Variation in Ventral Coloration Pattern and Aposematism in Tropical Warty Newts.

Aposematic coloration plays a crucial role in animal defense, and it is shaped by a complex interplay of factors such as physiological limitations and sexual and natural selection. Warty newts within the genus Paramesotriton exhibit significant variation in ventral coloration. In this study, we quantified the percentage of red ventral area to investigate aposematic ventral coloration in Paramesotriton deloustali and P. guangxiensis across eight populations in northern Vietnam. To assess the interaction between predators and the aposematic signals, we conducted experiments employing three types of clay replicas of newts: dorsal, red ventral, and black ventral models. Our findings revealed a significant variation in the red ventral area among different populations. Additionally, a significant correlation was detected between the red ventral area of the newt and the annual temperature range. In clay model experiments, a significant difference in predator attack rates was observed between dorsal and ventral clay models. Interestingly, there was no significant difference in attack rates between red and black ventral types. Our study suggested that the variation in the red ventral area of warty newts is probably influenced by multiple factors, including genetic constraints, sex, ambient environment, and diet. Furthermore, our results supported the effectiveness of displaying aposematic coloration as an antipredator defense mechanism in warty newts. However, variations in body size and the pressure of mammal predation might not play a significant role in determining aposematic coloration.

Radiological risk assessment of outdoor222Rn and220Rn around rare earth element and uranium mines from northern Vietnam.

The outdoor222Rn and220Rn concentrations at 320 sampling points at 1 m above the ground in different sites surrounding rare earth element (REE) and uranium mines from northern Vietnam were measured using the RAD7. Results showed that222Rn concentrations were always higher than220Rn concentrations with large variation ranges from 25.7 to 573 Bq m-3and from 18.5 to 385 Bq m-3, respectively. The high correlation between220Rn and228Ra concentrations in surface soil of the studied sites were observed. The highest220Rn and222Rn concentrations are found at the sampling points of the REE NX-Lai Chau site. The220Rn and222Rn activities surrounding the REE mines were found to be higher than those surrounding the uranium mines. The average annual committed effective doses originated from the inhalation of220Rn and222Rn outdoor concentrations is about five times higher than the worldwide average value.

Polybrominated diphenyl ethers in indoor dusts from industrial factories, offices, and houses in northern Vietnam: Contamination characteristics and human exposure.

Information about the occurrence of polybrominated diphenyl ethers (PBDEs) in indoor dusts from various industrial sectors in Southeast Asia is still scarce. In this study, concentrations and congener-specific profiles of PBDEs were determined in indoor dusts from industrial factories, offices, and houses in northern Vietnam. Levels of Σ8PBDEs were higher in the office dusts (median 270; range 230-300 ng/g) and factory dusts (170; 89-510 ng/g) than in the house dusts (61; 25-140 ng/g). BDE-209 was the most dominant congener, accounting for 27-98% (average 62%) of Σ8PBDEs, suggesting the abundance of products treated with deca-BDE mixtures. Residential, commercial, and industrial activities in the studied locations of this survey were not significant sources of PBDEs as compared to those of informal waste processing activities in Vietnam. Relatively low PBDE concentrations detected in our dust samples partially reflect effectiveness of the global PBDE phase-out. Human exposure and health risk associated with dust-bound PBDEs were estimated, indicating acceptable levels of risk (i.e., neurobehavioral effects). The contributions of workplace dusts in total daily intake doses of PBDEs via dust ingestion were more important for local workers in informal recycling areas than factory workers and general population, raising the need of appropriate labor protection measures.

A persistent epidemic of porcine epidemic diarrhoea virus infection by serological survey of commercial pig farms in northern Vietnam.

