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Industrial and agricultural advancements have increased the level of waste products created, most of which end up in the world’s oceans. One key area of concern is emerging contaminants and toxins in our water. Emerging contaminants are defined as diverse organic or inorganic compounds, usually found in very small amounts (nanograms to micrograms per litre) that can have deleterious effects on wildlife, humans and the ecosystem as a whole (Mostofa et al., 2013a). Pharmaceutical production, pesticides and agricultural run-off, and sewage outflow are all considered as sources of emerging contaminants. Whether inland, or coastal, the waste products of such facilities, make their way through the water system and into the marine environment, where their effects make themselves evident.  In this week’s pollution series we however look at pharmaceutical waste products and their effects on marine and freshwater habitats.

Current Research


Relationship between the age of wild roach and (a) the proportion of intersex roach samples from wild populations, and (b) the degree of sexual disruption (Tyler and Jobling 2008)

The influence of hormone medications, produced by many major pharmaceutical companies, has been noted in both freshwater and marine fish across Europe. Research conducted by Tyler and Jobling (2008, 1051) on roach (Rutilus rutilus) populations, a type of freshwater group-spawning fish, identified ‘natural and synthetic steroidal oestrogens [such as the contraceptive pill] and chemicals that mimic estrogens’ as some of the causative agents of feminisation in fish species. Research highlighted a positive correlation between the proportion of wild intersex roach populations that were analysed, and the concentration of the effluent at the different sampling sites (ibid. 1054). Effects were so extensive in some freshwater environments that had high levels of oestrogen recorded, that all male roach populations tested displayed feminisation to varying degrees.

What are the effects?

With a majority female population, reproductive success of the species decreases, which puts additional pressures on stocks for the fisheries industry, as well as reduction in biological diversity. Antibiotics and other drugs can also be an issue in the marine environment, not only as causes of direct mortality for the organisms exposed to the contaminants, but for anything that feeds on these creatures, such as humans. These compounds tend to bio-accumulate, meaning the substance cannot be removed from the body and so concentration continues to increase with exposure. Dangerous chemicals can build up in the flesh of fish and then be digested by human beings, causing serious, and even life threatening, illnesses (Halling-Sorensen et al., 1998). Rather than the companies, themselves, directly dumping (although this has been reported) the major cause for pharmaceutical products entering the water system is through incorrect drug disposal by the general public (Jones et al., 2001; Islam et al., 2010). Expired or excess tablets and medications, are often poured down sinks, or flushed for “safety”, but in fact are causing more harm than good. Only with correct drug disposal can this issue be resolved.

Seán & Orla-Peach


Halling-Sørensen, B., Nors Nielsen, S., Lanzky, P. F., Ingerslev, F., Holten Lützhøft, H. C., & Jørgensen, S. E. (1998) Occurrence, fate and effects of pharmaceutical substances in the environment–a review. Chemosphere

Islam, S., Alam, A. K. M. R., & Islam, S. (2010) Analysis of Metal in Wastewater Collected from Three Pharmaceutical Industries Located in Tongi Area of Gazipur District. Bangladesh Journal of Scientific and Industrial Research, 45, 277–282.

Jones, O., Voulvoulis, N., Lester, J., (2001). Human pharmaceuticals in the aquatic environment a review. Environmental Technology, 22, 1383-1394.

Mostofa, K. M. G., Liu, C. Q., Vione, D., Gao, K., & Ogawa, H. (2013) Sources, factors, mechanisms and possible solutions to pollutants in marine ecosystems. Environmental Pollution, 182, 461–478.

Tyler, C. R. and Jobling, S. (2008) Roach, Sex, and Gender-Bending Chemicals: The Feminization of Wild Fish in English Rivers. Bioscience Vol. 58 No. 11