Pollution created by man can take many different forms, some more or less understood.

Most of its negative effects are visible, such as disgusting landfills where humans and animals feed or the tons of plastic items found on our beaches, our glaciers or at the bottom of the sea. Unless a serious effort in junk removal and waste management is getting started in the world, this situation looks dire.

But some effects of pollution are more pernicious and less well-known, and we list two of them below.

Air Pollution Weakens Bones

The health effects of air pollution are already widely documented. Several studies have shown that fine particles increase asthma attacks, the risk of cardiovascular accidents or lung cancer. Poor air quality is thus responsible for nearly 800,000 deaths per year in Europe and 8.8 million worldwide.

The Barcelona Institute for World Health (ISGlobal) has just highlighted a new harmful effect of fine particles on bone density. The researchers, whose work was published in the specialized journal Jama Network Open, followed 3,700 people aged 35 on average between 2009 and 2012 in the Hyderabad region, in southern India, and estimated their exposure to PM2.5 fine particles (less than 2.5 micrometers) and carbon black.

The participants then underwent a bone densitometry at the level of the lumbar spine and the left hip. Result: for each increase of three micrograms of PM2.5 per cubic meter (µg/m3), the bone density decreases by 0.57 gram in the lumbar spine and by 0.13 gram in the hip. According to the authors, demineralization could be linked to oxidative stress and inflammation induced by the inhalation of fine particles, but also to the decrease in parathyroid hormone (PTH), which regulates calcium production. Pollution could also act as a filter against UV rays, reducing the synthesis of vitamin D.

Is genetic pollution linked to GMOs?

Genetic pollution, that is to say the introduction of foreign or modified genes into a wild genome, is one of the major fears vis-à-vis genetically modified organisms (GMOs). However, this pollution does not date from the invention of genetic manipulation and the creation of transgenic organisms, it is much older.

The first appearance of genetic pollution appeared a long time ago. In fact, since humans began to domesticate, select and transport plants and animals, they have created this new type of pollution. Indeed, the domestic species that he created and the exotic species that he moved, voluntarily or not, have genes different from local wild species. These domestic species and some of the exotic species are, however, inter-fertile with wild species. Examples of hybrids, born from genetic pollution, are crossed between lions and tigers for example.

This is how hybrids appear, such as the cochonglier (pig x wild boar) and the euramerican hybrid poplar (Populus deltoides x Populus nigra). So there were gene transfers and contaminations of wild genomes long before the appearance of GMOs.

Consequences of genetic pollution

However, these gene transfers are not trivial since they modify the genetic pool of populations adapted to their environment and, in the case of hybridization with domestic species, weaken this genome.

Even in the absence of GMOs, human activities can affect the genome of wild species. To avoid this, care must be taken to separate wild animals from domestic or exotic animals and fight against invasive species.