I have always been a big advocate of tap water-not because I think it harmless but because the idea of purchasing water extracted from some remote watershed and then hauled halfway round the world bothers me. Drinking bottled water relieves people of their concern about ecological threats to the river they live by or to the basins of groundwater they live over. It's the same kind of thinking that leads some to the complacent conclusion that if things on earth get bad enough, well, we'll just blast off to a space station somewhere else.

Here in the United States, a study of nearly 700 women in California showed an increased risk of fetal death among babies whose mothers lived near crops when certain pesticides were sprayed. The largest risks were found among pregnant women exposed during the critical first trimester and among those who lived in the same square mile where pesticides were used.

From the right to know and the duty to inquire flows the obligation to act.

By 1990, the EPA had tallied up 32,645 sites of past chemical waste dumping in need of cleanup. Some of these are actual waste landfills, but many are former manufacturing sites where drums full of chemicals have been simply abandoned. The names of the most notorious appear on the EPS's National Priorities List. These are the so-called Superfund sites, names for the super fund of money put together by Congress in 1980 to clean them up. In 2009, the Superfund list contained 1,331 sites.

Indeed, the quantity of PCBs still in use plus the quantity still languishing in waste dumps exceeds the total amount that has already escaped into the general environment. Without a program to recall and contain them, semivolatile PCBs will continue to insinuate themselves into the food chain for decades.

In the world outside this glass room, songbirds are feeding and resting in the trees. Some will take off tonight and not land until they reach Venezuela. Sandpipers, plovers, and broad-winged hawks have already left for Patagonia and Panama. Bats are headed for caves in Kentucky and Tennessee. Out in the Atlantic, humpback whales pass by on their way to the Caribbean. Even now, Canada geese are honking toward us from Quebec. It is a good day for the beginnings of journeys.Every time I look at you, I think, Now I cannot die.

The study of how substances alter gene expression is part of the field of epigenetics. Some chemical exposures appear to turn on and turn off genes in ways that disregulate cell growth and predispose for cancer. From this perspective, our genes are less the command-and-control masters of our cells and more like the keys of piano, with the environment as the hands of the pianist.