Goodbye for now

On April 1st I’m beginning a ten-day, silent Vipassana meditation course at a retreat center outside of Kathmandu. After that I’m headed up to the high peaks in Langtang National Park along the Tibetan border for some trekking meditation. So there won’t be too much activity on the blog here for the next month or so.

I’ll take lots of photos of the trek and post them here when I get back. And I’ll try to distill whatever metaphysical musings I get out of the experience for you as well. In the meantime, here are some books I’ve run across lately that I highly recommend…

From the Ground Up: Rethinking Industrial Agriculture. By Peter Goering, Helena Norberg-Hodge and John Page. This book concisely critiques several aspects of industrial agriculture such as the application of chemical fertilizers and pesticides, the treatment of animals, biotechnology and the use of hybrid seeds, the mechanization of farming, and the economic and social effects of industrial agriculture on small farmers and rural communities. It’s a quick read and a good general primer on what’s wrong with industrial agriculture.

The Unsettling of America. By Wendell Berry. This book should be required reading for anyone who eats food, because, as Berry points out, “eating is an agricultural act.” Two rare elements are combined in Wendell Berry’s writing: one, he is a great writer, and two, his message is exceedingly important. The Unsettling of America is another critique of industrial agriculture. But unlike the book by Goering et al. that provides mainly a step-wise, logical account of the factual problems in the way we do agriculture, Berry’s critique is much more spiritually based.

Ancient Futures: Learning from Ladakh. By Helena Norberg-Hodge. This book tells the story of a healthy, happy, enviable traditional society high in the mountains of western Tibet formerly based nearly exclusively on subsistence agriculture. Once the area was opened up to tourism, trade, and so-called “development,” however, their idyllic way of life quickly began to erode. This book is a powerful account of the workings of “development” and its negative effects on traditional cultures and ecological integrity.

The One Straw Revolution. By Masanobu Fukuoka. An entertaining and quick read that describes Fukuoka’s philosophy on life, industrial agriculture, self-reliance, and farming methods that mimic nature. A classic text among alternative agrarians.

The Power of Now. By Eckhart Tolle. This book is perhaps the best book ever written describing the way the mind works and the difficulties generated by the ego for health, happiness and connection with other people. Tolle is able to explain on a conceptual level how the mind works to cause anxiety, depression, pain and suffering; but, as he points out, a conceptual or intellectual understanding is insufficient for gaining control of the mind, ending suffering, and becoming fully present. However, his writing has the power to take you beyond intellectualizing and conceptual understanding to finally experience the workings of the mind directly – this makes it possible to get beyond egocentric ways of living.

Still the Mind. By Alan Watts. This is a quick-reading little book that provides easy access to the teachings and philosophy of Zen Buddhism. Watts’ style is whimsical and entertaining, and his book is full of koans – statements designed to interrupt the mind’s logical, linear processes to produce deep insights into life, the self, the nature of reality, etc. I can also recommend another of Watts’ books, Buddhism: The religion of no religion.

Well, happy reading! I’ll be back in contact around the first of May.

DIY Water Treatment, Part III

This post is the last of three discussing possibilities for self-reliance in water treatment using charcoal filtration. The first installment provided a general primer on the downsides of chemical pesticide application in industrial agriculture. In the second installment I summarized the results of our investigation into the particular agrochemicals of concern in northern Thailand. In this post I give some background on charcoal as a filter medium and describe our design for a drinking water treatment system.

DIY Water Filtration
Part III: System design

The US EPA, the World Health Organization and several academic studies identify granular activated carbon (GAC) as the best available technology for the control of many agrochemicals and synthetic organic chemicals in drinking water. Although it is not possible to produce high-grade GAC without an industrial process, lower-grade charcoal-derived GAC is readily made in earthen kilns and may exhibit appreciable capacity for aqueous contaminant adsorption. Studies have shown low-grade char from the burning of wheat straw to be 31 – 36% efficient for adsorbing dissolved pesticides compared with industrial-grade GAC. Taking conservative estimates for the capacity of homemade charcoal-based GAC to adsorb dissolved organic carbon (DOC), our research and calculations suggest that a maximum of 9 kg (20 lbs) of pulverized charcoal is needed to purify drinking water for one person for one year. In-depth molecular-scale characterization of various homemade charcoal materials to refine this estimate may permit a reduction in quantity by as much as ten times.

Charcoal filtering

Charcoal consists of elemental carbon in its graphite configuration. Carbon has been used for water purification for centuries, possibly dating back as far as ancient Egypt and India. Carbon, in the form of graphite, exhibits an exceptionally high surface area per volume: one gram of industrially produced activated carbon may have a surface area of 400 – 1500 m2 (a football field is about 5000 m2). Non-polar organic molecules dissolved in water are strongly attracted to this surface and bind due to van der Waals (induced dipole) interactions. Carbon filters are employed in commercial home water treatment systems (to improve water taste, for example) as well as in large-scale municipal treatment facilities.

