CO2 concentrations are increasing in the last decades mainly due to the increase of anthropogenic emissions.
Ground water sources are frequently contaminated with pesticides; nitrate concentrations are increasing and are often close to or above the legal standard of 50mg/ll.
It is also evident from Fig. 5b that the fluoride concentrations are increasing with increase of Na+/(Na+ + Ca2+), since Na+ replaces Ca2+ in a cation-exchange process, leading to enhancement of fluoride concentration in groundwater (Su et al. 2013; Li et al. 2014a, b).
We tested the applicability of multiple groundwater age tracers (3H, 3He, 4He, 14C, 13C, and 85Kr) in projecting future trends of nitrate concentration in 9 long-screened, public drinking water wells in Turlock, California, where nitrate concentrations are increasing toward the regulatory limit.
Where concentrations are increasing (decreasing), this suggests that historical loadings to our hypothetical ecosystems were less than (greater than) simulated deposition.
The non-linearity in transcription activation complicates the interpretation of the rate at which in vivo cAMP concentrations are increasing or decreasing.
