DOI: 10.5061/dryad.cnp5hqcbh
title: Tracking gold mining derived mercury pollution into human diets in the Madre de Dios region of Peru

description: Artisanal and small-scale gold mining (ASGM) is the largest global
 anthropogenic mercury (Hg) source and is widespread in the Peruvian
 Amazon. While numerous studies have examined fish Hg content near ASGM, Hg
 accumulation in other commonly consumed animal- and plant-based foods from
 terrestrial environments is often overlooked. These data were collected in
 2018 and 2019 to understand Hg exposure from food staples in Peru's
 Madre de Dios region. This dataset contains measurements of total Hg and
 methyl Hg content in locally sourced crops, fish, chicken meat, chicken
 feathers, and eggs from ASGM-impacted and upstream reference communities.
 Stable carbon and nitrogen isotope signatures from fish and chicken were
 also measured to characterize trophic position and magnification.
description: All data were collected from the Madre de Dios region of the
 Peruvian Amazon. Sampling sites are described in <em>Marchese et
 al.</em> (2024), and coordinates can be found in the data file
 entitled "Site.coordinates.csv". Sampling,
 laboratory analysis, and quality control methodology are presented in
 <em>Marchese et al.</em> (2024). In brief, we collected crops,
 fish muscle, chicken meat, chicken eggs, and chicken feathers from areas
 heavily and minimally impacted by mining. The data were used to determine
 how geogenic and anthropogenic Hg accumulates in terrestrial and aquatic
 organisms that serve as regional food staples. Samples were collected
 during June through August in 2018 and 2019. These data are predominantly
 comprised of total Hg measurements for crops, chicken, and fish plus
 methyl Hg for crops and chicken. Stable carbon and nitrogen isotope data
 are presented for chicken feathers and fish tissue. Survey data from
 individuals who contributed chicken samples to the study are included.
 Coordinates for each community from which samples were obtained can be
 found in the .csv files. The following is an excerpt
 describing sample collection, laboratory analysis, and quality control in
 crops, chicken muscle/organs, chicken feathers, chicken eggs, and fish
 muscle, as reported in <em>Marchese et al.</em>
 (2024): <em>"F</em><em>ifty crop
 samples were collected in seventeen Madre de Dios communities from June to
 August 2018. We purchased crops from every community we passed while
 traveling 200km by boat along the Madre de Dios River from Shipetiari to
 Laberinto. Crops were purchased from markets after vendors confirmed they
 were grown locally. Crop samples were washed with ultrapure water, placed
 in individual plastic bags, and stored in a freezer. They were transported
 frozen and stored </em><em>at -20 °C upon arrival to Duke
 University (Durham, NC, USA) </em><em>until lyophilization and
 grinding. </em> <em>Fish samples
 represented a variety of species, trophic levels, and origins. Fifteen
 locally accessible and commonly consumed species were selected. From June
 to August 2018, we purchased 98 fish samples from aquaculture farms,
 markets, and fishermen in eight Madre de Dios communities. River-caught,
 locally farmed, and imported ocean fish were
 collected. </em> <em>Sourcing fish from
 sellers rather than the river directly ensures the samples appropriately
 represent available foods and differentiates these data from prior
 regional studies </em>(Diringer et al., 2015; Martinez et al., 2018;
 Roach et al., 2013)<em>. Fish species and their origins were
 identified by vendors and confirmed using the Instituto de Investigaciones
 de la Amazonía Peruana (IIAP, Institute for Investigations of the Peruvian
 Amazon) guide to regional fish</em>(García et al., 2018)<em>.
 Since the whole fish was available for purchase in most cases, total
 length (mouth to tail) and standard length (mouth to last vertebra,
 excluding tail) were measured. Next, small muscle filets (&lt;5g fresh
 weight) were placed in plastic bags, stored in a cooler with ice packs,
 and transferred to a Credo Cube Series 20M during the remaining fieldwork.