Scanning electron microscope images of GAC. The grain on the left is about 1 mm across. The right image shows a close up of the pore space.


Carbon filters are effective for removing chlorine, mercury, iodine, and some inorganic compounds as well as many problematic organic contaminants such as hydrogen sulphide (H2S), formaldehyde (HCOH), and volatile orgnanic compounds (VOCs). Activated carbon does not bind well to certain chemicals including lithium, alcohols, glycols, ammonia, strong acids and bases, metals, and most inorganic substances such as sodium, lead, iron, arsenic, nitrates and fluoride. As a general rule, carbon will bind non-polar materials while polar materials will tend to remain in aqueous solution. Most pesticides are organic and strongly non-polar and thus should display an affinity for adsorption onto the carbon surface.

Water contaminants that can be reduced to acceptable standards – according to EPA National Drinking Water Standards – by activated carbon filtration include: organic arsenic, chromium and mercury complexes as well as inorganic mercury, benzene, endrin, lindane, methoxychlor, 1,2-dichloroethane, 1,1-dichloroethylene, 1,1,1-trichloroethane, trihalomethanes, toxaphene, 2,4-D, 2,4,5-TP (Silvex), and p-dichlorobenzene.

Carbon filters have limited capacity for removing microbial contaminants and should not be considered a sufficient method for eliminating this risk. The World Health Organization recommends coupling charcoal treatment with chemical (e.g. iodine, chlorine) or UV disinfection to ensure removal of microbial pathogens.ii

Charcoal Making

Charcoal is made by pyrolizing wood or other organic matter such as coconut or rice husks, nut hulls, peat, etc. This involves heating the base material to temperatures of 600 – 900 oC in the absence of oxygen. “Activation” of charcoal typically refers to physical or chemical processes designed to increase the reactive surface area of the carbon. Industrial activation processes may use chemicals and/or steam to enhance surface area, although simply heating the material to sufficient temperatures can produce a significantly activated charcoal. In conjunction with researchers in the United States, we are currently planning experiments to determine the degree of activation of locally produced charcoals as compared with high-grade industrial materials.

Earthen kiln method

An earthen kiln has been constructed at Pun Pun farm using adobe bricks and cob (a mixture of mud and straw) for charcoal production. The kiln is roughly hemispherical, with an inner diameter of about one meter. The walls are made of adobe brick and plastered with cob to a final thickness of about ten inches. The heat intake is approximately cylindrical, about twenty-four inches long and eight inches in diameter. The lid is about eight inches thick and made of cob reinforced with wood, steel rebar, and medium-gauge wire mesh.

The earthen kiln at Pun Pun: the base under construction.


And the completed kiln base.


Photos showing kiln lid construction detail.



Cob was first applied beneath the frame. With the frame in place, cob was applied to the interior. Then the upper layer of wire mesh was nailed into place and cob applied over the top. We made efforts to commingle the layers of cob with each other as much as possible. Nails sticking out of the wood frame provided additional surfaces for cob attachment. A layer of sand-rich earth plaster completes the lid. Holes were drilled in the four handles protruding from the cob for connection to a rope and pulley system. Owing to the weight of the lid, we’re installing a block-and-tackle mechanism attached to the center support beam of the kiln building for raising and lowering the lid.

The chimney (yet to be installed) connects to the bottom of the kiln base and will be about three meters long. The chimney will be made of tin metal, jacketed by a flowing-water heat exchanger. Smoke from the charcoal making process will be condensed in the chimney and collected to make wood vinegar, a useful natural pest deterrent. Effluent water heated by the smoke will be used to supply a hot shower or stored for watering the nearby gardens.

We estimated that the kiln will provide perhaps as much as 50 kg of charcoal per batch. Once a sufficient quantity (mass) of charcoal is obtained, it must be pulverized into grains fine enough to pass through a 3 mm sieve. The grinding process is necessary to increase the material’s surface area and enhance contaminant adsorption. The plastic mesh bags that produce (e.g. potatoes) is sold in are widely available, are free or inexpensive, and make a good sieve for the pulverized carbon.

Plastic mesh bag sieve.



Other sources of charcoal

In addition to making charcoal on-site, a variety of charcoal types are available locally. For example, several varieties of charcoal made from mangrove and tropical hardwoods as well as bamboo are available at local markets. Also charcoal made from rice husks can be found throughout Southeast Asia as it is widely used as a potting soil matrix for starting plants. The potential of rice husk charcoal as a filter medium are especially attractive since the coals are small and thus require little or no grinding to attain sufficiently small grains.

