A hypothesis generating study study such as this can easily be misinterpreted. The methods applied are in no way adequate to suggest that drinking water ingestion is the primary or even a significant route of contaminant exposure leading to these effects. Certainly we should look for clues. But there are many other environmental contaminants and exposure routes that may result in the differences in cancer rates.
Svirčev Z, Drobac D, Tokodi N, Lužanin Z, Munjas AM, Nikolin B, Vuleta D, Meriluoto J. Epidemiology of Cancers in Serbia and Possible Connection with Cyanobacterial Blooms. Journal of Environmental Science and Health. Part C, Environmental Carcinogenesis and Ecotoxicology reviews. 2014 Oct 2;32(4):319-337.
Cyanobacteria produce toxic metabolites known as cyanotoxins. These bioactive compounds can cause acute poisoning, and some of them may promote cancer through chronic exposure. Direct ingestion of and contact with contaminated water is one of the many exposure routes to cyanotoxins. The aim of this article was to review the incidence of 13 cancers during a 10-year period in Serbia and to assess whether there is a correlation between the cancer incidences and cyanobacterial bloom occurrence in reservoirs for drinking water supply. The types of cancers were chosen and subjected to epidemiological analyses utilizing previously published data. Based on the epidemiological and statistical analysis, the group of districts in which the incidences of cancers are significant, and may be considered as critical, include Nišavski, Toplički, and Šumadijski district. A significantly higher incidence of ten cancers was observed in the three critical districts as compared to the remaining 14 districts in Central Serbia. These elevated incidences of cancer include: brain cancer, heart, mediastinum and pleura cancer, ovary cancer, testicular cancer, gastric cancer, colorectal cancer, retroperitoneum and peritoneum cancer, leukemia, malignant melanoma of skin, and primary liver cancer. In addition, the mean incidence of five chosen cancers was the highest in the three critical regions, then in the rest of Central Serbia, while the lowest values were recorded in Vojvodina. Persistent and recurrent cyanobacterial blooms occur during summer months in reservoirs supplying water to waterworks in the three critical districts. People in Central Serbia mainly use surface water as water supply (but not all the water bodies are blooming) while in Vojvodina region (control region in this study) only groundwater is used. Among the 14 “noncritical” districts, reservoirs used for drinking water supply have been affected by recurrent cyanobacterial blooms in two districts (Rasinski and Zaječarski), but the waterworks in these districts have been performing ozonation for more than 30 years. We propose that the established statistical differences of cancer incidences in Serbia could be related to drinking water quality, which is affected by cyanobacterial blooms in drinking water reservoirs in certain districts. However, more detailed research is needed regarding cyanobacterial secondary metabolites as risk factors in tumor promotion and cancerogenesis in general.
The full paper is here (fee).
Temnerud J, Hytteborn JK, Futter MN, Köhler SJ. Evaluating common drivers for color, iron and organic carbon in Swedish watercourses. Ambio. 2014 Dec;43 Suppl 1:30-44. doi: 10.1007/s13280-014-0560-5.
The recent browning (increase in color) of surface waters across much of the northern hemisphere has important implications for light climate, ecosystem functioning, and drinking water treatability. Using log-linear regressions and long-term (6-21 years) data from 112 Swedish watercourses, we identified temporal and spatial patterns in browning-related parameters [iron, absorbance, and total organic carbon (TOC)]. Flow variability and lakes in the catchment were major influences on all parameters. Co-variation between seasonal, discharge-related, and trend effects on iron, TOC, and absorbance were dependent on pH, landscape position, catchment size, latitude, and dominant land cover. Large agriculture-dominated catchments had significantly larger trends in iron, TOC, and water color than small forest catchments. Our results suggest that while similarities exist, no single mechanism can explain the observed browning but show that multiple mechanisms related to land cover, climate, and acidification history are responsible for the ongoing browning of surface waters.
Click here for paper (Open Access).
Sun Z, Li G, Wang C, Jing Y, Zhu Y, Zhang S, Liu Y. Community dynamics of prokaryotic and eukaryotic microbes in an estuary reservoir. Scientific reports. 2014 Nov 10;4:6966. doi: 10.1038/srep06966.
