Unraveling the source-water fishy odor occurrence during low-temperature periods: Odorants identification, typical algae species and odor-producing potential.

In this study, odor characteristics and phytoplankton composition were systematically investigated in two winter periods in a reservoir with fishy odor in north China. Ten potential fishy odor-producing algae were isolated and odorant-producing potentials were evaluated. Olfactometry profile and odorant composition of water samples were analyzed using GC-Olfactometry combined with GC × GC-TOFMS. The results showed that 2,4-heptadienal and hexanal were major fishy odor contributors. The abundance of Uroglena sp., Synura sp. and Peridinium sp. was negatively correlated with total dissolved organic carbon, ammonia nitrogen, and nitrate, illustrating nutrient level might be major drivers for the succession of fishy odor-producing algae. Dinobryon sp. and Uroglena sp. made the greatest contribution to fishy odor, followed by Peridinium sp., Synura sp., and Ochromonas sp. Fishy odor in 2016 winter and the early of 2017 winter was mainly caused by Dinobryon sp., while Uroglena sp. contributes mostly in March in 2017 winter. This study demonstrates the main odorants and algae causing fishy odor in reservoir, which will provide a scientific basis for the management of seasonal fishy odor problems in water source.

Diagnosis and treatment of congenital tricuspid valve malformation in a case of monozygotic twins.

BACKGROUND: Congenital tricuspid valve malformations are known to occur, but tricuspid valve malformations associated with twins are rarely reported. We report this case from the point of view of a medical history, an auxiliary examination and a genetic pathogenesis to provide a reference for our peers. CASE PRESENTATION: We report a rare case of congenital heart disease in monozygotic twins of Hui nationality in Yunnan-Guizhou Plateau, they are normal conception. Twin 1 had Ebstein's anomaly, and received surgical treatment and recovered satisfactorily. Twin 2 had only partial tricuspid septal prolapse, and pulmonary hypertension occurred during follow-up. CONCLUSIONS: It is necessary to carry out individualized diagnosis and treatment for twins and follow-up observation by echocardiography for a long time. Choosing the right time for cardiac surgery is of great significance to the treatment of the disease.

Co-occurrence of odor-causing dioxanes and dioxolanes with bis(2-chloro-1-methylethyl) ether in Huangpu River source water and fates in O3-BAC process.

In recent years, dioxanes and dioxolanes have been intermittently detected in water environment and have caused several offensive drinking water odor incidents worldwide. In this study, the co-occurrence of eight dioxanes, twelve dioxolanes and bis(2-chloro-1-methylethyl) ether was investigated in Huangpu River watershed to explore potential sources and contributions to septic/chemical odor. Totally 8 dioxanes and dioxolanes were detected in river, with 1,4-dioxane (212 -8310 ng/L) and 2,5,5-trimethyl-1,3-dioxane (n.d.-133 ng/L) as the dominated dioxanes, 2-methyl-1,3-dioxolane (49.5 -2278 ng/L), 2-ethy-4-methyl-1,3-dioxolane (n.d.-167 ng/L) and 1,3-dioxolane (n.d.-225 ng/L) as the major dioxolanes. Bis(2-chloro-1-methylethyl) ether was detected (n.d.-1094 ng/L) with significant correlation with dioxanes and dioxolanes, illustrating their similar polyester resin-related industrial origins. 2-Ethy-4-methyl-1,3-dioxolane, 2,5,5-trimethyl-1,3-dioxane and bis(2-chloro-1-methylethyl) ether with individual maximum odor activity value above 1, should contribute to septic/chemical odor in Huangpu River water. The increased concentrations of these chemicals in the downstream of some industrial areas illustrated the association with industrial discharge. Fates in a waterworks using the river water as source water were further explored. The adopting ozone-biological activated carbon treatment could permit a relatively high removal for bis(2-chloro-1-methylethyl) ether and 2,5,5-trimethyl-1,3-dioxane (> 80%), while limited removal for other chemicals. This study provides valuable information for the management of drinking source water and water environment.