Several earthen charcoal kilns are located along the main road just north of Mae Taeng. Here charcoal can be purchased for 2 - 10 Baht per kilogram ($0.03 – $0.08 per pound).

Earthen kilns near Mae Taeng





A pit kiln for clandestine charcoal making (using illegally logged wood) located in the national forest one mile east of the Panya community.



Other uses for charcoal and its by-products

Charcoal has many uses in addition to water treatment. It is the preferred cooking fuel for the majority of rural people who cook indoors over an open fire as it burns longer and hotter than the common alternatives (cornhusks, bamboo) and produces less smoke. Charcoal is pulverized and used as an additive to bar soap as a scrubbing aid and skin exfoliant. Very finely ground charcoal has medicinal qualities and is used to treat stomach and enteric infections, as well as poisonings and overdoses following oral ingestion (it prevents absorption of the poison by the gastrointestinal tract).

Wood vinegar (pyroligneous acid) is a by-product of the charcoal making process. It is distilled by passing the smoke through a long chimney or heat exchanger to encourage condensation of water and a mixture of volatile organic compounds driven off from the pyrolizing wood. Its principal components are acetic acid, methanol and acetone. It is reputed to be a natural aid for various uses including mild pain relief such as tooth aches and to sterilize and promote the healing of minor wounds. Wood vinegar is also a mild natural pest deterrent and can be applied to crops or to wood surfaces to protect from termites.

Wood vinegar collection from kiln chimney.


Water treatment system design

Although we do not (yet) have precise laboratory data regarding the capacity of our homemade and locally available charcoal to adsorb the agrochemical contaminants of concern identified in the previous post, it is possible to design a drinking water purification system around a general set of parameters and make conservative estimates regarding its capacity for contaminant adsorption. In this case, we regard dissolved organic carbon (DOC) as our general contaminant and design the system around its removal. Several studies have shown that DOC adsorption by granular carbon can block or displace other adsorbed organics such as pesticides. Therefore, we estimate the capacity of locally produced charcoal to adsorb DOC in general, assuming a modest propensity for adsorption on the part of the charcoal and a generous concentration of DOC in the local canal water supply.

We make the following assumptions:

5 L/person-day: drinking water needs (double the US-EPA recommendations, due to the hot tropical climate and physically demanding nature of the farm work performed by the communities)

30 persons: average annual population of the tri-community

10 mg DOC/g charcoal: adsorption capacity of locally produced charcoal

50 mg DOC/L: DOC concentration in natural surface waters

Accordingly:

5 L/person-day x 30 persons = 150 L/day = 54,750 L/yr

50 mg DOC/L / 10 mg DOC/g charcoal = 5 g charcoal/L

54,750 L/yr x 5 g GAC/L = 274 kg charcoal/yr, or

9.125 kg charcoal per person per year (or about 20 lbs)

Note that this calculation admits no contribution of untreated harvested rainwater to the annual drinking water supply. Also, the assumption regarding the DOC adsorption capacity of locally produced charcoal is a conservative estimate based upon the reported capacity of char made from the open-air burning of wheat straw to adsorb particular organic pesticides. This material was shown to be 31 – 36% efficient for adsorbing dissolved pesticides compared with industrial-grade GAC.v Since the wheat straw is exposed to air during the charring process, it is likely that the charcoal purchased locally or made in the earthen kiln on-site is of appreciably higher quality than wheat straw char and thus may exhibit a significantly improved adsorption capacity, perhaps by as much as ten times. Also, it is likely that the DOC concentration of the local canal water is much less, perhaps ten times less than what was assumed for the above calculations.

All of these factors affect the outcome of the calculations strongly; thus taken together perhaps we may conservatively estimate that actual charcoal needs are one-tenth of the above reported value. However, additional experiments are recommended before serious revision of the estimates above can take place. To this end, we are sending samples of a variety of charcoals to a university laboratory in the U.S. for characterization. It would also be useful to analyze the local canal water for DOC content and the variability of this content over time throughout the year. While it is relatively easy to ship solid materials such as charcoal internationally, it is another thing entirely to ship liquids. We are attempting to make inroads with Thai universities or research stations to perform DOC analyses. Further literature search may also permit refining of our estimates.

Treatment system specifications

We recommend a three-stage treatment system: a sand pre-filter followed by a pulverized charcoal filter and germicidal UV lamp.



Conservative estimates suggest that the sand layer should be about 50 cm thick. A diffuser plate should be placed over the sand to reduce the turbulence of the influent and prevent channels forming through the sand.

Charcoal density is about 500 kg per cubic meter. Therefore, the volume of charcoal required to treat one year’s worth of drinking water for the tri-community is calculated

274 kg charcoal/yr / 500 kg/m^3 = 0.548 m^3

One concrete ring 50 cm high by 1 m diameter has a volume of (pi x r^2 x h) = 0.393 m^3. Thus the necessary volume of charcoal is roughly equal to 1.4 concrete rings in depth (0.548/0.393). The purpose of the gravel layer is to prevent clogging of the perforated pipe by carbon granules. This layer need only be about 20 cm in thickness.

