May2016-12 Possible river pollution: 1 Tichborne Stream at The Mill

One of Joan Robillard's comments, http://365project.org/jqf/365/2016-05-06 , gave me an idea for a series of photos on a possible cause of pollution on the upper reaches of the River Itchen in Hampshire.

In Spring 2015, invertebrate samples were collected from four sites on the Upper River Itchen*. These were professionally analysed to provide a biometric fingerprint of the sites.
The analysis paints a worrying picture on the health of the freshwater shrimp populations here. These were found to be below a tenth of the numbers expected. This is particularly alarming as these shrimps are the foundations of the aquatic food web and a key element of fish diets. They are also known to be extremely sensitive to pollutants, in particular herbicides and insecticides such as neonicotinoids. The spring 2015 data suggests the river is nowhere near what it should be, especially considering its protected status.

The University of Portsmouth was commissioned to carry out chemical sampling at the same four sites to look for the presence of substances such as herbicides and pesticides.
During the two-week pilot trial for the chemical work, there was no meaningful rainfall, so there was limited runoff into the river from the land. Even so, low concentrations of herbicides and pesticides were found at all sites.

So where could the chemicals have come from? Could they be originating from direct discharges into the river, such as those from businesses utilising water for commercial exploitation, agriculture or septic tanks? Further investigation is required.
* Information from http://www.salmon-trout.org/blog/view_entry.asp?blogid=85