Routine Storage Tank Cleaning Necessary to Eliminate Opportunistic Pathogens in Sediments

Struewing I, Yelton S, Ashbolt N. Molecular Survey of Occurrence and Quantity of Legionella spp., Mycobacterium spp., Pseudomonas aeruginosa and Amoeba Hosts in Municipal Drinking Water Storage Tank Sediments. Journal of Applied Microbiology. 2015 Apr 17. doi: 10.1111/jam.12831.

AIM: To examine the occurrence and quantity of potential pathogens and an indicator of microbial contamination in the sediments of municipal drinking water storage tanks (MDWSTs), given the absence of such data across the United States.

METHODS AND RESULTS: Sediment samples (87 MDWST) from eighteen locations across ten states of the U.S. were collected and assayed by qPCR for a range of potential enteric and opportunistic microbial pathogens and a sewage-associated Bacteroides marker. Potential opportunistic pathogens dominated, with the highest detection of occurrence (% positive detection; average cell equivalence [CE]) being Mycobacterium spp. (88.9%; 6.7 ± 8.5 x104 CE g-1 ), followed by Legionella spp. (66.7%; 5.2 ±5.9 x 103 CE g-1 ), Pseudomonas aeruginosa (22.2%; 250 ± 880 CE g-1 ), and Acanthamoeba spp. (38.9%; 53 ± 70 CE g-1 ), with no detected Naegleria fowleri. Most enteric pathogens (Campylobacter jejuni, Escherichia coli 0157:H7, Salmonella enterica, Cryptosporidium parvum and Giardia duodenalis) were not detected, except for a trace signal for Campylobacter spp. There was significant correlation between the qPCR signals of Legionella spp. and Acanthamoeba spp. (R2 =0.61, n=87, P=0.0001). Diverse Legionella spp. including L. pneumophila, L. pneumophila sg1 and L. anisa were identified, each of which might cause legionellosis.

CONCLUSIONS: These results imply that potential opportunistic pathogens are common within MDWST sediments and could act as a source of microbial contamination, but needing downstream growth to be of potential concern.

SIGNIFICANCE AND IMPACT OF THE STUDY: The results imply that opportunistic pathogen risks may need to be managed by regular tank cleaning or other management practices.

Click here for paper (fee).

Climate Models are Unreliable for Predicting the Future

This latest study is simply one more to confirm the unreliability of climate models. By fiddling with the assumptions an analyst can generate just about any outcome they would like. Consider this comparison of the various climate models and actual measurements.


Relying on climate models to predict or even comment on the future is squarely in the category of fortune telling. Such analyses are useful and worthwhile from an academic perspective, but they are being applied in a cavalier manner (e.g. here). Climate models are fraught with implicit assumptions that drive the outcome. To take just one, even Philosopher David Hume would object to the implicit assumption in every model that the future will be even remotely like the past. This is true even for the newest model in the paper cited below. There is no sound basis for this assumption. 

Comparing the model-simulated global warming signal to observations using empirical estimates of unforced noise Patrick T. Brown, Wenhong Li, Eugene C. Cordero, Steven A. Mauget. Scientific Reports; April 2015, Vol. 5 Issue: 1 p9957-9957

The comparison of observed global mean surface air temperature (GMT) change to the mean change simulated by climate models has received much public and scientific attention. For a given global warming signal produced by a climate model ensemble, there exists an envelope of GMT values representing the range of possible unforced states of the climate system (the Envelope of Unforced Noise; EUN). Typically, the EUN is derived from climate models themselves, but climate models might not accurately simulate the correct characteristics of unforced GMT variability. Here, we simulate a new, empirical, EUN that is based on instrumental and reconstructed surface temperature records. We compare the forced GMT signal produced by climate models to observations while noting the range of GMT values provided by the empirical EUN. We find that the empirical EUN is wide enough so that the interdecadal variability in the rate of global warming over the 20thcentury does not necessarily require corresponding variability in the rate-of-increase of the forced signal. The empirical EUN also indicates that the reduced GMT warming over the past decade or so is still consistent with a middle emission scenario’s forced signal, but is likely inconsistent with the steepest emission scenario’s forced signal.

Click here for full paper (Open Access).


