A GWENT company which polluted a water supply causing a risk to human health had a fine of more than £40,000 partially reduced on appeal.

One of the directors of Wormtech, Jackie Powell, sat in Cardiff Crown Court as the prosecution detailed why the company was originally fined, for contaminating the water on the Ministry of Defence base in Caerwent which hampered soldiers' training.

Prosecutor Richard Cole told the magistrates sitting in Cardiff the company, which holds a permit to compost green waste, had let a liquid normally contained in a holding tank seep out, creating a sewage fungus in a nearby stream, deadly to creatures living there due to its high concentration of ammonia and other substances.

Mr Cole, representing the Environment Agency, said an officer from that organisation concluded water was 'highly polluted' in that area.

The company had earlier admitted responsibility, pleading guilty to polluting the Nedern Brook between January 1 and April 6, 2010, for which they were originally fined £10,000 on sentence, and failing to comply with an enforcement notice served on August that year, which incurred a £25,000 fine, plus £6,000 costs and a £15 victim surcharge.

Soldiers at the MOD base were forced to quarantine certain parts of the base, fearing a risk to their health, while a brook around two kilometres away was also polluted.

Representing Wormtech, Nick Gedge told the court the company's actions amounted to carelessness rather than a deliberate act, and were not motivated by money.

Mr Gedge said his client was "operating in a situation of difficulty," as they rented the land from the MOD, and if they owned it, could have taken swifter action against the problems.

He added any profits went back into the business and the company had built up a 'constructive relationship' with the Environment Agency while learning "a difficult lesson."

The Recorder of Cardiff, Nicholas Cooke, decided a fine of £10,000 for polluting the Nedern Brook should stand, along with £6,000 prosecution costs, but the charge for failing to comply with the order was reduced to £15,000.