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There remains scientific uncertainty about the neurodevelopmental consequences of prenatal and postnatal exposure to low levels of methylmercury (MeHg). We examined the effects of low-level prenatal and postnatal mercury exposure from fish consumption on childhood neurodevelopmental outcomes in a longitudinal cohort.Neurodevelopment among 344 children at 1-8 years was assessed using the Bayley Scales of Infant Development-II (1,2,3y), Wechsler Preschool and Primary Scales of Intelligence-III (5y), and Wechsler Intelligence Scales for Children-IV (8y). We measured whole blood total mercury in serial maternal samples during pregnancy, and in children’s samples (cord, 1,2,3,4,5,8y). We surveyed maternal and child fish consumption and estimated intake of polyunsaturated fatty acids (PUFA). Associations between prenatal and postnatal mercury exposure and neurodevelopmental outcomes were examined using regression and structural equation modeling (SEM), adjusting for potential confounders. A majority of mothers (86%) reported consuming relatively small amounts of fish during pregnancy, mostly consuming fish with low MeHg content. Child fish consumption also included small amounts with low MeHg content. The geometric mean of maternal blood mercury was 0.64 ug/L. Children’s blood samples had lower concentrations (geometric mean range: 0.18 – 0.26 ug/L). Higher prenatal mercury concentrations were associated with lower scores on the Bayley Psychomotor Development Index (PDI). For each doubling of average maternal mercury concentration during pregnancy, the PDI decreased by 1.48 points (p=0.01). In the SEM model examining the joint effects of prenatal and postnatal mercury, each doubling of the prenatal mercury concentration was associated with a 1.55 point decrease in child PDI scores (p=0.03), and each doubling of child concurrent mercury concentration was associated with a 0.83 point decrease in PDI scores (p=0.10). We did not observe a consistent association between prenatal or postnatal mercury exposure and later child cognitive outcomes at ages 5 and 8 years. In this cohort of children with low mercury exposure from fish consumption, we found minimal evidence of detrimental effects from prenatal or postnatal mercury exposure on child cognitive abilities. However, we found negative effects from both prenatal and postnatal mercury exposure on infant and toddler motor abilities assessed at ages 1, 2, and 3 years, where prenatal exposure appeared to have a higher contribution to these mild deficits.

With the growing influence of China on the world economy, the learning of its official language, Mandarin, has become increasingly important in Australia. However, Mandarin is regarded as a difficult language for speakers of an Indo-European language, given the fact that it belongs to a different language system. To make Mandarin learnable and lower the cost of learning Mandarin for students in the Western Sydney Region (WSR) schools, this research explores the impact of language transfer on Australian non-Chinese-background students’ Mandarin learning from the perspective of a beginning teacher. A qualitative case study was conducted in a local school in the WSR. Data were collected from observation of the teacher researcher’s own Mandarin classes and her reflective journals. The data shed light upon how language transfer influences Mandarin learning in the perspectives of phonology, morph-syntax, and pragmatics. The major finding of the research is when the implementation of language transfer was constructed on teachers’ correct subject matter knowledge and students’ prior knowledge, the outcome of the learning experience was likely to be satisfactory. Otherwise, it led to students’ confusion and frustration. The conclusion of the research mainly includes two parts. First, the effectiveness of language transfer largely depends on teachers’ understanding of the learner and the subject matter. Second, including both Mandarin and English in teachers’ talk contributes to a TL-input rich and accessible learning experience.

Oil biodegradation at high concentrations was studied in microcosms. The experimental approach involved mixing clean sand with artificially weathered Alaska North Slope crude oil at the beginning of the experiment and monitoring oil biodegradation in microcosms over a 42-day observation time. An uncharacterized consortium of oil-degrading microorganisms was used to inoculate reactors at time-zero. Two types of nitrogen-containing nutrients were applied at a concentration of 100 mg as N/L: KNO3 and NH4Cl. Oil biodegradation was evaluated by monitoring CO2 production, oxygen and nitrogen consumption, and changes in oil constituents. Lipid phosphate, phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses were conducted to determine viable biomass and species composition of microbial populations. In the first experiment, three crude oil concentrations, 5, 20, 80g /kg sand, were studied in tidal flow microcosms. Results indicated that oil concentrations as high as 80g /kg sand were still amenable to bioremediation. More biomass growth was observed in the submerged (anoxic) zone of the sand columns and better oil degradation was found in reactors receiving potassium nitrate. In the second experiment, oil biodegradation was studied at an oil concentration of 20g /kg sand in continuous flow microcosms. Results indicated that the type of nitrogen source had no significant influence on oil biodegradation, since, in this case, oxygen was not limiting. Over 80 percent of target alkanes and around 50 percent of target PAHs were degraded by day-42. Most of the degradation occurred in the first 10 days. Two experiments, one with 20 g oil/kg sand, the other with 80 g oil/kg sand, were carried out in tidal flow microcosms. Three oxygen supply modes were used: anoxic, oxic, and oxic-anoxic. Results evidenced biodegradation of oil under anoxic conditions, but biodegradation was better in oxic reactors than in anoxic reactors. Oxygen had a stronger influence on oil biodegradation than did the type of nitrogen-nutrient fed. A Gram-negative bacterial group dominated the microbial community structure. Various Acinetobacter-affiliated species were present throughout the treatments, likely reflecting their flexibility in oxygen requirements coupled with their ability to degrade hydrocarbons.