Maine Coast Sea Vegetables

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Testing & Purity

Radioactivity Testing Results and Update

June 2017

For the 2016 harvest (products to be sold mostly in 2017), we again had samples of a selection of sea vegetables tested and the results are consistent with previous years, showing only background radioactivity. To see these most recent results, click here 2016 Harvest Results (173K PDF).

Since the tsunami and nuclear catastrophe at Fukushima, Japan, in March 2011, we have had samples of nearly all of our products tested for radioactivity. This includes samples from the 2011 harvest through the 2016 harvest. All results to date have shown only background radioactivity$(Ono(B evidence of fallout from Fuukushima. For example, there is a natural radioactive isotope of potassium (K-40) that is found in most if not all land and sea plants, as well as in seawater, soils, etc., and accounts for nearly all of the radioactivity observed in our seaweeds. See past results below.

2011 Harvest results Report dated June 2012 (37K PDF)

2012 Harvest results Report dated Oct. 2012) (61K PDF) and Report dated March 2013 (71K PDF)

2013 Harvest results Report dated March 2014 (176K PDF)

2014 Harvest results Report dated March 2015 (150K PDF)

2015 Harvest results Report dated June 2016 (150K PDF)

Going forward, we plan to continue testing samples of a selection of sea vegetables at least annually.

If you'd like more information about how our samples are tested, see a Letter from the UMaine lab (264K PDF), describing methods and equipment used, and details about Professor Thomas Hess, who runs the University of Maine lab. Feel free to contact us at with questions.

Here are links to resources on radioactivity we've found helpful:

Woods Hole Oceanographic Institution:
The ABCs of Radioactivity (plus associated links)

WHOI's Center for Marine and Environmental Radioactivity:
About Radiation
Our Radioactive Ocean

Health Physics Society: Geiger Counters and Sea Vegetables

US Food and Drug Administration:
Derived Intervention Levels for Radionuclides (PDF file)

Information Is Beautiful: Radiation Dosage Chart

Product Testing for Possible Contaminants

Report for Harvest Period 2016 (Products for 2017)

Why We Test
Although we harvest in remote areas of the Gulf of Maine, we cannot control the ocean currents. And although seaweeds have been consumed safely for centuries, we want to make sure there are no significant changes in a plant's analysis from season to season, particularly regarding trace metals.

When We Test
Microbiological testing is conducted throughout the year on a range of products, but most of our other tests are done with a sampling protocol after the harvest is completed at the end of the year. Therefore, the results in this report refer to plants/products that will be sold mostly in 2017.

What We TestWhat We Test For
  • Alaria granules (Alaria esculenta)
  • Alaria leaf (Alaria esculenta)
  • Bladderwrack granules (Fucus vesiculosus)
  • Dulse leaf (Palmaria palmata)
  • Dulse powder (Palmaria palmata)
  • Icelandic Kelp Blend (IKB) powder
  • Kelp leaf (Saccharina latissima)
  • Laver leaf (Porphyra umbilicalis)
  • Nori sheets, toasted (Pyropia yezoensis)
  • Rockweed granules (Ascophyllum nodosum)
  • Rockweed powder (Ascophyllum nodosum)
  • Sea Lettuce leaf (Ulva lactuca)
  • Pesticides
  • Herbicides
  • Petroleum Residues
  • PCBs
  • Heavy Metals
  • Microbiological Contaminants
  • Radioactivity (see above)

Who Does the Testing?
Our testing is performed or coordinated by Katahdin Analytical Services and Northeast Laboratory Services in Maine, and Brooks Applied Labs in Washington State, all certified and accredited laboratories. Our radioactivity testing is done at the University of Maine.

Northeast Laboratory Services
Katahdin Analytical Services
Brooks Applied Labs

General Notes on Product Testing
The seaweeds we harvest are wild, uncultivated marine algae. Specific analysis may vary from the above typical analysis. Naturally occurring fluctuations in the sea plants occur due to season, weather conditions, tidal flow and time of harvest. The information presented above is believed to be accurate and reliable, but represents averages and is not guaranteed as a condition of sale. Maine Coast Sea Vegetables makes no warranty, either express or implied, and assumes no liability for this information or the products described.

We believe that traditional whole foods such as seaweeds are well suited for nourishing human cells. Worldwide, seaweed is and has been consumed with healthy results. However, we are unable to predict your body's response. There may be elements of these plants not suitable for your particular biochemistry or condition. Only you can determine what's best for you, in consultation with your healthcare practitioner.

2016 Harvest Testing Results
  • Pesticides (21 compounds): None detected
  • Herbicides (10 compounds): N/A
  • Petroleum Residues (17 polycyclic aromatic hydrocarbons): N/A
  • PCBs (7 polychlorinated biphenyls): None detected
  • Heavy Metals (see table below)
  • Microbiological Contaminants (see table below)

Table of 2016 Results for Heavy Metal Testing

For more information on the presence of arsenic and other heavy metals in sea vegetables, see Trace Elements and Heavy Metals in Maine Coast Sea Vegetables as well as Sea Vegetables and Arsenic (78K PDF).

