01

Chemicals, IARC Group

Tri-Union tuna fish case is based on one chemical, methylmercury, which is an IARC Group 2B possible carcinogen, also recognized for developmental toxicity [28][29].

Mercury and inorganic mercury are not classifiable as to their carcinogenicity to humans (Group 3).

Methylmercury production is primarily a result of microbial activity in aquatic environments where anaerobic bacteria convert inorganic mercury into methylmercury. This process occurs naturally and may be enhanced by anthropogenic mercury emissions [33].​

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02

No Synergy Argued

The case did not offer any consideration of synergetic effect from the presense of other chemicals. 

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03

Industrial Scale of Mercury

Global mercury production was estimated only at 1,200 metric tons in 2023 [23]. Again, this is the amount of mercury, not methylmercury, which is harder to estimate, after the conversion in the environment.

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04

Mercury Emission

Experts testified that since the industrial revolution, atmospheric mercury has increased by a factor of three (Tuna Companies), or within a spread of two to four (State). Tri-Union, at 1563.

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05

Anthropogenic Increase of Mercury

Court accepted the Tuna Companies' experts conclusion that there has been no increase in the amount of methylmercury in ocean fish over the past 100 years. Tri-Union, at 1562.

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06

3 Studies Tested Anthropogenic Contribution of Mercury

Every study (3 of them) that had tested whether methylmercury in tuna has anthropogenic contribution had concluded it was naturally occurring: a change is not expected in methylmercury levels in the deep ocean because there is very little anthropogenic mercury in the deep ocean. Fitzgerald, 23 Tr. 2853:2-7; Morel, 25 Tr. 3181:22. Tri-Union, at 1388.

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07

Averaging was acceptable 20 years ago

The case was filed in 2004, and considered averaging.

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08

Museum Fish Studies

Museum Fish Studies: three studies existed prior to the case and compared methylmercury concentrations in museum fish caught prior to the industrial age with modern fish samples;  demonstrated that methylmercury concentration in ocean fish has not increased over time, notwithstanding increased contributions of mercury into the atmosphere due to manmade pollution. One study of museum and modern fish analyzed a fish that lives 2,000 to 3,000 meters deep in the ocean and has high levels of methylmercury. Anthropogenic pollution would not be expected at such depths because very little of the mercury deposited from the atmosphere into the oceans settles to the deep ocean. Tri-Union, at 1564.

09

NPS pollution for Mercury

Methylmercury emissions emanate from nonpoint sources (NPS). [1][6][17]. NPS pollution refers to diffuse contamination or pollution of water or air that does not originate from a single discrete source. Tuna, being a top predator, accumulates higher levels of methylmercury due to bioaccumulation [1][6]. This also makes it improbable to identify the source.

10

Mercury Travels Long Distances

Once released, mercury can be transported over long distances through the atmosphere before being deposited in oceans and other water bodies. [1][6]

01

Chemicals, IARC Group

Shellfish cases typically involve two industrially produced toxic chemicals, neither of which occur naturally from microbial activity in aquatic environments, as methylmercury does: 

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Cadmium (Cd) is an IARC Group 1 carcinogen (1993), OEHHA (2005), and U.S. EPA (2005), which is by two levels more dangerous than methylmercury. Cadmium is also a known reproductive and developmental toxicant. It affects both male and female reproductive health, impairing spermatogenesis, semen quality, and hormonal balance. Cadmium exposure is particularly harmful to pregnant women and can lead to adverse pregnancy outcomes and developmental issues in offspring 9 10 11. 

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Lead (Pb) is an IARC Group 2A probable carcinogen [29], and is known to cause reproductive and developmental toxicity. It has been extensively documented to impair fertility, reduce sperm quality, affect both male and female reproductive systems. Lead exposure is associated with miscarriages, stillbirths, and developmental disorders in children 6 8. 