Finally, we recommend running the filtered water under a germicidal UV light to eliminate bacterial and viral contaminants. We are currently gathering specifications of germicidal UV systems and will provide a feasibility report for this aspect of the treatment system separately. A combined system of charcoal filtration and UV decontamination represents, in our estimation, the best available technology to ensure a plentiful supply of clean drinking water to the tri-community. By employing this system, the tri-community would provide a demonstration of a working prototype for a simple, effective and inexpensive drinking water system extensible to communities worldwide seeking to advance their practice of self-reliant living.

DIY Water Treatment, Part II

This post is the second of three discussing possibilities for self-reliance in water treatment using charcoal filtration. The first installment provided a general primer on the downsides of chemical pesticide application in industrial agriculture. In this installment I summarize the results of our investigation into the particular agrochemicals of concern in northern Thailand. In the next post I’ll describe our work designing a drinking water treatment system.

DIY Water Filtration
Part II: Agrochemicals of concern

In order to have some idea of what contaminants might be in the canal water, we first had to come up with a list of particular agrochemical products commonly used in the region and in Thailand in general. We used three strategies to identify these suspect substances: (1) interviewing local farmers and the proprietors of local feed shops where the chemicals are purchased; (2) literature research via the web on the most prevalent imported agrochemicals in Thailand; and (3) investigating refuse (trash piles, garbage bins, etc.) in and around nearby fields and orchards.

Our pesticide detective work revealed the following:

Out of the twenty-nine agrochemical products we identified…
…sixteen are moderately to highly acutely toxic to humans
…eight are possible human carcinogens and three are known human carcinogens
…nine are cholinesterase inhibitors – neurotoxins, in other words
…eight are suspected endocrine disruptors
…five are reproductive or developmental toxins
…nine are classified as “Bad Actors” by the Pesticide Action Network
…and thirteen represent significant threats to groundwater contamination.

OK, so are you ready to go organic yet?

Chemical warfare, over-the-counter

An informal survey of local farmers and the staff of local feed shops (where agrochemicals are purchased by local farmers) identified several chemicals applied widely and liberally throughout the region that may constitute a threat to drinking water supplies. Of this list of seventeen pesticide products, nine are classified by the Pesticide Action Network (PAN) as “Bad Actors.” Bad Actors are chemicals that exhibit one or more of the following properties: high acutely toxicity, cholinesterase inhibition (neurotoxicity), known or probable carcinogenicity, known reproductive or developmental toxicity, or are known to constitute a groundwater pollution threat. Furthermore, PAN identifies propiconazole, tebuconazole, metalaxyl, mefenoxam and fluazifop as potential groundwater contaminants.

A wide variety of agrochemical products are available at a shop in nearby Ban Pajee.

In addition to surveying the products at the local feed stores, our research of the literature on pesticides in Thailand revealed that out of the ten most prevalent agrochemicals imported to Thailand, six are classified as PAN Bad Actors and seven constitute threats to groundwater contamination. These seven are: methyl parathion, methamidophos, methomyl, 2,4 D, atrazine, ametryn, and paraquat.

Biocides in our backyard

As the hot-and-dry season got hotter and drier, the grasses and trees in and around Pun Pun responded by turning a golden color and shedding their leaves. This seasonal transition gives the contrasting emerald green hue of the neighbor’s conventionally farmed orange grove and almost cartoony quality. Despite the examples set for successful organic gardening and permaculture by Pun Pun and the adjacent Panya Project, the absentee owner is practicing the unfortunately typical style of inefficient and chemical intensive farming.

These methods are inefficient because they depend on big inputs of capital, energy and materials that would be unnecessary under organic conditions. For example, instead of enriching the soil with organic matter, synthetic fertilizers are applied to provide nutrients to the trees. And instead of cultivating a diverse mixture of species that provide pest deterrence for one another, synthetic pesticides are applied in staggering quantities. Well, fertilizer causes everything to grow, including the weeds, which then necessitates either the application of herbicides or mechanical removal (i.e. mowing, weed-whacking).

The orange grove viewed from Pun Pun. The road leads up the hill to the cooking school at You Sabai. The thatch roof in the lower let corner is my house. Note the fishpond just below.


