If any egg laying flock does receive an antibiotic, it is usually under the supervision of a veterinarian and only for a short period of time to treat a specific disease outbreak or for prevention of a recurring disease on that farm. What does Grade A mean? Eggs are graded based on their quality and appearance. Grade AA eggs have thick, firm whites and high, round yolks. Their shells are clean and unbroken. Grade A eggs are like Grade AA, but their whites are reasonably firm. Grade A eggs are usually sold in stores. Grade B eggs have thin whites and wider yolks. The shells are unbroken, but might show slight stains. How are eggs packed? An egg is placed in the carton with the large end up.
Arsenic has been known since ancient times, though probably in compound form rather than in its pure state. It is used in combination with other materials in pigments, poison gases and insecticides (such as Paris Green, calcium arsenate and lead arsenate) and is well known from former use as a rat poison.
Acute toxic inorganic arsenic exposure and arsine gas exposure can rapidly result in death, and there are only a few ways to possibly save the patient's life. Hemodialysis can remove arsenic from the bloodstream, but only before it binds to the tissues so there is only a short time window for this treatment to work. Arsenic is also often found in rice, representing a potentially serious source of exposure in certain at-risk populations (especially children). 2  Many water sources in the world have high levels of arsenic in them, both due to normal arsenic leaching out of the ground and from mining and industrial waste.