Pollution from cemeteries

Cemeteries are potential sources of contamination

Since the Stone Age people have been in the habit of burying their dead in specific places. Today, we call the places intended for the burial of corpses a cemetery . The word cemetery originated from the Greek word koumetèrian , which means dormitory; and the word cadaver, of Latin origin, means “flesh given to worms”.

Corpses, depending on the conditions of the environment, can undergo destructive processes such as autolysis and putrefaction. In autolysis, the body’s cells are dissolved by the body’s own enzymes; and in putrefaction, the decomposition of organs and tissues by microorganisms occurs, with the release of hydrogen sulphide, carbon dioxide, methane, ammonia, sulfur, phosphine, cadaverine and putrescine, responsible for the smell of rotting meat. If soil moisture is high, saponification can occur, which is a process that slows down the decomposition of the corpse. In Brazilian cemeteries, due to the hot and humid climate and the invasion of the graves by underground and surface waters, saponification is common.

During the decomposition of corpses, a viscous, greyish-brown liquid, called necrochorume, is formed. It is composed of mineral salts, water, degradable organic substances, a large amount of viruses and bacteria and other pathogenic agents. In necrochorume, formaldehyde and methanol can also be found, used in the embalming of bodies, heavy metals (in coffin decorations) and hospital waste, such as medicines. For every kilogram of body mass, around 0.6 l of necrochorume is generated.

The oldest cemeteries do not present any type of planning; they were built in places where the subsoil is quite vulnerable. In most of them, rainwater drainage is precarious, with some tombs flooding. Rainwater, after passing through the cemeteries, falls into the urban rainwater network, and is then channeled into bodies of water, contaminating surface water with substances present in necrochorume. In cemeteries located where the water table is shallow, the chances of contamination of groundwater are high.

Concern about the proximity of cemeteries to cities dates back to the 18th century, but concern about pollution caused by cemeteries is much more recent. It was only in 1998 that the WHO published a report stating that cemeteries would be a potential source of pollution, which could cause environmental impacts on soil and groundwater due to the release of organic and inorganic substances and pathogenic microorganisms.

Groundwater samples taken around cemeteries with recent burials found water contamination by chloride and nitrate ions, viruses, bacteria and necrochorume.

CONAMA (National Council for the Environment), through resolutions 335/2003 and 368/2006, established criteria for the implementation of cemeteries, aiming to protect groundwater from infiltration of necrochorume, and imposed a deadline for cemeteries to implemented comply with the new rules.

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