When you stand back and look at the orange grove, what’s remarkable is that there’s all this green grass growing up between the trees. Everywhere else the grass is a nice gold color – dry – hanging out and waiting for the rains to come. But in the orange grove they have a real grass problem. The watering system is really inefficient – the sprinklers spray water everywhere: up into the air and onto the leaves of the trees where a lot of it evaporates before it even hits the ground. The sprinklers often spray water onto the road, which causes washouts and makes it hard to get up to You Sabai with the motorbike. The fertilizer is applied to make the orange trees grow, but the grass competes for it as well. So the owner is spending all this money buying chemicals and pumping water, most of which never make it to his cash crop and instead cause this lush green grass to grow, for which there’s no use so he’s got to hire some guys to go out there twice a week and mow all the grass down with gas powered weed eaters – and there’s more money and energy spent that perpetuates the self-stoking cycle of inefficiency that characterizes conventional agriculture.

And the dunderheadedness of this is not even the worst part. The truly bad news is that the orange grove is up-gradient from the water canal and Pun Pun’s several ponds – ponds stocked with fish to eat and to store water for showering and irrigation of our gardens. Within a landscape, ponds are hotbeds of ecological diversity and thus are critical features in permaculture design. But it turns out most agrochemicals wreak all kinds of havoc on aquatic ecosystems. So there’s serious concern about what’s being applied to those orange trees and what it will do once it reaches the ponds – an undoubted eventuality

Looking back at Pun Pun from above the orange grove. Pun Pun has several ponds in the low-lying area below the grove. Our water is pumped from the lowest pond – visible at the right edge of the photograph.


It’s pretty easy to work out which chemicals are applied in Thai farm fields because, sadly, it’s fairly common practice to toss empty containers in the weeds and leave half-empty bottles of chemicals lying about. The orange grove proved to be no exception in this aspect of agricultural intransigence. Our investigation of discarded agrochemical packaging and empty containers we found lying around the perimeter of the orange grove revealed that ethyl hydrogen phosphonate, chlorpyrifos, propiconazole, and dimethoate are among the pesticide chemicals being used. Thus far we haven’t found significant toxicological data for ethyl hydrogen phosphonate; however, chlorpyrifos, propiconazole, and dimethoate are all classified by PAN as Bad Actors, exhibit moderate to high acute toxicity to humans upon exposure, and are moderately toxic to very highly toxic to aquatic species.

Some discarded agrochemical product containers found in the weeds around the perimeter of the citrus grove and adjacent to the Pun Pun community.



Chlorpyrifos is a suspected endocrine disruptor. Both chlorpyrifos and dimethoate are associated with cholinesterase inhibition, an indicator of neurotoxicity, and can be absorbed through the skin. Propiconazole and dimethoate are possible human carcinogens as well as developmental or reproductive toxins, and are identified by PAN as potential groundwater contaminants.

A photo indicating the proximity of the discarded pesticide containers to one of Pun Pun’s fish ponds.


Back to the lab

When I signed up to learn about organic farming, seed saving and earthen building at Pun Pun, I had no idea that the experience would end up taking me back to the chemistry lab. In fact, I came to Thailand expressly to break my association with academic science and all its abstractions and frequent irrelevance to the “real world.”

But now I have a list of thirteen chemicals that are terribly destructive to the environment and stupendously poisonous to human beings and are in all likelihood leaching into groundwater supplies all over northern Thailand. And I want to know if an impossibly humble material – homemade charcoal – can effectively scrub these nightmarish substances out of our drinking water. So a trip back to the laboratory seems unavoidable…

Ideally, we could design some experiments to determine the adsorptive capacity of our homemade charcoal for the contaminants of concern. This will take some time though, and of course requires chemical reagents and analytical equipment not readily available in rural northern Thailand. But luckily I have some friends at universities around the US who are keen to help out. At the moment, we’re packing up samples to send to an environmental engineering professor who’s offered to run some analyses on the quality of our charcoal. We’ve also been trying to make inroads with Thai universities to see what collaborations may be possible. And I’m looking into potential sources of funding support. But for the moment, despite the lack of specific data I believe it’s possible to design a system around a general set of parameters and make conservative estimates regarding its capacity for contaminant removal. I’ll discuss this design strategy in the next post.

DIY Water Treatment, Part I

One of my main projects at Pun Pun has been to design and implement a system for purifying drinking water. For three to six months out of the year the community drinks rainwater harvested off of the roofs of the buildings. This is a great, free source of drinking water purified naturally by the hydrologic cycle. However, in a practical sense it just isn’t possible to store enough water during the rainy season to last all the way through the dry season.

A year-round source of freshwater is available from a network of canals fed by a nearby reservoir. However, prior to consumption this water must be treated for possible contamination by fertilizer and pesticide runoff from neighboring agricultural zones afflicted by conventional (i.e. agrochemical intensive) farming practices. My goal with this project is to design a simple, DIY (Do-It-Yourself) water treatment system that scrubs contaminants out of the canal water making it safe to drink using locally available and inexpensive materials.