 Samples were transported frozen to Duke University, skin was removed, and
 samples were stored </em><em>at -20 °C</em><em>
 until lyophilization and grinding. Fish samples were weighed before and
 after drying. Moisture content was calculated as
 follows:</em> <em>% moisture =   (fresh
 weight-dry weight )/(fresh weight)  *100</em>
 <em>From July to August 2019, we sampled feathers (n=38),
 eggs (n=16), and meat (n=8) from backyard chickens raised in a
 mining-impacted community (Boca Colorado) and an upstream community (Boca
 Manu). Fifteen commonly consumed chicken cuts were collected (liver, skin,
 leg, breast, intestine, gizzard, tail, back, thigh, neck, wing, heart,
 spleen, feet, fat). Multiple feathers were collected from the breast and
 back of each chicken. All internal tissue and feather samples were rinsed
 with ultrapure water, placed in individual plastic bags, and stored on dry
 ice inside a Credo Cube Series 20M until lyophilization at the IIAP
 Laboratorio de Mercurio y Química Ambiental (Mercury and Environmental
 Chemistry Laboratory, Madre de Dios). Lyophilized samples were transported
 to Duke University for analysis.</em>
 <em>Surveys were performed during the Boca Manu and Boca
 Colorado chicken sample collections. Consenting participants were asked
 about their primary protein sources and how frequently they consume
 different chicken cuts. Participants who raised chickens were asked about
 their chickens' living conditions and diets.</em>
 <em>Institutional Review Boards at Duke University
 (#2019-0530) and the University of Peru Cayetano Heredia (chicken:
 #104284) provided ethical clearance for this project. All participants
 provided verbal consent in the chicken collection survey. Survey data were
 deidentified for analysis. The Duke University Animal Care and Use
 Committee approved field methods involving live animals
 (#A161-19-07).</em> <em>Total Hg content of
 dried, homogenized crop and fish muscle tissue was measured at Duke
 University via thermal decomposition, amalgamation, and atomic absorption
 spectrophotometry (EPA method 7473) on a Milestone Direct Mercury Analyzer
 (DMA-80) per methodology in Gerson et al.</em>(Gerson et al.,
 2018)<em>. Samples were run in duplicate, and the average result was
 used for data analysis. If the relative percent difference (RPD) exceeded
 10% between the two sample runs, samples were rerun in duplicate.
 Instrument calibration was performed using the Brooks Rand Instruments
 Total Mercury Standard (1.0 ng/L). Continuous calibration verification
 (CCV), quality control standard (QCS), matrix spikes (MS), and blank
 measurements were performed after every tenth sample. Standard reference
 materials for crops, NIST 1633c (coal fly ash) and NIST 2709a (San Joaquin
 Soil), had percent recoveries of 95% ± 3% SD (n= 39) and 94% ± 3% SD
 (n=8), respectively. Blanks contained &lt;0.0037 mg/kg total Hg.
 Standard reference materials for fish tissue, NIST 1633c (coal fly ash)
 and DORM-4 (fish protein), had percent recoveries of 96% ± 3% SD (n=52)
 and 91% ± 7% SD (n=27), respectively. All blanks contained &lt;0.0023
 mg/kg  [total Hg]. The instrument detection limit for fish and crop total
 Hg analysis was 0.5 ng Hg. For fish, dry-weight (dw) total Hg was
 converted to fresh-weight (fw) total Hg as follows:</em>
 <em>[total Hg fw]=([total Hg dw])/((sample dw)/(sample
 fw))</em> <em>Chicken tissues and feathers
 were analyzed at the Biodiversity Research Institute (Portland, ME, USA)
 for total Hg following EPA method 7473 on a Milestone DMA-80. Samples were
 run in duplicate and rerun if the RPD exceeded 15%. For quality control,
