Indicator‐based spectrophotometric pH is commonly used for the analysis of seawater because of its high precision and long‐term reproducibility. Users come from an increasingly diverse range of disciplines, primarily motivated by studies focused on the causes and effects of ocean acidification. While the analysis is readily implemented and straightforward, there are many variables that must be predetermined or measured, all of which can contribute uncertainty to the measurement. The indicator equilibrium constant and molar absorption coefficient ratios are available in the literature, but for various reasons, the conditions of analysis can be different, creating errors. Most of the parameters are temperature, salinity, and pressure dependent, posing potential additional errors. Indicator impurities and indicator perturbation of the sample pH also create uncertainties. We systematically evaluate all of the sources of error and compute how the errors propagate into CO2 equilibrium calculations of the partial pressure of CO2 (pCO2) and calcium carbonate saturation states (Ω). The primary sources of uncertainty originate from wavelength and absorbance errors in low quality or poorly functioning spectrophotometers (0.007 to 0.020 pH units) and indicator impurities (0.000 to >0.040 pH units). These errors generate pCO2 and Ω uncertainties of 11‐200 µatm and 0.08‐0.38, respectively, depending upon the pH value and its uncertainty.

Recreational shooters kill millions of small mammals each year and scavengers that ingest the carcasses can be poisoned if lead bullets are used. Less toxic bullets exist, but their performance and potential risk to deposit lead in carcasses is understudied. In May 2016, shooters controlled populations of Columbian ground squirrels (Urocitellus columbianus) at ranches in Idaho and Montana, USA, by shooting them with .17 HMR (Hornady Magnum Rimfire), .22 LR (long rifle), and .223 Rem (Remington) rifles with expanding and nonexpanding lead and nonlead bullets. We recorded whether bullets instantly incapacitated ground squirrels and then counted the number of bullet fragments in each carcass to estimate concentrations of residual lead. All types of lead bullets left lead in at least one-third of the Columbian ground squirrels. Unexpectedly, estimated concentrations of lead in carcasses did not differ between expanding and nonexpanding bullets within the .17 HMR and .22 LR calibers, partially because of the high variability in fragmentation. The greatest estimated concentrations of lead were in Columbian ground squirrels shot with expanding ammunition in .17 HMR and .223 Rem, which had an average of 23.6 mg and 91.2 mg Pb/carcass, respectively. Nonlead bullets incapacitated similar to lead bullets. Our results indicate that nonlead bullets eliminate the risk of additional lead exposure to scavengers while maintaining the lethality of lead bullets.

The performance and solvation characteristics of two novel latex nanoparticle (NP) pseudo-stationary phases (PSPs) for EKC are determined and compared to those of previously reported micellar, polymeric, and NP materials. The new NPs have shells composed of strongly acidic poly(AMPS) as opposed to the poly(acrylic acid) shell of the prior NP, and have varied hydrophobic core chemistry of either poly(butyl acrylate) or poly(ethyl acrylate). The NPs poly(AMPS) shell shows only minor changes in mobility and selectivity between pH 4.9 and 9.4, allowing adjustment of pH to influence and optimize separation performance. All of the NP phases have significantly different solvation characteristics and selectivity relative to SDS micelles. The selectivity and solvent character are similar for NPs with poly(butyl acrylate) cores and different shells, but vary significantly between NPs with poly(butyl acrylate) versus poly(ethyl acrylate) cores. NPs with poly(butyl acrylate) cores are among the least cohesive PSPs reported to date, while the NP with poly(ethyl acrylate) core is among the most cohesive. The results demonstrate that PSPs with unique selectivity can be generated by altering the chemistry of the hydrophobic core.