Arsenic and Cardiovascular Disease, Inner Mongolia, China

The association between arsenic exposure and cardiovascular disease is not new. Whether the findings of this study apply to a general population elsewhere is highly debatable.

Wade TJ, Xia Y, Mumford J, Wu K, Le XC, Sams E, Sanders WE. Cardiovascular disease and arsenic exposure in Inner Mongolia, China: a case control study. Environmental health 2015 Apr 12;14(1):35.

Background: Millions of people are at risk from the adverse effects of arsenic exposure through drinking water. Increasingly, non-cancer effects such as cardiovascular disease have been associated with drinking water arsenic exposures. However, most studies have been conducted in highly exposed populations and lacked individual measurements.

Objective: To evaluate the association between cardiovascular disease and well-water arsenic exposure.

Methods: We conducted a hospital based case control study in Inner Mongolia, China. Cases and controls were prospectively identified and enrolled from a large hospital in the Hangjin Hou area. Cases were patients diagnosed with cardiovascular disease and controls were patients free from cardiovascular disease, admitted for conditions unrelated to arsenic exposure. Water from the primary water source and toenail samples were collected from each subject and tested for inorganic arsenic.

Results: Arsenic exposures were moderate with mean and median arsenic exposures of 8.9 μg/L and 13.1 μg/L, respectively. A total of 298 cases and 275 controls were enrolled. The adjusted odds ratio (AOR) and corresponding 95% confidence interval (95% CI) for a 10 μg/L increase in water arsenic were 1.19 (95% CI: 1.03, 1.38). Compared to exposures less than 10 μg/L, the AOR for water arsenic exposures above 40 μg/L was 4.05 (95% CI: 1.1-14.99, p = 0.04). Nail arsenic above 1.38 μg/g was also associated with an increased risk of cardiovascular disease.

Conclusions: By using standardized case definitions and collecting individual measurements of arsenic, this study addressed several limitations of previous studies. The results provide further evidence of the association between cardiovascular disease and arsenic at moderate exposures.

Click here for paper (Open Access).

Retrospective Modeling of Water Distribution System for Exposure Assessment an Academic Exercise

Once again exposure assessment is the primary limitation of a study. So much so here that the results are simply an academic exercise. In this case “These findings should be interpreted cautiously because of the study limitations…” really means the study results have no basis in reality.

Aschengrau A, Winter MR, Vieira VM, Webster TF, Janulewicz PA, Gallagher LG, Weinberg J, Ozonoff DM. Long-term health effects of early life exposure to tetrachloroethylene (PCE)-contaminated drinking water: a retrospective cohort study. Environmental health. 2015 Apr 12;14(1):36. doi: 10.1186/s12940-015-0021-z.

Background: While adult exposure to PCE is known to have toxic effects, there is little information on the long-term impact of prenatal and early childhood exposure. We undertook a retrospective cohort study to examine the effects of their early life exposure to PCE-contaminated drinking water. This retrospective cohort study examined whether prenatal and early childhood exposure to PCE-contaminated drinking water influenced the risk of a variety of chronic conditions among adults who were born between 1969 and 1983 in the Cape Cod area of Massachusetts.

Methods: Eight hundred and thirty-one participants with prenatal and early childhood PCE exposure and 547 unexposed participants were studied. Individuals completed questionnaires to gather information on demographic characteristics, chronic conditions, and other sources of solvent exposure. The location of residences from birth through 1990 were used to estimate PCE exposure with U.S. EPA’s water distribution system modeling software (EPANET) modified to incorporate a leaching and transport model.
Results: No associations were observed between early life PCE exposure and current occurrence of obesity, diabetes, cardiovascular disease, hypertension, color blindness, near- and far sightedness and dry eyes. In contrast, a 1.8-fold increased risk of cancer (95% CI: 0.8, 4.0) was seen among individuals with any early life exposure. These results were based on 31 participants (23 exposed and 8 unexposed) who reported cancers at a variety of anatomical sites, particularly the cervix. A 1.5-fold increase in the risk of epilepsy (95% CI: 0.6, 3.6, based on 16 exposed and 7 unexposed participants) was also observed among individuals with any early life exposure that was further increased to 1.8 (95% CI: 0.7, 4.6) among those with exposure at or above the sample median.

