Remorseless killer on land and in the sea


Ubiquitous plastics are wreaking havoc everywhere; they are causing flooding and killing animals and humans on land and sucking air and life out of aquatic animals.


Our environment is faced with an unprecedented threat from human activities, with huge amounts of plastics accumulating on land, oceans, seas and beaches. In 2013 alone, an estimated 299 million tonnes of plastic were produced across the world. Out of these, 50 million tonnes end up in the ocean. Considering that only 18 per cent of plastics get recycled, approximately 195 tonnes would either end up in landfills or get discarded elsewhere in the environment by 2050 if no action is taken. The life cycle of plastics, from manufacture to destruction, pollutes the air, land, and water, threatening human health and the environment through the release of toxic chemicals.

Each year, Kenya consumes 259,252 tonnes of plastic packaging materials, some of which are imported as raw plastics (184,708 tonnes) or ready plastics packaging (44,086 tonnes) and recycled secondary plastics (30,475 tonnes). Only 46,988 tonnes (18 per cent) are recycled and therefore nearly 173,698 tonnes find their way into the environment or illegal dumpsites every year. The plastic waste problem is even direr, considering that in 2017, plastic waste was estimated at 970,000 tonnes.

Plastic waste makes its way into gutters and storm drainages and clogs them up, causing flooding in major towns of Kenya. The plastics also end up blocking sewage lines, causing sewer bursts.

Unused or discarded plastic containers like bottles, buckets and cups are breeding grounds for mosquitoes that spread diseases like Malaria, Dengue Fever, Elephantiasis and Chikungunya.

Domestic animals are also not spared by the adverse effects of plastics. Animals die when they swallow plastic waste alongside their feed. In addition, plastics disposed of on land, line the soil surface where they prevent soil aeration and kill micro-organisms.

Most open dumps in Kenya are within settlement areas and receive mixed waste. Plastics retain water that creates filthy conditions when mixed with other organic wastes. As result, flies thrive and spread diarrheal diseases that affect children.

Kenya relies heavily on open dumping and burning to manage solid wastes, including plastics. Plastics gradually break down and release harmful chemical additives that leach and contaminate the soil and underground water. Eventually, these chemicals reach surface waters and harm aquatic life and human health. Gases released from such dumpsites also contribute to global warming.

Every year, up to 13 million tonnes – over 80 per cent originating from land-based sources – of plastic leak into our oceans and pose serious threats to marine ecosystems.

A Kenyan study has estimated that up to 15 plastic items accumulate in one metre of coastal beaches every day. Human behaviour contributes a large portion of this plastics build-up, as nine out of ten (90 per cent) of all plastics are packaging material for food products. In the absence of regular beach cleaning, this results in pile-ups that come with a wide range of socio-economic and ecological effects.

In addition to land-based sources, sea-based sources of plastics entering the oceans through fishing, shipping and tourism cruises, contribute to the menace of floating plastics in open waters. These include both large (macro-plastics) and smaller (meso and microplastics). Microplastics numbers vary; they average 110 particles and as high as 275 microplastic fragments per 1000 litres of ocean water. It is estimated that there are 163 floating plastics in every square kilometre of ocean surface.

In water, plastic pollution can kill aquatic wildlife directly through entanglement in fishing gear, including nets, which limit their movement. This can lead to starvation, suffocation, infection and possible death.

Studies have shown that water species including seals, turtles, ducks, fish, dolphins, among others, ingest plastics while looking for food. Sea turtles, for example, confuse discarded plastic bags with jelly fish, which are their main food.

Sea birds, too, confuse plastics for fish. Ingestion of plastics results in blockage of the digestive tract, mouth and stomach lining, thereby cutting airflow, leading to poor nutrition, starvation and even death.

As plastics drag along the sea beds, they smother corals increasing their susceptibility to diseases. They also cause habitat destruction by obstructing direct sunlight for benthic photosynthetic organisms. Plastics can also harbour chemicals and pollutants including metals and pesticides, like dichlorodiphenyltrichloroethane (DDT) among others. These chemicals present immediate and chronic threats to both aquatic and terrestrial food webs. Sea water and sunlight break down large plastics into microplastics (less than 5 mm in diametre).

Microplastics are contaminants that accumulate in the food chain after ingestion, leading to public health risks. Studies carried out along the Kenyan coast indicate that secondary producers (zooplankton) are exposed to microplastic ingestion.

Plastics threaten food supplies for humans when edible animals consume them or are poisoned by toxic chemicals emanating from plastics.  Not only are these animals exposed to possible death, the chemicals also enter our bodies and accumulate and persist over time and are transferred up the trophic hierarchy. Ultimately, they affect human health by causing cancers, affecting unborn babies and interfering with our bodily hormones.

Marine plastics also entangle propellers and block inlet valves of boats, resulting in high maintenance costs and delays in operations for ship operators. Beach-goers, swimmers and divers risk getting scratched, cut or entangled in fishing lines and ghost nets, which comes with serious health and economic implications. Fishermen spend a lot of time clearing up fouled nets, slowing down their operations.

Plastic-polluted Kenyan beaches attract few or no tourists at all. Tour operators and local communities in plastic littered beaches suffer loss of income and jobs as tourists opt for more pristine destinations.

As a first step in addressing the plastic pollution menace, the Kenyan government banned the manufacture, importation and use of secondary plastic packaging in 2017. Success in enforcement of the ban has been placed at over 80 per cent.

Despite the success, the ban continues to face a number of implementation challenges including the fact that alternatives to the banned plastic bags tend to be quite costly.

However, neighbouring countries still use polythene bags and the same are illegally imported to Kenya. Research has revealed a considerable decline in polythene bags collected along the coastal area. This shows that the polythene bags ban intervention has had a direct impact on the amount of marine litter reaching the oceans.

This is further expected to improve as Kenya recently effected a ban on single-use plastics in protected areas and beaches.

The writer Erick Okuku is a Principal Research Scientist and Center Director at kmfri at Kenya Marine and Fisheries Research Institute