 empty sample boats (blank boats, n=7) and blanks (no boat or sample, n=19)
 were run to test for residual Hg in the analyzer and the sample boats,
 respectively. All blanks and blank boats returned &lt;0.002 mg/kg
 [total Hg]. Standard reference materials used for feathers and tissues
 were Dolt-5 (dogfish liver; 97% recovery ± 0.7 % SD, n=25) and CE 464
 (tuna fish; 99% recovery ± 2% SD, n=25). The instrument detection limit
 for internal chicken tissue, egg, and feather total Hg analysis was 0.003
 ng Hg.</em> <em>Crops and internal chicken
 tissues were analyzed for MeHg at Syracuse University (Syracuse, NY, USA)
 on a Tekran 2500 spectrometer per the biomass method in Gerson et
 al.</em>(Gerson et al., 2017)<em>. 20 mg samples were digested
 in glass vials using 3 mL potassium hydroxide (25% w/w) in methanol at
 55</em><em> °C</em><em> for 48h and frozen
 </em>(Hall and St. Louis, 2004; Hintelmann and Nguyen, 2005; Horvat
 et al., 1993)<em>. Following digestion, samples underwent
 </em><em>direct aqueous ethylation with sodium
 tetraethylborate, purge and trap, and cold vapor atomic fluorescence
 spectrometry (CVAFS, EPA Method 1630). Calibration, CCV, MS, ongoing
 precision recovery, method detection limit, and blank samples were
 incorporated into the run. Standard reference materials for chicken
 tissues were ERM-CE477 mussel tissue (butyltins; 109.1% recovery
 </em><em>± 3.54% SD, n=3), TORT-2 (lobster hepatopancreas;
 98.8% recovery ± 11.01% SD, n=4), and DORM-4 (fish protein; 104.1%
 recovery ± 6.15% SD, n=4). The method detection limit for chicken tissues
 was 0.0007 ng Hg, and all blanks had &lt;0.0006 mg/kg   [MeHg]. The
 method detection limit for crops was 0.002 ng MeHg, and all blanks had
 &lt;0.0056 mg/kg MeHg.</em> <em>MeHg is
 reported as absolute values and percent MeHg. For samples with detectable
 MeHg, percent MeHg is defined as follows:</em>
 <em>%MeHg=  ([MeHg dw])/([total Hg
 dw])×100</em> <em>Different instrument
 detection limits led to MeHg values higher than total Hg in some samples.
 To avoid skewed representations of MeHg proportions, all MeHg percentages
 exceeding 100% were rounded down to 100%.</em>
 <em>Stable carbon and nitrogen isotope analyses were
 performed on ground feather samples and dried fish muscle tissue at the
 University of California-Davis Stable Isotope Facility (SIF; Davis, CA,
 USA) and the Duke Environmental Stable Isotope (DEVIL) Laboratory (Durham,
 NC, USA), respectively. δ<sup>13</sup>C and
 δ<sup>15</sup>N signatures were determined via mass
 spectrometry using an Elementar Micro Cube elemental
 analyzer</em><em> </em><em>interfaced to a PDZ
 Europa 20-20 isotope ratio mass spectrometer for feather samples and two
 Thermo-Finnigan Delta Plus XL continuous flow mass spectrometer systems
 for fish muscle tissue. </em><em>For quality control, samples
 were interspersed with several replicates of internal laboratory
 standards, which were calibrated against international reference
 materials. δ<sup>13</sup>C and δ<sup>15</sup>N
 values were normalized to correct for changes in instrument environment,
 parameters, and gas drift.</em><em> Stable isotope ratios are
 expressed in δ notation in parts per thousand (‰) relative to Vienna
 PeeDee Belemnite standards for <sup>13</sup>C and atmospheric
 N<sub>2</sub> for <sup>15</sup>N, as follows:
 </em> <em>δX = [(R_sample-R_standard) - 1]
 * 1000 (‰)</em> <em>where X represents
 <sup>13</sup>C or <sup>15</sup>N and R is
 <sup>13</sup>C/<sup>12</sup>C or
