Tuesday, February 24, 2015

Pesticides good and bad, and be very afraid of oxidane

Pesticides have impacts, and improperly used, some pesticides can be health hazards. No question about that. 

In the Islands, it’s become a meme in some groups that pesticides are necessarily awful. But as usual, black and white don’t serve us well in this discussion. The reality falls in the gray.

It’s also true that properly used pesticides can do more good than harm—they preserve our food, remove unwanted pests, protect us from diseases carried by vermin, help control the spread of allergens, and on and on.

In recent discussions, I’ve heard assertions that this man-made compound is an endocrine disruptor, and that compound causes birth defects, and another causes cancer. 

In many case, that may be true. It’s also true that endocrine disruption and birth defects and cancer occurred before modern pesticides were developed. 

Natural products can be associated with those conditions, too. Examples: soy for endocrine disruption; German measles for birth defects; sunlight and tobacco for cancer.

And, of course, there are genetic causes or increased sensitivities for these. See here, and here. Some individuals and families have a natural sensitivity to some endocrine disruptors.

What are we to make of all this? From my perspective, we should accept that nothing in this field is simple, and you are likely to be misled if you listen to people who claim it is simple.

Linda S. Birnbaum, director of the National Institute of Environmental Health Sciences, told a U.S. House of Representatives committee that her agency is seriously concerned about groundwater contamination. 

If you listened to much of the debate in Hawai`i, you might think agricultural chemicals were the only man-made products entering our groundwater. It’s not only agricultural chemicals, but also pharmaceuticals, sunscreen, flame retardants, plastics, cosmetics. All can be endocrine disruptors.

“Endocrine disruptors are naturally occurring or man-made substances that may mimic or interfere with the function of hormones in the body. Endocrine disruptors may turn on, shut off, or modify signals that hormones carry and thus affect the normal functions of tissues and organs,” she said. 

“Both naturally occurring and manmade substances can be endocrine disruptors,” Birnbaum said.

Other chemicals that pollute the groundwater? 

If you get enough people in a community drinking coffee, tea, and cola, then you’re likely to find caffeine—a pesticide—in the groundwater. A 2006-2007 survey on Kauai found caffeine in North Shore groundwater and streams anywhere downstream from human development.

It is possible to make a case against anything, but it may or may not be a valid case, and it may lack perspective.


Some entirely natural pesticides are far more dangerous than man-made ones. Take the natural pesticide in the castor bean plant, which can kill anything that eats the seed—aphids and ducks and horses and humans alike. The scientific name of castor bean is Ricinus communis . The poison is one of the most dangerous products in chemical warfare, ricin.
Another example:

A real bad guy is the chemical oxidane. It can cause death in minutes through inhalation. In its gaseous form it can burn the skin. It can be a greenhouse gas. It corrodes metals. It is an industrial solvent that is used in pesticides and nuclear plants. 

Not hard to make a case against oxidane with that information. Yet it is found in all our water supplies. For good reason. Oxidane is, of course, a scientific name for water.

In some of our Hawaiian legislative deliberations, we’re considering tossing the safest and the most dangerous chemicals in the same regulatory basket. That doesn’t make sense. 

This is not to say we should not apply rigorous testing to pesticides, and to require protective measures in their use as appropriate. 

It is to say this about making public policy: We are better served if we apply careful scientific discipline than if we heed slogans that fit on protest placards. 

© Jan TenBruggencate 2015

Thursday, February 19, 2015

`Opihi teeth are toughest biological material in the world.

You always knew `opihi were tough, but this tough? The teeth of this Hawaiian delicacy may be the strongest biological material known.

(Image: Three of the favored Hawaiian limpets At top with green border makaiauli; at right with yellow foot is 'alinalina; and at left with gray foot, is ko'ele. Their scientific names, in order are Cellana exarata, Cellana sandwicensis and Cellana talcosa.)

A new British study, published in the Journal of the Royal Society Interface, says limpet teeth are far stronger than the previous winner, spider silk.

