Seasonal Lead Release into Drinking Water and the Effect of Aluminum.

Monitoring lead in drinking water is important for public health, but seasonality in lead concentrations can bias monitoring programs if it is not understood and accounted for. Here, we describe an apparent seasonal pattern in lead release into orthophosphate-treated drinking water, identified through point-of-use sampling at sites in Halifax, Canada, with various sources of lead. Using a generalized additive model, we extracted the seasonally varying components of time series representing a suite of water quality parameters and we identified aluminum as a correlate of lead. To investigate aluminum's role in lead release, we modeled the effect of variscite (AlPO4·2H2O) precipitation on lead solubility, and we evaluated the effects of aluminum, temperature, and orthophosphate concentration on lead release from new lead coupons. At environmentally relevant aluminum and orthophosphate concentrations, variscite precipitation increased predicted lead solubility by decreasing available orthophosphate. Increasing the aluminum concentration from 20 to 500 µg L-1 increased lead release from coupons by 41% and modified the effect of orthophosphate, rendering it less effective. We attributed this to a decrease in the concentration of soluble (<0.45 µm) phosphorus with increasing aluminum and an accompanying increase in particulate lead and phosphorus (>0.45 µm).

Assessing the impact of multiple ultraviolet disinfection cycles on N95 filtering facepiece respirator integrity.

During the COVID-19 pandemic, N95 filtering facepiece respirators (FFRs) were recommended to protect healthcare workers when providing care to infected patients. Despite their single-use disposable nature, the need to disinfect and repurpose FFRs is paramount during this global emergency. The objectives of this study were to (1) determine if UV treatment has an observable impact on respirator integrity; (2) test the impact of UV treatment on N95 FFR user fit; and (3) test the impact of UV treatment on FFR integrity. Ultraviolet (UV) disinfection was assessed in maintaining N95 FFR integrity. Two models of FFRs were exposed to UV fluences ranging from 0 to 10,000 mJ cm-2 per side and subsequently tested for fit, respirator integrity, and airflow. Inspection of N95 FFRs before and after UV treatment via microscopy methods showed no observable or tactile abnormalities in the integrity of respirator material or straps. Tensile loading tests on UV-treated and untreated respirator straps also demonstrated no impact on breaking strength. Standardized fit test methods showed no compromise in user fit following UV treatment. Evaluation of particle penetration and airflow through N95 FFRs showed no impact on integrity, and average filtration efficiency did not fall below 95% for any of the respirator types or fluence levels. This work provides evidence that UV disinfection does not compromise N95 FFR integrity at UV fluences up to 10,000 mJ cm-2. UV disinfection is a viable treatment option to support healthcare professionals in their strategy against the spread of COVID-19.

Validation of a QuEChERS method for extraction of estrogens from a complex water matrix and quantitation via high-performance liquid chromatography-mass spectrometry.

The traditional approach to extracting estrogens from water matrices, solid-phase extraction (SPE), presents a number of challenges when applied to complex wastewater matrices. Conversely, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) clean-up method offers an alternative sample preparation approach that omits sample filtration and overcomes additional challenges associated with SPE. The objective of this study was to implement and validate a scaled QuEChERS method, using a standard addition approach, for extracting estrone (E1), 17ß-estradiol (E2), and estriol (E3) from the estrogenic influent of a recirculating aquaculture system containing American eels (Anguilla rostrata). While traditional QuEChERS protocols do not facilitate considerable sample concentration, a 500-fold concentration factor was implemented for reliable quantitation of parts-per-trillion concentrations of estrogens from an initial sample volume of 20 mL to a final extract volume of 40 µL. Following analysis via high-performance liquid chromatography-mass spectrometry, excellent process efficiencies were observed at spiked concentrations of 10 and 50 ng L-1 for E2 and E1 (101 to 111%; %RSD ≤ 16), and moderate to acceptable process efficiencies were achieved for E3 (75 to 87%; %RSD ≤ 16). Validation of method parameters, including specificity, linearity, accuracy (recovery and process efficiencies), precision (intra-day precision, and inter-day precision), matrix effects, method detection limit, and limit of quantitation, led to reliable quantitation of unknown concentrations of E1, E2, and E3 in the aquaculture influent as low as 52, 20, and 33 ng L-1, respectively. This study provides a validated analytical method for waste systems requiring quantitation of estrogens in their complex wastewater matrices.