 <sup>15</sup>N/<sup>14</sup>N."</em> <strong>References:</strong> Diringer, S.E., Feingold, B.J., Ortiz, E.J., Gallis, J.A., Araújo-Flores, J.M., Berky, A., Pan, W.K.Y., Hsu-Kim, H., 2015. River transport of mercury from artisanal and small-scale gold mining and risks for dietary mercury exposure in Madre de Dios, Peru. Environmental Sciences: Processes and Impacts 17, 478–487. https://doi.org/10.1039/c4em00567h García, C.R., Riveiro, H., Flores, M.A., Mejia de Loayza, J.E., Angulo, C.A.C., Castro, D., Estivals, G., García, A., Nolorbe, C., Dávila, G., Núñez, J., Mariac, C., Duponchelle, F., Renno, J.-F., 2018. Peces de consumo de la amazonía peruana. Gerson, J.R., Driscoll, C.T., Demers, J.D., Sauer, A.K., Blackwell, B.D., Montesdeoca, M.R., Shanley, J.B., Ross, D.S., 2017. Deposition of mercury in forests across a montane elevation gradient: Elevational and seasonal patterns in methylmercury inputs and production. J Geophys Res Biogeosci 122, 1922–1939. https://doi.org/10.1002/2016JG003721 Gerson, J.R., Driscoll, C.T., Hsu-Kim, H., Bernhardt, E.S., 2018. Senegalese artisanal gold mining leads to elevated total mercury and methylmercury concentrations in soils, sediments, and rivers. Elementa: Science of the Anthropocene 6. https://doi.org/10.1525/elementa.274 Hall, B.D., St. Louis, V.L., 2004. Methylmercury and Total Mercury in Plant Litter Decomposing in Upland Forests and Flooded Landscapes. Environ Sci Technol 38, 5010–5021. https://doi.org/10.1021/es049800q Hintelmann, H., Nguyen, H.T., 2005. Extraction of methylmercury from tissue and plant samples by acid leaching. Anal Bioanal Chem 381, 360–365. https://doi.org/10.1007/s00216-004-2878-5 Horvat, M., Bloom, N.S., Liang, L., 1993. Comparison of distillation with other current isolation methods for the determination of methyl mercury compounds in low level environmental samples. Anal Chim Acta 281, 135–152. https://doi.org/10.1016/0003-2670(93)85348-N Martinez, G., McCord, S.A., Driscoll, C.T., Todorova, S., Wu, S., Araújo, J.F., Vega, C.M., Fernandez, L.E., 2018. Mercury contamination in riverine sediments and fish associated with artisanal and small-scale gold mining in Madre de Dios, Peru. Int J Environ Res Public Health 15, 1–15. https://doi.org/10.3390/ijerph15081584 Roach, K.A., Jacobsen, N.F., Fiorello, C. V, Stronza, A., Winemiller, K.O., 2013. Gold Mining and Mercury Bioaccumulation in a Floodplain Lake and Main Channel of the Tambopata River, Perú. J Environ Prot (Irvine, Calif) 4, 51–60. https://doi.org/10.4236/jep.2013.41005  
description: # Tracking gold mining derived mercury pollution into human diets in the
 Madre de Dios region of Peru
 These files contain data
 from samples of crops, fish muscle, chicken meat, chicken eggs, and
 chicken feathers from areas both heavily and minimally impacted by
 artisanal and small-scale gold mining in the Madre de Dios region of the
 Peruvian Amazon. The data were used to determine how geogenic and
 anthropogenic Hg accumulates in terrestrial and aquatic organisms serving
 as local food staples. Samples were collected during June through August
 in 2018 and 2019. These data are predominantly comprised of total Hg
 measurements for crops, chicken, and fish plus methyl Hg for crops and
 chicken. Stable carbon and nitrogen isotope data are presented for chicken
 feathers and fish tissue. Survey data from individuals who contributed
 chicken samples to the study are included. Coordinates for each community
 from which samples were obtained can be found in the .csv files. ##
 Description of the data and file structure **A.   Dataset Identity**
 **Table 1** contains dataset identification information. All data are
 formatted as comma-separated value (.csv) files titled as described below.
