Tag Archives: North Carolina

Point-of-use filters as a screening method for suspect compounds in drinking water

Newton SR, McMahen RL, Sobus JR, Mansouri K, Williams AJ, McEachran AD, Strynar MJ.
Suspect screening and non-targeted analysis of drinking water using point-of-use filters.Environ Pollut. 2017 Nov 25;234:297-306. doi: 10.1016/j.envpol.2017.11.033.

Monitored contaminants in drinking water represent a small portion of the total compounds present, many of which may be relevant to human health. To understand the totality of human exposure to compounds in drinking water, broader monitoring methods are imperative. In an effort to more fully characterize the drinking water exposome, point-of-use water filtration devices (Brita® filters) were employed to collect time-integrated drinking water samples in a pilot study of nine North Carolina homes. A suspect screening analysis was performed by matching high resolution mass spectra of unknown features to molecular formulas from EPA’s DSSTox database. Candidate compounds with those formulas were retrieved from the EPA’s CompTox Chemistry Dashboard, a recently developed data hub for approximately 720,000 compounds. To prioritize compounds into those most relevant for human health, toxicity data from the US federal collaborative Tox21 program and the EPA ToxCast program, as well as exposure estimates from EPA’s ExpoCast program, were used in conjunction with sample detection frequency and abundance to calculate a “ToxPi” score for each candidate compound. From ∼15,000 molecular features in the raw data, 91 candidate compounds were ultimately grouped into the highest priority class for follow up study. Fifteen of these compounds were confirmed using analytical standards including the highest priority compound, 1,2-Benzisothiazolin-3-one, which appeared in 7 out of 9 samples. The majority of the other high priority compounds are not targets of routine monitoring, highlighting major gaps in our understanding of drinking water exposures. General product-use categories from EPA’s CPCat database revealed that several of the high priority chemicals are used in industrial processes, indicating the drinking water in central North Carolina may be impacted by local industries.

Improving Private-Well Water Quality, North Carolina

MacDonald Gibson J, Pieper KJ. Strategies to Improve Private-Well Water Quality: A North Carolina Perspective. Environmental health perspectives. 2017 Jul 7;125(7):076001. doi: 10.1289/EHP890.

BACKGROUND: Evidence suggests that the 44.5 million U.S. residents drawing their drinking water from private wells face higher risks of waterborne contaminant exposure than those served by regulated community water supplies. Among U.S. states, North Carolina (N.C.) has the second-largest population relying on private wells, making it a useful microcosm to study challenges to maintaining private-well water quality.

OBJECTIVES: This paper summarizes recommendations from a two-day summit to identify options to improve drinking-water quality for N.C. residents served by private wells.

METHODS: The Research Triangle Environmental Health Collaborative invited 111 participants with knowledge of private-well water challenges to attend the Summit. Participants worked in small groups that focused on specific aspects and reconvened in plenary sessions to formulate consensus recommendations.

DISCUSSION: Summit participants highlighted four main barriers to ensuring safe water for residents currently relying on private wells: (1) a database of private well locations is unavailable; (2) racial disparities have perpetuated reliance on private wells in some urbanized areas; (3) many private-well users lack information or resources to monitor and maintain their wells; and (4) private-well support programs are fragmented and lack sufficient resources. The Summit produced 10 consensus recommendations for ways to overcome these barriers.

CONCLUSIONS: The Summit recommendations, if undertaken, could improve the health of North Carolinians facing elevated risks of exposure to waterborne contaminants because of their reliance on inadequately monitored and maintained private wells. Because many of the challenges in N.C. are common nationwide, these recommendations could serve as models for other states.

Caffeine as an Ambient Water Quality Indicator

Spence PL. Using Caffeine as a Water Quality Indicator in the Ambient Monitoring Program for Third Fork Creek Watershed, Durham, North Carolina. Environmental health insights. 2015 Jun 25;9(Suppl 2):29-34. doi: 10.4137/EHI.S19588.

Caffeine has been suggested as a chemical indicator for domestic wastewater in freshwater systems, although it is not included in water quality monitoring programs. The Third Fork Creek watershed in Durham, NC, is highly urbanized, with a history of receiving untreated wastewater from leaking and overflowing sanitary sewers. The poor water quality originating in the Third Fork Creek watershed threatens its intended uses and jeopardizes drinking water, aquatic life, and recreational activities provided by Jordan Lake. Organic waste contaminants have been detected in both Third Fork Creek watershed and Jordan Lake; however, the sampling periods were temporary, resulting in a few samples collected during nonstorm periods. It is recommended that (1) the concentration of caffeine and other organic waste contaminants are determined during storm and nonstorm periods and (2) caffeine is monitored regularly with traditional water quality indicators to evaluate the health of Third Fork Creek watershed.

Ecologic Study of Private Well Drinking Water and Birth Defects of Limited Usefulness

These authors appear to have extracted out some statistical relationship from this data set. Torturing the data like this must be necessary to get a paper published, but it does not provide any new reliable information. At one time (long long ago) authors were much more careful when reporting statistical relationships. But being careful and precise does not generate funding. Given the 95% CI the PR would hardly qualify as having any practical significance, regardless of the PR reported. Surely there are more obvious and significant health issues than this where epidemiology studies would be useful. But more and more ecological studies of drinking water like this are not getting us anywhere.

