Background levels of heavy metals in plants of different taxonomic groups from a montane rain forest in Sri Lanka

An undisturbed natural reserve area iocated in a tropical montane rain forest at about 1800 m altitude in Sri Lanka served as a study site to investigate and assess the natural background concentration levels of As, Cd, Co, Cu, Ni, Pb and Zn in plants representing different taxonomic groups (divisions) in the plant kingdom. The plants selected were: the lichen,Usnea barbata (old man's beard);Pogonatum sp. (a moss);Lycopodium selago (epiphytic lycopod);Polypodium lanceolatum (epiphytic fern);Bulbophyllum elliae (epiphytic orchid) andActinodaphne ambigua (dicotyledonous large tree). Degree of homogeneity with respect to Cd, Cu, Pb and Zn in homogenised materials of all samples were within acceptable limits, whereasPogonatum sp. showed the highest degree of homogeneity for Pb. In addition to confirming extremely low levels of heavy metals in all plant species, the survey also found that generally the primitive plants,Usnea andPogonatum appear to have a greater tendency to accumulate As, Cd, Co and Pb; in particular,U. barbata appears to be an efficient accumulator for those heavy metals, suggesting its potential use in environmental studies.Actinodaphne ambigua was found to have a specific accumulating ability for nickel. Surface cleaning of theA. ambigua leaves resulted in a substantial decrease in the foliar contents of Cd, Ni, Pb and Zn. Variations in heavy metal contents observed in different plant genera are discussed in terms of their habits and place of growth in the forest. It is anticipated that the background levels presented in this paper from a remote, unpolluted tropical ecosystem will provide useful reference data for comparative environmental studies.     

Biomineralogy of human urinary calculi (kidney stones) from some geographic regions of Sri Lanka

Kidney stones (urinary calculi) have become a global scourge since it has been recognized as one of the most painful medical problems. Primary causative factors for the formation of these stones are not clearly understood, though they are suspected to have a direct relationship to the composition of urine, which is mainly governed by diet and drinking water. Sixty nine urinary calculi samples which were collected from stone removal surgeries were analyzed chemically for their Na, K, Ca, Mg, Cu, Zn, Pb, Fe and phosphate contents. Structural and mineralogical properties of stones were studied by XRD and FT-IR methods. The mean contents of trace elements were 1348 mg kg⁻¹ (Na); 294 mg kg⁻¹ (K); 32% (Ca); 1426 mg kg⁻¹ (Mg); 8.39 mg kg⁻¹ (Mn); 258 mg kg⁻¹ (Fe); 67 mg kg⁻¹ (Cu); 675 mg kg⁻¹ (Zn); 69 mg kg⁻¹ (Pb); and 1.93% (PO₄³⁻). The major crystalline constituent in the calculi of Sri Lanka is calcium oxalate monohydrate. Principal component analysis was used to identify the multi element relationships in kidney stones. Three components were extracted and the first component represents positively correlated Na-K-Mg-PO₄³⁻ whereas the␣second components represent the larger positively weighted Fe–Cu–Pb. Ca–Zn correlated positively in the third component in which Mn–Cu correlated negatively. This study indicates that during the crystallization of human urinary stones, Ca shows more affinity towards oxalates whereas other alkali and alkaline earths precipitate with phosphates.Contribution from the Environmental Geology Research Group (EGRG), Department of Geology, University of Peradeniya, Sri Lanka.     

Gender in integrated water management: an analysis of variation

Gender is an important variable in water use, policy, and intervention. This article explores this variation and its policy implications. Concepts are applied in several case studies to draw generic conclusions. Variation is related to the purpose of water use (consumptive or productive) and to the local, culture-specific patterns of the intra-household organization of consumption for family welfare (which includes domestic water provision) and income-generation (for which water is an input, especially in rural areas). For domestic water use, the intra-household sharing of unpaid domestic responsibilities is a key gender issue. Water for productive use, on the other hand, is embedded in the gendered organization of household economic activity, as elaborated for smallholder-irrigated agriculture. In female-managed and dual farming systems, where a high proportion of farm decision-makers are women, irrigation agencies need to better target their support. In male-managed farming systems, however, the majority of women lack their own farm enterprise in which water is an input. Women's access to land, markets and credits besides access to water, is at stake. To conclude, given the strong variation in water use along gender lines, gender analysis is indispensable for any concrete water policy and intervention.     