BACKGROUND: Porcine epidemic diarrhoea (PED) is a highly contagious infectious disease with negative economic impacts on the swine industry. PED outbreaks were reported from 2009 to 2015, but sporadic infection has been observed until now in Vietnam. However, the seroprevalence of PEDV infection has not yet been reported for commercial pig farms in Vietnam. The aim of this study was to assess the seroprevalence of PEDV infection in Vietnamese pig farms to reveal the endemic status of PEDV in northern Vietnam. RESULTS: A serological survey of PEDV infection was carried out using indirect ELISA in commercial pig farms in Hai Duong, Hung Yen and Thai Binh provinces in northern Vietnam in 2019. Twenty sera were randomly collected from each of 10 commercial pig farms, from each province; none of the farms had vaccinated for PEDV. Serological evidence of natural PEDV infection, expressed as a high antibody titre, was observed in the pig farms in all 3 provinces. The OD values were significantly higher (p < 0.001) for pig sera from Thai Binh than from Hai Duong and Hung Yen. No significant differences (p > 0.05) were detected for seropositivity to PEDV based on locality, age, pig breed and farm size. CONCLUSIONS: This study indicates serological evidence of natural PEDV infection with high antibody titre in commercial pig farms. PEDV infection was widespread among the pig population in these 3 provinces and that good management and strict biosecurity are needed at these pig farms.

Screening environmental risk evaluation of As and trace metals in soils and sediments from a developing area (Bac Giang Province, Northern Vietnam).

Despite the key role that areas close to the rivers Cau and Ngu Huyen Khê (Bac Giang Province, Northern Vietnam) play in the socio-economic development of Vietnam, poor information is available on the level of contaminants and their natural backgrounds in local soils and sediments. To partially fill this gap and to take into account for pressures and impacts on different zones and environment types (river sediments, crop fields, family wells, industrial and urban soils), the samples were collected and analyzed for fifteen trace elements at thirty sites distributed over the province. To overcome the lack of information on natural background and to identify the extent of the deviation from natural conditions, we coupled statistical analysis to contamination indices. The multivariate analysis was used to relate sediment chemical composition with a possible alteration from secondary inputs and to highlight those samples that most deviate from the distribution by category and are potentially more problematic. Geoaccumulation indexes and enrichment factors were calculated to discriminate between natural backgrounds and anthropic sources, SQGs were used for a screening evaluation of environmental risk in the study area. Results showed relatively high concentrations, sometimes exceeding international and national guidelines, and local sources could prevail over geogenic origins. Despite its significant natural contribution all over the study area, As evidenced some cases of anthropogenic contamination, similarly to that observed for Cd, Hg, and Zn. Their high concentrations may be a problem for public health, especially when found in family wells.

A preliminary investigation of 942 organic micro-pollutants in the atmosphere in waste processing and urban areas, northern Vietnam: Levels, potential sources, and risk assessment.

Of 942 organic micro-pollutants screened, 167 compounds were detected at least once in the atmosphere in some primitive waste processing sites and an urban area in northern Vietnam by using a polyurethane foam-based passive air sampling (PUF-PAS) method and an Automated Identification and Quantification System with a Database (AIQS-DB) for GC-MS. Total concentrations of organic pollutants were higher in samples collected from an urban area of Hanoi city (2300-2600 ng m-3) as compared with those from an end-of-life vehicle (ELV) dismantling area in Bac Giang (900-1700 ng m-3) and a waste recycling cooperative in Thai Nguyen (870-1300 ng m-3). Domestic chemicals (e.g., n-alkanes, phthalate ester plasticizers, and synthetic phenolic antioxidants) dominated the organic pollutant patterns in all the samples, especially in the urban area. Pesticides (e.g., permethrins, chlorpyrifos, and propiconazole) were found in the atmosphere around the ELV sites at more elevated concentrations than the other areas. Levels of polycyclic aromatic hydrocarbons and their derivatives in the Bac Giang and Thai Nguyen facilities were significantly higher than those measured in Hanoi urban houses, probably due to the waste processing activities. Daily intake doses of organic pollutants via inhalation were estimated for waste processing workers and urban residents. This study shall provide preliminary data on the environmental occurrence, potential emission sources, and effects of multiple classes of organic pollutants in urban and waste processing areas in northern Vietnam.

Arsenic and other trace elements in groundwater and human urine in Ha Nam province, the Northern Vietnam: contamination characteristics and risk assessment.

