Pathogens And Toxins In Sewage Sludge And Their Effects On Wildlife

Since sewage sludge contains manmade chemical toxins and, over and above that, pathogens, it poses a serious health risk to for humans. What are the effects that sewage sludge has on wildlife organisms and what kind of animals are affected in particular?

The Dangers Of Sewage Sludge

Even the EPA has acknowledged that pathogens in sewage sludge are “a major environmental concern (other than effects on public health) associated with land application“. The EPA further states that there are certain human pathogens that have the potential to “cross species lines and infect animals, particularly warm-blooded animals“.

Supposedly, what our Environmental Protection Agency does not know is how and to what extent these pathogens pose a threat to wildlife health. One thing is for certain, parasites can survive more than 5 years in soil and they affect our health as well as the health of wildlife, pets and livestock likewise.

How Can Toxins Enter The Organism Of Wildlife?

Freshly spread sludge poses the greatest danger to wildlife. Sludge pools are hazardous, as they almost always cause contamination by runoff. The consequence is that toxins accumulate in worms and insects over time. Birds and mammals that eat these animals also accumulate toxins in their organs as a result.

Pathogens found in sewage sludge spread through bodily fluids (blood, milk, urine, saliva, …) and can cause deadly Prion disease.

What Animals Are Affected?

Mammals, amphibians, insects, marine wildlife. Almost every animal species in ecosystems contaminated with sewage sludge are affected. Examples are:

• Peregrine falcons that could be commonly found in the eastern part of the U.S. but extirpated due to DDT (one of the toxins contained in sludge) causing eggshells to become too thin to enable incubation.
• Hormone disrupting chemicals contained in sludge are known to cause malformations in amphibians.

Sewage Discharge In Harbors And Port Areas

Both operational shipping and recreational activities on water cause sewage discharges. In addition to that, there is sewage produced in cities that originated from waste treatment plants.

These sources impact the contamination of coastal areas. As a result, an increased number of pathogens can be found in the water leading to oxygen depletion and diseases spreading. Other important factors are legal and illegal discharges of untreated sewage off the cost that affect marine wildlife.

More On Oxygen Depletion And Diseases

Sewage decomposes when getting into contact with oxygen dissolved in water. Mass mortality in fish and other marine wildlife that don’t get enough oxygen is one of the severe consequences, which shows the importance of dissolved oxygen in water.

Diseases caused by pathogens in sewage also pose a risk to shellfish, which don’t have any protection mechanisms to counteract infestation.

Future Concerns

Until today, the EPA is unable to state with absolute certainty that existing regulations can broadly protect the terrestrial wildlife and native plants in our country. Wildlife is threatened by (1) the direct toxicity of sewage sludge toxins and (2) also affected by changes induced in plants and invertebrate animals.