This study demonstrates both prokaryotic and eukaryotic community structures and dominant taxonomies in different positions of the greatest estuary reservoir for drinking water source in the world in four seasons of one year using 454 pyrosequencing method with total of 312,949 16S rRNA and 374,752 18S rRNA gene fragments, including 1,652 bacteria OTUs and 1,182 fungus OTUs. During winter and spring, the community composition at the phylum level showed that microorganisms had similar structures but their quantities were different. Similarly, obvious changes at the genus level were observed among the samples taken in winter and spring between summer and fall. Microorganisms located the reservoir inlet were founded to be different from those in rear at both phylum and genus level. Air temperature had a stronger effect than sampling location on the microbial community structure. Total nitrogen and dissolved oxygen were algae-monitoring indicators during the whole year. Moreover, Bacillus was an efficient indicator during summer and autumn for bacteria OTUs.
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J. Wu, S. C. Long, D. Das and S. M. Dorner. Are microbial indicators and pathogens correlated? A statistical analysis of 40 years of research. Journal of Water and Health. 2011.
Indicator organisms are used to assess public health risk in recreational waters, to highlight periods of challenge to drinking water treatment plants, and to determine the effectiveness of treatment and the quality of distributed water. However, many have questioned their efficacy for indicating pathogen risk. Five hundred and forty cases representing independent indicator–pathogen correlations were obtained from the literature for the period 1970–2009. The data were analyzed to assess factors affecting correlations using a logistic regression model considering indicator classes, pathogen classes, water types, pathogen sources, sample size, the number of samples with pathogens, the detection method, year of publication and statistical methods. Although no single indicator was identified as the most correlated with pathogens, coliphages, F-specific coliphages, Clostridium perfringens, fecal streptococci and total coliforms were more likely than other indicators to be correlated with pathogens. The most important factors in determining correlations between indicator–pathogen pairs were the sample size and the number of samples positive for pathogens. Pathogen sources, detection methods and other variables have little influence on correlations between indicators and pathogens. Results suggest that much of the controversy with regards to indicator and pathogen correlations is the result of studies with insufficient data for assessing correlations.
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Ina Kristiana, Arron Lethorn, Cynthia Joll, Anna Heitz. To add or not to add: The use of quenching agents for the analysis of disinfection by-products in water samples. water research 59 (2014) 90
The formation of disinfection by-products (DBPs) is a public health concern due to their potential adverse health effects. Robust and sensitive methods for the analysis of DBPs, as well as appropriate sample handling procedures, are essential to obtain accurate, precise and reliable data on DBP occurrence and formation. In particular, the use of an appropriate quenching agent is critical to prevent further formation of DBPs during the holding time between sample collection and analysis. Despite reports of decomposition of DBPs caused by some quenching agents, particularly sulphite and thiosulphate, a survey of the literature shows that they are still the most commonly used quenching agents in analysis of DBPs. This study investigated the effects of five quenching agents (sodium sulphite, sodium arsenite, sodium borohydride, ascorbic acid, and ammonium chloride) on the stability of seven different classes of DBPs commonly found in drinking waters, in order to determine the most appropriate quenching agent for the different classes of DBPs. All of the quenching agents tested did not adversely affect the concentrations of trihalomethanes (THMs) and haloacetic acids (HAAs), and thus are suitable for quenching of disinfectant residual prior to analysis of these DBPs. Ascorbic acid was found to be suitable for the analysis of haloacetonitriles (HANs) and haloketones (HKs), but should not be used for the analysis of chlorite. Sodium arsenite, sodium borohydride, and ascorbic acid were all acceptable for the analysis of haloacetaldehydes (HALs). All of the quenching agents tested adversely affected the concentration of chloropicrin. A ‘universal’ quenching agent, suitable for all groups of DBPs studied, was not identified. However, based on the results of this study, we recommend the use of ascorbic acid for quenching of samples to be analysed for organic DBPs (i.e. THMs, HAAs, HANs, HKs, and HALs) and sodium sulphite for analysis of inorganic DBPs. Our study is the first comprehensive study on the effects of quenching agents on the stability of DBPs involving a wide range of DBP classes and quenching agents.
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The City of Aurora Water Dept wants a 1-mile drilling buffer around Spinney Mountain Reservoir….to protect it from the perceived evils of oil and gas drilling…..
Colorado’s economy is essentially government union-controlled, with environmental activist groups opposing just about everything having to do with water resources development….so let the battles begin…..click here for more….
One thyroid patient receiving I-131 treatment could excrete enough of the substance to be measurable in a watershed…..but below concentrations of concern.
Click here for more in Philadelphia….