The contamination characteristics of arsenic and other trace elements in groundwater and the potential risks of arsenic from the groundwater were investigated. Elevated contamination of arsenic, barium and manganese was observed in tube-well water of two villages (Chuyen Ngoai and Chau Giang) in Ha Nam province in the Northern Vietnam. Concentrations of As in the groundwater ranged from 12.8 to 884 µg/L with mean values in Chuyen Ngoai and Chau Giang were 614.7 and 160.1 µg/L, respectively. About 83 % of these samples contained As concentrations exceeding WHO drinking water guideline of 10 µg/L. The mean values of Mn and Ba in groundwater from Chuyen Ngoai and Chau Giang were 300 and 657 µg/L and 650 and 468 µg/L, respectively. The mean value of Ba concentration in groundwater in both Chuyen Ngoai and Chau Giang was about 22 % of the samples exceeded the WHO guideline (700 µg/L). Arsenic concentrations in human urine of residents from Chuyen Ngoai and Chau Giang were the range from 8.6 to 458 µg/L. The mean values of Mn and Ba in human urine of local people from Chuyen Ngoai were 46.9 and 62.8 µg/L, respectively, while those in people from Chau Giang were 25.9 and 45.9 µg/L, respectively. The average daily dose from ingesting arsenic for consuming both untreated and treated groundwater is from 0.02 to 11.5 and 0.003 to 1.6 µg/kg day, respectively. Approximately, 57 % of the families using treated groundwater and 64 % of the families using untreated groundwater could be affected by elevated arsenic exposure.

Accumulation and potential health risks of cadmium, lead and arsenic in vegetables grown near mining sites in Northern Vietnam.

The effect of environmental pollution on the safety of vegetable crops is a serious global public health issue. This study was conducted to assess heavy metal concentrations in soil, irrigation water, and 21 local vegetable species collected from four sites near mining activities and one control site in Northern Vietnam. Soils from vegetable fields in the mining areas were contaminated with cadmium (Cd), lead (Pb), and arsenic (As), while irrigation water was contaminated with Pb. Average concentrations of Pb and As in fresh vegetable samples collected at the four mining sites exceeded maximum levels (MLs) set by international food standards for Pb (70.6 % of vegetable samples) and As (44.1 % of vegetable samples), while average Cd concentrations in vegetables at all sites were below the MLs of 0.2. The average total target hazard quotient (TTHQ) across all vegetable species sampled was higher than the safety threshold of 1.0, indicating a health risk. Based on the weight of evidence, we find that cultivation of vegetables in the studied mining sites is an important risk contributor for local residents' health.

Assessment of the level and risk of radioactive hazards in coastal sediments in northern Vietnam.

Radioactivity in coastal sediments in northern Vietnam was examined using data from five sediment cores to assess radioactivity concentrations and radiation risk indices. Radiation risk indices included radium equivalent activity (Raeq), the absorbed dose rate (ADR), the annual effective dose equivalent (AEDE), the activity utilization index (AUI), the external hazard index (Hex), the representative level gamma index (Iγr), and the annual gonadal effective dose rate (AGDE). The radioactivity concentrations of 40K, 232Th, 226Ra, 238U, and 137Cs were 567, 56.1, 35.1, 37.9, and 1.18 Bq/kg, respectively. The average concentrations of 40K, 232Th, 226Ra, and 238U were above the global average at five sites, except for 137Cs, which was low. The Raeq, Hex, and AUI indices were below the recommended values, while the AEDE, ADR, AGDE, and Iγr indices were above the recommended values. Moreover, 40K, 232Th, 226Ra, and 238U had significant impacts on the radiation hazard indices Raeq, ADR, AEDE, Iγr, AUI, Hex, and AGDE. There are three coastal sediment groups on the northern coast of Vietnam: Group 1 has a higher radioactivity and radiation risk index than Group 2 but a lower value than Group 3. Group 3 had the highest radioactivity and radiation risk index. The values of 40K, 232Th, 226Ra, and 238U and the ADR, AUI, Iγr, and AGDE indices in the sediment threaten the living environment.

First record of the genus Camptotheca (Nyssaceae) in Vietnam and the lectotypification of C.acuminata.

As a primary source of anticancer camptothecin, Camptotheca (Nyssaceae) is an economically valuable genus and has long been recorded as endemic to China. Here, Camptotheca is reported as a new record to the flora of Vietnam with the discovery of a wild population of C.acuminata from Lai Chau Province of northern Vietnam. Based on the consultation of relevant literature and type specimens of C.acuminata, a lectotype of the species is designated. Photographic illustrations, morphological description and a distribution map of C.acuminata is provided, and a key to all known species of Nyssaceae in Vietnam is presented, too.