Rattanawat Chaiyarat

PHYTOSTABILIZATION OF A PB-CONTAMINATED MINE TAILING BY VARIOUS TREE SPECIES IN POT AND FIELD TRIAL EXPERIMENTS

The potential of 6 tree species (Leucaena leucocephala, Acacia mangium, Peltophorum pterocarpum, Pterocarpus macrocarpus, Lagerstroemia floribunda, Eucalyptus camaldulensis) for phytoremediation of Pb in sand tailings (total Pb >9850 mg kg−1) from KEMCO Pb mine in Kanchanaburi province, Thailand, were investigated employing a pot experiment (3 months) and field trial experiment (12 months). In pot study E. camaldulensis treated with Osmocote fertilizer attained the highest total biomass (15.3 g plant−1) followed by P. pterocarpum (12.6 g plant−1) and A. mangium (10.8 g plant−1) both treated with cow manure. Cow manure application resulted in the highest root Pb accumulation (>10000 mg kg−1) in L. floribunda and P. macrocarpus. These two species also exhibited the highest Pb uptake (85-88 mg plant−1). Results from field trial also showed that Osmocote promoted the best growth performance in E. camaldulensis (biomass 385.7 g plant−1, height 141.7 cm) followed by A. mangium (biomass 215.9 g plant−1, height 102.7 cm), and they also exhibited the highest Pb uptake (600-800 μg plant−1). A. mangium with the addition of organic fertilizer was the best option for phytostabilization of Pb-contaminated mine tailing because it retained higher Pb concentration in the roots.

Effects of Soil Amendments and EDTA on Lead Uptake by Chromolaena Odorata: Greenhouse and Field Trial Experiments

Greenhouse and field trial experiments were performed to evaluate the use of Chromolaena odorata with various soil amendments for phytoextraction of Pb contaminated soil. Pb mine soils contain low amount of nutrients, so the additions of organic (cow manure) and inorganic (Osmocote and NH4NO3 and KCl) fertilizers with EDTA were used to enhance plant growth and Pb accumulation. Greenhouse study showed that cow manure decreased available Pb concentrations and resulted in the highest Pb concentration in roots (4660 mg kg−1) and shoots (389.2 mg kg−1). EDTA increased Pb accumulation in shoots (17-fold) and roots (11-fold) in plants grown in soil with Osmocote with Pb uptake up to 203.5 mg plant−1. Appli- cation of all fertilizers had no significant effects on relative growth rates of C. odorata. Field trial study showed that C. odorata grown in soil with 99545 mg kg−1 total Pb accumulated up to 3730.2 and 6698.2 mg kg−1 in shoots and roots, respectively, with the highest phytoextraction coefficient (1.25) and translocation factor (1.18). These results indicated that C. odorata could be used for phytoextraction of Pb contaminated soil. In addition, more effective Pb accumulation could be enhanced by Osmocote fertilizer. However, the use of EDTA in the field should be concerned with their leaching problems.

Elucidation of distribution patterns and possible infection routes of the neurotropic black yeast Exophiala dermatitidis using AFLP.

Distribution of populations of the opportunistic black yeast Exophiala dermatitidis was studied using AFLP. This fungus has been hypothesized to have a natural habitat in association with frugivorous birds and bats in the tropical rain forest, and to emerge in the human-dominated environment, where it occasionally causes human pulmonary or fatal disseminated and neurotropic disease. The hypothesis of its natural niche was investigated by comparing a set of 178 strains from natural and human-dominated environments in Thailand with a worldwide selection of 107 strains from the reference collection of the CBS Fungal Biodiversity Centre, comprising 75.7% clinical isolates. Many isolates had unique AFLP patterns and were too remote for confident comparison. Eight populations containing multiple isolates could be distinguished, enabling determination of geographic distributions of these populations. Some of the populations were confined to Thailand, while others occurred worldwide. The local populations from Thailand contained strains from natural and urban environments, suggesting an environmental jump of the fungus. Strains from human brain belonged to widely dispersed populations. In some cases cerebral isolates were identical to isolates from the human intestinal tract. The possibility of cerebral infection through intestinal translocation was thus not excluded.

Organochlorine pesticide levels in the food web in rice paddies of Bueng Boraphet wetland, Thailand

The contamination by organochlorine pesticides (OCPs) of water, sediments, rice grains and leaves, and animals of different trophic levels, collected from rice paddies surrounding Bueng Boraphet wetland, central Thailand, was studied during November 2009 to February 2010. The levels of total dichlorodiphenyltrichloroethanes (ΣDDT) were too low to be detected in any samples. High levels of total hexachlorocyclohexanes (ΣHCH) and total aldrins (ΣALD) and low levels of total chlordanes (ΣCHL) were detected in both sediments and rice grains. α-HCH, β-HCH, γ-HCH, and aldrin in rice grains exceeded the acceptable limits set by the Ministry of Public Health of Thailand. Rice grains were at high risk of contamination due to the direct spraying of OCPs. Fishes were contaminated with moderate levels of aldrin. Continued surveys of pesticide contamination in water, sediments, and organisms of each trophic level are recommended to more effectively monitor and control agricultural pesticide usage around Bueng Boraphet wetland and to further assess the ecological risks and impacts on human health.