 Please note that values of "BDL" imply that the value is below
 detection limit, and any values of "NM" signify that the
 parameter was not measured for that sample. **Table 1: Dataset
 identities** | **Data file name** | **Description** | **Size** | |
 :------------------- |
 :-------------------------------------------------------------------------------------------------------------- | :------- | | Crops.csv | Contains data for all crop samples used in the study | 2 kb | | Fish.csv | Contains data for all fish tissue samples used in the study | 11 kb | | Chicken.csv | Contains data for all chicken tissue samples used in the study | 10 kb | | Site.Coordinates.csv | Contains information on site type, latitude, and longitude for all crop, fish, and chicken samples in the study | 1 kb | | Chicken.Survey.csv | Contains data for all participants who raised chickens in the study | 431 kb | **B.    Variable information** Descriptions and information for variables in each data set are listed below. **Table 2: Crops.csv** | Attribute | Definition | | | :----------- | :---------------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Sample.ID | Identification used for laboratory analysis |   | | Sample.Type | Common name of crop sample collected |   | | Site | Community name in which each sample was collected |   | | Mining.Level | Level of gold mining (present or minimally present) in the community of sample collection |   | |   | **Value** | **Definition** | |   | Mining | Extensive mining and/or amalgam burning near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | |   | Minimal.Mining | Minimal observed or documented mining and/or amalgam burning activity near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | | THg.ug.kg | Total mercury measured in each sample in micrograms per kilogram (μg/kg) |   | **Table 3: Fish.csv** | **Attribute** | **Definition** | | | :-------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------ | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Sample.ID | Identification used for laboratory analysis |   | | Species | Common name of each fish sample collected |   | | Trophic.Level | Trophic level assigned to each fish species based on a literature review |   | | Site | Community name in which each sample was collected |   | | Purchase.Location | Setting within each community where each sample was purchased |   | |   | **Value** | **Definition** | |   | River | From a fisherman, caught in the nearby river | |   | Market | From a local vendor at the established market | |   | Meal | At a restaurant with a meal | |   | Feria | At an open-air market | |   | Household | From someone's house | |   | Canned | Canned from the store, not fresh | | Purchase.Mining.Level | Level of mining (present or minimally present) in the community of sample collection |   | |   | **Value** | **Definition** | |   | Mining | Extensive mining and/or amalgam burning near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | |   | Minimal.Mining | Minimal observed or documented mining and/or amalgam burning activity near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | | Fish.Origin | Setting from which fish originated based on conversations with individuals who provided samples to the study & known fishing practices by species |   | |   | **Value** | **Definition** | |   | River | The fish was caught in the river | |   | Farm | The fish was farmed | |   | Ocean | The fish was caught in the ocean | |   | Lake.River.Farm | The researchers and those who provided samples could not reliably differentiate if the fish came from a lake, river, or fish farm | | Origin.Mining.Level | Mining level in the area where the fish was farmed or caught |   | |   | **Value** | **Definition** | |   | Mining | Extensive mining and/or amalgam burning near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | |   | Minimal.Mining | Minimal observed or documented mining and/or amalgam burning activity near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | | Length.Tail.cm | Total body length of the fish from mouth to the end of the tail in centimeters |   | | Length.No.Tail.cm | Total body length of the fish from mouth to last vertebra (excluding tail) in centimeters |   | | Weight.g | Fresh weight of the fish sample in grams |   | | Percent.Moisture | Moisture content of each fish sample was calculated as follows: |   | | Thg.mg.kg.FW | Total mercury measured in each sample in milligrams per kilogram (mg/kg) on a fresh weight basis (fw) |   | | DN15 | Stable nitrogen isotope signatures of each fish sample |   | | DC13 | Stable carbon isotope signatures of each fish sample |   | **Table 4: Chicken.csv** | **Attribute** | **Definition** |   | | :------------ | :----------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Sample.ID | Identification used for laboratory analysis |   | | Sample.Type | Tissue type for each collected sample |   | | Site | Community name in which each sample was collected |   | | Mining.Level | Level of mining (present or minimally present) in the community of sample collection |   | |   | **Value** | **Definition** | |   | Mining | Extensive mining and/or amalgam burning near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | |   | Minimal.Mining | Minimal observed or documented mining and/or amalgam burning activity near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | | THg.ug.kg | Total mercury measured in each sample in micrograms per kilogram (μg/kg) |   | | DN15 | Stable nitrogen isotope signatures of each chicken feather sample |   | | DC13 | Stable carbon isotope signatures of each chicken feather sample |   | **Table 5: Site.Coordinates.csv** | **Attribute** | **Definition** |   | | :------------ | :----------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Study.Site | Community from which samples were collected |   | | Longitude | Longitude in decimal degrees |   | | Latitude | Latitude in decimal degrees |   | | Urban.Rural | Urban or rural classification of each community