Environmental monitoring of the sediment pollution along the Thai: Laos Mekong

The Mekong is an essential source of water and protein for the denizens of Thai Laos countries. However historic pollution is adversely affecting the water and sediment quality that threatens the short- and long-term supply/use of this major river system. This can have a major impact on the health and population of the marine life and ultimately adversely affect human health and the economy for both countries. As a first stage in the assessment of the scale and extent of the pollution problem, an in-depth program of sampling and analysis has been carried out for both water and sediments for three seasons since 2000. A range of water quality parameters were measured from ten sampling stations. These included the PolyAromatic Hydrocarbons (PAHs) initially measured as chrysene equivalents, then as individual compounds of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3,cd)pyrene. A range of heavy metals were measured including chromium, cadmium, mercury, copper, zinc, lead, and titanium. This paper presents the results of the field study to date and provides a preliminary evaluation of the extent of the pollution and potential for bioaccumulation within the local food chain

The potential effect of development on the sustainability of the Thai-Laos Mekong

Paper examining the potential effect of development on the sustainability of the Thai-Laos Mekong

Effects of cations, anions and PAHs an the adsorption of cadmium by the Mekong River sediments

The transport of organic anions and cations has interested physiologists for many years despite the generally held view that these transport mechanisms are involved principally in the elimination of foreign substances and metabolites from the body. This paper examines the effects of cations, anions and PAHs an the adsorption of cadmium by the Mekong River sediments

Seasonal variation of polycyclic aromatic hydrocarbons (PAHs) in the Thai-Laos Mekong river, 2003-2004

The great change in the water level of the Mekong River in each season creates the variation in many environmental factors including polycyclic aromatic hydrocarbons (PAHs). Seasonal monitoring of PAHs in water samples from 10 sampling stations along Thai/Laos Mekong River in April 2003- January 2004 from Golden Triangle to Kongchiam were analysed. Quantative analysis of the 16 priority PAHs namely: naphthylene, acenaphthylene, acenaphthene, fluorene, phenathrene, anthracene, flouranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylene and indeno[1,2,3,cd]pyrene were performed

The ecological complexity of the Thai-Laos Mekong River : I. Geology, seasonal variation and human impact assessment on river quality

The objective of this study is to assess the variation of pollution in the Thai-Laos Mekong associated with seasonal dynamics concomitant with the natural geological features and human activities that impact on the adverse quality of the river. The complex ecology of the 1500 km stretch of the Thai-LaosMekong River has been studied in this paper to understand the relationship with the geomorphology, with the sub-tropical monsoonal climate and the impact of human activity. Sub-surface geology controls the nature and extent of the drainage basin and of the river channel. The volume flow of the river varies naturally and dynamically in phase with the rainfall; traditional models based on steady state hydraulics are inappropriate. Continuous erosion of the river banks and bed generates a sediment load of impure silt, mica, quartz and clay minerals that inhibits light penetration and limits the primary productivity of the river. The river separates two countries at different stages of development; it flows through or close to eight non-industrial conurbations (Populations 350,000-2,000,000) but is otherwise sparsely populated. The river is used for subsistence agriculture, village transport, fishing including aquaculture and as a source of domestic water. Hydroelectricity is generated from the Laos tributaries. The river is a depository for partially treated urban waste and untreated village waste, hence populations of E.coli bacteria sometimes render the water unsuitable for drinking unless treated with the highest value of 240/100ml found at station 7 during the summer season of 2003. Furthermore the river is polluted by trace metals, notably cadmium and mercury, and by Polycyclic Aromatic Hydrocarbons (PAHs), which are particularly concentrated in the sediments. Previous work has shown that cadmium and mercury exceed the Probable Effect Level (PEL) values of Canadian Environmental Quality Guidelines and that the PAH concentrations were also greater than the Interim Sediment Quality Guidelines (ISQG). Consequently the fish stock, a vital source of protein for the local human population maybe seriously affected. As conflict between the demands of human activities will be exacerbated by the continuing development of the basin; monitoring must be continued and a better model of the river's ecology is needed to predict the impact of development