Assessing lead-contaminated drinking water in a large academic institution: a case study

Drinking water is an important source of lead exposure, and de ﬁ nitively characterizing the sources of lead in drinking water, particularly in large institutional settings, can be time-consuming and costly. This study examined lead concentrations in drinking water at a large university, focusing on variability in ﬁ rst-draw samples and variability with dispensed volume. Over 350 sources were sampled twice by independent groups, and while 78% of these samples were within 2.5 μ g/L, almost 10% differed by > 10 μ g/L. In both sampling events, approximately 50% of sources had lead concentrations > 1 μ g/L, 6% were > 15 μ g/L, and 30% were between 1 and 15 μ g/L. The highest lead concentration detected was 400 μ g/L, with ﬁ ve sources > 100 μ g/L. Nine sources were sampled more intensively and six had ﬁ rst-draw sample ranges > 5 μ g/L. Lead concentration versus dispensed volume pro ﬁ les indicated that while most sources had decreasing lead concentrations after the ﬁ rst draw, others had maximum lead concentrations at higher dispensed volumes. The variability observed suggests that assessments using only one or two samples per source may not identify all sources with elevated lead concentrations, and management strategies should account for this possibility.


INTRODUCTION
Exposure to low amounts of lead can lead to adverse health effects in both children and adults (Bellinger et   The most common approach to assess WLL in schools and elsewhere is through 'first-draw' sampling where water is collected from a source after a long (6-8 h) period of stagnation (United States Environmental Protection Agency attention because of the large number of women of childbearing age and the adverse effects, including deficits in memory recognition, language learning, and IQ (Geng et al. ; Dzwilewski & Schantz ), in young children exposed to lead in utero. Variability in WLL may be especially high in university settings, given the range of building age and size on many campuses, and use patterns that may be less predictable compared with elementary and secondary schools.
This study of lead-contaminated drinking water on a large public university campus in California adds to the body of research on variability in WLL in institutional settings and considers the implications of variability for decision-making in these settings. In this study, we examined WLL variability within individual drinking water sources as well as campus-wide variability. To characterize variability in individual fountains and faucets, we conducted repeated first-draw sampling and also investigated WLL as a function of the volume dispensed for a subset of fountains and faucets. In addition to presenting the results of this investigation, we discuss the difficulty in completely characterizing lead concentrations in drinking water from all water sources in a large institutional setting and the impact of this difficulty on decision-making and risk communication.

MATERIALS AND METHODS
The study was conducted at the California State University, Sacramento (CSUS) between December 2016 and August 2017. CSUS is a regional comprehensive university in north central California with approximately 30,000 students, 1,700 faculty, and 1,400 staff. CSUS sits on a 300-acre campus and uses 53 buildings for teaching and research, administration, and residential housing for students (CSUS a). A map of the campus showing the distribution of these buildings can be found online (CSUS b). The campus is also used throughout the year by a variety of groups from the community, including children, that are not directly affiliated with the University.
First-draw sampling of 452 campus drinking water sources, which included sinks and fountains, was conducted by CSUS faculty and students in January 2017, after a preliminary survey of 30 fountains in eight buildings, con-

First-draw sampling
Approximately half of the drinking water sources sampled by CSUS and the external organization had lead concentrations below 1 μg/L (Table 1) We found mostly good agreement between percentages of samples in various ranges (e.g., >15 μg/L, between 1 and 5 μg/L, and <1 μg/L) measured by our group and the external consultant (Table 1). We also found mostly good agreement for paired first-draw samples collected by our with the online version of this paper). We also did not observe a clear relationship between building age (Supplementary Material, Table S1, available online) and lead concentrations, although all buildings where WLL >100 μg/L were observed were over 40 years old.
As a result of co-sampling and sampling for variability as a function of dispensed volume (discussed below), first-draw samples were collected from nine fountains and faucets at least three and as many as seven times during the study.

Variability with dispensed volume
Variability of lead concentrations with volume occurred in three distinct patterns (Figure 4). In six sources, elevated lead concentrations were detected in the first draw, and lower concentrations occurred as water was flushed through the system (Figure 4(a)). This pattern suggests that lead accumulated near the outlet over a period of time and was flushed relatively rapidly from the system. A second pattern (Figure 4   Tiered sampling approaches that assume a volume versus concentration relationship like that of Figure 4(a) will fail to address outlets that behave differently. Therefore, approaches to remediation and management of lead must be robust enough to account for possible missed sources, so that lead exposure will be reduced to very low levels or, ideally, eliminated as quickly as possible.
As noted above, the flushing strategy employed by pri-

CONCLUSIONS
In the first large-scale study of WLL on a university campus, lead was found to be a widespread contaminant of drinking water at a large public university in California, with WLL ranging from non-detect (<0.11 μg/L) to > 400 μg/L in campus fountains and faucets. These data, in combination with the growing body of work on lead in institutional settings, demonstrates that variability in WLL, whether between first draws or as a function of dispensed volume, presents challenges for both assessment and management of lead in drinking water at large institutions. Sources of drinking water with variable first-draw concentrations or peaks in WLL at larger dispensed volumes may appear to meet acceptable standards during assessments based on a single first draw, but may dispense water with WLL greater than a given threshold value. Similarly, daily flushing of fountains may fail to lower WLL below target levels depending on the kinetics of lead leaching in that specific source.
Our paired sampling on a large number of sources indicated that sources with low first-draw WLL tended to be low during both sampling events. However, further studies in which volume profiles were developed for sources with low first-draw WLL should be conducted to determine whether WLL may increase with larger dispensed volumes from these sources as well.
In light of the challenges variability in WLL of drinking water sources present, the option of providing clearly identified lead-free drinking water sources (Doré et al. ) seems to be a reasonable management strategy in a university setting. On the CSUS campus, at least one bottle filler with filters certified to remove lead has been installed in each building. Clear communication to users about the relative safety of all drinking water sources available is an important component of this management approach, so that those at greatest risk may make informed choices about which sources to use.