Seaweeds are really good at sucking up chemicals in the water and therefore there is reasonable concern about the safety of seaweeds. There is now almost nowhere in the globe where the sea is not polluted from humans. The seaweed is grown in areas with low population and industrial presence. It is not harvested within a week of high intensity storms, where there is a risk of flooding and ocean pollution. We test the water and the seaweed and the levels in the seaweed pass the current permitted levels. We do not ship any product that has more than detectable levels. Why eat to be healthy but then ingest levels of toxic chemicals.
Batch tests completed include the following. None of the latest tests have shown any elevated levels. Most heavy metals exist naturally but some are the result of pollution from mining or industry.
- Lead (Pb) Permitted levels = 10 ppm. Tested level 1.1ppm
- Mercury (Hg) Permitted level limit 0.5ppm. Tested level = Not Detected
- Cadmium (Cd) Permitted level 0.3ppm. Tested Level 0.23ppm
- Arsenic (Ar) Permitted limit 0.3 ppm. Tested level = Not Detected
- Manganese (Mn) No limit but recommend RDA is 2.8 mg per day. Seaweed tested = less than 1% DV
- Biological contamination tests (E.coli, Aerobic plate count, Yeasts, Moulds, and Salmonella detection) are regularly carried out.
But in some areas and for some species they do concentrate and are used in water remediation. There is seaweed grown in the mouth of the Rhine River to extract out nitrogen, lead, cadmium to reduce the levels going into the North Sea.
Other seaweed is not harvested but washes up on the shore after storms. In contrast our seaweed is grown in the clean sea (monitored), harvested, dried and put into product.
All with the latest state of the art gate to plate tracking process and formally organically certified.
So be careful of seaweed products is grown in river mouths, or is not carefully monitored.
NB. Back in 2012,researchers found seaweed (K. alvarezii extract) exhibits potent anti-genotoxicity effects in a fish model; and thus seaweed extracts may be recommended as a supplement in fish meal and may benefit humans ingesting Hg-contaminated fish.
Interaction with Selenium and Sulfur
There is a complication to the heavy metal issues. Seaweed has a moderate amount of both selenium and sulfur (sulphur) and these are protective against heavy or toxic metals.
- Selenium is protective against cadmium, arsenic, mercury, and lead
- Sulfur (being to a lesser degree protective of the same), is helpful to lower aluminum levels.
See Nagarani, Nagarajan & Janakidevi, Velmurugan & Yokeshbabu, M & Kumaraguru, Arumugam. (2012). Protective effect of Kappaphycus alvarezii (Rhodophyta) extract against DNA damage induced by mercury chloride in marine fish. Toxicological & Environmental Chemistry. 94. 10.1080/02772248.2012.707792.
 Roth 2016. Selenium and Sulfur. Cellular Nutrition https://acu-cell.com/ses.html