Mold Ecology
Page 11
Is this mold? Frequently a fluffy white material in a basement is a salt rather than mold. Water vapor carrying salt moves from moist soil on the outside to the inside of the basement. When it evaporates on the inside, the salt is deposited. It will frequently accumulate along cracks in the concrete, but can occur anywhere that the moisture transfer occurs. It can be determined if it is salt or mold by placing a drop of water or vinegar on it. The salt can generally be dissolved by the water or vinegar and mold cannot. The salt is generally white, but it can be other colors depending on the type of mineral present in the soil. The salt is not a health concern, but continued exposure to the salt can deteriorate the concrete. Keeping the soil surrounding the basement dry will reduce the amount of salt being deposited in the concrete.