02

Significant Synergetic Effect of Pb and Cd

Cd and Pb synergy. Studies “suggest that exposure to Cd and Pb mixtures produces more pronounced effects compared to the response observed after exposure to single metal solutions” [31]. The combination of cadmium and lead is more toxic to the kidneys than either heavy metal alone or in combination with methylmercury [32].

03

Industrial Scale of Lead and Cadmium

In 2023, approximately 4.5 million metric tons of lead was produced [24]. Lead historically had a broader range of applications and a higher total volume of use compared to mercury, particularly due to its use in gasoline, paints, pipes, batteries, plumbing systems, which resulted in widespread environmental contamination [20].

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Production of cadmium was estimated to be around 22,600 metric tons in 2023 [25]. Cadmium is present in fossil fuel combustion, phosphate fertilizers, chemicals, petroleum, iron, steel, textile, leather and cement production, mining, roofs, plastic waste, rechargeable nickel-cadmium batteries, PVC (plastic) products, non-ferrous metal smelters, in the electronic waste, as well as in pigments, coatings, etc. [22].

04

Lead and Cadmium Emission

According to the NCBI report, the sum of industrial lead emissions is approximately 700 times the sum of natural emissions into the atmosphere [26]. “230-fold increase in lead deposition rates in Greenland ice cores over the last 3,000 years, from 0.03 ng/cm2 per year in prehistoric ice cores (800 BC) to about 7 ng/cm2 per year in contemporary ice cores… Comparable increases in the Northern Hemisphere have since been documented in pond and lake sediments, the oceans, pelagic sediments” [30].

05

Anthropogenic Increase of Lead

Studies “have shown the pandemic scale of lead contamination… Lead concentrations in the atmosphere are now 100 times natural concentrations,.. in remote surface waters of the North Pacific and the North Atlantic are at least 10 times natural concentrations,.. in terrestrial organisms are 100 times natural concentrations” [27].

06

Large Body of Studies Confirm Anthropogenic Sourses

No such studies are found for lead and cadmium in shellfish, but a body of the opposite studies, and for a reason: the cultivation of shellfish occurs in coastal and estuarine environments where the waters are shallow. Shellfish, which are filter feeders, accumulate toxins from sediments and the surrounding water [3][4][5].

“Estuarine and coastal marine environments are affected by a wide range of pollutants owing to increased anthropogenic activity from a burgeoning population in the coastal zone.” [19]. “There are many well-documented cases of destruction of productive oyster bottoms by human activities.” [18]. The issue of lead and cadmium contamination in shellfish is a recognized public health concern which is widely known; many companies properly place both on-label and online warnings for consumers, for decades now, regarding the risks associated with consuming shellfish. Despite progress in reducing lead exposure in U.S. communities, elevated blood lead levels remain an issue for children [21]

07

Post-Beechnut regulations prohibit averaging teratogens

20 years of added science since the Tri-Union suggests no averaging for teratogens is appropriate. In addition, the levels of contamination involved in shellfish cases, amount to dangers of immediate health consequences, especially for developing fetuses, from a single exposure.

08

Pre-Columbian Studies

We were unable to find such “museum” peer-reviewed studies for lead and cadmium in shellfish, while the scientific evidence of anthropogenic pollution by lead and cadmium is unsurmountable, see for instance: “Studies incorporating rigorous trace-metal analysis have shown that the natural background lead concentration of North American Indians in pre-Columbian times was 0.3 mg per 70-kg adult [citations]. The body of an average North American urban adult contains 100–1,000 times as much lead.” [27].

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09

PS Pollution for Lead and Cadmium

Lead and cadmium contamination in shellfish is associated with point source pollution, which can be traced back to specific, identifiable sources [3][4][5].

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10

Lead and Cadmium Depose Locally

Lead and cadmium can enter aquatic environments through direct and identifiable discharges from industrial processes, mining operations, wastewater treatment plants, rooftops, traffic, fuel combustion, power plants. [3][4][5]