Conclusions: These results suggest that the risk of epilepsy and certain types of cancer such as cervical cancer may be increased among adults who were exposed to PCE-contaminated drinking water exposure during gestation and early childhood. These findings should be interpreted cautiously because of the study limitations and confirmed in follow-up investigations of similarly exposed populations with medically-confirmed diagnoses. This relatively young study population should also be monitored periodically for subsequent changes in disease risk.

Click here for paper.

Powdered Activated Carbon in Deep Bed Filtration

Altmann J, Ruhl AS, Sauter D, Pohl J, Jekel M. How to dose powdered activated carbon in deep bed filtration for efficient micropollutant removal. Water Research. 2015 Apr 10;78:9-17. doi: 10.1016/j.watres.2015.03.031.

Direct addition of powdered activated carbon (PAC) to the inlet of a deep bed filter represents an energy- and space-saving option to remove organic micropollutants (OMPs) during advanced wastewater treatment or drinking water purification. In this lab-scale study, continuous dosing, preconditioning a filter with PAC and combinations thereof were investigated as possible dosing modes with respect to OMP adsorption efficiency. Continuous dosing resulted in decreasing effluent concentrations with increasing filter runtime due to adsorption onto accumulating PAC in the filter bed. Approximately constant removal levels were achieved at longer filter runtimes, which were mainly determined by the dose of fresh PAC, rather than the total PAC amount embedded. The highest effluent concentrations were observed during the initial filtration stage. Meanwhile, preconditioning led to complete OMP adsorption at the beginning of filtration and subsequent gradual OMP breakthrough. PAC distribution in the pumice filter was determined by the loss on ignition of PAC and pumice and was shown to be relevant for adsorption efficiency. Preconditioning with turbulent upflow led to a homogenous PAC distribution and improved OMP adsorption significantly. Combining partial preconditioning and continuous dosing led to low initial effluent concentrations, but ultimately achieved concentrations similar to filter runs without preconditioning. Furthermore, a dosing stop prior to the end of filtration was suitable to increase PAC efficiency without affecting overall OMP removals.

Click here for paper (Open Source).


Reducing Intake of Sugar-Sweetened Beverages in Children and Adults

Vargas-Garcia EJ, El Evans C, Cade JE. Impact of interventions to reduce sugar-sweetened beverage intake in children and adults: a protocol for a systematic review and meta-analysis. Systematic Reviews. 2015 Feb 21;4(1):17. doi: 10.1186/s13643-015-0008-4.

Background: Sugar-sweetened beverages (SSBs) have been stressed as relevant targets of public health interventions considering the negative outcomes derived from their excessive intake. Though the evidence from published literature grows to support a cause-and-effect association of SSBs with obesity and other diseases, little is known on the effectiveness that strategies alone or as part of multi-component programmes have had to influence this particular dietary behaviour across all ages. Therefore, this review and meta-analysis aim to evaluate the effect that interventions have had to decrease their consumption or increase water intake in children and adults so as to guide the design of future programmes and inform policy making.

Methods: Included studies in this review will be randomised controlled trials and quasi-experimental interventions (with a control group) that have reported baseline and post-intervention intakes of SSBs or water and that have been published from 1990 in any language. A thorough search will be performed in MEDLINE, EMBASE, Scopus, Web of Science, Cochrane’s central register of controlled trials, and the Global Health Library. Two independent reviewers will conduct initial screening of potentially included articles and will later extract data to analyse domains of intervention design and delivery (with emphasis on behaviour change techniques used as rationale), as well as results in changes on consumption patterns and behavioural determinants. Internal and external validity of each study will also be appraised. A meta-analysis will be performed if a sufficient number of studies are available, and if not, a narrative review will be conducted instead.

Discussion: The results from this review aim to strengthen public health initiatives tackling obesity through improvements in non-alcoholic drinking patterns. As a subject of growing attention globally, this review will help determine which strategies available are the most effective in different contexts. Knowledge gained from this work will also aid resource allocation in future research and government agendas.

Click here for paper (Open Access).

How do Climate Models Account for Volcanic Eruptions?

I wonder if any warming occurs at the earth’s surface as a result of a volcanic eruption? Like this one in Chile courtesy of Russian Television (RT). Think there is any PM10, PM2.5, CO2 or SO2 being emitted?

video h/t: iceagenow

More on this eruption given by Dr Roy Spencer.