This post is installment one (of three) that provides some background on the use of chemical pesticides in industrial agriculture. In the next post I’ll summarize the results of our investigations of particular agrochemicals of concern in northern Thailand. In the final post I’ll go into the details of the design for the treatment system.

(Note: To save space I’ve left out endnotes and references. Email me if you’d like an annotated version.)

DIY Water Treatment, Part I
A primer on chemical pesticides

Industrial agriculture – the predominant form of agriculture now being practiced worldwide – relies heavily on the use of chemical pesticides to control crop loss from insects, animals and microorganisms. Over the past several decades, pesticides have revolutionized farming techniques and have facilitated the shift from small-scale, self-sufficient and diversified agriculture towards industrial mono-cropping. Only when viewed from a narrow and distorted economistic perspective does the application of chemical pesticides seem beneficial. It is now widely known that the agrochemicals being applied in staggering quantities worldwide pose serious hazards to both the environment and human health. Furthermore, as target pests mutate and evolve in response to pesticide application the chemicals decrease in effectiveness and thus must be applied in increasing quantity or replaced with new and stronger chemical varieties.

In developed nations such as the United States, concern over the impacts on human health and the environment has led to the banning of many pesticides and the strict regulation of others. However, agrochemicals represent a multi-billion dollar industry and the multinational corporations that manufacture large quantities of pesticides find markets for their products in the developing world. For example, seventy percent of the pesticides used in India are banned or severely restricted in the West. A survey in the Indian state of Punjab detected DDT and BHC – agrochemicals banned in the west – in all of seventy-five samples of human breast milk. During the 1980s, the US was producing 100 – 150 million pounds per year of pesticides considered too dangerous for domestic use. These chemicals were produced for export to nations with less stringent environmental standards. Ironically, such nations often use these chemicals on crops that they grow for export back to the US and Western Europe – in this way citizens of developed countries may be exposed to chemicals banned by their own governments.

Pesticide and fertilizer contamination of drinking water from agricultural runoff is now a worldwide concern. This is especially true in Southeast Asian countries. Thailand imports the most pesticides in the region and over the past three decades has exhibited an annual growth rate in the agrochemical market reaching as high as 8.8 percent. The liberal pesticide market in Thailand has resulted in the widespread availability and use of imported chemicals. Seventy-three percent of the agrochemical imports into Thailand are classified by the World Health Organization (WHO) as category Ia (extremely hazardous), or Ib (highly hazardous). These substances proliferate under a wide variety of trade names and thus are difficult to track or regulate. For example, a 1990 study reported that monocrotophos was being sold under 274 different trade names, methyl parathion under 296 names, and paraquat under 55 names.

Quantity of Pesticide Imports to Thailand 1976-1995


The tax policies of the Thai government have generally been favorable to the growing market of agrochemical imports. A 1997 report indicated that since 1991, pesticides have been exempted totally from import duty and business and municipal taxes. This tax exemption can be interpreted as an indirect subsidy for pesticide imports and contributes to low pesticide prices.iii Additionally, the Thai government maintains a fund for pest outbreaks wherein pesticides are given to farmers for free. Researchers identified this fund as a major pesticide subsidy and indicative of the Thai government and agricultural extension service’s support for agrochemical use.iii Furthermore, the Bank of Agriculture and Agricultural Cooperatives (BAAC) – the major Thai institute for the implementation of agricultural credit policy – has issued short-term credits for agricultural inputs including pesticides.

A major factor in the increased use of pesticides over the past few decades in Thailand and elsewhere is pest resistance and resurgence. Many pests quickly develop resistance to specific chemicals and maintain that resistance even when dosages are increased. Worldwide, the United Nations Food and Agriculture estimates that between 1957 and 1980 the number of insect arthropods resistant to at least one form of insecticide rose from twenty-five to over 430. And while pesticide usage dramatically increased in the US in the thirty years prior to 1974, pre-harvest insect losses rose from seven to about thirteen percent over the same time period.

In Thailand, a 1993 study revealed that the intensification of pesticide application by farmers led to the most severe outbreak of brown plant hopper on record. This organism did not constitute a threat to crops until pesticide application killed off the insects that naturally control its population; increased pesticide application thus served only to increase the severity of the outbreak. Similarly, a 1988 report indicated that pyrethroid application to cotton crops in Thailand decreased in efficacy from around eighty to nearly zero percent within one decade. Other studies have shown that resistance among vegetable crop pest has led to overdosing of pesticides by as much as a factor of eight times the recommended rate.