They accomplish this with a unique bit of layering—in the same way that wood gains strength when formed into plywood, or carbon fiber canoes get strength from being laid up in a bed of epoxy. The `opihi teeth are made of extremely thin iron oxide fibers in protein. 

Tests on their teeth exhibit “an absolute material tensile strength that is the highest recorded for a biological material, outperforming the high strength of spider silk currently considered to be the strongest natural material, and approaching values comparable to those of the strongest man-made fibres,” write the authors, Asa H. Barber , Dun Lu , Nicola M. Pugno.

Right up there with carbon fiber, they say.

They “exploit distinctive composite nanostructures consisting of high volume fractions of reinforcing goethite nanofibres within a softer protein phase to provide mechanical integrity when rasping over rock surfaces during feeding,” they write.

Goethite is a form of iron oxide.

“This work demonstrates a high-strength composite found in nature and highlights a design strategy towards strong, engineered composites reinforced with a high volume fraction of nanofibrous material,” the authors write.

`Opihi need tough teeth because of the way they feed—they scrape the algae they eat directly off the rock substrate. The paper’s authors suggest that the example of the `opihi may even be useful in improving human teeth.

“As the limpet tooth is effective at resisting failure owing to abrasion, as demonstrating during rasping of the tooth over rock surfaces, corresponding structural design features are expected to be significant for novel biomaterials with extreme strength and hardness, such as next-generation dental restorations,” they write.

The research was done on the common limpet, which is found in European waters. It is of a different genus and species than Hawai`i’s `opihi, although there’s no reason to believe the tooth structure would be significantly different in our species.

There are four limpets commonly seen in the Islands. They include the three shown in the photo above, plus the less appetizing `opihi `wa or false `opihi, Siphonaria normalis.

© Jan TenBruggencate 2015

Monday, February 16, 2015

Mildew on mango: chemical and organic controls all have impacts

My Keitt mango tree is in full flower, and infested with the same powdery mildew that last year killed off every flower or fruit.

The fungus, Oidium mangiferae, infests the flowering portions and young fruit, killing them and turning them black. 

Instead of their normal vibrant yellows and pinks, the flowering stalks of infested mango turn brown and gray. The fungal disease is a main culprit in mango yield in the Islands.

In researching solutions, I entered the bizarre world of plant disease control, in which few options are without unwanted impacts, and the safest alternatives are illegal.  

 If you don’t care to read through this, the takeaway is that every recommended anti-mildew product has environmental and/or health impacts, whether it is synthetic or natural, chemical or organic. But while they all have impacts, the impacts can be quite different.

Even the option of doing nothing is hazardous, since fungal spores can cause breathing problems.

There are all kinds of ways to approach fungal disease issues on plants. Here are the main ones:

Biological control (living creatures that attack the living creatures causing the disease); cultural control (keeping the area clean so things like rotting leaves don’t harbor disease agents); chemical control (using an array of natural and manufactured products to kill off disease agents); natural resistance (selecting species that fight off the disease—which is, of course, no longer an option when you’ve got a mature fruiting tree); integrated pest management (which can be blending any of the above.)

The University of Hawaii Cooperative Extension Service has a leaflet on powdery mildew on mango, which it says can reduce fruiting in mango by 90 percent. It’s a bigger problem in areas that have rain during the mango flowering season.

Each possible treatment has its downsides as well as its benefits. Some only work well in conjunction with others. Some barely work at all.

Says the leaflet: “The fungicides registered for control of mango powdery mildew in Hawai‘i fall into several groups based upon their active ingredients: clarified hydrophobic neem oil; mono- and dipotassium salts of phosphorous acid; carbonic acid, monopotassium salt; kerosene (petroleum) hydrodesulfurized; aliphatic petroleum solvent; sulfur; mancozeb; and myclobutanil.”

Two of the safest anti-fungal approaches ironically are illegal for use in Hawaii: baking soda and milk.

“Baking soda (sodium bicarbonate) mixed with water is an old home-remedy spray for powdery mildew. However, because baking soda is not labeled as a fungicide, it may not legally be used for disease control, according to Hawai‘i Department of Agriculture regulations. Some growers report that foliar sprays of milk can be effective against powdery mildew, but the same use restriction may apply,” said the UH leaflet.

