2024 Bathing Water Profile for Penzance
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Mounts Bay is on the south coast of Cornwall. There are four designated bathing waters located around the bay - Wherry Town, Penzance, Long Rock and Marazion. All the beaches are sandy resorts backed by sea defences. Penzance beach is approximately 530 metres wide.
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Cornwall
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Cornwall
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The Environment Agency have carried out extensive additional catchment monitoring throughout the Penzance/Marazion area of Mounts Bay alongside the Environment Agency routine bathing water monitoring. The Environment Agency are using a DNA tracing technique to help us identify whether sources of faecal pollution are animal or human with surveys carried out in wet and dry weather conditions. The aim is to pinpoint pollution problems in the freshwater streams flowing into Mounts Bay and the local sewerage infrastructure so that the Environment Agency can improve water quality at the bathing waters.
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There are no storm or emergency overflows affecting this bathing water, however, there are several that discharge directly and indirectly into the Mounts Bay area. The operation of the overflows can lead to a temporary drop in bathing water quality.
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In the past there were a number of private discharges and combined sewer overflows (CSO) that affected this bathing water, as well as the general contamination of Penzance Bay from numerous sources. The sewage treatment scheme for Penzance and St Ives was completed by South West Water in early 1995. The scheme included extensive sewerage, improvements to intermittent discharges and the removal of untreated sewage discharges. Wastewater from St Ives is pumped to Hayle sewage treatment works (STW), where it receives secondary treatment before its discharge through a 2.7km long sea outfall west of Godrevy Head. The Hayle STW was enlarged and upgraded in 1995 and again in 2000. In 1998, further improvements were also made to CSOs at Long Rock, and Marazion pumping station CSO was sealed in November 2001.
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The urban area of Penzance immediately behind the beach is served by a combined (surface and sewer) system. There are no outfalls from the system onto the beach.
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For the four year (2020-2023) assessment period where data is available, seaweed (macroalgae) was assessed as being sufficient to be objectionable for 18% of visits, with 59% 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.
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For the four year (2020-2023) assessment period where data is available, phytoplankton (microscopic algae) was not assessed as being sufficient to be objectionable, but was observed as being present on 2% of visits. 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.
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This bathing water is subject to short term pollution procedures. The Environment Agency makes a daily pollution risk forecast at this site based on the effects of rain, wind and seasonality on bathing water quality. These factors affect the levels of bacteria that get washed into the sea from livestock, sewage and urban drainage via rivers and streams and how they disperse. When these factors combine to make short term pollution likely we issue a pollution risk warning on this website and the beach manager will display a sign advising against bathing at the bathing water. After a short term pollution event, levels of bacteria typically return to normal after a day or so but it’s possible to have several warning days in a row. Details of the work to reduce the sources of bacteria at this bathing water are detailed in this profile. In 2023 7 pollution risk warnings were issued for this bathing water. All bathing waters have the potential to be affected by a pollution incident and if this occurs a pollution risk warning will be issued with associated advice against bathing on this website.
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2024 Bathing Water Profile for Penzance
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2024-09-30
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2024-05-01
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Streams and rivers are typically affected by human sewage, animal slurry and runoff from roads. There are no streams directly affecting this bathing water, however, there are several flowing into Mounts Bay nearby which can affect water quality during and after heavy rainfall.
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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.
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Environment Agency samplers make observations of litter present on the beach at every visit, this includes assessments of sewage debris, litter and tar. At Penzance 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 33% of visits. Tarry residue was not noted at this site.
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The catchment surrounding Penzance is approximately 3,350 hectares. There are no streams which flow directly to the beach at the Environment Agency monitoring point, however, the catchment affecting the water quality at the beach contains the rivers Newlyn Coombe and Lariggan which enter Mounts Bay at distances of 1300 metres (m) and 700m west of the Environment Agency monitoring point respectively. These two streams have a combined length of approximately 30km and rise from the high ground of the Penwith peninsula sloping steeply in the headwaters and then more gently towards the coast. Land use is a mixture of rural and urban. The rural areas are mostly improved and unimproved grasslands and heath, the urban areas are concentrated at the coast and includes most of Penzance and Newlyn. The catchment lies within part of the Cornwall Area of Outstanding Natural Beauty (AONB).
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Penzance
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Penzance
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Sampling point at Penzance
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147340
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50.11465387695735
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-5.5355728915244
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29830
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Sampling point at Penzance
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p152 dT23 h59 m59 s
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2024 05 01 t00:00:00
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2024-05-01T00:00:00
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2024 09 30 t23:59:59
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2024-09-30T23:59:59
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2024 30400:1
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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.
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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.
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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.
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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.
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Discharges from sewage treatment works have improved substantially in England since the 1980s.
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