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Shannon Murphy, Ph.D. [email protected] Office of Environmental Health Hazard Assessment California Environmental Protection Agency Delta Tributaries Mercury Council September 13, 2016

Shannon Murphy, Ph.D. [email protected]€¦ · May effect nervous system development in ... Evaluate and select available fish contaminant data from a water body. ... Calculate

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Shannon Murphy, Ph.D.

[email protected]

Office of Environmental Health Hazard Assessment California Environmental Protection Agency

Delta Tributaries Mercury Council

September 13, 2016

OEHHA mandate

Chemicals of concern and health risks

Health benefits of eating fish

Advisory development process

Recent OEHHA advisories

Hg, PCBs

OEHHA Fish Advisory Program

California Health and Safety Code

Section 59009, to protect public health

Section 59011, to advise local health authorities

California Water Code

Section 13177.5, to issue health advisories

www.oehha.ca.gov/fish/advisories

Chemicals of Concern and Health Risks

Hg, PCBs

Pictures from California Geological Survey and USGS

Mining, fossil fuels, volcanoes Industrial lubricants

Legacy pesticides

Discharges into sewer systems and waterways

Flame retardants

The Risks of Mercury in Fish…

Hg, PCBs

Hg, PCBs

Why is Mercury in Fish a Concern?

Fish consumption is the major source of mercury exposure for most people

Almost all fish contain some mercury

Hg, PCBs

Mercury can change forms:

Mercury can be methylated to form MeHg in certain aquatic environments

Methylmercury (MeHg)* is the more toxic and most common form of mercury found in fish

Hg+CH3 (mercury + methyl)

*MeHg and mercury will be used interchangeably in this presentation

Hg, PCBs

Are mercury levels different in different fish species?

Predator fish have more mercury than prey fish; Older fish have more mercury than younger fish

Hg, PCBs

…The brain is target organ of methylmercury toxicity

Adults with high exposures reported:

• Mental confusion • Loss of balance • Irritability • Fine tremors • Numbness and tingling • Changes in vision

Hg, PCBs

…The fetus is more sensitive to the effects of methylmercury than adults

Passes through the placenta to

the baby

MeHg = methylmercury

Hg, PCBs

…Children are also more sensitive than adults

The developing nervous system is more sensitive to toxins, including methylmercury, than adults

Effects occur at lower exposures in the fetus and children than in adults

Hg, PCBs

How do we determine a safe level of mercury exposure?

Several large studies conducted on children in seaf00d-eating populations

Faroe Islands, Seychelles Islands, New Zealand

Identify lowest dose with an adverse effect

Hg, PCBs

How is this information used to set safe exposure levels?

USEPA sets something called an oral reference dose (RfD):

An estimate of a how much of a chemical people can be exposed to every day over their entire lives without significant risk of getting sick as a result Includes sensitive individuals

Incorporates uncertainty factors to account for incomplete data and individual variability (for MeHg, UF = 10)

Hg, PCBs

MeHg Reference Dose (RfD)

The newer RfD was set to protect the fetus and young children

The original RfD was based on effects in adults and is 3 times higher (i.e., adults are 3 times less sensitive)

Hg, PCBs

OEHHA uses the RfD:

To recommend the maximum number of fish servings to eat each week at a location

OEHHA uses the MeHg RfD to make fish consumption recommendations for women 18-45 years and children 1-17 years

OEHHA uses the original RfD to make fish consumption recommendations for women 46 years and older and men 18 years and older

Hg, PCBs

The Risks of PCBs and other contaminants in Fish…

Hg, PCBs

Why are PCBs and Pesticides in Fish a Concern?

PCBs and legacy pesticides (chlordanes, DDTs, dieldrin, toxaphene) do not break down easily

Bioaccumulate in fish

May effect nervous system development in fetuses or children

Some of these chemicals have caused cancer in animals

Emerging concern: PBDEs can be developmental and reproductive toxicants

Hg, PCBs

Can warning people about contaminants in fish have unintended negative consequences?

2007 National Report: “Seafood Choices: Balancing Benefits and Risks”

State fish advisory “warnings can change perceptions and beliefs….

….but unintended effects, such as overreactions, may occur”

Hg, PCBs

The Benefits of Omega-3s in Fish…

What are “Omega-3s”

A specific type of polyunsaturated fat

ALA – shorter compound

DHA and EPA – longer compound

Research has shown “omega-3s” to have beneficial effects on the heart

Major Dietary Omega-3s

ALA (Plant-based)

Flaxseed Oil

Walnuts

Canola

DHA

Fish oil

Breast milk

EPA

Fish oil

Beneficial effects on the heart:

Lower risk of abnormal heart beats

Lower triglyceride levels

Slowed growth of plaque in the arteries

Slightly lower blood pressure

What about the benefits of fish consumption during pregnancy?

