Analysis of munitions constituents in groundwater using a field-portable GC-MS.

The use of munitions constituents (MCs) at military installations can produce soil and groundwater contamination that requires periodic monitoring even after training or manufacturing activities have ceased. Traditional groundwater monitoring methods require large volumes of aqueous samples (e.g., 2-4 L) to be shipped under chain of custody, to fixed laboratories for analysis. The samples must also be packed on ice and shielded from light to minimize degradation that may occur during transport and storage. The laboratory's turn-around time for sample analysis and reporting can be as long as 45 d. This process hinders the reporting of data to customers in a timely manner; yields data that are not necessarily representative of current site conditions owing to the lag time between sample collection and reporting; and incurs significant shipping costs for samples. The current work compares a field portable Gas Chromatograph-Mass Spectrometer (GC-MS) for analysis of MCs on-site with traditional laboratory-based analysis using High Performance Liquid Chromatography with UV absorption detection. The field method provides near real-time (within ~1 h of sampling) concentrations of MCs in groundwater samples. Mass spectrometry provides reliable confirmation of MCs and a means to identify unknown compounds that are potential false positives for methods with UV and other non-selective detectors.

Spontaneous onset of bacterial cellulitis in lower limbs with chronic obstructive venous disease.

BACKGROUND: Cellulitis, often recurrent is a common complication of severe chronic venous disease (CVD) when dermatitis or ulcer is present. The skin breakdown obviously provides easy entry for bacteria but other factors such as oedema and lymphatic dysfunction likely play a role in pathogenesis as well. An iliac obstructive lesion is commonly present and correction with stent(s) often heals dermatitis/ulcer and relieves cellulitis. The current manuscript focuses on a relatively infrequent "spontaneous" variety of cellulitis which also occurs in obstructive venous disease in the absence of overt skin breakdown. Stenting results are of particular interest in this subset because its therapeutic efficacy can be related to factors other than healing of dermatitis/ulceration (portal of entry). MATERIAL AND METHODS: One thousand and nine limbs underwent iliac vein stenting for symptomatic CVD over a 7 year period; 29 limbs that were stented to treat spontaneous recurrent cellulitis of two or more prior attacks and 16 additional limbs with only one prior episode (stented for other indications) are analysed. Eighty two percent of the limbs had obvious swelling and the remainder had none at the time of stenting when cellulitis was inactive. Iliac vein outflow obstruction was found by intravascular ultrasound (IVUS) and all limbs were stented. RESULTS: Median age was 54 and male to female ratio 1:2. Aetiology of iliac obstruction was post-thrombotic in 33% and non-thrombotic in 67%. Preoperatively, lymphatic abnormalities were present in 17 (38%) of the limbs: no activity in 7, delayed flow in 8 and pooling of isotope in the lower leg in 2 limbs. Swelling and pain improved significantly after stent placement. Cumulative freedom from recurrent attacks of cellulitis was 76% at 3 years. CONCLUSION: Iliac vein outflow obstruction may underlie CVD limbs afflicted with cellulitis. IVUS examination is recommended if cellulitis is recurrent and conventional therapy had failed. Correction of outflow obstruction by venous stent placement appears to yield moderate freedom from repeat infections in the near term.