ee86fe60c445:b52956e6bc3a

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens tAs reference · Collard greens, cooked

Reference and scope

HMI collard greens tAs reference · Collard greens, cooked. Collard greens, cooked; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	≤3	≤3	3.9
Alternative weighting	≤3	≤3	3.6

27 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
FDA Total Diet Study	27	100%

Methods

HMI pools subgroup medians for collard greens, cooked on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

FDA Total Diet Study is the only compatible sampling family for collard greens, cooked on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

FDA Total Diet Study

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-48b9567c639f:7f3296ef4c4e

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens tAs reference · Collard greens, as sold

Reference and scope

HMI collard greens tAs reference · Collard greens, as sold. Collard greens, as sold; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	≤2.5	≤2.5	≤2.5
Alternative weighting	≤2.5	≤2.5	≤2.5

1 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
WHO GEMS/Food	1	100%

Methods

HMI pools subgroup medians for collard greens, as sold on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

WHO GEMS/Food is the only compatible sampling family for collard greens, as sold on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

WHO GEMS/Food

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-3e3f01b97e56:64841b0c94f8

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens tHg reference · Collard greens, cooked

Reference and scope

HMI collard greens tHg reference · Collard greens, cooked. Collard greens, cooked; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	≤1	≤1	1
Alternative weighting	≤1	≤1	1

27 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
FDA Total Diet Study	27	100%

Methods

HMI pools subgroup medians for collard greens, cooked on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

FDA Total Diet Study is the only compatible sampling family for collard greens, cooked on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

FDA Total Diet Study

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-ad5858444896:da4886c8fcc6

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens Ni reference · Collard greens, cooked

Reference and scope

HMI collard greens Ni reference · Collard greens, cooked. Collard greens, cooked; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	≤40	≤40	≤40
Alternative weighting	≤40	≤40	≤40

27 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
FDA Total Diet Study	27	100%

Methods

HMI pools subgroup medians for collard greens, cooked on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

FDA Total Diet Study is the only compatible sampling family for collard greens, cooked on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

FDA Total Diet Study

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-f6b2e4776ad9:6602e74b6a6f

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens Cr reference · Collard greens, cooked

Reference and scope

HMI collard greens Cr reference · Collard greens, cooked. Collard greens, cooked; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	≤50	≤50	≤50
Alternative weighting	≤50	≤50	≤50

27 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
FDA Total Diet Study	27	100%

Methods

HMI pools subgroup medians for collard greens, cooked on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

FDA Total Diet Study is the only compatible sampling family for collard greens, cooked on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

FDA Total Diet Study

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-0ab0291414b1:fc4d873f1100

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

HMI collard greens U reference · Collard greens, cooked

Reference and scope

HMI collard greens U reference · Collard greens, cooked. Collard greens, cooked; As sold, as eaten or fresh weight, µg/kg; no moisture conversion. Distribution of subgroup median concentration values.

Reference (µg/kg)	Q1	Median	Q3
Primary HMI reference	≤1	≤1	1.3
Alternative weighting	≤1	≤1	1.2

27 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing family	Reference units	Weight
FDA Total Diet Study	27	100%

Methods

HMI pools subgroup medians for collard greens, cooked on a as sold, as eaten or fresh weight basis: monitoring results summarized as one median per reporting region, sampling type and collection year, total diet composites and printed sample values as single observations, and printed subgroup medians from ordinary farms or markets. Each sampling family has equal total weight. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Other forms, other bases, targeted sampling and results from mining, industrial, wastewater-affected, experimental, fertiliser or manufacturer settings are kept out of this reference.

Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1 to Q3 spread are required. This is a display eligibility rule, not statistical validation.

Limitations

FDA Total Diet Study is the only compatible sampling family for collard greens, cooked on this basis in the completed collard greens ledger, so this single-family reference cannot represent other markets. Reporting regions and purchase markets are not growing areas. Non-detects with differing limits widen the bounds. A position is descriptive concentration, not a safety or compliance judgment.

Admitted source families

FDA Total Diet Study

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:collard-greens-4571c7e579b0:85121c52f529

The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.

How metals reach collard greens

No study in the library compared collard greens from contaminated and ordinary settings, so the routes by which metals reach it are not measured here.

