Protecting our Marine Environment - Jersey Harbours - Harbour Water Quality Report 2009 - Submission

Assessment of  Water Quality in  St Helier Harbour

Report No 14.

Fisheries and Marine Resources  Planning & Environment  Department  

Howard Davis Farm  

Trinity  

Jersey  

July 2009  

Harbour Sampling Programme.

1. Introduction

In 1998 an Environmental Review was undertaken by Jersey Harbours. Within this review, which covered a wide range of environmental issues, the subject of water quality was highlighted. The review suggested that some form of monitoring was implemented for public health and general environmental well-being. Aesthetics were also considered.

This report presents the 14th review of certain physical, biological and chemical parameters, following sampling on Wednesday 8 July 2009.

2. Methods and Results

Biological and chemical parameters were analysed at the States Analyst. Physical parameters were recorded in situ and the location of the 12 sample sites can be found in Appendix 1.

A detailed description of the techniques involved in the collection and subsequent laboratory analysis extends beyond the remit of the report suffice to say that all collections followed the protocols laid down in the Environmental Review as did the analysis within the guidelines of the laboratory.

1. Weather

Wind   W-NW F4/5

Temperature  Max 200C  Min140C

Cloud  2

Visibility  Good

Rain   Nil

Tide   0757 (BST)   1428 (BST)

9.66m  2.50m Sampling regime  HW +/- 1hr

2. Physical Parameters.

The physical parameter data are shown in Table 1 (see page 2). The average (mean) sea temperature within the confines of the harbour complex was 17.060C +/- 0.50C.

These temperatures are approximately consistent with the average sea temperature for this time of year. Slight temperature variations are to be expected given the various depths of water, surface heating, water exchange and fresh water input.

The average (mean) levels of dissolved oxygen were 6.0mg/L +/- 0.2mg/L. The % saturation of the water with reference to dissolved oxygen ranged from 79.7% to 74.8%. These levels are less than previous years, where a fully saturated body of water (>100%) was detected. The lower levels detected this year may be due to increased  biological  activity  and  growth  of  phytoplankton.  Such  an  increase  in Biological Oxygen Demand (BOD) can be associated with raw sewage pollution. However there was no uniform increase in faecal coliforms across sites, as one would expect from a pollution problem (Table 2.). At the time of sampling there had been a prior period of high water temperatures and fair weather, which may have driven an increase in phytoplankton growth and BOD.

Table 1. Physical Parameters (Temperature; mg/L O2; % O2 saturation)

3. Biological Parameters.

The biological parameter data are shown in Table 2. Most stations sampled had very low levels of total coliforms, E. coli and faecal streptococci, below the stringent guide levels set in the bathing water directive. Noticeably, St. Helier Marina had high levels of  total  coliforms  and  faecal  coliforms,  suggesting  sewage  pollution  from  either vessels in harbour, or terrestrial run-off.

Table 2. Biological Parameters (Total coliforms; faecal coliforms; faecal streptococci)

4. Chemical Parameters

As with previous surveys very low levels of hydrocarbon pollutant was detected with the harbour complex. Levels of less than 0.01 mg/L were recorded at three sample stations with a slightly higher level at the La Collette Yacht Basin. However this level is still below the 0.05 mg/L found in previous years.

Table 3. Chemical Parameter (Hydrocarbon content)

3. Comment.

In general, the water quality within the Harbour complex remains good, comparable with previous surveys and conforms to the high standards laid down for EU bathing waters, with the exception of the high coliform counts found in St. Helier Marina. The uniformly low dissolved O2 at all sites is most likely not associated with a pollution problem due to the absence of uniformly high coliform counts across all sites. This may be the result of high BOD from a period of comparatively good weather. The high coliform result for St. Helier Marina maybe caused by flushing of heads whilst in the Marina and may warrant further investigation by Jersey Harbours.

.

JPS 6/8/21

Appendix 1 Sampling stations

Appendix 2

EU Bathing Water Directive (76/160/EEC)

Note  cfu  colony forming unit