Sugar cane : arsenic :: love : marriage

Whew! Deriving today's title required summoning dusty recollections of analogies from the recesses of my mind. Anyway, many locals know one of Hilo's worst-kept secrets: that Hilo Bay and environs are polluted with arsenic, a by-product of the Canec industry. Canec is a building material, made only in Hawaii, that was popular and cheap, and made from sugar cane stalks treated with arsenic.

From 1932 to 1963 the Hawaiian Cane Products plant in Hilo manufactured Canec from bagasse, the fiber left after sugar cane stalks are crushed for their juices. The process included treating Canec with arsenic to deter insects and minimize mildew. Although Canec hasn't been manufactured in decades, contamination survived. At least one study reported arsenic concentrations in the sediments of Hilo Bay as high as 6370 ppm, approximately 34 times higher than anywhere else in the state.

A few years ago the plan was to cover shoreline soils with three feet of fresh soil. I'm not quite sure what that would--or did--accomplish, since the proposed fix seemed as ineffective as the discredited "solution to pollution is dilution." Nevertheless, as recently as late April, the Hawaii Tribune Herald reported that work was continuing on efforts to cover up contaminated soil on the site of the future Target and Safeway stores in Hilo, where high levels of arsenic, dioxins and petroleum compounds were found.

So, if covering up a heavy metals problem, well, only covers it, what's the alternative? Yup, you guessed it. Vetiver!

Research conducted at least since the mid 1980s confirms that Vetiver tolerates a wide range of soil acidity, alkalinity, salinity, sodicity, and elevated levels of Aluminium, Manganese, and heavy metals such as Arsenic, Cadmium, Chromium, Nickel, Lead, Zinc, Mercury, Selenium and Copper in the soil. (Truong, P., et al).

It also absorbs large quantities of heavy metals from industrial waste and, in the process, protects ground water from contamination, claim a duo of researchers at India's Kerala University.

In a paper presented at the Kerala Environment Congress 2010, concluded on Saturday, researchers D.S. Jaya and G. Dhanya report that the penetrating roots of fast-growing
Vetiver can effectively remove hazardous heavy metals from industrial effluents.

Since industrial waste poses a great threat to the environment, Vetiver will become a great boon, say the researchers, who are the faculty members of the Department of Environment Science of Kerala University. Vetiver planted around industrial firms that flush out metal-rich waste water will remove the metals from the water. "Thus the soil and ground water of the region will be protected without being degraded," Jaya said.

Large numbers of Vetiver plants could be grown in artificial wetlands around factories and industrial units and thus protect the environment, she said, adding that technologies were also available to recover the metals from the plant material.

"Another interesting fact is that the plants have shown different efficiency for absorbing different metals. Good results are shown for zinc, lead and cadmium," Jaya said.

Vetiver...it's not just for the birds.

This feed by G. Mahadevan of The Hindu just in from Kerala, India, the birthplace of Vetiver. Our favorite plant will take a lead role in stabilizing a lake and creating a forest-like environment for birds:

Polluted and stagnant water, crumbling banks and dwindling fauna may soon be a thing of the past at the lakes inside the Thiruvananthapuram zoo. The old-world charm of the 3.5-acre lake is being recreated as part of a substantial cleaning and beautification project being implemented by the Centre for Science and Technology for Rural Development (COSTFORD).

The de-silting of the small lake at the zoo has already started. The silt from the small lake and the large, 3.5-acre one, will be deposited at the island in the middle of the latter. Clumping bamboo and Vetiver (Raamacham) will be planted along the perimeter to prevent soil erosion. In addition to purifying the air, Vetiver plants also soak up heavy metals present in the lake’s water, COSTFORD director P.B. Sajan told The Hindu.

Varieties of fish endemic to the State, and quickly reproducing, will be introduced in the water body to ensure an adequate supply of food for the large number of birds, including migratory ones, that visit the lake every day. The 1.5-acre patch of land that straddles the lake and the zoo’s boundary wall will be densely planted with trees, creepers and climbers.

The idea is to create a forest-like environment for the birds to rest and nest. Visitors will not be permitted to access this part of the lake.

An observation deck and a tower will allow visitors to see the birds at their natural best. While the deck will jut out into the lake to allow visitors to see the fish, the tower will be tall enough to allow a clear view of the lake’s island. The designs of the deck and the tower will complement the lake’s ambience.

As part of the project, rainwater that now drains from the zoo compound will be directed to a settling pond near the small lake, and then flow to the small lake. Water will enter the city’s drainage system only when the large lake overflows. Intermittent flow of rainwater through the two lakes will keep their waters fresh. A spring that feeds the small lake has temporarily been diverted to facilitate de-silting activities.

Once the lakes are cleaned and beautified a fishpond—with a fountain—encircled by benches and seats, will be created on the lawns near the Museum’s Corporation gate. This will replace the present visitor center, which is the bandstand opposite the Museum compound. March 2010 is the targeted completion deadline, Mr. Sajan adds.