Monosodium methanearsonate (MSMA) is frequently used as an herbicide for the control of weeds in turf grasses at golf courses in Florida. There are concerns about arsenic (As) contamination of local shallow groundwater from the application of MSMA. The distinction between "free" As and colloid-bound/complexed As in soil solution is important for understanding the mobility and bioavailability of As in the environment. In this study, the equilibrium membrane (500 and 3500 Da) dialysis method was employed to determine the "free" and "bound" As in water extracts of five types of golf-course soils containing coated and uncoated sands in various proportions with peat. All samples were evaluated for arsenic species (arsenite, AsIII and arsenate, AsV), dissolved organic matter, and additional constituents (iron, aluminum, and calcium). The impacts of microbial growth were evaluated by conducting experiments with and without the addition of sodium azide for one particular soil type. Results indicate that (1) the presence of peat in the soils plays a significant role in the distribution of As in the dissolved phase of soil solutions; (2) the majority of As present in the soil extracts from soils containing peat was associated with substances of molecular weight (MW) between 500 and 3500 Da; (3) the association of As and dissolved organic matter (DOM) in the soil solution strongly affected As bioavailability, thus determining As transformations via microorganism-mediated processes; and (4) the presence of peat greatly enhanced the release of iron, aluminum, and calcium from soil. Amendment of sand with peat is a common practice at Florida golf courses. However, the addition of peat will alter the properties of the soils, which in turn could affect As transport and transformation. The results of this study are useful for understanding the factors controlling As trapping and transport within porous soil media and in developing comprehensive plans for managing and remediating As contaminated environments, such as golf courses.

Polymorphisms in GSTM1 and GSTT1 may be associated with asthma risk, yet several studies and metaanalyses have reported inconclusive results. Therefore, an updated meta-analysis was conducted. Literature searches were performed using the Pubmed, Embase and Web of Science databases until October 2012. Variant 'null' genotype was compared with wild-type 'present' in the pooled data. All statistical analyses were performed using STATA 11.0. A total of 26 casecontrol studies were suitable for inclusion in the metaanalysis. In the overall population, a significant association was found for both the GSTM1 (odds ratio (OR) = 1.452; 95% confidence interval (CI): 1.192-1.770) and GSTT1 polymorphism (OR = 1.792; 95% CI:1.293-2.483). For subgroup analysis by age, GSTM1 significantly increased risk for both children (OR = 1.368; 95% CI: 1.051-1.781) and adults (OR = 1.859; 95% CI: 1.183-2.921). For GSTT1, a significant association was only found in the adult population (OR = 2.312; 95%CI: 1.204-4.439). Based on subgroup analysis by ethnicity, a significant association for GSTM1 was found in Europe (OR = 1.303; 95% CI: 1.018-1.667), Africa (OR = 2.175; 95%CI: 1.560-3.031) and Latin America (OR = 2.265; 95%CI: 1.375-3.729). For GSTT1, significantly increased risk was found only for Asian (OR = 2.105; 95% CI: 1.101-4.025) and Russian (OR = 2.747; 95% CI: 1.071-7.046) populations. This metaanalysis provides evidence that GSTM1 and GSTT1 polymorphisms may be risk factors for asthma.