Communities haunted by mining contamination can look to unique plants to fight their worst fears. “Phytomediation can help us clean tainted environment,” explains Dr. Augustine Doronila, a senior research fellow at the University of Melbourne in Australia.
Phytoremediation is the use of living plants to mop up pollution in the environment like metal contaminants in the soil, and restore ecological balance in a mining area.
Doronila recently proposed assembling a multidisciplinary research group to study the various aspects of using phytoremediation in the country. The group will be called Philippine Metalophyte Research Consortium to be based in Ateneo de Manila University. Its research mission will cover the determination of botanical, chemistry, biological, geological, ecological, and anthropological aspects of implementing phytoremediation in the Philippines.
A visiting scientist under the Department of Science and Technology’s Balik Scientist Program, Doronila says there are endemic plant species in the country that can help restore mining-damaged soils.
Metal accumulating plant species
A group of botanists including Manila-based Dr. Domingo Madulid discovered in 2003 a prolific contaminant fighting species called Phyllanthus balgooyi (Euphorbiaceae). The shrub can be found only in two locations--in open patches of a stunted forest in Palawan and in Sabah. A cut stem of the plant secretes jade-green liquid that contains 88,580 ug Ni/g of dry weight. Its leaves and stems can also accumulate significant amounts of nickel and chemicals used in extracting nickel.
Phyllanthus balgooyi is a hyper accumulator, or a plant that can accumulate extraordinarily high levels of metals in its system. It’s a rare trait as there are only 450 taxa of hyper accumulators discovered in the whole world so far.
There are only four species of nickel hyper accumulating species in the Philippines, all found in Palawan, and belong to the Euphorbiaceous, Meliceae, Ochnaceae, and Dichapetalaceae families.
In a visit to Zambales, Doronila discovered a possible new nickel hyper accumulator that belongs to the Euphorbiacea family. “Tropical hyper accumulator plants are poorly studied,” he said. “These are most likely found on ultramafic or serpentine rock formations.” Serpentine or ultramafic soils often contain high concentrations of magnesium and some toxic metals.
Mining and soil damage
The country is among the world's top producers of chromite, copper, nickel, and gold. Various estimates rank the Philippines’ gold and copper reserves as the world's fifth-largest.
According to the Department of Environment and Natural Resources’ Mines and Geosciences Bureau, there are 24 operating medium to large scale metallic mines in the country, up from 18 in 2006. Moreover, there are over 800 abandoned mines scattered all over the country.
Mining can set off severe effects on the environment. Wastes from extraction and processing of mineral resources are laden with heavy metals and chemicals that can seriously contaminate soil and water. Exposure to these contaminants affects people’s health and livelihood. Contaminants also have adverse effects on other organisms and biodiversity.
Moreover, contaminated soils can no longer be profitably used for crop production. “Normally, people who grow crops on infertile contaminated soils will only earn about P5,500 net per hectare every year,” he says. “Once the soil is restored, earnings can go up as high as P165,000 net per hectare.” Doronila based his figures in an actual phytoremediated base-metal smelter in South Africa.
In a previous visit to a mining site in Acoje, Zambales, Doronila noted the highly-contaminated soil and its effects to surrounding plants. Some pitcher plants, shown in his slide presentation, were yellowish but surviving very well. “And look at those shoots growing out of the fallen tree’s branches,” he noted. “It’s a sign of hope. Those budding shoots tell us that the plant can grow very well in contaminated soil.” He suggested that the area be planted with the newly discovered hyper accumulator.
The growth of vegetation in a mining contaminated area is a sign that the topsoil can still be restored. “The most important thing that mining operations can do is to protect the topsoil,” he says. Topsoil resource is the major source that plant materials need in post-mining reclamation and restoration, he adds.