Sanders AP, Desrosiers TA, Warren JL, Herring AH, Enright D, Olshan AF, Meyer RE, Fry RC. Association between arsenic, cadmium, manganese, and lead levels in private wells and birth defects prevalence in North Carolina: a semi-ecologic study. BMC Public Health. 2014 Sep 15;14(1):955.

BACKGROUND: Toxic metals including arsenic, cadmium, manganese, and lead are known human developmental toxicants that are able to cross the placental barrier from mother to fetus. In this population-based study, we assess the association between metal concentrations in private well water and birth defect prevalence in North Carolina.

METHODS: A semi-ecologic study was conducted including 20,151 infants born between 2003 and 2008 with selected birth defects (cases) identified by the North Carolina Birth Defects Monitoring Program, and 668,381 non-malformed infants (controls). Maternal residences at delivery and over 10,000 well locations measured for metals by the North Carolina Division of Public Health were geocoded. The average level of each metal was calculated among wells sampled within North Carolina census tracts. Individual exposure was assigned as the average metal level of the census tract that contained the geocoded maternal residence. Prevalence ratios (PR) with 95% confidence intervals (CI) were calculated to estimate the association between the prevalence of birth defects in the highest category (>=90th percentile) of average census tract metal levels and compared to the lowest category (<=50th percentile).

RESULTS: Statewide, private well metal levels exceeded the EPA Maximum Contaminant Level (MCL) or secondary MCL for arsenic, cadmium, manganese, and lead in 2.4, 0.1, 20.5, and 3.1 percent of wells tested. Elevated manganese levels were statistically significantly associated with a higher prevalence of conotruncal heart defects (PR: 1.6 95% CI: 1.1-2.5).

CONCLUSIONS: These findings suggest an ecologic association between higher manganese concentrations in drinking water and the prevalence of conotruncal heart defects.

Click here for full article (Open Access).

AMO and solar activity explain climate change in North Carolina

M. Gorji Sefidmazgi, M. Sayemuzzaman, A. Homaifar, M. K. Jha, and S. Liess. Trend analysis using non-stationary time series clustering based on the finite element method. Nonlinear Processes in Geophysics, 21, 605-615, 2014. doi:10.5194/npg-21-605-2014
http://www.nonlin-processes-geophys.net/21/605/2014/

In order to analyze low-frequency variability of climate, it is useful to model the climatic time series with multiple linear trends and locate the times of significant changes. In this paper, we have used non-stationary time series clustering to find change points in the trends. Clustering in a multi-dimensional non-stationary time series is challenging, since the problem is mathematically ill-posed. Clustering based on the finite element method (FEM) is one of the methods that can analyze multidimensional time series. One important attribute of this method is that it is not dependent on any statistical assumption and does not need local stationarity in the time series. In this paper, it is shown how the FEM-clustering method can be used to locate change points in the trend of temperature time series from in situ observations. This method is applied to the temperature time series of North Carolina (NC) and the results represent region-specific climate variability despite higher frequency harmonics in climatic time series. Next, we investigated the relationship between the climatic indices with the clusters/trends detected based on this clustering method. It appears that the natural variability of climate change in NC [North Carolina] during 1950–2009 can be explained mostly by AMO and solar activity.

Click here for full paper (Open Source).

Wake Forest (NC) residents drink contaminated water…

“The EPA called families in the community this past summer, saying their water is contaminated with a cancer-causing chemical called trichloroethylene, or TCE, and to not drink, bathe or cook with the water.”

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North Carolina farm camps have substandard drinking water

Werner E. Bischoff, Maria Weir, Phillip Summers, Haiying Chen, Sara A. Quandt, Amy K. Liebman, and Thomas A. Arcury. The Quality of Drinking Water in North Carolina Farmworker Camps. Am J Public Health. 2012;102: e49–e54. doi:10.2105/AJPH.2012.300738

Objectives. The purpose of this study was to assess water quality in migrant farmworker camps in North Carolina and determine associations of water quality with migrant farmworker housing characteristics.

Methods. We collected data from 181 farmworker camps in eastern North Carolina during the 2010 agricultural season. Water samples were tested using the Total Coliform Rule (TCR) and housing characteristics were assessed using North Carolina Department of Labor standards.

Results. A total of 61 (34%) of 181 camps failed the TCR. Total coliform bacteria
were found in all 61 camps, with Escherichia coli also being detected in 2. Water
quality was not associated with farmworker housing characteristics or with access to registered public water supplies. Multiple official violations of water quality standards had been reported for the registered public water supplies.

Conclusions. Water supplied to farmworker camps often does not comply with
current standards and poses a great risk to the physical health of farmworkers
and surrounding communities. Expansion of water monitoring to more camps and changes to the regulations such as testing during occupancy and stronger enforcement are needed to secure water safety.