BOSS Eric Potter has been ordered to pay more than £13,000 in fines and costs after his firm polluted the sewage system in Lydney with toxic heavy metals.

Dangerous levels of zinc and nickel were found in the public sewer in the town and the acid level of the water was also above safe legal limits, Gloucester magistrates were told.

The 67-year-old, who runs Forest of Dean Metal Finishers at Harbour Road, Lydney, pleaded guilty to three charges of breaching his licence to discharge trade effluent.

The charges were that nickel levels in the public foul water sewer reached 9.49 milligrams per litre, the zinc content was 17.1 milligrams per litre and the pH value of the water was 10.2.

The limits which should not have been exceeded were 5mgs for nickel, 10mgs for zinc and a pH level of 10, said Emma Winney, prosecuting for Severn Trent Water.

The court heard it was Mr Potter's third conviction for similar offences. In 2003 the levels of zinc and chromium were found to be too high and he was fined £800. And in 2006 levels of cyanide, nickel and zinc were all excessive and he was fined £500 on each charge.

Magistrates fined him £3,000 on each charge – a total of £9,000 – plus prosecution costs of £4,001.19 and a £15 surcharge.

Potter told the court he could not pay the fine immediately. He said he has not drawn any money from the business for a year because of economic circumstances.

He was told to see the court fines officer to arrange time to pay.

Miss Winney had told the court that samples taken by a commercial waste technician revealed excessive acid, nickel and zinc levels.

"These limits are imposed to ensure that the amount of trade effluent does not adversely affect the capacity of the sewerage works," she said.

"If too much effluent is discharged it cannot perform efficiently. Zinc and nickel are toxic metals and can kill bacteria which is used to degrade sewage."

Potter, who was not legally represented, said that sludge from his business processors had built up at his premises because of a change in tipping regulations.

But he conceded that he could have got extra skips to store the sludge safely.

The court said the offences were particularly serious in our 'eco-friendly times.'