Housing anxiety and multiple geographies in post-tsunami Sri Lanka

Tsunami intervention has been an extraordinary and unprecedented relief and recovery operation. This article underlines the complexities posed by shelter and housing intervention in post-tsunami Sri Lanka, revealing a pragmatic, reductionist approach to shelter and housing reconstruction in a contested and fragmented environment. Competition, housing anxiety and buffer zone implementation have resulted in compulsory villagisation inland, stirring feelings of discrimination and tension, and becoming major obstacles to equitable rebuilding of houses and livelihoods. A new tsunami geography has been imposed on an already vulnerable conflict-based geography, in which shelter has been conceived as a mono-dimensional artefact. An analysis of the process and outcomes of temporary and permanent post-tsunami housing programmes yields information about the extent to which shelter policies and programmes serve not only physical needs but 'higher order' objectives for a comprehensive and sustainable recovery plan.     

Observations on metal concentrations in commercial landings of two species of tilapia (Oreochromis mossambicus and Oreochromis niloticus) from reservoirs in six river basins in Sri Lanka

Samples of the muscle of two species of tilapia (Oreochromis mossambicus and O. niloticus; 17–20 cm length) were obtained from at least one reservoir in each of the six river basins (Aruvi Aru, Kala Oya, Kirindi Oya, Ma Oya, Mahaweli, and Walawe Ganga catchments) in Sri Lanka. The metals Ca, Cu, Fe, K, Mg, Mn, Na, and Zn were consistently detected in the muscle tissue. Overall, there were few differences in the concentration of metals between the two species of fish, although there were also some statistically significant differences (p < 0.05) in the concentrations of some metals in fish obtained from some of the reservoirs. Aruvi Aru stands out as a river basin in which the two fish species have significantly lower concentration of metals when compared to other river basins. The concentration of the metals studied were below WHO and FSANZ guideline values for fish, suggesting that the consumption of the metals found in tilapia from these reservoirs poses little risk to human health.     

Recent Changes in Land-Use in the Pambala–Chilaw Lagoon Complex (Sri Lanka) Investigated Using Remote Sensing and GIS: Conservation of Mangroves vs. Development of Shrimp Farming

Shrimp aquaculture is currently one of the major threats to mangroves, their destruction causing both environmental and social problems. This study investigated the mangrove area in the Pambala–Chilaw Lagoon complex (07°30 N, 079°49 E) in Sri Lanka. Using air-borne remote sensing, a land-use map was constructed in a geographical information system of the study area and pond managers were interviewed about the functioning of their shrimp farms. Based on fieldwork during the four years after taking the aerial photographs, an updated GIS-based land-use map was constructed and compared the original situation. This revealed that shrimp farms had expanded with by 25 ha in four years, mainly at the expense of mangrove forest (approx. 13 ha) and coconut plantations (approx. 11 ha). Official documents from the World Conservation Union advise conservation of the undisturbed habitats in Pambala, but this study's observations do not corroborate an eventuation of this. Other authors reported political patronage as the main cause of this adverse situation. Since the shrimp industry depends on various ecological services provided by the mangrove ecosystem in order to maintain production (cf. ecological footprint concept) the mangrove destruction is counter-productive and these observations are therefore alarming for the aquaculturists as well. The low ratio (2.6 : 1) of remaining mangrove to shrimp pond area suggests that the industry may experience severe problems, particularly as mangrove areas continue to be reclaimed for aquaculture or other land uses, unless drastic measures are taken.     

