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Microplastics (MPs) contamination in water supply sources is presently an important ecological problem due to they are able to move through the food chain and accumulate in living organisms, they might contain harmful contaminants on their surfaces and become a secondary source of contaminants. This study investigated the contaminated MPs in three water supply sources--Pa Ton, Pa Daet, and U-Mong water supply stations in Chiang Mai province, Thailand. Sampling and analysis referenced the National Oceanic and Atmospheric Administration (NOAA) method using plankton nets. The results showed the average number of MPs at these three sites were 3,880 ± 1,150, 3,810 ± 1,355 and 3,320 ± 628 pieces/m3, respectively, The MP types were polyester, polyurethane, nylon, polyethylene, polyethylene terephthalate and polypropylene observed by microscope and Fourier-transform infrared spectroscopy (FT-IR). Further, there were the positive correlation between the number of MPs and the physical water parameters (Total Suspended Solid) at the 0.05 level of probability. This is the first scientific report that investigates MP contamination in the water supply sources in Chiang Mai province. The findings are knowledgeable and fruitful for environmental concern regarding MPs contamination in water supply sources. [ABSTRACT FROM AUTHOR]

Severe droughts during the dry season and floodings during the rainy season are among the major problems encountered in the valleys along the Ping River in Thailand. Improving our understanding of the groundwater resources in this agricultural area is an important issue for the sustainable development of the region. Hence, in order to gain understanding on the groundwater flow dynamics in the unconsolidated shallow aquifers along the Ping River, stable (13C, 18O, 2H, noble gases) and radioactive (3H, 14C) isotope techniques were combined with hydrogeochemical tools. The comprehensive interpretation of the chemical and isotope data consistently showed different origins for groundwater in the northern and southern areas of the investigated aquifers. Groundwaters in the northern part have younger 3H/3He ages, are less mineralized, and have suffered a stronger evaporation than groundwaters in the southern part of the aquifer. Overall, our results are consistent with the hydrogeological situation of the investigated area, namely shallow groundwaters and a spatially extended recharge. 3H/3He apparent ages indicated that young groundwater (<50 years) is present in all the investigated wells. Elevated concentrations of some pollutants (nitrate and phosphate) in parts of the aquifer evidenced a relatively high vulnerability of the aquifer to surface pollution. [ABSTRACT FROM AUTHOR]

Edwardsiella tarda is a pathogen that causes edwardsiellosis in aquatic animals. The emergence of multiple antibiotic‐resistant strains makes antibiotic treatment difficult. This study aimed to investigate the antibiotic susceptibility patterns and the genotypic characterization of E. tarda isolated from cage‐cultured red tilapia in Thailand. A total of 30 isolates were identified as E. tarda using biochemical and molecular analysis. The disc diffusion method for testing antibiotic susceptibility showed all the isolates were resistant to colistin sulphate and oxolinic acid. High levels of resistance to amoxicillin, ampicillin, ceftazidime, oxytetracycline and sulphamethoxazole/trimethoprim were observed as well. The multiple antibiotic resistance index ranged from 0.25 to 0.92, indicating that these isolates had been exposed to high risk sources of contamination where antibiotics were commonly used. All the isolates carried the blaTEM gene based on polymerase chain reaction (PCR). The tetA and sul3 genes were detected in 90% (27/30) and 26.7% (8/30) of the isolates respectively. Nine different genetic groups of isolates were obtained using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC‐PCR). A correlation between genetic types and multiple antibiotic‐resistant patterns was found. These results highlight the potential risks of multiple antibiotic‐resistant isolates for humans and the environment. [ABSTRACT FROM AUTHOR]

