Hair mercury concentrations in residents of Sundarban and Calcutta, India.

Few studies on hair mercury have been conducted in India despite the fact that India is the world's third largest producer of coal and coal is India's primary energy source. No studies have been conducted in the Indian state of West Bengal which has a coastline with the Bay of Bengal. This study examined the concentration of mercury in hair in two diverse populations in West Bengal, India: Sundarban, a mangrove wetland where fishing is a common occupation, and Calcutta, a megacity and India's oldest functioning port. Individuals from whom scalp hair was collected (N=100) were asked a series of questions on occupation, education, age, smoking and alcohol consumption, and fish consumption. SAS was utilized to generate descriptive statistics including frequency and univariate analyses and to perform regression analyses to determine significant predictors of hair mercury in this population. The mean hair mercury increased across the first three age categories (<21, 21-30, 31-45) and decreased in the fourth category (>45). Hair mercury concentration was significantly higher among residents of Sundarban compared to Calcutta (p=0.0005). In multivariable analysis, location (Sundarban vs. Calcutta) and age were significant predictors of hair mercury concentration (p=0.0120 and p=0.0161, respectively). Average hair mercury concentrations in this study were not particularly elevated. Smoking and alcohol consumption were predictors of hair mercury concentration. The hair mercury in Sundarban residents compared to Calcutta residents may be elevated due to greater consumption of fish and type of fish consumed.

Landscape influences on headwater streams on Fort Stewart, Georgia, USA.

Military landscapes represent a mixture of undisturbed natural ecosystems, developed areas, and lands that support different types and intensities of military training. Research to understand water-quality influences of military landscapes usually involves intensive sampling in a few watersheds. In this study, we developed a survey design of accessible headwater watersheds intended to improve our ability to distinguish land-water relationships in general, and training influences, in particular, on Fort Stewart, GA. We sampled and analyzed water from watershed outlets. We successfully developed correlative models for total suspended solids (TSS), total nitrogen (TN), organic carbon (OC), and organic nitrogen (ON), which dominated in this blackwater ecosystem. TSS tended to be greater in samples after rainfall and during the growing season, and models that included %Wetland suggested a "build-and-flush" relationship. We also detected a positive association between TSS and tank-training, which suggests a need to intercept sediment-laden runoff from training areas. Models for OC showed a negative association with %Grassland. TN and ON both showed negative associations with %Grassland, %Wetland, and %Forest. Unexpected positive associations were observed between OC and equipment-training activity and between ON and %Bare ground + Roads. Future studies that combine our survey-based approach with more intensive monitoring of the timing and intensity of training would be needed to better understand the mechanisms for these empirical relationships involving military training. Looking beyond local effects on Fort Stewart streams, we explore questions about how exports of OC and nitrogen from coastal military installations ultimately influence estuaries downstream.

Identifying sources of fecal contamination inexpensively with targeted sampling and bacterial source tracking.

Most bacterial source tracking (BST) methods are too expensive for most communities to afford. We developed targeted sampling as a prelude to BST to reduce these costs. We combined targeted sampling with three inexpensive BST methods, Enterococcus speciation, detection of the esp gene, and fluorometry, to confirm the sources of fecal contamination to beaches on Georgia's Jekyll and Sea Islands during calm and stormy weather conditions. For Jekyll Island, the most likely source of contamination was bird feces because the percentage of Ent. faecalis was high (30%) and the esp gene was not detected. For the Sea Island beach during calm conditions, the most likely sources of fecal contamination were leaking sewer lines and wildlife feces. The leaking sewer lines were confirmed with fluorometry and detection of the esp gene. For the Sea Island beach during stormflow conditions, the most likely sources of fecal contamination were wildlife feces and runoff discharging from two county-maintained pipes. For the pipes, the most likely source of contamination was bird feces because the percentage of Ent. faecalis was high (30%) and the esp gene was not detected. Sediments were also a reservoir of fecal enterococci for both Jekyll and Sea Islands. Combining targeted sampling with two or more BST methods identified sources of fecal contamination quickly, easily, and inexpensively. This combination was the first time targeted sampling was conducted during stormy conditions, and the first time targeted sampling was combined with enterococcal speciation, detection of the esp gene, and fluorometry.