Regulation 3
1. Every sludge producer shall ensure that sludge produced by him and supplied for the purpose of use in agriculture is tested in accordance with this Schedule as soon as reasonably practicable after the operative date, and thereafter at intervals of not more than six months, and in any event where changes occur in the characteristics of the waste water being treated.
2. Representative samples of sludge intended to be used on agricultural land shall be taken after processing, but before delivery to the user.
3. Each sample shall be analysed so as to determine–
(a)the pH value thereof;
(b)the percentage content of dry matter, organic matter, nitrogen and phosphorus; and
(c)the concentration in milligrams per kilogram of dry matter of–
(i)chromium;
(ii)the elements listed in column 1 of the sludge table below.
4. The average annual rate of addition referred to in regulation 3(4) shall be ascertained for each of the elements in the sludge table by taking the average amount of that element in the sludge used on that land in the period of ten years ending on the date of such use.
| (1) | (2) | (3) |
|---|---|---|
| Element | Kilograms per hectare per year | Limit of detection (mg/kg of dry matter) |
| Zinc | 15 | 50 |
| Copper | 7.5 | 25 |
| Nickel | 3 | 10 |
| Cadmium | 0.15 | 1 |
| Lead | 15 | 25 |
| Mercury | 0.1 | 0.1 |
5. The analysis requisite to ascertain the concentration of metals referred to in paragraph 3(c) above shall be carried out following strong acid digestion; the reference method of analysis shall be that of atomic absorption spectrometry, and the limit of detection for each metal shall not exceed the appropriate limit value specified in column (3) of the sludge table or, in the case of chromium, 25 milligrams per kilogram of dry matter.