Toxic elements in well water from Malaysia

Toxic elements present in well water that is used for drinking pose a threat to the human health in many countries. However, there are few reports on the toxic elements in well water in Malaysia. Since a native doctor informed us about the increasing number of patients with depigmented skin (vitiligo) in Rosob Village, Sabah State, Malaysia, the origin of diseases associated with well water was suspected. Thus, the concentrations of 15 toxic elements in 52 well water samples from Rosob (n = 21), and the control areas of Pitas (n = 8) and Telaga (n = 23) within the same state were measured. No toxic elements with levels exceeding that of the WHO health-based guidelines were detected in the well water samples from Pitas and Telaga. On the other hand, the concentration levels of arsenic (As), uranium (U), and manganese (Mn), independently found in 19% (4/21), 4.8% (1/21), and 19% (4/21), respectively, of the well water samples from Rosob, exceeded the levels given in the WHO health-based guidelines. In the well water samples from Rosob, the average concentration of Mn was found to be higher and its maximum value with levels up to 10-fold higher, respectively, than the value in the WHO health-based guidelines. Significant correlations between Mn and As and between Mn and U were noted. Thus, for the first time, the results of this pilot study showed that the levels of the toxic elements in 42.9% (9/21) of well water samples from Rosob in Malaysia were higher than the values in WHO health-based guidelines indicating the need for further studies.     

The relationship of the monoterpene composition in the atmosphere,the foliar emission gas and the leaf oil of Pinus densiflora

Monoterpene compositions in the atmosphre in a pine forest, the foliar emission gas and the leaf oil of pine needles were compared. The emission rate of each monoterpene from pine needles was proportional to the product of the amount in the leaf oil and the approximate vapor pressure. The composition of monoterpenes in the atmosphere is rather well explained by considering foliar emission rates with the supposition that the terpenes emitted into the atmosphere react with ozone and photochemically with nitrogen oxides.     

Low dose beta-emitter source induces sexual reproduction instead of fragmentation in an earthworm, Enchytraeus japonensis

We examined whether background radiation, or radiation at a slightly higher level, plays a role in the reproduction of a terrestrial earthworm. Enchytraeus japonensis a recently described terrestrial oligochaete, reproduces asexually by fragmentation and subsequent regeneration. Following radiation exposure in which the worms were subjected to a 32P beta-emitter source at 15 times the background dose rate (4.5 microGy/h), a statistically significant decrease in the number of fragmentations was observed as compared with the sham controls. At that time, in a stained preparation with haematoxylin and eosin (HE), sexual reproduction occurred instead of asexual fragmentation, and mature oocytes were observed in the body of grown worms. However, increasing the radiation dose rate by 30 microGy/h resulted in the complete disappearance of the radiation-induced effects, i.e., fragmentation again occurred after 14 h. The results of this study indicate that a lower dose of radiation may be essential to achieve sexual reproduction, inducing an inhibition of fragmentation (asexual reproduction), but at higher, more cytotoxic doses of radiation these effects are negated.     

Effects of elevated temperature on larval settlement and post-settlement survival in scleractinian corals, <Emphasis Type="Italic">Acropora solitaryensis</Emphasis> and <Emphasis Type="Italic">Favites chinensis</Emphasis>

We examined the effects of elevated temperature under different exposure periods on larval settlement and post-settlement survival in scleractinian corals, Acropora solitaryensis and Favites chinensis. In the first experiment with the subtropical coral, A. solitaryensis, the numbers of larvae settling and those dead were examined daily for 5 days at 20, 23 (ambient), 26 and 29°C conditions. Larval settlement of A. solitaryensis was initially greater at higher temperature conditions, but the peak in number of settled larvae shifted from 29 to 26°C by day 5, due to ca. 90% post-settlement mortality at 29°C condition. In order to determine the effects under short-term exposure, larvae of F. chinensis were exposed to 27 (ambient), 31 or 34°C only for one hour in the second experiment. The number of larvae settling for 24 h after the exposure and their survivorship over subsequent week was monitored in the ambient temperature condition. Larvae of F. chinensis exhibited greater settlement at higher temperature treatments and constantly low post-settlement mortalities (< ca. 17%) in all temperature treatments, resulting in the highest number of settled larvae at 34°C treatment. These results suggested two different effects of elevated temperature on the early stages of recruitment process of scleractinian corals; (1) the positive effect on larval settlement and (2) the negative effect on post-settlement survival under prolonged exposure.     