Benefits the developing nervous system in the fetus

Not yet well understood whether the benefits of fish consumption during pregnancy are:

solely the result of omega-3s in fish or

due to some combination of nutrients that may include omega-3s

FDA/USEPA, 2014

Fish you can catch in California that have higher omega-3 levels

Salmon

Rainbow trout

Brown trout*

Steelhead

Shad

Bass* – largemouth, smallmouth, striped

*May contain high levels of MeHg – check statewide or local advisories

Mercury PCBs, Pesticides “Omega-3s”

What’s a person to do

www.oehha.ca.gov/fish/advisories

Historic Gold and

Mercury Mines

in California

Source for Gold and Mercury Mines data: U.S. Geological Survey (USGS). 1998. Minerals Availability System (MAS/MILS database). By J. Douglas Causey. USGS, Denver, CO.

Altoona Mine

OEHHA Fish Advisories

Mercury is the primary driver in 97% of CA

advisories.

OEHHA’s Approach to Advisories

OEHHA, 2008 and 2011

Data Evaluation

Evaluate and select available fish contaminant data from a water body.

Ensure that data meets quality criteria and sampling plan guidelines.

Select Species

Determine fish species for which adequate data are available to issue advice.

Calculations

Calculate appropriate measure of central tendency (often weighted mean), and descriptive stats of contaminant data for chemicals of potential concern for selected species.

OEHHA’s Approach to Advisories (continued)

OEHHA, 2008 and 2011

Advisory Tissue Levels (ATLs)

Compare chemical concentrations with ATLs for each chemical of potential concern; evaluate Hazard Indexes for potential exposure to multiple chemicals for the sensitive population.

Develop Advice

Develop advice based on thorough data review and best professional judgement; consider local/cultural practices and regulations (legal fish size or take), local fishing pressure, geography/access and environmental justice factors.

Advisory Tissue Levels (ATLs)

ATLs- acceptable chemical levels in fish tissue, based on chemical toxicity across a range of consumption rates

Not “bright lines”

Part of a complex process of data evaluation and interpretation

Builds on Fish Contaminant Goals (FCGs-do not consider benefits)

Incorporates benefits and risks

Considers the sensitive population (MeHg)

OEHHA, 2008 and 2011

Data Sources

CEDEN: California Environmental Data Exchange

Network

USGS studies

UC Davis studies

SWRCB and Regional Board efforts

FERC: Federal Energy Regulatory Commission

Licensing bioaccumulation studies

Sampling Plan Criteria (Minimum)

3 target species

9 individuals/species (legal/edible size)

3+ collection sites, depending on water body size

Seasonal - avoid collection during spawning

Collect during typical fishing season for target species

OEHHA, 2005

Data Criteria (Minimum)

Appropriate sample handling and processing

chain of custody

Skinless fillets or eviscerated whole bodies (prey fish)

QA/QC verification and appropriate methods used

Report moisture and lipid concentrations

Results expressed as wet weight (preferred)

OEHHA, 2005

New Fish Advisories 2015-2016 Water Body Chemical Driver Species

Lake Piru (Ventura County)

Mercury Black Bass, Brown Bullhead, Sunfish

Shadow Cliffs Lake (Alameda County)

Mercury, PCBs Black Bass, Carp, Catfish, Sunfish

Lexington Reservoir (Santa Clara County)

Mercury

Black Bass, Inland Silverside, Rainbow Trout, Sunfish, Threadfin Shad

French Meadows Reservoir

(Placer County)

Mercury

Brown Trout, Rainbow Trout, Crayfish

Hell Hole Reservoir (Placer County)

Mercury

Brown Trout, Crayfish, Kokanee, Lake Trout

Elkhorn Slough (Monterey County)

Mercury, PCBs

Asian Clam (Corbicula), Bat Ray, Leopard Shark, Speckled Sanddab,

Surfperch

New Fish Advisories

OEHHA Collaborators

SWRCB and Regional Boards CDPH

SWAMP CDFW

BOG UC Davis

Delta MERP DTMC

Visit us at www.oehha.ca.gov/fish

MeHg, PCBs

Conclusion:

Fish*

*Fish and shellfish

Eat Fish, Choose Wisely (higher DHA+EPA, lower MeHg and PCBs)