Monthly Archives: December 2015

No Increased Lung Cancer Risk at ~100 to 150 ug/L Arsenic

No one wants arsenic in their drinking water. But continued effort to push the health goal for arsenic lower and lower in the absence of evidence of harm is counter productive.

Lamm SH, Ferdosi H, Dissen EK, Li J, Ahn J. A Systematic Review and Meta-Regression Analysis of Lung Cancer Risk and Inorganic Arsenic in Drinking Water. Int J Environ Res Public Health. 2015 Dec 7;12(12):15498-515. doi: 10.3390/ijerph121214990.

High levels (> 200 µg/L) of inorganic arsenic in drinking water are known to be a cause of human lung cancer, but the evidence at lower levels is uncertain. We have sought the epidemiological studies that have examined the dose-response relationship between arsenic levels in drinking water and the risk of lung cancer over a range that includes both high and low levels of arsenic. Regression analysis, based on six studies identified from an electronic search, examined the relationship between the log of the relative risk and the log of the arsenic exposure over a range of 1-1000 µg/L. The best-fitting continuous meta-regression model was sought and found to be a no-constant linear-quadratic analysis where both the risk and the exposure had been logarithmically transformed. This yielded both a statistically significant positive coefficient for the quadratic term and a statistically significant negative coefficient for the linear term. Sub-analyses by study design yielded results that were similar for both ecological studies and non-ecological studies. Statistically significant X-intercepts consistently found no increased level of risk at approximately 100-150 µg/L arsenic.

Microalgae Removal with Moringa oleifera

Barrado-Moreno MM, Beltran-Heredia J, Martín-Gallardo J. Microalgae removal with Moringa oleifera. Toxicon. 2015 Dec 11;110:68-73. doi: 10.1016/j.toxicon.2015.12.001.

Moringa oleifera seed extract was tested for algae (Chlorella, Microcystis, Oocystis and Scenedesmus) removal by Jar-test technique. This coagulant can be used in drinking water treatment. Jar-test has been carried out in order to evaluate the efficiency of this natural coagulant agent inside real surface water matrix. The influence of variables has been studied in this process, including operating parameters such as coagulant dosage, initial algae concentration, pH, agitation time and water matrix. Removal capacity is verified for water with high contamination of algae while the process is not affected by the pH and water matrix. Coagulation process may be modelling through Langmuir and Freundlich adsorption hypothesis, so acceptable r2 coefficients are obtained.

Child Intelligence and Water Arsenic and Manganese Reduction

Wasserman GA, Liu X, Parvez F, Factor-Litvak P, Kline J, Siddique AB, Shahriar H, Uddin MN, van Geen A, Mey JL, Balac O, Graziano JH. Child Intelligence and Reductions in Water Arsenic and Manganese: A Two-Year Follow-up Study in Bangladesh. Environmental health perspectives. 2015 Dec 29.

BACKGROUND: Arsenic (As) exposure from drinking water is associated with modest intellectual deficits in childhood. It is not known whether reducing exposure is associated with improved intelligence.

OBJECTIVE: To determine whether reducing As exposure is associated with improved child intellectual outcomes.

METHODS: Three hundred and three 10-year-old children drinking from household wells with a wide range of As concentrations were enrolled at baseline. In the subsequent year, deep community wells, low in As, were installed in villages of children whose original wells had high water As (WAs ≥50 µg/L). For 296 children, WISC-IV intelligence, using a version modified for the study population, was assessed at baseline and approximately two years later; analyses considered standardized scores for both Full Scale IQ and Verbal Comprehension, Perceptual Reasoning, Working Memory, Processing Speed Indices. Creatinine-adjusted urinary arsenic (UAs/Cr), blood As (BAs) and blood manganese (BMn) were assessed at both times.

RESULTS: UAs/Cr concentrations declined significantly by follow-up for both the High and Low (< 50 µg/L) WAs subgroups. At baseline, adjusting for maternal age and intelligence, plasma ferritin, head circumference, home environment quality, school grade and BMn, UAs/Cr was significantly negatively associated with Full Scale IQ, and with all Index scores (except Processing Speed). After adjusting for baseline Working Memory scores and school grade, each 100-µg/g reduction in UAs/Cr from baseline to follow-up was associated with a 0.91 point increase in Working Memory (95% CI: 0.14, 1.67). The change in UAs/Cr across follow-up was not significantly associated with changes in Full Scale IQ or Index scores.

