Councillors call for an investigation into suspected discharges into Bottesford Beck at Scunthorpe.
The slick at Firestone Bay in Plymouth was dispersed naturally by the tide and wave action.
Infrastructure and Environment says 16 bays across the island were routinely tested this week.
Hundreds of volunteers survey Scotland's watercourses and report any issues of concern quickly.
An ecologist says it'll take a generation for the River Lugg in Herefordshire to recover from damage done by farmer John Price
A misconnection happens when wastewater is incorrectly diverted into surface drains.
Infrastructure and Environment bosses say they believe significant rainfall has caused poor results.
The Wye has become the first river in the UK to have a charter covering it from source to sea.
The electric boat is funded by the Port of London Authority as part of its efforts to clean up the river.