Petrified trunks in Mueang Kamphaeng Phet District, upper Central Thailand, were unearthed in Quaternary deposits on the western rim of the Ping River. The sediments consist mainly of semi-consolidated gravel, sand, silt, and clay, indicating that the woods were transported by the ancient Ping River. Macroscopic features revealed that preservation of these fossils (e.g., intercellular spaces, iron oxides, quartz crystals, colors, and weathering conditions) shared many similarities to some petrified trunks in Tak Province. We investigated both large (approx. 0.50–0.7 m wide, at least 10–20 meters long) and small fragments of fossils for both wood anatomical features and mineralogy. Diffuse porosity with indistinct growth rings and wide vessels at low densities suggest a tropical lowland forest paleoenvironment. Parenchyma patterns are aliform to confluent, banded, and diffuse-in aggregate. At least four distinct types of wood were recognized from this site. Among them, three wood types originate from legume trees (Fabaceae), while the fourth is from a eudicotyledonous tree. Two of the three legumes show closest resemblance to a tall (canopy emergent) legume tree, Koompassia cf. malaccensis Maingay ex Benth. and one resembles the legume Koompassia cf. malaccensis or cf. Pahudioxylon bankurensis Chowdhury, Ghosh, et Kazmi. The other legume-like wood shows banded parenchyma. Petrified wood from Kamphaeng Phet is correlative with other Quaternary paleofloras found in Northern Thailand in both preservation and taxa. The past climate, as inferred according to the Köppen-Geiger classification, was possibly similar to modern-day tropical rainforests (Af) in southern Thailand, Malaysia, and Indonesia in contrast to the modern vegetation in Mueang District, Kamphaeng Phet that is a mixed deciduous and dry dipterocarp forest where the modern climate in the area is tropical wet and dry (Aw). [ABSTRACT FROM AUTHOR]

A study on the diversity of benthic diatoms and water quality of the Ping River, Northern Thailand were carried out from December 2004-December 2005. Samples were collected from 15 sites covering the whole river. The water quality was based on specific physical and chemical factors indicated the water in the Ping River was moderately clean and classified in the mesotrophic status, except in the upstream area which was clean to moderate and of the oligo-mesotrophic status. Changing in water quality depended on the environmental status surrounding the sampling sites and seasonal changes. Two orders, forty genera and one hundred and twenty eight species of benthic diatoms were found and classified into the Division Bacillariophyta. Most of them (97%) were pennate diatoms in the Order Bacillariales. The remaining 3% were centric diatoms in the Order Biddulphiales. The relationship between water quality and dominant benthic diatoms in each sampling site and season were determined. It was found that Nitzschia palea (Kützing) W. smith, Nitzschia sp. 2 and Synedra ulna var. aequalis (Kützing) Hustedt were indicator species for moderate water quality whilst Cymbella turgidula Grunow, Gomphonema lagenula Kützing and Navicula symmetrica Patrick were indicator species of clean to moderate water quality.

A simple sequential injection (SI) system with capability to determine multi-parameter has been developed for the determination of iron, manganese, phosphate and ammonium. A simple and compact colorimeter was fabricated in the laboratory to be employed as a detector. The system was optimized for suitable conditions for determining each parameter by changing software program and without reconfiguration of the hardware. Under the optimum conditions, the methods showed linear ranges of 0.2–10 mg L −1 for iron and manganese determinations, and 0.3–5.0 mg L −1 for phosphate and ammonium determinations, with correlation coefficients of 0.9998, 0.9973, 0.9987 and 0.9983, respectively. The system provided detection limits of 0.01, 0.14, 0.004 and 0.02 mg L −1 for iron, manganese, phosphate and ammonium, respectively. The proposed system has good precision, low chemical consumption and high throughput. It was applied for monitoring water quality of Ping river in Chiang Mai, Thailand. Recoveries of the analysis were obtained in the range of 82–119%. [ABSTRACT FROM AUTHOR]

The water quality in a river (water environment) is very important for human health and aquatic organisms. In 2015, the highly regarded Water Resources Management Strategy of Thailand was announced by The Ministry of Industry in Thailand. In this study, the water quality of the Ping river in Northern Thailand, including Chiang Mai and Lamphun provinces, was focused on and measured for three different seasons (summer, rainy, and winter seasons). Anions (F - , Cl - , NO 2 - , NO 3 - , and SO 4 2- ) and cations (Na + , Mg 2+ , Si 4+ , S 6+ , K + ) in the Ping river at upstream (countryside) locations were lower than that at downstream (closer main city) locations, which indicated that the fertilizers, industrial or household wastewaters had been flowing into the Ping river at downstream locations. Additionally, the concentration of anions and cations in the rainy season was higher than other seasons. The present results provide the water quality of the Ping river which was not yet reported officially by the Thailand government.2+ ) were qualified by an ion chromatograph and an inductively coupled plasma optical emission spectrometry, respectively. The concentration of anions and cations (except for Mg 2+ and Ca 2+ ) in the Ping river at upstream (countryside) locations were lower than that at downstream (closer main city) locations, which indicated that the fertilizers, industrial or household wastewaters had been flowing into the Ping river at downstream locations. Additionally, the concentration of anions and cations in the rainy season was higher than other seasons. The present results provide the water quality of the Ping river which was not yet reported officially by the Thailand government.