CONCLUSIONS: Installation of deep, low As, community wells lowered UAs, BAs and BMn. A greater decrease in UAs/Cr was associated with greater improvements in Working Memory scores, but not with a greater improvement in Full Scale IQ.

Organic Pollutants Removed by a beta-cyclodextrin Polymer

This study has received press recently (e.g. here). It looks very interesting. A research breakthrough is good. But like other new water treatment technologies commercialization will be very difficult.

Alaaeddin Alsbaiee, Brian J. Smith, Leilei Xiao, Yuhan Ling, Damian E. Helbling, William R. Dichtel. Rapid removal of organic micropollutants from water by a porous β-cyclodextrin polymer. Nature (2015) doi:10.1038/nature16185

The global occurrence in water resources of organic micropollutants, such as pesticides and pharmaceuticals, has raised concerns about potential negative effects on aquatic ecosystems and human health. Activated carbons are the most widespread adsorbent materials used to remove organic pollutants from water but they have several deficiencies, including slow pollutant uptake (of the order of hours). Furthermore, regenerating spent activated carbon is energy intensive (requiring heating to 500–900 degrees Celsius) and does not fully restore performance. Insoluble polymers of β-cyclodextrin, an inexpensive, sustainably produced macrocycle of glucose, are likewise of interest for removing micropollutants from water by means of adsorption. β-cyclodextrin is known to encapsulate pollutants to form well-defined host–guest complexes, but until now cross-linked β-cyclodextrin polymers have had low surface areas and poor removal performance compared to conventional activated carbons. Here we crosslink β-cyclodextrin with rigid aromatic groups, providing a high-surface-area, mesoporous polymer of β-cyclodextrin. It rapidly sequesters a variety of organic micropollutants with adsorption rate constants 15 to 200 times greater than those of activated carbons and non-porous β-cyclodextrin adsorbent materials. In addition, the polymer can be regenerated several times using a mild washing procedure with no loss in performance. Finally, the polymer outperformed a leading activated carbon for the rapid removal of a complex mixture of organic micropollutants at environmentally relevant concentrations. These findings demonstrate the promise of porous cyclodextrin-based polymers for rapid, flow-through water treatment.

Cloud-Enabled Microscopy Detects Escherichia coli in 8 hrs

Golberg A, Linshiz G, Kravets I, Stawski N, Hillson NJ, Yarmush ML, Marks RS, Konry T. Cloud-enabled microscopy and droplet microfluidic platform for specific detection of Escherichia coli in water. PloS One. 2014 Jan 27;9(1):e86341. doi: 10.1371/journal.pone.0086341.

We report an all-in-one platform – ScanDrop – for the rapid and specific capture, detection, and identification of bacteria in drinking water. The ScanDrop platform integrates droplet microfluidics, a portable imaging system, and cloud-based control software and data storage. The cloud-based control software and data storage enables robotic image acquisition, remote image processing, and rapid data sharing. These features form a “cloud” network for water quality monitoring. We have demonstrated the capability of ScanDrop to perform water quality monitoring via the detection of an indicator coliform bacterium, Escherichia coli, in drinking water contaminated with feces. Magnetic beads conjugated with antibodies to E. coli antigen were used to selectively capture and isolate specific bacteria from water samples. The bead-captured bacteria were co-encapsulated in pico-liter droplets with fluorescently-labeled anti-E. coli antibodies, and imaged with an automated custom designed fluorescence microscope. The entire water quality diagnostic process required 8 hours from sample collection to online-accessible results compared with 2-4 days for other currently available standard detection methods.

Online Biosensor for Toxicants in Water

Eltzov E, Slobodnik V, Ionescu RE, Marks RS. On-line biosensor for the detection of putative toxicity in water contaminants. Talanta. 2015 Jan;132:583-90. doi: 10.1016/j.talanta.2014.09.032.

Potential threat on drinking water requires monitoring solutions, such as the one proposed herein, as a real-time, wide ranged, water monitoring system to detect the presence of toxicants in water. We studied the role of a selected number of parameters affecting performance and, thus, improved the prototype into an optimized next-generation device, resulting in enabling increased measurement duration, coupled with increased sensitivity. The chosen parameters in question were the peristaltic flow system, the fiber probe matrix stability through a re-design of the fiber probe holder and flow unit cell, as well as the modulation of bacterial medium concentration to increase bioreporter performance while keeping biofouling in check. Measurements were made with spiked samples and validated with polluted field-collected samples.

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