Resident of Rivers State and other states in the Niger Delta Region have in the last five years complained of persistent soot, dropping and covering everywhere. They have been apprehensive of the situation, which has raised questions on where the soot is coming from; what are the implications on human health and environment; and how deadly it could be?

Soot, sometimes called lampblack or carbon black, is a fine black or brown powder that can be slightly sticky; it is a product of incomplete combustion. A major component of soot is black carbon. Since soot is sticky, it tends to stick to exhaust pipes and chimneys where the combustion occurs.

Unfortunately, medical experts have associated the persistent soot in the region to rising cases of cancer and infertility. Their assertions were corroborated by a recent study published in Journal of Health and Pollution. The study is titled “Exposure to Heavy Metals in Soot Samples and Cancer Risk Assessment in Port Harcourt, Nigeria.”

The researchers include Ihesinachi Kalagbor; Amalo Dibofori-Orji; and Ozioma Ekpete. According to the researchers, Port Harcourt is an oil-rich city in Nigeria’s Niger delta region. For over two years, Port Harcourt experienced black soot deposition in the environment. In November 2016, residents woke up to black soot covering cars, clothes, houses, plants, etc. Soot concentrations continued to increase until the first quarter of 2017. After public outcry, the frequency and concentration of soot deposition began to decline.

The researchers said they carried out the study to determine the presence and levels of heavy metals in soot along with a cancer risk assessment of heavy metals exposure in Port Harcourt.

The researchers concluded: “Non-carcinogenic and carcinogenic health risks of these heavy metals were evaluated using the target hazard quotient (THQ) and the incremental lifetime cancer risk (ILCR). Obtained ILCR values were within the acceptable limits for cancer risks. However, the total ILCR values for Cd and Pb for children were three times higher than those for adults. This is a source of concern as their prevalence in ambient air puts children and residents in Port Harcourt metropolis at risk of various types of cancers.”

The study was corroborated by a clinical research fellow at Nigerian Institute for Medical Research (NIMR) Yaba, Lagos, Dr. Dan Onwujekwe, told The Guardian that the prevalence of soot over Rivers and perhaps Bayelsa states is much older. “I would say, at least two decades. Prof. Tekena Harry informed us then that they could not spread their laundry outside; overnight white clothing and bed sheets would be coated with soot,” he said.

Prof. Tekena Obu Harry is a renowned virologist with more than 40 years experience. Onwujekwe said the soot comes from the persisting practice of flaring natural gas encountered during oil exploration in these locations.

The clinical researcher said the direct impact of this prolonged air pollution on life is on respiratory system disorders, cancer, etc.
President, African Fertility Society (AFS), Joint Pioneer of In Vitro Fertilisation (IVF) in Nigeria and Medical Director, Medical Art Centre (MART), Prof. Oladapo Ashiru, told The Guardian: “The soot covering the atmosphere in Port Harcourt and environs are the products of oil exploration, oil fossils, and other by products of the oil industry and petrochemicals. The soot contains various chemicals that constitute environmental toxins and Endocrine Disruptors Chemicals (EDCs). They affect various organ systems including but not limited to the respiratory and cardiovascular system and the reproductive health.

“A number of the EDC cause abnormalities in the male reproductive system such as low sperm count and motility, testicular dysgenesis, hypospadia, and testicular cancer. In the female, they cause an ovulation miscarriage and in some the effects can pass through generations. For example a pregnant mother exposed to EDC will have problems with herself, the daughter she is carrying and the offspring of the daughter. The good thing is that EDC can be removed from the body through detoxification process.”

A consultant pharmaceutical chemist and Chief Executive Officer (CEO), Bloom Public Health, Prof. Chimezie Anyakora, told The Guardian: “I have not done any specific investigation or research on these droppings but I assume they are coming from the heavy industrial and oil prospecting activities in the area. These are associated with polycyclic aromatic hydrocarbons, which are known to be toxic and carcinogenic. I think the government should view this with some level of urgency. These contaminants may not have short-term health implication but on the long term it can do lots harm to the population. All those exposed to these contaminants are at a risk of developing some form of cancer or the other. I have done a lot research in this field and there is overwhelming literature on this. Continuing exposure of the population to these contaminants is irresponsible and citizens should demand that it get solved.”

The increased presence of soot in the environment is suspected to come from illegal refining around Port Harcourt. This illegal refining is also known as artisanal refining, where crude oil is taken unofficially (most often by theft) by breaking pipelines. The crude oil is collected and then heated in large drums to distill the various fractions. These refining activities are hard to predict, as most take place at night and vary from day to day. Over 40 illicit refineries were identified in Port Harcourt during this period.