1	(nitrate* or nitrite* or no3* or no2* or nitroso or nitrogen).kf,tw,mp.
2	exp Nitrates/ or exp Nitrites/
3	1 or 2
4	(cancer* or tumo?r* or carcino* or neoplas* or malignan* or adenocarcinoma*).kf,tw,mp.
5	exp Neoplasms/
6	4 or 5
7	(((public or well or drinking or bottled or suppl* or consum* or tap or potable) adj5 water*) or groundwater).kf,tw,mp.
8	exp Drinking Water/
9	7 or 8
10	3 and 6 and 9
11	10 not (exp animals/ not humans.sh.)