Influence of temperature and soil type on the toxicity of three pesticides to Eisenia andrei

Expansion of agriculture in the tropics has increased the use of pesticides that may affect the soil ecosystems. Few studies so far determined the effects of pesticides in the tropics and tropical risk assessment therefore often relies on data from temperate conditions. Hence we compared the toxicity of chlorpyrifos, carbofuran and carbendazim to the earthworm Eisenia andrei at two different temperatures reflecting temperate and tropical conditions. The toxicity of the three pesticides in both conditions decreased in the order carbendazim > carbofuran > chlorpyrifos. For chlorpyrifos and carbofuran, but not for carbendazim, survival was more sensitive at the higher temperature, probably due to increased earthworm activity. Sub-lethal effects (reproduction and growth) however, varied inconsistently with temperature and soil types. We conclude that toxicity of pesticides in tropics may not be predicted from data generated under temperate conditions, even within the same species.     

Post-disaster recovery dilemmas: challenges in balancing short-term and long-term needs for vulnerability reduction

Following disasters, governments often clamor to quickly reduce risk, rebuild communities and restore permanence. The pressure to urgently address complex, difficult decisions can result in reactive policies that may increase long-term vulnerability of affected populations. Sri Lanka in the aftermath of the 26 December 2004 tsunami represents such an example: a hastily designed coastal buffer zone policy has incited massive relocation of affected populations and resulted in social, economic and environmental problems that threaten the well-being of poor coastal communities. We review the impacts of this policy from its inception, days after the tsunami hit the island, until its revision, approximately 10 months following the disaster. We then apply a framework to conceptualize the components of vulnerability within Sri Lanka's coastal, human–environment system and to identify where post-disaster policies should focus to reduce vulnerability of coastal populations more effectively. From this analysis, it is apparent that the buffer zone policy gave disproportionate attention to reducing exposure to future tsunamis and, subsequently, did not address the critical social, economic and institutional factors that influenced sensitivity to the hazard. Post-disaster policies aimed at sustainable re-development should be informed by an analysis of the components of vulnerability that comprise a system and how these can be most effectively influenced during the separate short-term and long-term phases of rebuilding.     

Use of seaweeds for monitoring trace elements in coastal waters

Concentrations of a wide range of trace elements: arsenic, cadmium, cobalt, chromium, hafnium, nickel, thorium, uranium, zinc and the rare earth elements, cerium, europium, samarium, terbium and ytterbium were determined by instrumental neutron activation analysis in the brown alga,Fucus vesiculosus from Eckwarder Hörne, North Sea and from Rügen, Baltic Sea. Another brown alga,Sargassum filipendula from Sri Lanka, Indian ocean (representing an unpolluted control station) was similarly investigated. Cobalt, chromium and nickel concentrations were highest inF. vesiculosus from the North Sea while zinc was highest in samples from the Baltic Sea, reflecting high levels of these elements in coastal waters of the North and the Baltic sea. Cadmium, cobalt, nickel and zinc levels were lowest inS. filipendula from Sri Lanka, probably demonstrating lower levels of those elements in coastal waters. Concentration levels of hafnium, thorium, uranium, and the rare earth elements were highest inS. filipendula. Two years later in 1994,S. filipendula along withUlva sp. (green alga) was resampled from the same sampling site, and in addition to the above elements, six other trace elements (Ag, Ba, Br, Rb, Se and Sr) were determined.Sargassium filipendula showed a particular affinity for Ag, As, Br and Sr. For the other elements, marginal concentration differences were observed betweenS. filipendula andUlva sp., probably reflecting the regional background levels. Substantially higher concentrations of Hf, Th, U, and the rare earths were found again in the 1994Sargassum andUlva samples, reflecting the effect of a substrate rich in rare earth elements. The brown algae used in this study may be used to monitor trace elements in coastal waters.