Urushiol Pain and Products

Chinese ancestor chair
After more than a century, lacquer has cured on this Chinese ancestor chair

A week after nightly creaming my face and arms with hydrocortisone I’m still itching. Each exposure makes the reaction worse next time. A few people, including our gardener, are lucky they don’t react to poison ivy, nor wildlife or pets protected by hair or feathers. Even after cautiously walking on a woodland path or weeding, the unwary can become victims simply by cuddling a canine companion who brushed against a vine.

Poison ivy is not strictly a poisonous plant although the allegation is rooted in the scientific literature as it belongs to the genus Toxicodendron, along with poison sumac and poison oak. The allergic irritant in its leaves, stem and root is urushiol, which presumably evolved to deter to grazing animals (and gardeners). I read that trace amounts exist in mango skins. Eek!

So potent is the oil that when microscopic droplets penetrate the skin, Langerhans cells recruit ‘armed’ T-lymphocytes to fight the invader. The process kills cells as collateral damage and causes blistering, swelling and a blazing red rash. As a slight consolation, my palms and soles never react because they have thicker layers of keratin.

Wakened at night by the urge to scratch, it’s hard to find a polite word for the irritant, but urushiol has a larger story. Once used in herbal remedies when plants were the basis of the pharmacopeia, it still finds a place in traditional Chinese medicine. Its anti-tumor properties encourage researchers to overcome insolubility in water to create a medication for testing in the body. I doubt they will find volunteers for a clinical trial !

Urushiol research is mostly based in Asia where it has long been used as a lacquer for furniture and other wood products. It is collected from lacquer trees, like tapping maple trees or rubber trees. The name of the tree in Japanese gave urushiol its name. Painted in thin layers, it oxidizes and polymerizes to a hard, stable coating.

If your arms become inflamed after resting on a table made in China, it wasn’t your mom’s scold that came back to haunt you from breaking domestic etiquette. The lacquer may not have cured completely.

Next Post: Wood Stork

Phosphatemia—How Green is your Water?

Phosphate in drinking water
Colorimetric phosphate test

My swimming pool has a thin green carpet. The fish and frog pond is choked with weed and slime. Even sugar water in the hummingbird feeder turned cloudy in 24 hours. What’s going on?

Now I’ve lit my pipe let’s start the inquiry, Dr. Watson.  Does the water have a common source? Is it polluted?

Yes and no, Holmes. The water originated from our faucet, but we didn’t spread fertilizer in the garden.

Hmm. Tell me, then, what can make stuff grow quickly in water?  

My dear Holmes, I’m reminded of rapidly growing dead zones in the Bay during summer, though the tides were ‘red’ with algae, never green. But if I have the same problem at home the answer must be phosphate.

Congratulations on your deduction and commiseration with the slimy state of your water. Now give it a test.


A combination of colorimetric and laboratory tests confirmed high levels of phosphate in samples from all three sources, but even higher straight out of the tap people drink from. In excess of 4,000 parts per billion, exceeding the sanitation capacity of free chlorine in the pool. How so, when only <100 ppb from the garden well and rainwater barrel?

Remember Flint, Michigan, in 2014? The city managers (that’s what they call them) switched the water supply to save money. Instead of the Detroit river where phosphate was added they drew from the Flint river which has only a low natural level.

Phosphate is added to domestic water supplies around this country, Britain and others included, to avoid poisoning children in homes that still have lead plumbing. It reduces lead in drinking water by coating pipes. Few people seem to know or ask what’s in their water. Phosphate isn’t mentioned in the James City County Water Quality Report, although plenty about bacteria.

Like other living organisms, bacteria need phosphorus to grow, and some kinds are able to liberate more from insoluble mineral. The municipal answer to lead provides more food (PO4) for bacteria and algae to grow, and that consequence is fixed by pumping more chlorine in our water.

Holmes didn’t seem worried about drinking our local water (or that in Baker’s Street, London). He is glad of a generous helping of phosphate in his diet to top up his hydroxyapatite and ATP reserves, but spurns colas supercharged with phosphoric acid for the sake of his brain.

Waldeinsamkeit

Yellowstone National Park
Photo: Yellowstone National Park (RG)

Is there anything about the pandemic that hasn’t been said a hundred times already? It is no secret that one of the healthiest places to rest from screen fatigue and lockdown lethargy is outdoors.

People have rushed to national and state parks and to the coast for a dose of ‘nature.’ Take, for example, Yellowstone National Park. Gate registrations of recreational vehicles surged every month in 2020. In the peak month July 2020, 365,937 were recorded compared with 320,464 12 months earlier. When this post goes out, I too will be breathing mountain air, except in the ‘Mon.’ Phew. That feels better!

Seeking peace through a mindful stroll among trees has a long history among forest-loving Celtic people and forest-bathing Japanese. So important is it in Germany that a new word was created by conjugating two unrelated words, for which the language has a facility. Waldeinsamkeit (forest plus loneliness/ solitude) captures an entirely positive feeling with no English equivalent.

Nothing green and vegetable is more loved than a tree. Perhaps because we venerate their long lives—counting rings and planting saplings to memorialize life events. Perhaps out of gratitude for what they provide—permaculture food and the most versatile material for crafting our needs. They keep on giving: hardly something we can boast. It’s hard to imagine a civilization emerging without them or human beings even evolving. Weren’t we molded from the genome of an arboreal ape?

To go to the woods and forests is to go home, as if on a family visit to a third parent. They grew deep roots in mythology and religion. The Druids had their sacred groves and other cultures cherished the Banyan tree, Bodhi tree, and Christmas tree as symbols of growth, decay and renewal. Dryad spirits of the woods populate poetry and literature while Tolkien’s Ents guarded the forest. And, despite casting off superstition in the modern age, the mystique endures through scientific discovery of the wood wide web in which vibrant communities connect tree to tree and tree to fungus and microbe.

Recent best-selling books about trees or set in forests add to a perennial genre: The Overstory, The Hidden Life of Trees, Game of Thrones, etc. Children’s books too: The Magic and Mystery of Trees, The Tree Lady, etc.

I close in contradiction. One of the goals of going outdoors is to leave paper and screen behind, but hurry home to one of the finest short stories for children and adults. The Man Who Planted Trees by Jean Giono is an inspiring story of a shepherd living as a hermit in the desolate mountains of Provencal. He transforms the landscape by planting acorns that grow into a forest. A CBC cartoon movie narrated by Christopher Plummer and available on YouTube captures the story beautifully of how an unselfish activist can make a difference for humanity and the environment.