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Wildfires have destroyed multiple residential communities in California in recent years. After fires in 2017 and 2018, high concentrations of benzene and other volatile organic compounds (VOCs) were found in public drinking water systems in fire-affected areas. The sources of the contamination and appropriate remediation have been urgent matters for investigation. This study characterizes target and non-target VOCs and semi volatile organic compounds (SVOCs) in water from a highly contaminated service line after the 2018 Camp Fire (Paradise, CA). Ninety-five organic compounds were identified or tentatively identified in the service line. Laboratory combustion experiments with drinking water pipes made of polyvinyl chloride (PVC), cross-linked polyethylene (PEX) and high-density polyethylene (HDPE) and a review of the literature were used to evaluate potential sources of the detected chemicals. Among the service line contaminants were thirty-two compounds associated with PVC pyrolysis and twenty-eight organic compounds also associated with the pyrolysis of polyethylene. The service line sample also contained fifty-five compounds associated with uncontrolled burning of biomass and waste materials. The findings support hypotheses that wildfires can contaminate drinking water systems both by thermal damage to plastic pipes and intrusion of smoke. Residual chlorine disinfectant in the water system modifies the contaminant distribution observed.

This article documents the employment discrimination experienced by Americans "regarded as" disabled (but not medically verified as such), using the Integrated Mission System of the U.S. Equal Employment Opportunity Commission (EEOC). Claimants who were perceived as disabled, as contrasted with those with documented disabilities, were more likely to file charges of discrimination based on the issues of discharge or hiring. Decisions by the EEOC in favor of claimants perceived to have disabilities disproportionately exceeded those in favor of claimants with documented disabilities. This finding lends support to the assertion that unconscious/implicit bias is persistent in the workplace. (Contains 6 tables.)

This study examines the effects of electrolytes on microcystin (MC) electrospray ionization (ESI) mass spectrometry and quantitative LC-MS-MS. Sodium replacement ions (SRI) are prominent in MC ESI spectra in protic solvents such as HPLC grade methanol. In a methanol-water-0.006% acetic acid (v/v) gradient, envelopes with up to 11 SRI were apparent in both the + 1 and +2 charge states with structures [[M + [Na.sub.x] - (x-1)H].sup.+] and [[M + [Na.sub.x] - (x-2)H].sup.+2]. The m/z 135 product ion, [[[empty set]-C[H.sub.2]-CH=O-C[H.sub.3]].sup.+], widely used in tandem LC-MS-MS determination of MC, is a low collision energy fragment of many doubly charged MC precursor ions (e.g., [[M+Na+H].sup.+2], [[M+Na+N[H.sub.4]].sup.+2], [M+Na+H+ C[H.sub.3]OH].sup.+2], [[M+2H].sup.+2]). These phenomena impair congener-specific LC-MS-MS detection of MC and degrade quantitative accuracy and precision. Pulse addition experiments established that ammonium formate (AF) strongly suppresses SRI in both +1 and +2 charge states and enhances M[H.sup.+] and MN[H4.sup.+] adducts in neutral MC. Addition of the buffer either post-column or by incorporation in the mobile phase increases specificity for all of the MC which were determined as the MN[H.sub.4.sup.+] > M[H.sup.+] and M[H.sup.+] > [[MH- 134].sup.+] transitions for neutral MC (MCLA, MCLF, MCLW) and [[M+2H].sup.+2] > [135.sup.+] and [[M+2H].sup.+2] > [[M+2H - 135].sup.+] transitions for arginine-containing MC (MCLR, MCYR, MCRR). These findings shed light on mechanisms of electrolyte-induced ionization suppression, and demonstrate beneficial use of a buffer electrolyte for improved specificity and analytical ruggedness in quantitative LC-MS-MS.

This study evaluates a new model for identifying unknown compounds in atmospheric pressure ionization mass spectrometry based on a mass-to-structure (MTS) paradigm. In this method, rudimentary ESI spectrum interpretation is required to recognize key spectral features such as M[H.sup.+], M[Na.sup.+], and MN[H.sub.4.sup.+], which lead to the unknown's monoisotopic mass. The unknown's mass is associated directly with known organic compounds using an Access 2003 database containing records of 19 438 substances assembled from common sources such as the Merck Index, pesticide and pharmaceutical compilations, and chemical catalogues. A user-defined mass tolerance ([+ or -] 0.001-0.5 Da) is set according to the instrument mass accuracy-unit mass resolution data require a wide mass tolerance (~0.5 Da) while tolerances for accurate mass data can be as narrow as [+ or -] 0.001 Da. Candidate structures retrieved with the MTS Search Engine appear in a report window providing formulas, mass error, and Internet links. This paper provides examples of structure elucidation with 15 organic compounds based on ESI mass spectra from both unit mass resolution (e.g., quadrupole ion trap and triple-stage quadrupole) and accurate mass instruments (e.g., TOF and Q-TOF). Orthogonal information (e.g., isotope ratios and fragmentation data) is complementary and useful for ranking candidates and confirming assignments. The MTS Search Engine identifies unknowns quickly and efficiently, and supplements existing interpretation schemes for unknown identification.

The author presents industrial hygiene review focusing on the advancements in biological monitoring. The subjects of interest include toxic substances research, development of new pharmaceuticals, agrochemicals and food additives.

The crystal structure characterization of streptococcal coaggregation regulator (ScaR) of Streptococcus gordonii which is a manganese-dependent transcriptional regulator is described. The differences observed for the metal ion binding suggested that ScaR and its closely related homologues are activated by a mechanism distinct from that of either DtxR or MntR.

In the last two-year review, the authors posed a question as to whether industrial hygiene analytical chemistry was a 'mature' field (A1). They concluded that this was not the case. Our survey of the recent literature leads us to the same conclusion. Analytical chemistry research remains highly innovative and productive in the industrial hygiene field. This makes perfect sense when one considers how rapidly the nature of work itself is changing in the industrialized world. New commercial processes and technologies in the workplace have lead to many technical challenges for the analytical chemistry laboratory. Even new industries have appeared in the past decade, and change promises to accelerate as we enter the next century.