OpenLegislation

Division 1 Poor quality

United Kingdom

Original text. Later amendments are not shown.

Bathing waters are to be classified as ‘poor’ if, in the set of bathing water quality data for the last assessment periodf1, the percentile valuesf2 for microbiological enumerations are worsef3 than the ‘sufficient’ values set out in Annex I, column D.

Annotations

Footnotes

f1

‘Last assessment period’ means the last four bathing seasons or, when applicable, the period specified in Article 4(2) or (4).

f2

Based upon percentile evaluation of the log10 normal probability density function of microbiological data acquired from the particular bathing water, the percentile value is derived as follows:

  1. (i)

    Take the log10 value of all bacterial enumerations in the data sequence to be evaluated. (If a zero value is obtained, take the log10 value of the minimum detection limit of the analytical method used instead.)

  2. (ii)

    Calculate the arithmetic mean of the log10 values (μ).

  3. (iii)

    Calculate the standard deviation of the log10 values (σ).

The upper 90‐percentile point of the data probability density function is derived from the following equation: upper 90‐percentile = antilog (μ + 1,282 σ).

The upper 95‐percentile point of the data probability density function is derived from the following equation: upper 95‐percentile = antilog (μ + 1,65 σ).

f3

‘Worse’ means with higher concentration values expressed in cfu/100 ml.