Castor Seeds

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Infobox on Castor Seeds
Example of Castor Seeds
Castor seed-1.jpg
Origin See text
Stowage factor (in m3/t) 1,98/2,12 m3/t (bags)
Humidity / moisture -
Ventilation -
Risk factors See text

Castor Seeds


The Castor Bean is the only member of the genus Ricinus, and it has no immediate relatives. As a member of the Spurge family of plants (Euphorbiaceae), it is distantly related to the poinsettia, true rubber tree, cassava, croton, tung oil tree, Chinese tallow tree and crown of thorns. While the Castor Bean is native only to Africa, people have introduced the species around the world. It has escaped from cultivation and can be found as a wild and sometimes invasive plant in Australia, many Pacific Islands, and in 27 states (including New Jersey). In tropical areas it grows as a shrub or a tree that can reach 40 feet in height along streams and rivers and on bottomlands with well-drained, nutrient rich soils. They are intolerant of frost, and die as soon as the temperature drops below 0°C. Castor Bean plants are impressive. Their huge, 5 –11 lobed, star-shaped leaves can reach 3 feet in length. The plant’s coarse texture makes a bold statement in a garden, and contrasts nicely with fine textured companions. They look attractive in groups, or as individual specimen plants. There are numerous varieties of ornamental Castor Beans. Many have been selected for bright red or purple foliage, instead of typically green leaves. Leaf shapes and plant size distinguish other varieties.

Castor Bean flowers are relatively inconspicuous. They lack petals and rely on the wind for pollination. The flowers are monoecious, meaning there are separate sexed flowers on the same plant. Flowers are found in terminal clusters, with the male blossoms below and the female blossoms above. Male flowers senesce shortly after shedding their pollen, while the female flowers develop ½ -1 inch long capsules covered with soft spines. The capsules open at maturity, revealing 3 smooth, attractive, ½ inch long seeds that are a mosaic of muted black, gray, brown, yellow-brown, maroon and white colors. Each seed seems to have its own unique color pattern. The superficial resemblance of the seeds to a specific species of European tick led to the genus name of the plant. It is the seeds of Castor Bean plants that have historically, and currently, been of interest. They contain a valuable oil, but also some extremely toxic compounds.

Castor Oil makes up about 50% of the weight of the seeds. The oil is mostly ricinoleic acid, with small amounts of dihydroxystearic, linoleic, oleic, and stearic acids. It is fast drying, non-yellowing, and is valued for industrial and medicinal purposes. Most of the world’s production of castor oil goes into lubricants for fine machinery and auto engines, plastics, paints, inks, soaps, linoleum, dyes, leather preservatives, waxes, polishes, cosmetics, candles, and crayons. Evidence in Egyptian tombs indicates that the oil was used in medicine over 6,000 years ago. Hundreds of medicinal uses have been claimed over the ensuing years, with purgative, laxative, and general cure all properties cited most frequently. Ingesting large quantities of the oil can result in poisoning, and many medical professionals feel the oil is a dangerous ingredient in a variety of folk remedies.

After the oil is pressed from the seeds, the remaining “seed cake” can be used as fertilizer or as an animal feed. For feed use it first must be carefully boiled, heated, or treated by other means to inactivate the toxins present in it. The toxins in the seeds are water soluble, not lipid (oil) soluble. So, the toxins remain in the seed cake and are not released during the pressing process. The crop residues of stems are made into paper and wallboard in some parts of the world. India is the world’s leader in castor oil production, but commercial production also occurs in California and the southern United States, Australia, Brazil, Venezuela, Morocco, Taiwan, South Africa, Thailand, Haiti, Belgium, Germany, Holland, Peru, China, Argentina, Mexico, Paraguay, Ecuador, and Ethiopia. Worldwide over 500,000 metric tons of castor oil are produced annually.

Lately, the extremely toxic components of Castor Beans (including the protein ricin and the alkaloid ricinine) have been the subject of much interest. The most notorious is ricin, a deadly poison found in abundance in the seed and in smaller amounts throughout the rest of the plant. Ricin is a water-soluble protein that inhibits protein synthesis in animal cells, leading to their death. Poisoning occurs when animals ingest broken seeds or chew the seeds. Intact seeds may pass through the digestive tract without releasing ricin.

Ricin is incredibly toxic. As little as 0.5 mg (the amount contained in several seeds) can kill an adult. One seed can kill a child. We are not the only sensitive animals. Four seeds will kill a rabbit, 5 a sheep, 6 an ox or horse, 7 a pig, 11 a dog, but it takes 80 to kill a duck. Ricin has been investigated for its potential use as an insecticide.

Symptoms of ricin poisoning begin within hours after exposure by ingestion or inhalation. They include stomach irritation, vomiting, bloody diarrhea, abdominal pain, increased heart rate, low blood pressure, profuse sweating, collapse, convulsions, and death within a few days. Victims that do not die in 3 to 5 days usually recover. There is no antidote for ricin poisoning. The only remedy is to give supportive medical care to minimize symptoms, and hope for the best. There are some potential medicinal uses for ricin, since it is so cytotoxic. It might be useful in bone marrow transplant procedures, and as an anti-tumor agent.

Shipment / Storage / Risk factors

Shipped in bulk or in bags. Should bags burst, seed will scatter and penetrate. Must not be stowed near or with foodstuffs or other edible commodities due to the poisonous nature of the seeds. The husk, when fractured or broken, may become separated into tiny splinters, which if ingested causes internal damage in humans and animals. Heating cannot usually be detected by external examination, but can be ascertained by internal discolouration.

The seeds from which castor oil is obtained, which being of a poisonous nature must not be stowed with or near grain and foodstuffs. Heavy claims have had to be met where such stowage was permitted. Separate stowage compartment if possible. Avoid stowing in a 'tween deck when there are foodstuffs in bulk in the lower hold. Clean stowage space or container thoroughly after discharge. Contact with the dust or crushed beans can cause severe irritation to the eyes or skin. Respirators should be used when the dust is agitated.

Surface ventilation only, either natural or mechanical, shall be conducted, as necessary, during the voyage for this cargo.

Castor beans are listed in the International Maritime Solid Bulk Cargoes Code.