Polychlorinated biphenyls (PCBs) in sediments in Hong Kong: a congener-specific approach to the study of coplanar PCBs in aquatic ecosystems

Patterns of contamination by polychlorinated biphenyls (PCBs) were investigated in fourteen samples of coastal sediments from Hong Kong. Congener-specific analyses revealed nine sediment samples from Junk Bay to contain PCBs at concentrations ranging from 31 to 2200 ng g(-1) dry weight, concentrations generally increasing with distance north in the Bay. By contrast, five sediments from the Tolo area to the north-east of Hong Kong exhibited total PCB levels of only 6.6 to 45 ng g(-) dry weight. The patterns of relative abundance of PCB congeners in the northern Junk Bay sediments suggested the existence of ongoing source(s) of PCBs in this area; biphenyls of lower chlorination were present at high concentration in these samples. Three coplanar PCBs (3', 4, 4'-tetrachlorobiphenyl; 3,3',4,4',5-pentachlorobiphenyl; and 3,3',4,4',5,5'-hexachlorobiphenyl) were found to be present in Junk Bay sediments; these are highly toxic and are cause for concern in aquatic environments. The abundance of the three coplanar PCBs in the sediments studied was similar to that in commercial PCB mixtures, suggesting that these congeners are not enriched over other PCBs by the sediments of coastal ecosystems. It is concluded that the preferential enrichment of coplanar PCBs occurs in the biosphere, rather than in sediments.     

Influence of velocity field on driftwood accumulation at a bridge with a single pier

Environmental Fluid Mechanics - Transport of driftwood during heavy rainfall events can intensify the flood hazard. Driftwood accumulates at a bridge and backwater rises. Accumulated logs sink...     

Accumulation features and temporal trends of PCDDs, PCDFs and PCBs in Baikal seals (Pusa sibirica)

This study investigated the accumulation features and temporal trends of PCDD/Fs, dioxin-like PCBs (DL-PCBs) and non-dioxin-like PCBs (NDL-PCBs) in the blubber of Baikal seals collected in 1992 and 2005. DL-PCBs (480-3600 ng/g) and NDL-PCBs (980-35,000 ng/g) were dominant contaminants. Concentrations of PCDDs and PCBs in males were significantly higher than in females. In males, age-dependent accumulation was observed for PCDDs, mono-ortho PCBs and NDL-PCBs. PCDFs and non-ortho PCBs showed no such trends, implying that exposure of seals to these contaminants has been decreasing in recent years. No decreasing temporal trend was observed for PCDDs, mono-ortho PCBs and NDL-PCBs, suggesting that Baikal seals are still exposed to PCDDs and PCBs. TEQs of PCDDs and mono-ortho PCBs in seals collected in 2005 accounted for 62-77% of total TEQs. The TEQ levels in 40% of the specimens exceeded the threshold level for immunosuppression observed in harbor seals (209 pg/g).     

Neonatal outcomes of congenital diaphragmatic hernia in full term versus early term deliveries: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to review the optimal timing of delivery at term for neonates with prenatally diagnosed congenital diaphragmatic hernia (CDH). We reviewed the literature up to December 19, 2022 using MEDLINE and the Cochrane Library databases. The inclusion criteria were original articles, comparative studies of CDH neonates delivered at an early term (37–38 weeks of gestation) and at full term (39 weeks of gestation or later), and comparative studies investigating outcomes of CDH neonates. Six studies met the inclusion criteria, including 985 neonates delivered at an early term and 629 delivered at full term. The cumulative rate of survival to discharge showed no significant difference between CDH neonates delivered at an early term (395/515; 76.7%) or at full term (345/467; 73.9%) (risk ratio [RR] 1.01; 95% confidence interval [CI], 0.89–1.16; p = 0.85). Furthermore, the number of neonates requiring oxygen therapy at discharge was not significantly different between CDH neonates delivered at an early term (32/370; 8.6%) and at full term (14/154; 9.1%) (RR, 0.99; 95% CI, 0.36–2.70; p = 0.99). Therefore, the optimal timing of delivery at term for neonates with CDH remains unclear.     

A minority group's response to a severe climatic event: a case study of rural Indo-Fijians after Tropical Cyclone Winston in 2016

This paper investigates the impacts of Tropical Cyclone Winston (2016) on rural Indo-Fijians and their response to the devastation. Studies have previously examined how rural communities in Pacific Island countries respond to severe climatic events, arguing that traditional knowledge of the climate, together with indigenous techniques, contribute substantially to recovery from a disaster. Strong communal bonds have also been identified as an influencing factor. Disaster risk reduction frameworks often assume the availability of such knowledge and capital. Yet, little research has been done on how minority groups with limited access to such knowledge and capital cope with disaster-related damage. The current study shows that rural Indo-Fijians responded to the consequences of Tropical Cyclone Winston differently to indigenous Fijians, owing to relatively limited access to traditional awareness of the climate, communal labour sharing, and intra- and/or inter-community networks. The findings point to the necessity to implement a more inclusive disaster risk reduction framework.