Seasonal variations in cell abundance of Noctiluca scintillans in the coastal waters off Chonburi Province, the upper Gulf of Thailand

Seasonal variations in cell abundance of Noctiluca scintillans was studied from June 2003 to November 2004 in the coastal waters off Chonburi Province, the upper gulf of Thailand. Eight stations from Bangpakong River mouth to Angsila were designed to cover the area where red tides often occurred and were under the influence of Bangpakong River. Numerical abundance was analyzed in relation with some environmental parameters. A total of 9 N. scintillans red tides, 7 Ceratium furca red tides and 4 diatom red tides were found in this study. Noctiluca and Ceratium red tides were often found when salinity was in the range of 22 to 33psu. and 12 to 27psu., respectively. Those red tides were not associated with apparent negative effects to marine animals. N. scintillans cells could be observed almost all year round at offshore stations where the water depth was more than 10 meters except strong wind periods, suggesting that Noctiluca in coastal waters were supplied by cells from offshore stations. In contrast, no consistent pattern was observed in the distribution of N. scintillans in coastal waters, in particular near the river mouth. Only the relationship between phosphate concentrations and cell densities of Noctiluca has been found statistically significant. However, the high cell densities of both Noctiluca and Ceratium were often observed in the rainy season, especially on the calm day after heavy rain. These observations suggested that the red tides of those two species in coastal waters were growth response to the influence of freshwater run off from Bangpakong River

Petroleum hydrocarbon residues in the marine environment of Koh Sichang-Sriracha, Thailand

This study describes petroleum hydrocarbon (PHC) contamination in water, sediment and green mussels (Perna viridis) of the coastal area of Koh Sichang-Sriracha, Chonburi along the Eastern coast of the Gulf of Thailand. The concentrations of PHC in coastal waters, as determined by UVF technique, were found to range from 0.01-12.55μgl(-1) (chrysene equivalents) with higher values generally confined to port/pier areas. Analysis of surface sediments for PHC revealed that most of the sediments contained appreciable quantities of PHC. The concentrations of PHC in surface sediments varied from 1.1 to 153.4μgg(-1) dry weight, with the mean value of 29.4±30.0μgg(-1). The majority of values of PHC concentration in the surface sediments of Koh Sichang-Sriracha coastal area exceeded 10μgg(-1) and the trend is indicative of transfer of PHC loads from the inshore areas to the offshore sediments. The average concentration of PHC burdens in the mussel tissues at Sriracha ranged from 8.1 to 161.0μgg(-1) wet weight, with the average value of 43.7±55.5μgg(-1), while that at Koh Sichang ranged 9.6-62.4μgg(-1) and the mean value was 23.1±17.2μgg(-1). Bioconcentration factor (BCF) for PHC in green mussels was determined and found to vary from 1.7×104 to 3.5×105. The possible sources of oil contamination in the coastal waters of Koh Sichang-Sriracha marine area were the discharge of oily wastewater and lubricating oil from intensive shipping/boating activities at the port/pier areas, disposal of wastes from anchorage vessels, municipal and industrial discharges.Proceedings of the Horiba International Conference "New Direction of Ocean Research in the Western Pacific" : Past, Present and Future of UNESCO/IOC/WESTPAC Activity for 50 years and the JSPS Project "Coastal Marine Science"Section I: Research Articles/Pollutio

Ambient concentrations of polychlorinated biphenyls and organochlorine pesticides in selected Thai estuarine sediments and mussels

Over the past few decades, the occurrence of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the environment is of great concern due to their persistent and long-range transportable nature as well as toxic biological effects. While most of developed countries have already banned or restricted the production and usage of these compounds, some developing countries still use OCPs for agricultural and the public health purposes. This paper presents data on the concentrations of PCBs and OCPs in selected Thai estuarine sediments and mussels. A total of 20 composite sediment samples and 10 composite mussel samples were collected from two estuaries draining to the inner Gulf of Thailand, namely the Thachin and Bangpakong estuary in 2004. Aldrin, dieldrin, endrin, and heptachlor were not detected in either the mussels or sediments from both study sites. The most frequently detected pesticides were DDTs and chlordanes (CHLs), with relatively low concentration of hexachlorocyclohexanes (HCHs). Low concentrations of PCBs were only detected in sediment and mussel samples from the Bangpakong estuary, with penta-, hexa- and hepta-chlorinated congeners are the dominant homologues. The results from this study demonstrate that ambient concentrations of PCBs and OCPs in Thai estuaries are low, and in most cases lower than concentrations reported for estuaries in many Asian countries.Proceedings of 4th JSPS-VAST Joint Seminar on 'Coastal Marine Science', Hai Phong, Viet Nam, 26-28 October 2009Ocean Pollutio