U = Undetected above method detection limit

ppm = parts per million, equivalent to micrograms per gram, or milligrams per kilogram

Arsenic (As)
Cadmium (Cd)
Lead (Pb)
Mercury (Hg)
ALARIA granules 0.051 2.02 0.116 U
ALARIA whole leaf 0.093 1.42 0.0548 U
BLADDERWRACK granules 0.442 0.707 1.26 0.0096
DULSE powder 0.048 0.529 0.374 U
DULSE whole leaf 0.023 0.409 0.0841 U
(IKB) powder
<3.0 <1.5 <3.0 <0.07
KELP whole leaf U 1.64 0.0515 U
LAVER whole leaf 0.015 3.62 0.216 U
NORI sheets (toasted) U 1.46 0.145 U
ROCKWEED powder 0.208 0.519 0.0854 0.0153
ROCKWEED granules 0.088 0.274 0.422 0.0121
SEA LETTUCE whole leaf 0.038 0.023 N/A U


Table of 2016 Results for Microbiological Contaminants

All results preceded by a < (less than) indicate that none were detected above the given limit of detection.
MPN/g = Most Probable Number per gram, and is a unit of microbial numbers in a sample.

ND = Not Detected

E. coli
Aerobic Count
ALARIA granules <100 ND <100 100
ALARIA whole leaf <100ND <100 <100
BLADDERWRACK granules <100 ND <100 1,500
DULSE powder <100 ND 330 12,000
DULSE whole leaf <100ND <100 1,600
(IKB) powder
<100 ND/25g <1,000<10,000
KELP whole leaf <100ND <100<100
LAVER whole leaf <100 ND 100 1,300
NORI sheets (toasted) <100ND <100 510
ROCKWEED powder <100ND 210 1,600
ROCKWEED granules <100 ND <100 100
SEA LETTUCE whole leaf <100 ND 100 <100


Trace Elements and Heavy Metals in
Maine Coast Sea Vegetables

The presence of certain elements in sea vegetables causes alarm to some consumers. The following information addresses those concerns. Critical to evaluating this issue are the following: what form are these elements in, in what amounts, bioavailability, and the historical, cultural, or epidemiological evidence. Because sea vegetables have often been as low on the scientific research priority list as they are on the food chain, at times we have to infer from studies of other food groups, as well as use our native intelligence and intuition.

Sea vegetables contain a wide array of major minerals and trace elements, including calcium, magnesium, phosphorus, chromium, lead, cadmium, aluminum, zinc, arsenic, and many more. Many of these, in the right quantities and forms (often "organic") are proven or estimated to be essential to human health. In the straight "inorganic" form and in excessive quantity, they can be toxic. Let's look at arsenic as an example.

Arsenic occurs in many forms in biological systems, but there are two basic types, inorganic and organic. Inorganic arsenic occurs naturally (20th most abundant element in the earth's crust), and has also been used in many industrial products such as pesticides, paint, and a host of manufactured chemical compounds. Inorganic arsenic is known to be toxic at substantial levels, causing skin lesions, organ damage, and promoting tumor growth, and, in acute overdose, is fatal. Organic arsenic is potentially found in all living organisms. Plants absorb the mineral from the soil (or in the case of sea vegetables, from the ocean) and transform it into one of many forms of organic arsenic, possibly as a way to detoxify the arsenic.

Animal studies have shown arsenic to be essential to heart and skeletal muscle function in goats, and beneficial in small amounts to a variety of laboratory animals. Recent work indicates that arsenic may have a role in methionine metabolism. Therefore, it is plausible to suggest that humans have an essential need for trace amounts of arsenic, at an estimated requirement of 12 to 50μg (micrograms) per day.

Scientists looking at Japanese sea vegetables and consumption habits concluded that eating seaweed provided on average about 100 to 150μg arsenosugars (a form of organic arsenic) per day.1 Even with this high intake, there are no reports that the Japanese population demonstrates symptoms of arsenic toxicity due to sea vegetables.

The same sort of reasoning often applies to other metals as well. They occur naturally; they are taken up and transformed by land or sea plants, and are utilized or excreted as needed by mammals and other animals. For example, aluminum is an abundant metallic element, about 8% of the earth's crust and in the organic form is commonly found in vegetation. Beans contain 20-250 ppm, peppers and peanuts contain 50-200 ppm, corn and wheat contain 20-300 ppm. We can eat these without toxic consequences because metallic aluminum has been transformed by the plants' metabolic processes into nontoxic organic, colloidal forms. It's even logical to suspect that our bodies, which evolved from the earth's elements, might have a use for this very common element in organic form. Inorganic aluminum, however, is known to be toxic, and is implicated in Alzheimer's and breast cancer

A conversation with Dr. Ernest Foulkes, a heavy metals researcher at McGill University in Montreal focused on whether the bound organic metallic compounds are broken down at all in the human stomach (pH 1). And, if they are, how they may recombine in the small intestine (pH 6) with hundreds of chelating substances (proteins, amino acids, bile salts, complex sugars and fibers) and pass harmlessly through the gut.

As there's much yet to learn, we recommend that you consult a healthcare professional if you have any questions about your intake of heavy metals. Dietary deficiencies and genetic variability, for instance, can affect how well an individual processes metals, nutrients, or any other substance. Furthermore, vocational or environmental exposure may impact one's body load of metals and effect metabolic capacities.

Please refer to our annual Statement of Product Testing for test results for certain trace metals in our sea vegetables


1Study of in vitro cytotoxicity of a water soluble organic arsenic compound, arsenosugar, in seaweed, Sakurai et al, Toxicology, 122 (1997), 205-212.





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