Determination of antimony and barium in UK air quality samples as indicators of non-exhaust traffic emissions.

The aim of this study was to determine concentrations of antimony and barium in air quality samples and assess the potential suitability of these metals as tracer elements for non-exhaust traffic emissions sources. Air quality filters sampled at monitoring sites around the UK for the purposes of the UK Heavy Metals Monitoring Network were subjected to microwave digestion in hydrogen peroxide and nitric acid, then analysed by ICP-MS for a suite of metals including antimony and barium. The average antimony concentration found across all the network sites was 1.84 ng m-3; the average barium concentration was 6.33 ng m-3. The range of antimony concentrations observed was 0.13-8.02 ng m-3; barium concentrations ranged from levels below the detection limit of 0.18 to 39.9 ng m-3. There are no legislative limits for antimony and barium in ambient air, but the maximum concentrations found are well below the Workplace Exposure Limits specified by the UK Health and Safety Executive. The highest concentrations were found at roadside sites situated to monitor traffic environments, supporting the suitability of antimony and barium to be considered tracer elements for traffic emissions sources. Strong correlations were observed between antimony, barium and copper, indicating they share a common traffic-related source. Based on the strong correlation with copper at urban and traffic locations, indicative annual UK atmospheric emission estimates for antimony and barium in brake and tyre wear were calculated as 6 and 19 tonnes respectively.

Association of anal symptoms with anal high grade squamous intraepithelial lesions (HSIL) among men who have sex with men: Baseline data from the study of the prevention of anal cancer (SPANC).

BACKGROUND: The association between anal high-grade squamous intraepithelial lesion (HSIL) and anal symptoms has not been systematically investigated. METHODS: The Study of Prevention of Anal Cancer is a prospective cohort study of men who have sex with men (MSM) ≥ 35 years old in Sydney, Australia. Self-reported symptoms were collected. Anal cytology and high-resolution anoscopy were undertaken. Using baseline visit data, men negative for squamous intra-epithelial lesion (SIL) were compared with men diagnosed with composite-HSIL (cytology and/or histology). Logistic regression analyses were performed to assess the association of symptoms with HSIL. RESULTS: Among 414 MSM included (composite-HSIL (n = 231); negative for SIL (n = 183)), 306 (73.9%) reported symptom(s) within the last 6 months. There was no association between any symptom and composite-HSIL. A significant association between anal lump and a larger burden of HSIL (at least 2 intra-anal octants) (anal lump within last month: p = 0.014; anal lump within last 6 months: p = 0.010) became non-significant after adjusting for HIV-status and recent anal warts (anal lump within last month: p = 0.057; anal lump within last 6 months: p = 0.182). CONCLUSIONS: Among MSM age 35 years and older, most anal symptoms are not a useful marker of anal HSIL.