relative to the region |   | | Mining.Level | Level of mining (present or minimally present) in the community of sample collection |   | |   | **Value** | **Definition** | |   | Mining | Extensive mining and/or amalgam burning near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | |   | Minimal.Mining | Minimal observed or documented mining and/or amalgam burning activity near the community based on previously published maps, satellite imaging data, and observations of mining activity during sample collections | **Table 6: Chicken.Survey.csv** | **Attribute** | **Definition** |   | | :--------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | :------------------------------------------------------------------------------------------------------------------------------ | | Participant | Identification number associated with each survey participant |   | | Site | Community name in which each survey was performed |   | | Chicken.Source1 | Participant responses when asked, "When you eat chicken, where do you primarily obtain it from?" |   | |   | **Value** | **Definition** | |   | Raise.Own | Participants raise their own chickens | |   | Friend.Raises.Own | Participant gets chicken meat from someone they know locally who raises their own chickens | |   | Restaurant | Participant gets chicken from a restaurant | |   | Local.Vendor | Participant gets chicken from a local vendor (market) | | Chicken.Source2 | If a participant had multiple sources for their chicken meat, they specified where else they obtain it from |   | |   | **Value** | **Definition** | |   | Frozen.Imported | Participant's chicken arrives frozen from a different city | |   | Raise.Own | Participants raise their own chickens | |   | Friend.Raises.Own | Participant gets chicken meat from someone they know locally who raises their own chickens | |   | Restaurant | Participant gets chicken from a restaurant | |   | Local.Vendor | Participant gets chicken from a local vendor (market) | | Chicken.Source3 | If a participant had multiple sources for their chicken meat, they specified where else they obtain it from |   | |   | **Value** | **Definition** | |   | Friend.Raises.Own | In addition to 2 other sources, participant also gets chicken meat from someone they know locally who raises their own chickens | | Egg.Meals.Wk | Participants were asked, "How many meals per week do you consume eggs from locally raised chickens?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Eggs.Meal | Participants were asked, "When you eat eggs, how many eggs do you eat per meal on average?" |   | | Chk.Meals.Wk | Participants were asked, "How many meals per week do you consume meat from locally raised chicken (not frozen)?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Breast.Servings | Participants were asked, "How many servings of chicken breast do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Leg.Servings | Participants were asked, "How many chicken leg servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Wing.Servings | Participants were asked, "How many chicken wing servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Gizzard.Servings | Participants were asked, "How many chicken gizzard servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Heart.Servings | Participants were asked, "How many chicken heart servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Liver.Servings | Participants were asked, "How many chicken liver servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Intestine.Servings | Participants were asked, "How many chicken intestine servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Neck.Servings | Participants were asked, "How many chicken neck servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Tail.Servings | Participants were asked, "How many chicken tail servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Feet.Servings | Participants were asked, "How many chicken feet servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Back.Servings | Participants were asked, "How many chicken back servings do you eat per week?" If participants answered less than once per week, a monthly intake was recorded and divided by 4 to convert to a per-week basis. |   | | Skin.Yes.No | When you eat chicken meat, do you consume the skin? (yes/no) |   | | Primary.Protein.Source | What do you consider to be your primary protein source for most of the year? |   | |   | **Value** | **Definition** | |   | Fish |   | |   | Chicken |   | |   | Bush.Meat | Locally hunted meat (not chicken or fish) | |   | Seasonal | Seasonally dependent consumption of chicken and fish | | Chicken.Diet1 | Participants who raised chickens were asked, "What do you feed your chickens?" (select all that apply) |   | |   | **Value** | **Definition** | |   | Market.Corn | Participant feeds their chickens corn from the store/market, but they are unsure of the origin | |   | Local.Corn | Participant feeds their chickens corn that they believe is grown locally | | Chicken.Diet2 | If a participant had multiple sources of food for their chickens, they specified what else they feed their chickens |   | |   | **Value** | **Definition** | |   | Packaged.Feed | Participant gives their chickens prepackaged feed | |   | Food.Scraps | Participant gives their chicken leftovers/food scraps | | Chicken.Habitat | Participants described their chickens' environment and asked, "Where do your chickens live?" |   | |   | **Value** | **Definition** | |   | Outside.Day.Coop.Night | Chickens roam freely outside during the day and are secured in a coop at night | |   | Outdoor.Corral | Chickens remain in an outdoor corral | |   | Outside.Exclusively | Chickens are raised outside exclusively | | Chicken.Habitat2 | If a participant had multiple aspects to their chicken's environment, they are described here |   | |   | **Value** | **Definition** | |   | Coop | Chickens have free access to a coop in addition to the outdoor corral | |   | Outdoor.Corral | Chickens are corralled during the day |