Reactions: The fate of heavy fuel oil, and the origin of bromine for hydrilla

Letters to the editor

Green fuels for shipping

The article “Green Fuels for Shipping” was quite fascinating, and it seemed to be trying to be comprehensive, but there was a loose end that I couldn’t help but wonder about (C&EN, Feb. 28, 2022, page 22). The heavy fuel oil (HFO) currently used to power those behemoth vessels is essentially a by-product of crude oil refining that people found a use for. As such, when it is replaced by other energy sources for the shipping industry, it will continue to be produced as an oil that is refined for the myriad other purposes that petroleum products are used for.

There is no mention in the article of other uses for HFO, and certainly none in comparable quantities. This leads me to wonder what’s going to happen to all that HFO when the shipping industry is successful in replacing the HFO with noncarbon or low-carbon sources of energy but petroleum keeps being refined. Is it simply going to become another source of pollution when there’s no other way to get rid of it? It’s obviously not simply going to magically disappear.

Howard Mark
Suffern, New York

Eagle-killing aetokthonotoxin

Your article on aetokthonotoxin (C&EN, Feb. 28, 2022, page 6) mentioned the enzymatic conversion and coupling of two tryptophans by cyanobacteria that live on the invasive aquatic plant Hydrilla verticillata and that produce aetokthonotoxin. The first reported case of bald eagles dying from avian vacuolar myelinopathy was in 1994, near DeGray Lake in Arkansas. That area is at least 250 mi (402 km) from the bromine-containing salty Gulf Coast.

So where does the hydrilla find bromine to incorporate into this toxin? It is very likely that bromine is from the minerals in the ground or freshwater lakes in Arkansas. This environmental disaster has the potential to affect the health of our domestic animals and humans.

Wallace Fu
Holland, Michigan