Assess and predict food and drinking water safety 9/11/19 - - PowerPoint PPT Presentation

Re Results from N7: Assess and predict food and drinking water safety

Presented By: Brian Laird, University of Waterloo Kelly Skinner, University of Waterloo Pieter Aukes, University of Waterloo

9/11/19

Traditional Food Consumption Notices in the NWT: Mercury and Cadmium

• Elevated levels of contaminants sometimes seen in traditional foods
• Cd: up to 94 mg/kg ww in moose’s kidney (Larter et al., 2018)
• Hg: to 3.1 μg/g ww (Laird et al., 2018)
• GNWT responsible for issuing consumption notices when

contaminant levels may pose health risks

• Moose: organ specific, location specific
• Fish: species, lake, length specific + group at risk

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“But what do these results mean for our health?”

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§ Contaminant biomonitoring to better answer that

question.

§ Consultation process of up to 18 months before the

implementation.

§ Design according to the local concerns (sampling, types of

contaminants, working with co-located researchers, etc.)

Consultation Sample Collection Questionnaires Chemical Analysis Communication & Follow Up

By the numbers….

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+300 person-days in the field 537 participants 917 samples collected: 443 hair, 276

blood, 198 urine

523 questionnaires completed: 237

FFQ, 199 24h recall, 87 risk perception

111 biomarkers: 23 metals, 49 POPs,

cotinine, 19 PAHs, 13 phthalates, 5 arsenic species, 2 n-3 PUFA

Levels♠, Determinants♣, and Sources♦:

♠ ♣ ♦: Mercury; PAHs; Cadmium ♠ ♣ Lead, ♠ Manganese, Arsenic; Many More

Select Findings So Far:

• Although fish mercury levels are

sometimes elevated, overall exposures to mercury have remained low.

• Cadmium and PAH exposures more

strongly linked with smoking than food consumption

Biomonitoring: Lead

• Average levels appeared similar-to-higher than reported in the CHMS or FNBI.
• < 2% of participants had BLL over health based guidance values (e.g., 100 μg/L for the general

population; 50 μg/L for susceptible subpopulations).

• Significant regional differences in Pb biomarkers.

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Lead Mackenzie Valley 2016-2018 CHMS(2) 2009-2011 FNBI 2010-2012 DR (%) GM 95th centile GM 95th centile GM 95th centile Blood (n=276) (μg/L) 100 16 70 13 32 12 33 Urine (n=198) (μg/L) 99. 0.59 4.0 0.52 1.9 0.51 2.3 (μg/g creat.) 0.69 3.8 0.48 1.6 0.56 2.2

Health Health and and Ris isk Communic unicatio tion n in in th the e Sa Sahtú an and De Dehch cho re regions

Health Messages Survey (n=87)

3 Terminology Workshops

Community Interviews (n=12)

Stakeholder Interviews (n=7)

6 communities 2 communities 1 community Yellowknife

Health Messages Survey

Co Country F y Foods Co Consumption P Patterns a and Pr Preferences

• 99% reported consuming country

foods

• 38% overall preferred to eat only

country foods rather than store- bought or a mix of both

• 45% Females; 29% males
• 49% Sahtú; 27% Dehcho

Health Messages Survey

Awareness of Co Consumption Notices

Male (%) Female (%) Dehcho (%) Sahtú (%)

Overall (%)

Consumption Notices/Advisories (n=87) Have you heard any advisories or messages about fish that had high levels

• f mercury?

66 73 68 72

70

Have you heard any advisories or messages about moose with high levels

• f cadmium?

26 16 25 21

21

Health Messages Survey

Sources of Co Consumption Notices/Advisories

Fish and Mercury Advisories – Where or who did you hear that from? (n=35) Male (%) Female (%) Dehcho (%) Sahtú (%)

Overall (%)

a Researcher or Scientist 52 50 53 48

51

the Radio 44 47 43 48

48

Friends 44 47 53 39

46

Health Messages Survey

Behavioural Ch Changes from Co Consumption Notices

Since hearing the messages about fish and mercury (n=59)*: Male (%) Female (%) Dehcho (%) Sahtú (%)

Overall (%)

I am more concerned about the fish I eat 46 42 43 45

42

In general, I have decreased the amount of fish I eat 32 35 37 31

34

I have reduced my consumption of only some kinds of fish (e.g. whitefish, trout) that I eat 29 21 32 17

24

I have changed the location where I usually fish 29 15 21 21

20**

I eat smaller fish 21 12 21 10

15

I eat less predatory fish (examples of predatory fish are walleye, lake trout or northern pike) 13 6 15 3

8

*Results are reported for those who chose Strongly Agree or Agree. **Statistically significant association with lower mercury concentration in hair (p=0.03)

Dis Dissolv lved O Organ anic M ic Matter & & Dr Drin inkin ing W Water

Dissolved Organic Matter (DOM)

• Heterogeneous mixture of organic molecules
• Comprised mainly of C
• Influences aquatic health & drinking water quality
• Freshwater concentrations increasing in Northern hemisphere

Disinfection By-Products (DBP)

• Chlorine added as disinfectant
• Amount needed generally based on [DOM]
• More DOM ~ more chlorine needed
• Reacts with organic matter to form harmful disinfection by-products (DBP)
• Reactivity à DOM amount and composition

Dis Dissolv lved O Organ anic ic Ma Matter ( r (DOM) M) in in th the e NWT

Wide range in the amount of DOM

• Large differences in concentration across small

spatial scale

• i.e: Yellowknife (YK) subsurface vs YK lake

Not all DOM is the same

• High [DOM] with large components found from YK

subsurface

• Creeks and rivers contain lower concentrations of

small DOM components

Dr Drin inkin ing W Water T Treatment & & DO DOM

Differences in the ratio

• Relationship with overall amount of DOM is

not linear

• Other factors must control chlorine

consumption Need to better predict this to effectively treat water with changes to DOM

DB DBP & & DO DOM in in t the NW NWT

• Untreated water samples
• Higher THM than HAA concentrations
• Larger, more terrestrial-like DOM forms

higher concentrations of DBP

• Increased permafrost thaw + increases to

terrestrial DOM observed in other circumpolar nations

• Complicates drinking water treatment options

in the NWT

Thank You; Mahsi Cho; Merci

• All communities and participants
• Mylene Ratelle, Heidi Swanson
• Students and staff
• Danielle Brandow, Leicester Fung, Sara Packull-McCormick, Aaron Tang, Jean Napenas,

Christina Lam, Victoria Leger

• GNWT Dept of Health and Social Services
• Community and Regional Partners
• Collaborators, co-investigators,
• And many more…..

Funding and support from: NCP, NWF, Health Canada, NSERC, School of Public Health and Health Systems, University of Waterloo