第6章 Tracers

The lab at three in the morning belonged to whoever was foolish enough to be awake in it, and Delyth had always liked the quiet of it, the hum of the hoods, the way the instruments asked their questions without wanting anything back. She ran the spill first, and then the seam from the core, and then, for comparison, a control of ordinary aquifer ice she had collected two seasons earlier, and she watched the chromatograph draw its peaks in blue on the black screen. The machine was old and it was honest, which was the only reason she trusted it. It separated everything in a sample by how fast it moved through a column, and it drew a picture of whatever was left, and it had no opinion about whether you liked the picture. She had run ten thousand samples through it and it had never once flattered her. Tonight it drew three pictures in a row and the third one disagreed with the other two in a way she had never seen it disagree with anything. The spill came back as a perfluorinated compound, a fully fluorinated tracer designed to be invisible and persistent, the kind of molecule hydrologists had used for half a century to follow water they could not see. You injected it upstream and you looked for it downstream and you learned where the water went. It was a tool for honest people and a tool for liars, and it did not care which, and it did not decay. The seam from the core came back as the same compound, at a concentration that made her sit very still. The control ice came back as nothing at all. She ran the numbers twice, then a third time with a fresh column, and the answer did not change. The tracer in her core was not a contaminant that had touched the outside of the ice during drilling. It was inside the ice. It had been frozen into the water when the water froze, which meant the water had carried it, which meant the water had come from somewhere the tracer had been put. Delyth pulled up the isotope results she had set aside the week before and laid them beside the tracer numbers, and the two records fit together like a key in a lock. The ice in her core was far too light in heavy hydrogen to be the old basin ice. It had formed from water that had recently been through a cycle at low temperature, water that had been melted and refrozen, water that carried an industrial tracer. It was not native ice. It was manufactured ice. The word sat on the bench and would not move. Ice was the one thing on this planet nobody manufactured, because the planet made it for free, and a manufactured aquifer was an aquifer that had been filled, and a filled aquifer was a policy, and a policy that was not in any public document was a lie with a schedule attached to it. She thought about the covert rig and the unlit tanks and the line that ran warm into the dark, and the two facts in front of her fit together with a click she could almost hear. Water was being pushed into the cavity at K-7. The cavity was filling with ice. The ice was carrying a tracer so somebody could watch it go. And if the cavity was being filled from the top while the same cavity was being emptied at the bottom, then the whole arrangement existed for a single purpose, which was to make water easy to move while making it impossible to count. She sat back on her stool and put her hands flat on the bench and made herself say the sentence out loud, in the quiet room, because a sentence you will not say is a sentence you can still pretend not to believe. "Highline is not sublimating water into the air. It is pumping water into the ground, and it is pumping it into the cavity at K-7, and somebody has been doing it for eleven nights running in the dark." Her own voice sounded strange in the empty lab. She looked at the chromatograph, and then at the survey she had spent a year building, and then at the tank farm she had seen in the dark with no name on any map, and she understood the shape of the lie at last. Aphelion had come to make air. That was the poster. But water vapor added to a sky that did not hold it would sublimate and be lost to space within a season, and everyone in the colony who had done the arithmetic knew it. The Highline Program's real product was not atmosphere at all. Its real product was the water itself, moved from the ground the colonists owned into a reservoir the colonists could not see, there to be counted as inventory, to be exported as propellant and coolant to buyers who never set foot on the basin, to be sold a liter at a time out from under the ten thousand people who believed the ice beneath them was their future. The colony was not gaining a sky. It was quietly losing its water, and the loss was being filed as progress. She had been hired to prove there was enough water. She was now holding proof that the number she had been hired to defend had been spent, quietly, on something the colony had never agreed to buy. It was not a crime that would make the news on Earth. Nobody would die of it this year, or next year, and the arithmetic that killed a colony did not announce itself; it arrived a decade late, in a reservoir that came up short, in a ration that got a little thinner every season, in a town with a single well and a well that was lower than the paper said it was. The company had found the perfect crime, which was one where the victim would not notice for ten years and by then would be too far from home to complain. Delyth checked the time. It was nearly four. In two hours the shift would turn and the corridor lights would come up on schedule and the basin would wake and go on believing, and she would have to sit in it and know what she knew. She thought about the ten thousand people asleep around her, and about how the only thing standing between them and a decade of quiet thirst was a file that a company lawyer could call provisional. She thought about the way a colony dies, which is never all at once, and never with an alarm, but with a budget that comes up short, and a ration that thins, and a well that keeps giving slightly less than the year before. She had spent her whole career trying to keep that day far away. It turned out the day was not far away; it had been walking toward the colony for eleven nights, at night, while everyone slept. She boxed the samples, wrote the results in her own hand in her own notebook, made one copy of the memory to a card she put inside the lining of her jacket, and left the lab before anyone else arrived. She wanted the record to be out of the building before the building knew she was holding it. Halfway down the corridor, her wrist chimed. It was Wim, from the instrument bay, and the message was six words long. *Patrol came by. They logged the sled.* Delyth stopped walking. Behind her, the lab door clicked shut on its spring, and the lights over the concourse came on, one section at a time, right on time, and she stood in the middle of them and understood that she had used up the last of the safe nights. ---