Urinary biomarkers and low-level environmental benzene concentration: assessing occupational and general exposure

The categories of urban workers undergoing prolonged exposure to gasoline due to vehicle emissions, evaporation and traffic fumes are considered occupationally exposed to benzene, even if at low concentrations. The aim of this study was to evaluate the specificity of unmetabolized benzene excreted in urine (UBz) and S-phenylmercapturic acid (SPMA) as biomarkers of exposure to very low levels of benzene, and to study the impact of putative individual confounders like smoking and alcohol habits, co-exposure to other toxicants and body mass index on the exposure assessment. Environmental and biological monitoring of exposure to benzene were performed in 114 Urban Policemen. The mean value of UBz in non-smokers was significantly lower than in either groups of light to moderate smokers and heavy smokers (0.24, 1.82 and 2.82 microg L(-1), respectively). On the contrary, SPMA values did not discriminate exposure resulting from smoking habits. Moreover, the concentration of UBz in non-smokers appears to be correlated with environmental benzene concentration (BenzA) (R(2)=0.13, beta=0.37, p=0.002). On the other hand, no significant correlation was found between SPMA concentration (corrected for creatinine excretion and log transformed, LogSPMA) and LogBenzA (R(2)=0.003, beta=0.05, p=0.6). Our findings reinforce previous research on the use of unmetabolized urinary benzene as a specific and sensitive biomarker of low-level exposure to benzene and confirm that smoking habits strongly influence the excretion of UBz.     

Variation in litter size: a test of hypotheses in Richardson's ground squirrels

We studied litter size variation in a population of Richardson's ground squirrels (Spermophilus richardsonii) in Alberta, Canada, from 1987 to 2004. Litter size at first emergence of juveniles from the natal burrow ranged from 1 to 14; the most common litter sizes, collectively accounting for 41.0% of 999 litters, were 6 and 7. The number of offspring surviving to adulthood (attained on emergence from hibernation as yearlings) increased with increasing litter size, a result that was not predicted by Lack's "optimal litter size" hypothesis, Mountford's "cliff-edge" effect, or the "bad-years" effect. Contrary to the negative effects predicted by the "cost of reproduction" hypothesis, litter size had no significant influence on survival of mothers to the subsequent year or on the size of the subsequent litter. Rather, our results best fit the predictions of the "individual optimization" hypothesis, which suggests that litter size is determined by the body condition and environmental circumstances of each mother. Supporting this hypothesis, survival of individual offspring was not significantly associated with litter size. Additionally, year-to-year changes in maternal body mass at mating were positively associated with concurrent changes in litter size (r = 0.56), suggesting that litter size depends on the body condition of the mother. Because the mean number of recruits to adulthood increased as litter size increased (r2 = 0.96) and litter size increased with maternal condition, offspring productivity was greater for mothers in better body condition.     

An assessment of the quality of various bottled mineral water marketed in Turkey

Fifteen bottled mineral waters purchased at random all over Turkey were analyzed for their chemical composition by OPTIMA-2000 ICP-AES Perkin Elmer techniques. Results show a wide spread in the chemical specification of these mineral waters, with differences in chemical composition observed in the regions being due to the geological environment and the majority of bottled mineral waters exceeding the pH limit of Turkish drinking water standards. When the concentrations of elements are evaluated, it can readily be seen that generally there are three types of mineral water in Turkey. The concentrations of Al, B, Ba, Cd, Cu, Cr, Fe, Mn Pb and Zn in mineral water were compared with the limits established by the Turkish Standard for Natural Mineral Waters (Turkish Official Gazette 2004); water standards prepared by World Health Organization (2006) and the United States of America Environmental Protection Agency (US EPA) drinking water standards (1993). Such a comparison shows that, except for Ba and Mn, the concentrations of the other heavy metals are lower than the limit of the US.EPA in Turkey. Some parameters examined were found to comprise strong correlations pair-wise.     

Reconnecting to the Biosphere

Humanity has emerged as a major force in the operation of the biosphere, with a significant imprint on the Earth System, challenging social-ecological resilience. This new situation calls for a fundamental shift in perspectives, world views, and institutions. Human development and progress must be reconnected to the capacity of the biosphere and essential ecosystem services to be sustained. Governance challenges include a highly interconnected and faster world, cascading social-ecological interactions and planetary boundaries that create vulnerabilities but also opportunities for social-ecological change and transformation. Tipping points and thresholds highlight the importance of understanding and managing resilience. New modes of flexible governance are emerging. A central challenge is to reconnect these efforts to the changing preconditions for societal development as active stewards of the Earth System. We suggest that the Millennium Development Goals need to be reframed in such a planetary stewardship context combined with a call for a new social contract on global sustainability. The ongoing mind shift in human relations with Earth and its boundaries provides exciting opportunities for societal development in collaboration with the biosphere--a global sustainability agenda for humanity.