Virus brings risk of groundwater contamination through graves

The outbreak of the coronavirus has dramatically disrupted global economies and halted people’s daily activities.

There is no report yet of any clinically approved antiviral treatment or vaccines that are effective against Covid-19. This has resulted in lots of casualties and  mass burials in developed countries such as Italy, Spain and the US.

The above scenario portends a looming disaster for the world’s most impoverished countries. South Africa, on the other hand, is in a position to learn from the lessons of more developed countries in planning and preparing for the possibility of increased fatalities, which might exceed existing burial and crematorium facilities.

There is a genuine concern that the bodies of people who die of Covid-19 may aid  in spreading the virus, especially to those processing them for burial.

At the same time there is a huge debate on whether burying the bodies of Covid-19 victims may facilitate the viral spread through the unsaturated zone to the groundwater table.

Though these are all compelling concerns, more research studies are needed particularly at field scale to validate these claims. Burial in any means causes soil contamination, which in turn leads to groundwater pollution via the discharge of amino acids, inorganic nutrients, phosphate and chlorides.

Most contamination or pollution in the form of heavy metals from cemeteries are from coffins and embalming processes, as well as from cosmetics, medical implants and jewellery.

Microbial and chemical contamination can also occur in cemeteries as a result of unmanaged, untreated and incorrectly sited sanitation services, solid waste, and wastewater which allows for the flow of microorganisms and contaminants into cemeteries.

In general bodies that are treated and buried in correctly sited and constructed cemeteries do not pose a threat to public health, and are not a source of pollution.

The WHO guidelines clearly stipulates that there has been no evidence to suggest that individuals have become infected from exposure to the bodies of people who have died from Covid-19.

If conducted according to the usual recommended health and safety practices, choosing to bury or cremate a person who has died from Covid-19 should pose no additional risk to people or the environment.

However, in  South Africa, based on known religious and cultural practices around death, as well as the lack of sufficient crematoriums, Covid-19 victims are highly likely to be buried in cemeteries.

SA also has serious issues with access to land in metropolitan areas, as well as  in rural areas. As a result conservation and residential developments take precedence, not cemeteries, because they are not considered sustainable.

The Water Research Commission has published generic guidelines for cemeteries, mostly addressing sanitary and geotechnical risks. These have been compiled cognisant of typical contaminants emanating from cemeteries, including a variety of metals, nutrients, organics and pathogens.

When properly sited and according to sound scientific judgment, cemeteries should protect surface water and groundwater from contamination regardless of cause of death.

Provided that the capacity of the cemetery is not breached, the placement and design of the cemetery have a built-in resilience to supply enough time for the attenuation of contaminants on-site.

In some cases, poorly sited cemeteries may be at higher risk. In these cases, groundwater or surface water will be the most direct receptors of pollution, and the most at risk will be on-site users of water such as workers.

The SA Cemeteries Association (Saca) has provided interim guidelines to assist municipalities for the preparation of mass burials and cremation of Covid-19 victims.     

There have been no reported cases of the coronavirus being detected in drinking water in either private boreholes or public drinking water systems coming from cemeteries. This can be related to the travel time that the virus would  need to remain infective.

Travel time can be important because viruses lose their infectivity with time in the subsurface, dependent on temperature, pH, and other factors. At this stage it is too early to predict if and through what mechanisms the virus could contaminate groundwater systems.

However, the following steps can be taken to prevent any potential threats to the groundwater system by the coronavirus. Soil textures of about 2mm in diameter combined with an unsaturated zone of at least 0.5m between the bottom of the grave and the water table are the most suitable conditions to avoid excessive moistening of the graves and groundwater contamination from any microbial pathogens.

The preferred burial site should have a soil of sand-clay mix of low porosity and a small fine-grain texture, and the water table should be at least 2.5m deep to allow for traditional grave depth of 1.8m.

A groundwater monitoring network must   be established to monitor boreholes near cemeteries and to assess the potential risk of  microbial groundwater contamination.

So far, Covid-19 does not have a high level of persistence in the environment, due to it being an enveloped virus, and it can be eliminated effectively by water treatment, especially chlorination, therefore posing a minimal risk to drinking water.

As the outbreak continues, and in the unlikely event more people succumb to Covid-19; particularly in Sub-Saharan Africa, more water-quality and hydrogeological experiments are needed before major conclusions can be drawn on the virus in cemetery environments.

Yazeed van Wyk is a research manager at the Water Research Commission.