Neem oil might be most folks’ first choice, although it is moderately toxic to bees and can irritate the eyes.  And if there’s an aquatic environment nearby? “The compound was more or less toxic to all the tested species,” says a study of neem toxicity to aquatic species including insects, crustaceans, amphibians and fish.

Hydrodesulfurized kerosene and aliphatic petroleum solvent are both fossil fuel products with various risks, including skin irritation, and they can be hazardous to aquatic animals.

Some recommend a natural product called potassium bicarbonate for powdery mildew. It can be found in commercial products like GreenCure. According to one product, Kaligreen, the products work by disrupting the potassium or sodium ion balance in the fungus and causing cell walls to collapse. 

There’s some evidence of eye and skin irritation in lab animals, but these may be the safest of the alternatives: 

EPA has concluded that aggregate exposure to sodium bicarbonate or potassium bicarbonate over a lifetime will not pose appreciable risks to human health. EPA concludes that there is a reasonable certainty that no harm will result from aggregate exposure to sodium bicarbonate or potassium bicarbonate residues.” 

(Despite that finding, of course, sodium bicarbonate or baking soda remains off-limits for powdery mildew on mango in Hawai`i.)

Researchers in Egypt experimented with integrated pest control in seeking out environmentally friendly responses to the powdery mildew on mango, and found that none of the known natural solutions worked really well alone. So they tried mixing several different substances together. They combined three biological control agents (Verticillium lecanii, Bacillus subtilis and Tilletiopsis minor), plus a soluble potassium salt (monopotassium phosphate), plus a clay product (kaolin), and ascorbic acid.

They worked with two mango varieties, and despite the significant complexity of the treatment, combining all of them worked better than any of them alone: “Mixtures of all four natural compounds were more effective in significantly reducing powdery mildew severity and conidia counts on blossom clusters and fruit set and increasing fruit set and yields on trees of both cultivars than mixtures of two or three or single applications.”

Oh, and those natural biological agents they tested? They’re pretty safe, but in certain circumstances can also be problematic.

Verticillium lecanii is a fungus that is sometimes used for biocontrol, but it can kill some insects.

Bacillus subtilis is a bacterium used as a fungicide, and incidentally is used to make the antibiotic bacitracin. It has been associated with liver damage in humans.

Tilletiopsis minor is a fungus that has been known to cause fungal infection in humans. 

Those are “organic" solutions. The chemical solutions also come with warnings. 

The systemic fungicide myclobutanil is listed as only slightly toxic  but there are warnings about eye and skin contact and inhalation.

The non-systemic fungicide mancozeb is listed as not acutely toxic, but may enter groundwater and may be an endochrine disruptor. It is toxic to fish and some other creatures. 

The takeaway, as mentioned at the start of this article, is that every recommended anti-mildew product has impacts, whether synthetic or natural, chemical or organic. 

Nothing is without impacts. Indeed, even doing nothing at all has impacts. 

© Jan TenBruggencate 2015

Sunday, February 15, 2015

The Apple iCar--your next ride?

Electric cars are certainly part of Hawai`i’s automotive future, but they are currently barely a niche planet in the automobile universe.

They won’t stay that way, says Tesla’s Elon Musk. 

“All cars will be electric cars,” he says confidently.

The latest data point is the interest of iconic techno-giant Apple, which clearly has the means to wade into that arena. Apple’s now worth north of $700 Billion—with cash reserves reported at more than $170 billion.

Let’s get clear how much money that cash reserve is. At current market values, Apple could buy Ford, General Motors, Fiat/Chrysler AND Tesla without having to take out a loan.

Apple itself isn’t admitting anything, but rumors are all over that the company is actively developing an electric car, has hired a Ford engineer to oversee it, has hundreds of employees working in secret on it, and has contracted with a battery manufacturer for it, and that it looks like a minivan. (More on the minivan later.)