Lead tolerance and accumulation in Pteris vittata and Pityrogramma calomelanos, and their potential for phytoremediation of lead-contaminated soil.

A field survey was conducted to search for Pb accumulation in fern species at Bo Ngam Pb mine, Thailand. Eleven fern species including Pteris vittata accumulated Pb in the range of 23.3–295.6 mg kg−1 in the aboveground parts. Hydroponic, pot, and field trial experiments were carried out to investigate Pb-accumulation ability in ferns; including P. vittata and the ornamental species, Pityrogramma calomelanos, Nephrolepis exaltata cv. Gracillimum, and N. exaltata cv. Smirha. In hydroponic experiment, Pi. calomelanos accumulated the highest concentration of Pb (root 14161.1 mg kg−1, frond 402.7 mg kg−1). The pot study showed that P. vittata, Pi. calomelanos, and N. exaltata cv. Gracillimum grew well when grown in soil Pb at 92900 mg kg−1. N. exaltata cv. Gracillimum accumulated the highest Pb concentration in the frond (5074 mg kg−1) and P. vittata accumulated the highest Pb concentration in the root (16257.5 mg kg−1). All fern species exhibited TF values less than 1 in both hydroponic and pot experiments. When P. vittata and Pi. calomelanos were grown at mine soils for 6 months, P. vittata tolerated higher soil Pb (94584–101405 mg kg−1) and accumulated more Pb in frond (4829.6 mg kg−1) and showed TF > 1 after 2 months of growth. These results indicated that P. vittata can be potentially useful for phytoremediation of Pb-contaminated soil.

Populations of domesticated cattle and buffalo in the Western Forest Complex of Thailand and their possible impacts on the wildlife community

The Western Forest Complex (WEFCOM) of Thailand is comprised of many protected areas and has one of the highest wildlife populations in the country. Populations of wildlife in the WEFCOM have decreased dramatically over recent years. Rapid economic development has resulted in the conversion of forest into agricultural and pastoral land, which has directly and indirectly impacted the wildlife community. This research aimed to evaluate populations of domesticated cattle (Bos indicus) and buffalo (Bubalus bubalis) in the WEFCOM and their possible impacts on the wildlife community. Domesticated cattle and buffalo keepers from 1561 (or 3.3%) of houses in and near WEFCOM were interviewed. The average number of animals per household was 15.6 cattle and 8.5 buffalo. Most villagers released domesticated cattle and buffalo to forage in the protected areas. This tended to have a high impact on the wildlife community in Huai Kha Khaeng Wildlife Sanctuary and Tungyai Naresuan Wildlife Sanctuary. The least impacted areas were Luam Khlong Ngu National Park, Thong Pha Phum National Park and Chaleam Ratanakosin National Park. With a high risk to the wildlife community, law enforcement should be used in combination with a certain level of co-management with local communities.

Effects of Grazing on Nesting of the Oriental Pratincole (Glareola maldivarum) in Bueng Boraphet Wetland, Thailand

Livestock grazing may negatively impact bird nesting in wetland habitats. This study evaluated the effect of grazing on the nests of the Oriental pratincole (Glareola maldivarum) along the grassland of a wetland at six study sites with different densities of grazing cattle and buffalo. Species richness, density, cover, and height of vegetation in the study areas were different (P < 0.05). The density of cattle and buffalo at the various sites affected vegetation composition and amount, which in turn influenced bird nest density. The estimated trampling rates, number of fledglings, and number of trampled eggs were different among study sites (P < 0.05). The density of cattle and buffalo has an influence on nest failure rates. The factors that influenced the mortality rates of the Oriental pratincole were trampling and unhatched eggs. Only 48.5% of the nests were successful at sites where cattle and buffalo continuously grazed in the grasslands at high densities. Thus, increases in the density of cattle and buffalo will reduce the number of nests of the Oriental pratincole, which may result in a reduction of the overall population in the future.

Captive breeding and reintroduction of the oriental pied hornbill (Anthracoceros albirostris) in Khao Kheow Open Zoo, Thailand

This article discusses two related issues of the captive breeding and reintroduction of the Oriental pied hornbill (Anthracoceros albirostris) in order to increase its population in the natural habitats. Oriental pied hornbills were bred in Khao Kheow Open Zoo. Three pairs were separated and kept in breeding cages. Females occupied artificial nests between February and April 2005-2007. Eggs were laid and incubated between February and March each year from 2005 to 2007. Nestlings hatched in late March and left the nest in late April 2005-2007. Each breeding pair was fed with approximately 400 g of food each day. All three pairs reproduced resulting in mature offspring of seven in 2005, six in 2006, and five in 2007. Four of sixteen 3-year-old birds were randomly selected and equipped with a GPS receiver on their backs. Activities of the birds attached and unattached with GPS were not significantly different. The first two birds (one female, one male with GPS) were reintroduced on August 5, 2006, and another nine birds (four birds with GPS) were reintroduced on December 26, 2006. The average home range of these reintroduced birds was 0.13 km(2) . Their foods consisted of wild plants and animals in the home range. The first reintroduced pair was able to breed naturally by laying and hatching eggs in an artificial nest. Two juveniles left the nest in April 2008. These results indicate that both captive breeding and reintroduction are potentially important ways to increase the population of the Oriental pied hornbill in natural habitats.