This bathing water is included in the Surfers Against Sewage “Safer Seas Service”.
This service can alert you to Combined Storm Sewer Overflow discharges via a phone
App and in addition, it includes the Environment Agency Pollution Risk Forecast warnings
where they are available. Further details of the service can be found at - http://www.sas.org.uk/safer-seas-service/
The South West Water scheme for Perranuthnoe sewage treatment works (STW) was completed
in June 1999, with the untreated sewage discharge at Maen-du Point retained as a combined
sewer overflow and pumping station emergency overflow.
Sewage from Perranuthnoe is pumped to the Hayle STW, where it receives secondary treatment
and discharges through a 2.7 kilometre (km) long sea outfall west of Godrevy Head
in St Ives Bay. The STW at Hayle was enlarged and upgraded in 1995 to take the additional
flow.
For the four year (2020-2023) assessment period where data is available, seaweed (macroalgae)
was assessed as being sufficient to be objectionable for 7% of visits, with 68% of
visits noting the presence of seaweed (macroalgae). The bathing water can become covered
with large amounts of seaweed, depending on tides and the weather. This bathing water
does not have a history of large amounts of seaweed, but that it can be noticeable
from time to time.
For the four year (2020-2023) assessment period where data is available, phytoplankton
(microscopic algae) was not noted at this site. Phytoplankton (microscopic algae)
naturally increase in number at certain times of the year. This process is known as
a phytoplankton bloom. This bathing water does not have a history of phytoplankton
blooms.
The risks to human health from contact, ingestion or inhalation with marine algae
that currently occur in UK coastal waters are considered to be low. However, some
individuals may be more sensitive and display some reactions.
A common marine algae found in UK coastal waters is Phaeocystis, which is often mistaken
for sewage as it forms foam and a brown scum, but it is non-toxic.
There are no active pollution risk forecasts made at this bathing water. However any
bathing water has the potential to be affected by a pollution incident and if this
occurs a pollution risk warning with associated advice against bathing will be issued
on this website.
Sewage from the Penzance area is pumped to Hayle STW for treatment, and discharges
to the sea off the North Cornwall coast. This discharge is designed to protect bathing
water quality.
Environment Agency samplers make observations of litter present on the beach at every
visit, this includes assessments of sewage debris, litter and tar. At Perranuthnoe
for the four year (2020-2023) assessment period where data is available, sewage debris
was not noted at this site. Litter was not assessed as being sufficient to be objectionable,
but was observed as being present on 22% of visits. Tarry residue was not noted at
this site.
The catchment surrounding Perranuthnoe is approximately 83 hectares and includes
the small village of Perranuthnoe and surrounding hamlets. There are no streams discharging
directly to the beach. Surface water drains to the beach from the catchment. The catchment
is in the Cornwall Area of Outstanding Natural Beauty (AONB).
Seaweed (macroalgae) and phytoplankton (microscopic algae) are a natural part of the
marine and freshwater environment. Below we note whether these have been recorded
in quantities sufficient to be a nuisance.
The majority of sewers in England are “combined sewers” and carry both sewage and
surface water from roofs and drains. A storm overflow operates during heavy rainfall
when the sewerage system becomes overwhelmed by the amount of surface water. The overflow
prevents sewage from backing up pipes and flooding properties and gardens. An emergency
overflow will only operate infrequently, for example due to pump failure or blockage
in the sewerage system.
Heavy rain falling on pavements and roads often flows into surface water drains or
highway drains, ending up in local rivers and ultimately the sea. The quality of bathing
water may be adversely affected as a result of such events.
It is the Environment Agency role to drive improvement of water quality at bathing
waters that are at risk of failing higher standards. It is natural for water to run
off the land to the sea. Water quality at a bathing water is dependent upon the type
and area of land (the catchment) draining to the water and the activities undertaken
in that catchment.