Mercury content of several predacious fish in the Andaman sea

During April 1975 thirty-six muscle samples of six predacious species of fish from the Andaman sea were collected for an analysis of their total mercury concentrations. The total mercury levels ranged from 0.026 to 0.234 ppm in yellowfin tuna (Neothunnus albacora), from 0.027 to 0.233 ppmin bigeye tuna (Parathunnus sibi), and from 0.057 to 0.478 ppm in four species of shark. Statistical analysis also showed positive linear regression and there was correlation between the mercury concentration and the weight of the yellowfin tuna, bigeye tuna, and shark. The rates of total mercury accumulation in yellowfin and bigeye tuna were not significantly different. A comparison between the total mercury level in the Andaman yellowfin and the Central Pacific yellowfin tuna is discussed.     

Heavy metals,organochlorine pesticides and PCBs in green mussels,mullets and sediments of river mouths in Thailand

This investigation was undertaken to determine the levels of lead, zinc, copper, cadmium, and mercury and certain organochlorines including DDT and PCBs in green mussels, mullets, and bottom sediments of the mouths of the river Mae Klong, Ta Chin, Chao Phraya, and Ban Pakong. The four river mouths are contaminated by the five heavy metals to some extent. The contamination of lead in mussels, mullets and sediments was quite obvious, at values significantly higher than those previously reported. Contamination of the other four metals in mussels and mullets was still within acceptable limits, except for mercury in the Chao Phraya river mouth which was approaching the limit. Organochlorines, especially DDT and its metabolites, are detectable in some samples of mussels, mullet, and sediments. PCBs were detectable in some samples of mussels and mullets, but none were detected in the sediments. The levels of these organochlorines are considered to be comparable to baseline levels.     

Water pollution and habitat degradation in the Gulf of Thailand

The Gulf of Thailand has been a major marine resource for Thai people for a long time. However, recent industrialization and community development have exerted considerable stress on the marine environments and provoked habitat degradation. The following pollution problems in the Gulf have been prioritized and are discussed in details: (1) Untreated municipal and industrial waste water are considered to be the most serious problems of the country due to limited waste water treatment facilities in the area. (2) Eutrophication is an emerging problem in the gulf of Thailand. Fortunately, the major species of phytoplankton that have been reported as the cause of red tide phenomena were non-toxic species such as Noctiluca sp. and Trichodesmium sp. (3) Few problems have been documented from trace metals contamination in the Gulf of Thailand and public health threat from seafood contamination does not appear to be significant yet. (4) Petroleum hydrocarbon residue contamination is not a problem, although a few spills from small oil tankers have been recorded. A rapid decrease in mangrove forest, coral reefs, and fisheries resources due to mismanagement is also discussed.