Which forms and regions measured lower

For cadmium, the HMI reference median was lowest for collard greens, cooked (22 µg/kg) and highest for collard greens, as sold (27 µg/kg); forms differ in water content, so this compares foods as sold or eaten, not uptake.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →} The HMI reference for lead in collard greens, cooked pools 27 subgroup units from 1 sampling family, with a median of below 4 µg/kg and a middle half spanning below 4 (lower quartile) and below 4 µg/kg (upper quartile).^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →} For lead in collard greens, as sold, the reference median was below 7 µg/kg, with a middle half from below 7 to between 5.5 and 8 µg/kg across 19 units.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →} For cadmium in collard greens, cooked, the reference median was 22 µg/kg, with a middle half from 16 to 34 µg/kg across 27 units.^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}

Processing, cooking and preparation

No processing study for metals in this food is in the library yet.

Mitigation for collard greens

Lot testing against the applicable limit is the check that can be verified.

No measured way to lower metals in this food is in the library yet.

Trade-offs and limits of controls

Metals do not move together, so a lot that passes a lead limit says little about cadmium, arsenic or nickel unless those are tested as well.

Testing collard greens for metals

Results depend on the method and its reporting limit. Reporting limits for lead ranged from 3 µg/kg (WHO GEMS/Food) to 3,000 µg/kg (WHO GEMS/Food), so a non-detect from a less sensitive method says much less.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →} Reporting limits for cadmium ranged from 1 µg/kg (FDA Total Diet Study) to 2 µg/kg (WHO GEMS/Food), so a non-detect from a less sensitive method says much less.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →} Reporting limits for total arsenic ranged from 2.5 µg/kg (WHO GEMS/Food) to 3 µg/kg (FDA Total Diet Study), so a non-detect from a less sensitive method says much less.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}

A useful lot result names the form, the basis and a quantification limit well below the limit that applies.

Buying and verifying collard greens

No maximum level for metals in collard greens was verified from primary text for this page; buyers should confirm the limit that applies in the destination market.

Exposure from collard greens

No source in the library converted collard greens concentrations into a verified estimate of intake for a defined population. Concentrations describe the food, not individual risk.

Evidence review and remaining gaps

Every source record that names collard greens was decided on its content: 3 occurrence extracted, 3 records in all. The occurrence table renders every extracted result; held values remain visible with their reason.

References identify the sources used in these answers. The Sources index preserves additional discovery links; inclusion there does not mean a source has been reviewed for this assessment. Corrections, completed searches, new direct evidence and changes in requirements should reopen the relevant answer.

Collard greens FAQs

What heavy metals are found in collard greens?

The library reports lead, cadmium, total arsenic, total mercury, nickel, chromium and uranium in collard greens, most often lead, cadmium and total arsenic.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}^{3Spungen JH, et al. · 2024Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Food Additives & Contaminants: Part ARead source →} WHO GEMS/Food submissions reported lead in collard greens, as sold from 70 results in 1 reporting region, with subgroup medians below 7 µg/kg, mostly non-detects.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}

Which types of collard greens have the lowest levels?

For cadmium, the HMI reference median was lowest for collard greens, cooked (22 µg/kg) and highest for collard greens, as sold (27 µg/kg); forms differ in water content, so this compares foods as sold or eaten, not uptake.^{1World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}^{2U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →}

References

Works cited on this page, in citation-number order. See Sources for this page’s source inventory. Each title links to a source record with bibliographic details, reported findings, and document provenance.

GEMS/Food Contaminants database heavy-metal exportsWorld Health Organization · GEMS/Food Contamination Monitoring and Assessment Programme · 2026 · extranet.who.intDataset
FY2018-FY2020 TDS Elements Analytical ResultsU.S. Food and Drug Administration · FDA Total Diet Study · 2022 · www.fda.govDataset
Infants’ and young children’s dietary exposures to lead and cadmium: FDA total diet study 2018-2020Spungen JH and et al. · Food Additives & Contaminants: Part A · 2024 · doi.org/10.1080/19440049.2024.2396910Peer-reviewed

Sources

Browse Collard greens Sources for sources cited on this page and additional discovery candidates. The searchable index distinguishes verified citation use from discovery relationships whose relevance has not been established.

Update history

22 October 2026: Rebuilt from every collard greens record in the library: 3 occurrence sources, references by form and basis, same-study contrasts.

Referenced by

Vegetables

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1

2

Food and Drug Administration

3

Food Additives

Heavy metals in Collard greens

Collard greens overview

What counts as collard greens

Heavy metal contamination profile of collard greens

How metals reach collard greens

Which forms and regions measured lower

Processing, cooking and preparation

Mitigation for collard greens

Trade-offs and limits of controls

Testing collard greens for metals

Buying and verifying collard greens

Exposure from collard greens

Evidence review and remaining gaps

Collard greens FAQs

References

Sources

Update history

Related ingredients

Referenced by

Graph View