Here are some of the reports on Apple's car. See Digital Trends, New York Post, Wall Street Journal (paywall).

Some folks are already calling it the iCar. 

There is certainly no shortage of electric car models, ranging from vehicles that just look like top end golf carts, to midrange cars like the Nissan Leaf and Chevy Volt, to the Tesla’s top end speedsters—the Roadster and the Model S. And lots in between.

Chevy is promising a mainstream electric car, the Bolt, and Musk insists his next electric car will be significantly less expensive than the Bolt.  Virtually every big automaker is working on electric cars.

What does it take to take the electric car mainstream? 

Price: if you want mainstream buying, you need mainstream pricing. Musk says he is shooting for $30,000 before any rebates.

Range: Early electric cars got ranges in the tens of miles. Musk’s Roadster pushed it to 300, but everyone else has fallen short—largely because the batteries are so expensive. Most electric cars still can barely make it around the island without stopping to recharge.

Style and design: Golf cart chic won’t make it. Tesla’s Lotus-inspired Roadster is smoking hot but has virtually no storage space. If it’s true that Apple’s working on an electric minivan—but what’s more mainstream, family-friendly and Middle America than that? 

Minivans aren’t sexy, but if they have an Apple logo on the hood, that might be all the sexy they need.

On the other hand, if you wanted to keep the hype under control, what better way than to let it out that you were working on a minivan? Nothing more boring than a minivan.

Nobody knows the truth yet, except Apple—and maybe Musk, who’s recently been seen visiting Apple. There's an intriguing bit of technological cooperation.

© Jan TenBruggencate 2015

Saturday, February 7, 2015

Pacific winds and waves to change significantly in coming century: new report

A complex projection of wave and wind trends in the Pacific over the next century suggests a lot of change in our future.

The just-published study looks at models of wind speed and direction, wave height and period and other features. Perhaps surprisingly, not everything goes in the same direction, nor even keeps going in the direction it started in over the coming century.

If that sounds strangely complicated, well, yes, it is. But also important for planning mitigation measures for coastal communities that will be threatened by changing wind and wave regimes.

“Waves…impact coastal infrastructure, natural and cultural resources, and coastal-related economic activities of the islands,” the paper’s authors write.

The study for the U.S. Geological Survey is entitled “Future Wave and Wind Projections for United States and United States-Affiliated Pacific Islands" and was prepared by Curt D. Storlazzi, James B. Shope, Li H. Erikson, Christie A. Hegermiller  and Patrick L. Barnard.

It starts with the warning that “Changes in future wave climates in the tropical Pacific Ocean from global climate change are not well understood.”

It ran multiple models for multiple locations for multiple time periods. 

The study suggests that during the winter months, December to February, in general, we can expect wave heights to increase through the first half of the century, and then to decrease for the second half.

In summer, June to August, wave heights are expected to increase throughout the century. 

And during the fall, September to November, they are expected to decrease throughout the century.

But those are general statements. There are significant regional differences.

Depending on the statistical model used, not only wave height and wind speed, but wave directions and wind directions also change seasonally with location and season.

The specifics of the study are dense, and beyond the capacity of this report, but for those interested in coastal mitigation, the wave and wind projections are an important resource.

“The data generated by this effort are expected to be crucial in projecting future transient sea level extremes on coasts and small islands, because winds and waves are the key processes driving extreme water levels and inundation,” the authors write.

Here is a USGS press release on the study. It includes this line from Jeff Burgett, Science Coordinator for the Pacific Islands Climate Change Cooperative: “Natural resource managers, communities, and engineers will all benefit by being able to prepare for the shifts in inundation risk shown by this study.  This work shows that the degree of change we see will depend on how greenhouse-gas emissions change."

Citation: Storlazzi, C.D., Shope, J.B., Erikson, L.H., Hegermiller, C.A., and Barnard, P.L., 2015, Future wave and wind projections for United States and United States-affiliated Pacific Islands: U.S. Geological Survey Open-File Report 2015–1001, 426p., http://dx.doi.org/10.3133/ofr20151001

© Jan TenBruggencate 2015