Nitrogen can substitute helium as a mobile phase in the analysis of wastewater treatment matrices for persistent organic pollutants by gas chromatography - electron capture detection system.

Municipal wastewater treatment plants are required to monitor persistent organic pollutants (POPs) in their wastewater treatment related discharges and to assess the impact of the discharges on the environment and public health. One tool for monitoring chlorinated organic pollutants particularly is a gas chromatographic (GC) system coupled to a pair of halogen-specific electron capture detectors (ECDs) with helium (He) as the mobile phase. He supplies, however, has become inconsistent and unreliable lately. In its place, N2 gas is evaluated in this study as a potential substitute for He in quantifying organochlorine pesticides, polychlorinated biphenyls, chlordane congeners and toxaphene in wastewater treatment related matrices (influent, effluent, benthic sediment, mussel tissue, and biosolids/sludge). N2 is inert, inexpensive and requires no additional hardware to incorporate into the basic functions of a GC-ECD. Our results show that, with the usual data quality controls (blank, laboratory control, matrix spike/duplicate and proficiency testing samples, and the fact that certified reference materials data met requirements), N2 can replace He for regulatory purposes. And when necessary, the N2-based retention times (tN) can be predicted reliably from He-based retention times (tHe), irrespective of column chemistry or POPs (here: tN = 1.90tHe + 0.04, R2 = 0.996).

Assessing the health risks of consuming 'sachet' alcohol in Acoli, Uganda.

The increased mortality rate among the Acoli people of northern Uganda is anecdotally blamed on excessive consumption of cheap and widely available sachet-packaged alcohol in the region. In this paper, we quantify this perceived association by determining statistically the health risks associated with ingesting 20 heavy metals in 17 popular spirits products consumed in Acoli. Thirteen of these products were industrially packaged in sachets (locally known as 'sachet,' waragi, arege or moo lyec) and four were locally produced Lira-Lira spirits from Bolo, Awere and Teso Bar in the region and Nsambya in southern Uganda. A Scottish whisky purchased in San Diego (USA) was our reference. Risk assessment was performed according to standardized protocols developed by the United States Environmental Protection Agency (US EPA). Our results show that a strong correlation indeed exists between health risks and ingestion of spirits in Acoli. At >2.5 sachets/day for 240 day/year over a lifetime for example, the risk of developing cancer due to exposure to As, Pb and Cr alone is 1 in 102,041. This estimate excludes ethanol, a known carcinogen, and 17 heavy metals also studied due to lack of their cancer slope factors. The primary non-cancer related health risk factor in all samples tested is ethanol with unacceptably high health index of four. The Lira-Lira spirits, with 100-6000% copper above the US EPA limit for intake by oral ingestion in water, would be the 'cleanest' without copper and at par with the Scottish whisky. Collectively, we find that no amount of alcohol consumed in Acoli is safe. Preventive measures are therefore recommended to reduce mortality in Acoli in particular, and in Uganda in general. These measures should include public education, better public policies, creating productive economic activities other than brewing alcohol, and social activities that engage people away from drinking.

The effect of a massive wastewater discharge on nearshore ocean chemistry.

An opportunity to study the effect of a massive wastewater discharge on a nearshore ocean environment arose in 2015 over a 42-day period when the City of Los Angeles diverted 9.4 billion gal of treated wastewater effluent from an outfall located 5 mi in the Pacific Ocean to a 1-mi backup in the Santa Monica Bay (SMB). SMB is a heavily used waterbody and is home to many marine organisms. To understand the impact of this diversion on human health and on SMB ecosystem, samples of the wastewater effluent, the receiving seawater, and sediments from around the backup outfall were analyzed, among others, for metals, semivolatile organic compounds (SVOC), nutrients, and total organic carbon (TOC) during the diversion project. Results show that these parameters were present at levels below local water quality guidelines (i.e., not enough to cause health or environmental concerns). In the effluent, metal levels were < 10 µg/L except Zn (23 ± 9.9 µg/L); phosphate, ammonia-nitrogen, organic-nitrogen, and TOC levels were 3.48 ± 0.37, 42.7 ± 5.3, 4.7 ± 1.4, and 19.0 ± 4.9 mg/L, respectively. In seawater and sediments around the backup outfall, metal levels were < 1.5 µg/L and < 25 mg/kg, respectively. Apart from 4,4'-DDE, SVOCs were not detected in sediments. To assess whether changes to native levels of pollutants in SMB occurred due to the diversion project, pre-diversion and post-diversion datasets were compared statistically. No significant differences were found between the two datasets (p > .05, paired t test), meaning the diversion did not change the SMB chemistry.