Temporal and spatial distribution patterns of heavy metals in soil at a long-standing sewage farm

Australia's oldest sewage farm in Werribee, Victoria is a significant public asset with more than 110 years of history and it now treats half of Melbourne's municipal sewage. Currently three parallel methods, i.e. lagoon, land filtration and grass filtration were used to treat raw sewage from Melbourne. The land filtration area is soil-pasture-cattle complex system and it operates on 3,633 ha of permanent pastures for livestock grazing. The land filtration area by intermittent irrigation of sewage occurs during the months of high evaporation from October to April. The monitoring study was aimed to find out the temporal and spatial distribution patterns of heavy metals in the soil at land filtration area in the long standing sewage farm. The monitoring results show that the temporal distribution patterns of Cd, Cr, Cu, Ni, Pb and Zn follow the exponential regression equations in soil layer 0-20 cm and the linear equations in soil layer 20-40 cm respectively. The accumulated concentrations of heavy metals in the soils are high enough for the land to be considered contaminated. The exponential trend of heavy metal of soil in land filtration area should be controlled immediately by soil remediation or by change of treatment process of flow configuration.

Periodontal disease as one possible explanation for the Mexican paradox

Mexican-American women have similar low socio-economic status as compared to Non-Hispanic Blacks. However, Mexican-American women have consistently been shown to have a lower rate of low birth weight births as compared to Non-Hispanic Blacks and similar to Non-Hispanic Whites. This phenomenon is referred to as the "Mexican paradox", and the explanation for this is still unclear. We used data from the third US National Health and Nutrition Examination Survey (NHANES III) to compare the rate of periodontal disease in Non-Hispanic Black, Non-Hispanic White and Mexican-American pregnant and non-pregnant women. We found that Mexican-American women have a lower rate of periodontal disease before and during pregnancy when compared to Non-Hispanic Blacks. Since periodontal disease has been associated with an increased risk of preterm birth and low birth weight, we hypothesize that the lower prevalence of periodontal disease before and during pregnancy among Mexican-American women may contribute to the "Mexican paradox".

Periodontal disease and adverse pregnancy outcomes: a systematic review

BACKGROUND

Recent studies suggest that periodontal disease, as a source of subclinical and persistent infection, may induce systemic inflammatory responses that increase the risk of adverse pregnancy outcomes.

OBJECTIVES

To examine the existing evidence on the relationship between periodontal disease and adverse pregnancy outcomes.

SEARCH STRATEGY

Published studies identified via searches of the MEDLINE, EMBASE, CINAHL, and Current Contents full-text databases.

SELECTION CRITERIA

We identified and selected observational studies (i.e. case-control, cross-sectional, and cohort) and nonrandomised controlled studies or randomised controlled trials that examined periodontal disease as a risk factor for adverse pregnancy outcomes.

DATA COLLECTION AND ANALYSIS

Odds ratios (OR) or risk ratios (RR) were extracted or calculated from the studies' data. We calculated pooled effect size for two clinical controlled trials but not for the observational studies due to the heterogeneity in definitions for periodontal disease and adverse pregnancy outcomes across studies.

MAIN RESULTS

Twenty-five studies (13 case-control, 9 cohort, and 3 controlled trials) were identified. The studies focused on preterm low birthweight, low birthweight, preterm birth, birthweight by gestational age, miscarriage or pregnancy loss, and pre-eclampsia. Of the chosen studies, 18 suggested an association between periodontal disease and increased risk of adverse pregnancy outcome (ORs ranging from 1.10 to 20.0) and 7 found no evidence of an association (ORs ranging from 0.78 to 2.54). Three clinical trial studies suggest that oral prophylaxis and periodontal treatment can lead to a 57% reduction in preterm low birthweight (pooled RR 0.43; 95% CI 0.24-0.78) and a 50% reduction in preterm births (RR 0.5; 95% CI 0.20-1.30).

AUTHOR'S CONCLUSIONS

Periodontal disease may be associated with an increased risk of adverse pregnancy outcome. However, more methodologically rigorous studies are needed for confirmation.

Tracing the origins of “fetal origins” of adult diseases: Programming by oxidative stress?

Too small size at birth (due to poor fetal growth and/or preterm delivery) has been associated with substantially elevated risks of the metabolic syndrome (dislipidemia, insulin resistance, hypertension), type 2 diabetes and cardiovascular disease in adulthood. The mechanisms of such "fetal origins" or "programming" of disease phenomenon remain unresolved. Too large size at birth seems also associated with an increased risk. Many known or suspected causes of or conditions associated with adverse (poor or excessive) fetal growth or preterm birth have been associated with oxidative stress. Plausibly, oxidative stress may be a common link underlying the superficial "programming" associations between adverse fetal growth or preterm birth and elevated risks of certain chronic diseases. The mechanisms of oxidative stress programming may be through directly modulating gene expression or indirectly through the effects of certain oxidized molecules. Experimental investigations have well demonstrated the role of redox balance in modulating gene expression, and recent studies indicate that both the insulin functional axis and blood pressure could be sensitive targets to oxidative stress programming. Adverse programming may occur without affecting fetal growth, but more frequently among low birth weight infants merely because they more frequently experienced known or unknown conditions with oxidative insults. As oxidative stress levels are easily modifiable during pregnancy and early postnatal periods (which are plausible critical windows), the hypothesis, if proved valid, will suggest new measures that could be very helpful on fighting the increasing epidemic of the metabolic syndrome, type 2 diabetes and cardiovascular disease. Currently, there are several ongoing large randomized trials of antioxidant supplementation to counter oxidative stress during pregnancy for the prevention of preeclampsia. It would be invaluable if long-term follow-ups of infants born to women in such trials could be realized to test the oxidative stress programming hypothesis in such experimental trial settings.

Bioremediation of contaminated surface water by immobilized Micrococcus roseus

The problems caused by contaminated surface water have gradually become more serious in recent years. Although various remediation technologies were investigated, unfortunately, no efficient method was developed. In this paper, a new bioremediation technology was studied using Micrococcus roseus, which was immobilized in porous spherical beads by an improved polyvinyl alcohol (PVA) - sodium alginate (SA) embedding method. The experimental results indicated that COD removal rate could reach 64.7 % within 72 hours when immobilized M. roseus beads were used, which was ten times as high as that of free cells. The optimum inoculation rate of immobilized M. roseus beads was 10 % (mass percent of the beads in water sample, g g(-1)). Suitable aeration was proved necessary to enhance the bioremediation process. The immobilized cells had an excellent tolerance to pH and temperature changes, and were also more resistant to heavy metal stress compared with free cells. The immobilized M. roseus beads had an excellent regeneration capacity and could be reused after 180-day continuous usage. The Scanning Electronic Microscope (SEM) analysis showed that the bead microstructure was suitable for M. roseus growth, however, some defect structures should still be improved.