Petroleum hydrocarbon residues in the marine environment of Koh Sichang-Sriracha, Thailand

This study describes petroleum hydrocarbon (PHC) contamination in water, sediment and green mussels (Perna viridis) of the coastal area of Koh Sichang-Sriracha, Chonburi along the Eastern coast of the Gulf of Thailand. The concentrations of PHC in coastal waters, as determined by UVF technique, were found to range from 0.01-12.55μgl(-1) (chrysene equivalents) with higher values generally confined to port/pier areas. Analysis of surface sediments for PHC revealed that most of the sediments contained appreciable quantities of PHC. The concentrations of PHC in surface sediments varied from 1.1 to 153.4μgg(-1) dry weight, with the mean value of 29.4±30.0μgg(-1). The majority of values of PHC concentration in the surface sediments of Koh Sichang-Sriracha coastal area exceeded 10μgg(-1) and the trend is indicative of transfer of PHC loads from the inshore areas to the offshore sediments. The average concentration of PHC burdens in the mussel tissues at Sriracha ranged from 8.1 to 161.0μgg(-1) wet weight, with the average value of 43.7±55.5μgg(-1), while that at Koh Sichang ranged 9.6-62.4μgg(-1) and the mean value was 23.1±17.2μgg(-1). Bioconcentration factor (BCF) for PHC in green mussels was determined and found to vary from 1.7×104 to 3.5×105. The possible sources of oil contamination in the coastal waters of Koh Sichang-Sriracha marine area were the discharge of oily wastewater and lubricating oil from intensive shipping/boating activities at the port/pier areas, disposal of wastes from anchorage vessels, municipal and industrial discharges.Proceedings of the Horiba International Conference "New Direction of Ocean Research in the Western Pacific" : Past, Present and Future of UNESCO/IOC/WESTPAC Activity for 50 years and the JSPS Project "Coastal Marine Science"Section I: Research Articles/Pollutio

Ambient concentrations of polychlorinated biphenyls and organochlorine pesticides in selected Thai estuarine sediments and mussels

Over the past few decades, the occurrence of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the environment is of great concern due to their persistent and long-range transportable nature as well as toxic biological effects. While most of developed countries have already banned or restricted the production and usage of these compounds, some developing countries still use OCPs for agricultural and the public health purposes. This paper presents data on the concentrations of PCBs and OCPs in selected Thai estuarine sediments and mussels. A total of 20 composite sediment samples and 10 composite mussel samples were collected from two estuaries draining to the inner Gulf of Thailand, namely the Thachin and Bangpakong estuary in 2004. Aldrin, dieldrin, endrin, and heptachlor were not detected in either the mussels or sediments from both study sites. The most frequently detected pesticides were DDTs and chlordanes (CHLs), with relatively low concentration of hexachlorocyclohexanes (HCHs). Low concentrations of PCBs were only detected in sediment and mussel samples from the Bangpakong estuary, with penta-, hexa- and hepta-chlorinated congeners are the dominant homologues. The results from this study demonstrate that ambient concentrations of PCBs and OCPs in Thai estuaries are low, and in most cases lower than concentrations reported for estuaries in many Asian countries.Proceedings of 4th JSPS-VAST Joint Seminar on \u27Coastal Marine Science\u27, Hai Phong, Viet Nam, 26-28 October 2009Ocean Pollutio

Seasonal variations in cell abundance of Noctiluca scintillans in the coastal waters off Chonburi Province, the upper Gulf of Thailand

Seasonal variations in cell abundance of Noctiluca scintillans was studied from June 2003 to November 2004 in the coastal waters off Chonburi Province, the upper gulf of Thailand. Eight stations from Bangpakong River mouth to Angsila were designed to cover the area where red tides often occurred and were under the influence of Bangpakong River. Numerical abundance was analyzed in relation with some environmental parameters. A total of 9 N. scintillans red tides, 7 Ceratium furca red tides and 4 diatom red tides were found in this study. Noctiluca and Ceratium red tides were often found when salinity was in the range of 22 to 33psu. and 12 to 27psu., respectively. Those red tides were not associated with apparent negative effects to marine animals. N. scintillans cells could be observed almost all year round at offshore stations where the water depth was more than 10 meters except strong wind periods, suggesting that Noctiluca in coastal waters were supplied by cells from offshore stations. In contrast, no consistent pattern was observed in the distribution of N. scintillans in coastal waters, in particular near the river mouth. Only the relationship between phosphate concentrations and cell densities of Noctiluca has been found statistically significant. However, the high cell densities of both Noctiluca and Ceratium were often observed in the rainy season, especially on the calm day after heavy rain. These observations suggested that the red tides of those two species in coastal waters were growth response to the influence of freshwater run off from Bangpakong River