Many farmers and farm workers are poisoned each year by pesticide exposure. A 1983 United Nations study estimated that between four hundred thousand and two million farmers worldwide were poisoned by pesticides each year, resulting in between twenty thousand and forty thousand deaths. A 1988 report estimated that three hundred thousand farm workers in the US alone suffered from pesticide-related illnesses.vii

Anecdotal evidence from speaking with farmers in and around our community at Pun Pun suggests that sufficient precautions are not taken by farm workers in the region when handling and applying pesticides. Our research so far corroborates these assertions. For example, a 1992 study concluded that farmers generally do not care about or are not aware of potential hazards pesticides may cause for themselves or the consumer. About one-half of Thai farmers apply higher than recommended concentrations and do not pay any or very little attention to labels and protective clothing.

A backpack sprayer used for pesticide application. The bottle contains 2,4 D, a potential groundwater contaminant and possible human carcinogen.


The majority of farmers interviewed in these studies sprayed pesticides frequently, especially in the vegetable and fruit sector, and harvested their crops for marketing before the end of the products’ recommended waiting period.vi Economic factors tend to drive farmers to market rather than accept the losses associated with this waiting period. This has resulted in pesticide exposure to consumers: a 1995 study by the Thai Division of Toxic Substances found that around 37 percent of vegetables, 20 percent of kale, 10 percent of cowpea and 73 percent of tangerines were contaminated with pesticide residues, consisting mainly of malathion, monocrotophos and methyl parathion.

Several studies have identified a lack of information among farmers regarding the danger of application and handling of pesticides as well as regarding the quality and formulation of pesticides, their production date and contents. One study reports that farmers’ perceptions of crop loss are usually higher than their actual crop losses, prompting pesticide overdosing. Furthermore, farmer’s decisions regarding pesticide usage are often based on information given by retailers, other farmers, agricultural extension service agents and even the pesticide companies themselves.iii

The consequences of pesticide misinformation are far reaching. One study of Hmong agricultural workers in highland communities and in urban Chaing Mai indicated that 20-69% of the adults surveyed exhibited risky or unsafe levels of cholinesterase inhibition (an indicator of neurotoxicity) as evidence of exposure to organophosphate and carbamate pesticides. The study also indicated the potential of increased risk among Hmong women who posses less Thai language skill than men and therefore have reduced access to information concerning the hazards of pesticide exposure or the use of protective clothing. For the years 1980 – 1994, an average of around 3,350 occupational pesticide poisoning cases were reported in Thailandiii; however, many cases of pesticide poisoning are never reported. For example, a 1985 study concluded that only 2.4% of Thai workers who have been poisoned by pesticides go to the hospital.iv

Furthermore, the World Health Organization identifies pesticide ingestion as one of the leading suicide methods worldwide. An estimated three million cases of pesticide poisoning occur every year, resulting in an excess of 250,000 deaths, representing a substantial fraction of the 900,000 people who die by suicide every year. This phenomenon is particularly significant in rural areas, especially in Asian countries. The WHO estimates that in the last decade between 60% and 90% of suicides in China, Malaysia, Sri Lanka were due to pesticide ingestion. A 2005 study found that pesticide ingestion is the second leading method of suicide in northern Thailand, accounting for about one-quarter of suicide cases in the most recent years.

Numerous studies have reported the detection of pesticide residues in soils and groundwater in Thailand. One such survey by the National Environment Board found residues in one hundred percent of soil samples and 86 percent of water samples.iv This discouraging reality motivates our present efforts to design an effective drinking water treatment system that is simple and elegant in design, inexpensive to build, operate, and maintain, and will enhance the potential for community self-reliance in the vital sector of drinking water. The next two posts discuss the details of this design project.

I am so hooked up!

Thanks and much love to Christene at You Sabai for setting me up with the sweet apartment share in Kathmandu! The people and the place are super nice!

The apartment belongs to a Tibetan Lama who spends a lot of time traveling around the world giving teachings. When he's gone he rents out his place to travelers. I have a big room all to myself -- it's the Lama's alter room and so it's decorated with all sort of colorful Tibetan artifacts. Very groovy!

It appears the internet connections here are pretty slow, but I'll do my best to keep the blog updated.

For the time being you can read my buddy Tim's blog. He threw me some mad props in a recent post. That's one thing that's great about Tim -- he's always saying nice things about people. Kind of the opposite of me, since I am always giving folks a hard time.

The king made it rain

I know I'm supposed to be an anarchist and all, but the king of Thailand is pretty flippin' cool.

For example, on New Year's Eve, when there were several bombings around Bangkok early in the day, the King altered the flow of time to cause midnight to happen almost three hours early to protect people from other potential attacks at the "traditional" midnight. And it worked. Thai people celebrated their New Year right along with the king at the "new" midnight. If you ask Thai people, they'll tell you they celebrated at midnight, not earlier. So the king did it -- he altered the flow of time. Cool, eh?

You think so? Well, for his next trick, the other day he made it rain in northern Thailand. In the midst of the dry season. When it never rains. Huh? It turns out he holds a patent on rain-making technology. So he sent some jets up to seed the clouds using his technique as part of the "King's Project."

