Co-Selection of Bacterial Metal and Antibiotic Resistance in Soil Laboratory Microcosms.

Accumulation of heavy metals (HMs) in agricultural soil following the application of superphosphate fertilisers seems to induce resistance of soil bacteria to HMs and appears to co-select for resistance to antibiotics (Ab). This study aimed to investigate the selection of co-resistance of soil bacteria to HMs and Ab in uncontaminated soil incubated for 6 weeks at 25 °C in laboratory microcosms spiked with ranges of concentrations of cadmium (Cd), zinc (Zn) and mercury (Hg). Co-selection of HM and Ab resistance was assessed using plate culture on media with a range of HM and Ab concentrations, and pollution-induced community tolerance (PICT) assays. Bacterial diversity was profiled via terminal restriction fragment length polymorphism (TRFLP) assay and 16S rDNA sequencing of genomic DNA isolated from selected microcosms. Based on sequence data, the microbial communities exposed to HMs were found to differ significantly compared to control microcosms with no added HM across a range of taxonomic levels.

Are Households in Kiribati Nutrition Secure? A Case Study of South Tarawa and Butaritari.

BACKGROUND AND OBJECTIVES: This study assessed the nutritional status among householders in urban South Tarawa and rural Butaritari in Kiribati. METHODS AND STUDY DESIGN: In this cross-sectional study, we assessed energy and nutrient intakes, food variety scores, and dietary diversity scores of men and women from 468 households randomly selected in South Tarawa (n = 161) and Butaritari (n = 307) using a 24-hour dietary recall. Nutrient adequacy ratios and mean adequacy ratios of selected nutrients were also determined from 3-day weighed food records collected among participants living in a further 28 households from South Tarawa (n = 29) and Butaritari (n = 44). RESULTS: Based on the 24-hour dietary recall, the average energy intake for men and women was 2536 kcals and 2068 kcals, respectively. Carbohydrate (CHO), fat, and protein intakes for men and women were 332.5 g, 76.5 g, and 130.4 g and 291.7 g, 55.1 g, and 103.5 g, respectively. The mean and standard deviation of household Food Variety Score and Dietary Diversity Score was 3.90 ± 1.25 and 5.44 ± 1.92, respectively. Intakes of vitamin A, calcium, and iron, and zinc were notably deficient in both locations, with the urban participants having lower intakes of vitamin B-1, vitamin B-2, magnesium, and potassium than their rural counterparts. Mean sodium intakes exceeded recommendations for all age groups in South Tarawa except children aged 4 to 6 years. CONCLUSIONS: Food consumption patterns of the households in South Tarawa and Butaritari reflected high consumption of nontraditional diets and refined foods, which manifested in inadequate micronutrient intake estimates and low dietary diversity: strong risk factors for noncommunicable diseases such as obesity and diabetes.

Health Hazards Associated with Consumption of Roof-Collected Rainwater in Urban Areas in Emergency Situations.

The greater Wellington region, New Zealand, is highly vulnerable to large earthquakes because it is cut by active faults. Bulk water supply pipelines cross the Wellington Fault at several different locations, and there is considerable concern about severe disruption of the provision of reticulated water supplies to households and businesses in the aftermath of a large earthquake. A number of policy initiatives have been launched encouraging householders to install rainwater tanks to increase post-disaster resilience. However, little attention has been paid to potential health hazards associated with consumption of these supplies. To assess health hazards for householders in emergency situations, six 200-litre emergency water tanks were installed at properties across the Wellington region, with five tanks being allowed to fill with roof-collected rainwater and one tank being filled with municipal tapwater as a control. Such tanks are predominantly set aside for water storage and, once filled, feature limited drawdown and recharge. Sampling from these tanks was carried out fortnightly for one year, and samples were analysed for E. coli, pH, conductivity, a range of major and trace elements, and organic compounds, enabling an assessment of the evolution of water chemistry in water storage tanks over time. Key findings were that the overall rate of E. coli detections in the rain-fed tanks was 17.7%, which is low in relation to other studies. We propose that low incidences of may be due to biocidal effects of high zinc concentrations in tanks, originating from unpainted galvanised steel roof cladding. Lead concentrations were high compared to other studies, with 69% of rain-fed tank samples exceeding the World Health Organisation's health-based guideline of 0.01 mg/L. Further work is required to determine risks of short-term consumption of this water in emergency situations.

Cumulative impacts assessment along a large river, using brown bullhead catfish (Ameiurus nebulosus) populations.

The effects of point-source and diffuse discharges on resident populations of brown bullhead catfish (Ameiurus nebulosus (LeSueur, 1819)) in the Waikato River (New Zealand) were assessed at sites both upstream and downstream of point-source discharges. At each site, the population parameters, relative abundance, age structure, and individual indices, such as condition factor, organ (gonad, liver, and spleen) to somatic weight ratios, and number and size of follicles per female, were assessed. Physiological (blood), biochemical (hepatic ethoxyresorufin-O-deethylase [EROD] and plasma steroids), and other indicators (bile chemistry and liver metals) of exposure or response also were measured. No impacts on brown bullhead health were obvious at individual geothermal, municipal sewage, or thermal discharge sites or cumulatively along the river. Brown bullhead from the bleached kraft mill effluent site showed elevated levels of EROD, decreased numbers of red blood cells, increased numbers of white blood cells, and depressed levels of sex steroids. However, growth rates, condition factor, age structure, and gonadosomatic index suggest that discharges with significant heat or nutrients benefit catfish despite physiological impairment at one site. Consideration of brown bullhead population-level responses to discharges in a monitoring framework revealed three different population-level response patterns resulting from the point-source discharges.

Sorption of lead and thallium on borosilicate glass and polypropylene: Implications for analytical chemistry and soil science.

Adsorption of 10-100 ppb lead and thallium by borosilicate glass and polypropylene surfaces was studied. No thallium was adsorbed by either substrate at pH 7.0. About 50-60% of the lead was adsorbed by borosilicate glass at pH 5.5 and pH 7.0, with statistically indistinguishable conditional equilibrium constants (KD* values) of 1.47±0.40 mL cm-2 and 1.80±0.11 mL cm-2, respectively. Polypropylene adsorbed significantly more lead than borosilicate glass at pH 7.0 (80.9%, KD* =5.33±0.45 mL cm-2), and substantially less at pH 5.5 (16.7%, KD* = 0.27±0.03 mL cm-2), indicating a fundamental change in the nature of the polypropylene surface. All adsorption data fitted Freundlich plots. Preliminary experiments indicate that at pH 5.5, a fraction of the lead sequestered by the borosilicate glass may be bound irreversibly by migrating into the glass matrix. The results suggest that tectosilicates and silicate glasses may represent important adsorbents of some heavy metals in soils, despite showing very low intrinsic cation exchange capacities.