The "King's Project" is big news in Thailand these days. It includes all kinds of programs to promote a clean environment, organic agriculture and self-sufficiency for Thai communities and the nation as a whole. The king made it rain the other evening to help combat the drought that's been brought on by deforestation, and to scrub some of the forest fire pollution out of the air.

So, for a king, he's pretty switched on to the whole environment and self-reliance thing. And apparently he plays trumpet and is an accomplished oil painter. And the Thai people love him. So I gotta hand it to the guy.

Anyway, we had a nice downpour the other night. We were all so fascinated since we have seen or felt a rain drop for months and months and didn't expect any rain for at least the next six weeks. Folks were running around grabbing their laundry off the lines with this kind of frantic demeanor like "What's happening? What do we do? Wait, what? Rain? OK. OK. What shouldn't get wet? OK, I got it. OK laundry...yeah..." and throwing their stuff inside. And we found out how good of a thatch job we did on various buildings...

Personally, I was stoked that I could sleep in a bit for once and not have to get up early to water the gardens.

Ever vigilant with the camera, Ryan caught this lightning strike above our yoga center during the storm. (See more of Ryan's amazing photos on his website.)

Kickin' it monkstyle

Some reasons why my new haircut rocks...

* I'm going to Nepal soon to hang around in monasteries and it will be good to blend in with the Tibetan monks there.

* Thailand is hella hot!

* It's good finally gettin' my shampoo budget under control.

* It feels cool, and it feels cool when people rub my head. If you rub it one way it's all smooth; the other way it's kind of spiky and rough. So there's another way I am like a shark.

* Aerodynamics, for when I am in the zone while gardening or building with cob.

* It's better than having dirty, sticky hair all full of mango sap (see next post just below).

FIRE! (again...)

A couple of weeks ago a poorly placed candle ignited the rice husks and straw lining the composting toilet over at Baan Thai (recently renamed the Panya (Thai for wisdom) Project).

Over at Pun Pun we had just finished dinner and were celebrating Adam's birthday with beer, whiskey, wine, cake and cookies. The call came "Fire at Baan Thai!" and we rolled our eyes and groaned "Not again?!?"

This time it wasn't the villagers burning the surrounding forests. From across the hill at Pun Pun we could see flames reaching fifty, sixty feet in the air and originating from a spot dangerously close to the community's main sala.

So, bellies full of curry, beer, cake and cookies, we sprinted over to fight the fire. I grabbed hoes and shovels from the tool shed along the way. Right away Pi Jeni dove headlong into the flaming dungpile to try to bring the blaze under control.

The flames were so intense I thought my face was going to melt off. The smell was incredible: burning eucalyptus, bamboo, straw, hardwood and thatch, plus human excrement as well as bags of cow and chicken manure that were stacked next to the building. I knew that the tall grasses grew right up to the back of the structure, so immediately I headed around the back and started hoeing under hot coals and flaming embers and throwing dirt over everything that was on fire. The heat was so intense that my clothes were soaked through with sweat within seconds.

Just then I noticed the mango tree growing right up against the back of the outhouse. The flames were so hot that the limbs hissed with the sound of boiling sap and escaping steam. Any moment that tree was going to burst into flame. Then -- forgetabouit -- the fire would surely spread to the whole hillside, taking Christian's house and who knows how much else with it. So I sprinted for the tool shed and returned armed with a bow saw.

In a matter of seconds I brought down several branches that were the most exposed to the heat and flames. Limbs and spatters of molten mango sap rained down on me, as well as on Pi Jeni who was in the thick of it and Ryan who was leaping in and out of the action snapping photos. (All the shots in this post are his.)

We finally managed to get the situation under control, everyone working together to smother the embers with dirt and douse the flames with buckets of water. Until the day before, Baan Thai was in the midst of a water crisis as their well had dried up. They had just finished digging a new and deeper well, and begun pumping water to fill their tanks the day of the fire. It was lucky the fire happened when it did and not earlier or there would have been nothing to do but watch it burn and spread!

Two weeks later, however, small parts of the pile are still smoldering, and the smell of burned excrement still hangs in the air.

As for me, the nest morning my hair was gummed together and sticky with mango sap. It wasn't coming out with warm water, shampoo, nothing. So I figured the time had come for a new hairdoo -- something a little more minimalist...




Workin' the hoe while the heaping dungpile blazes up!


Pi Jeni is a machine! Look at him climbing barefoot over the hot coals!


Here I am workin' the bow saw and trying to save what I can of the mango tree while Pi Jeni launches an attack on the flames.

Seed saving

Seed saving operations are in full swing at Pun Pun. (Thanks to Hadar for these photos from the gardens.)