Part 1 - Introduction

In This Section

Topics

Sampling and Analysis Protocol
Part 1 - Introduction

Author:	OMAFRA Staff; MOE Staff
Creation Date:	20 July 2007
Last Reviewed:	20 July 2007

Background to Act and Regulation
Health and Safety
Sampling Frequencies
Averaging of Results
Sampling Locations

Proper sampling and analytical techniques are critical to accurately determine the nutrient content and other properties of materials. This has always been important, but has now become a legal requirement under the Nutrient Management Act, 2002 ("NMA"). The techniques described in this document are intended to meet the requirements of the Regulation under the Act. They can also provide guidance for other sampling and analysis requirements with similar goals.

1.1 Background to Act and Regulation

A key component of the Regulation is the requirement for a nutrient management plan ("NMP"). To complete a meaningful NMP, it may be necessary to know the concentrations of nutrients and contaminants in both the soil and the materials that may be applied to land.

The Regulation lays out what materials need to be sampled and analyzed, how frequently they need to be sampled, and which parameters need to be measured. These are minimum requirements. It may be desirable to sample more frequently, or to analyze for additional parameters, to optimize the management of land applied materials.

1.2 Health and Safety

There may be hazards associated with the physical act of sampling or with handling materials that could contain toxic material or E. coli. It is the responsibility of the sampler to have taken all necessary precautions and to act according to any applicable health and safety regulations.

1.3 Sampling Frequencies

1.3.1 Soils

Soils may be sampled for two different purposes: to assess the initial nutrient levels in the soil, which will guide the application of nutrient containing materials for agronomic and environmental purposes, and to determine the acceptability of the site for receiving the particular material.

Soils Receiving Nutrients

Persons applying nutrients to fields on farm units where a NMP is required, must collect a representative soil sample from each field as part of developing the initial NMP, and then at least once during each five-year period for subsequent plans. The results from analyzing these samples are entered into the NMP.

Where nutrient levels fluctuate widely within the five year interval it may be appropriate to sample a field more frequently than is required. This situation can occur on sandy soils where crops that are removing large amounts of nutrients are grown. Silage corn, forages and processing tomatoes all remove large quantities of potassium from soil; therefore, soil test levels for potassium can decline quickly to the point where yields are reduced.

Soils must be analyzed for soil pH and, if the soil has a pH below 6.0, for buffer pH. They must also be analyzed for available phosphorus (using the sodium bicarbonate extractant) and available potassium (using the ammonium acetate extractant). In addition, the sample may be analyzed for available magnesium, nitrate nitrogen, or the manganese and zinc availability indices.

It is necessary to know the available phosphorus concentration of a soil prior to applying nutrients so that application rates and setback distances can be properly determined. The soil must have been tested for sodium bicarbonate extractable phosphorus content within the five years immediately prior to applying the nutrients to land.

Soils Receiving Non-Agricultural Source Materials

Persons applying non-agricultural source materials must, in addition to the nutrient analyses, have representative samples analyzed for the total content of each of the eleven regulated metals (Tables 1-1 and 1-2). These samples must have been collected within five years prior to the application of non-agricultural source materials, as part of the preparation of the initial and subsequent NMPs.

In the Regulation, the maximum allowable metal concentrations in soils receiving sewage biosolids, are based on the "mean metal content of uncontaminated Ontario soils". In many soils, metal concentrations will be higher than the mean. For some soils, one or more metal concentrations may already exceed the maximum allowed in the Regulation. It is therefore necessary that soil testing be conducted prior to the first application of sewage biosolids or other wastes to determine the suitability of the soil. Samples collected as per Section 2.1 of this document shall be analyzed for the eleven metals listed in the Regulation. The sampling and testing for pH, sodium bicarbonate extractable phosphorus, and the eleven regulated metals must have been undertaken within the five years preceding application of a non-agricultural source material to land.

Summaries of acceptable analytical methods are presented in Section 4.

Table 1-1.

Standards for Regulated Metals for Sewage Biosolids
Regulated Metals	Maximum metal concentration in material to be applied up to 22 tonnes per ha per 5 years (mg / Kg of TS¹ dw²)	Maximum metal concentration in material to be applied up to 8 tonnes per ha per 5 years (mg / Kg of TS¹ dw²)	Maximum permissible metal addition to soil receiving non-agricultural source materials (Kg / Ha / 5 Years)	Maximum metal concentration in soils receiving non-agricultural source materials (mg / Kg of Soil, dw)
Arsenic	75	170	1.40	14
Cadmium	20	34	0.27	1.6
Cobalt	150	340	2.70	20
Chromium	1060	2800	23.30	120
Copper	760	1700	13.60	100
Mercury	5	11	0.09	0.5
Molybdenum	20	94	0.80	4
Nickel	180	420	3.56	32
Lead	500	1100	9.00	60
Selenium	14	34	0.27	1.6
Zinc	1850	4200	33.00	220

¹ TS means total solids.
² dw means dry weight.

Table 1-2.

Standards for Regulated Metals for Land Applied Materials Other than Sewage Biosolids
Regulated Metals	Maximum metal concentration in materials that contain total solids of less than 10,000 mg of material per litre (mg of material/ L)	Maximum metal concentration in materials that contain total solids equal to or greater than 10,000 mg of material per litre (mg / Kg of TS¹ dw²)	Maximum permissible metal addition to soil receiving non-agricultural source materials (Kg / Ha / 5 Years)	Maximum metal concentration in soils receiving non-agricultural source materials (mg / Kg of Soil, dw)
Arsenic	1.70	170	1.40	14
Cadmium	0.34	34	0.27	1.6
Cobalt	3.40	340	2.70	20
Chromium	28	2800	23.30	120
Copper	17	1700	13.60	100
Mercury	0.11	11	0.09	0.5
Molybdenum	0.94	94	0.80	4
Nickel	4.20	420	3.56	32
Lead	11	1100	9.00	60
Selenium	0.34	34	0.27	1.6
Zinc	42	4200	33.00	220

¹ TS means total solids.
² dw means dry weight.

1.3.2 Non-Agricultural Source Materials

Non-agricultural source materials are required to be sampled and analyzed at least as frequently as specified in the following tables. The sampling requirements in Table 1-3 apply to all non-agricultural source materials. The requirements to sample for E. coli analysis apply only to Sewage Biosolids.

Table 1-3. Sampling frequencies for regulated metals¹, E. coli, total Kjeldahl nitrogen, ammonium nitrogen, nitrate nitrogen, total solids, volatile solids² and total phosphorus

Size of Generators: Generators of sewage biosolids and with an approved design capacity not greater than 45,400 m³/ day, or generators of other non-agricultural source materials that generate not more than 2,500 tonnes/year, dry weight basis.

Sampling Frequencies: Two samples within 30 days prior to actual land application and 2 additional samples within 90 days prior to land application with samples taken a minimum of 2 days apart.

Size of Generators: Generators of sewage biosolids, with an approved design capacity greater than 45,400 m³/day, or generators of other non-agricultural source materials that generate more than 2,500 tonnes/year, dry weight basis.

Sampling Frequencies: 2 samples per month, with samples taken a minimum of two days apart.

¹See Table 1-1 for the list of regulated metals.
²For the purpose of the General Regulation, volatile solids shall be taken as equivalent to organic matter.

For all situations, results must be available for at least one sample collected within 30 days prior to (and including) the day of land application and two additional samples collected within 90 days prior to land application.

Reduction of Sampling Frequency

For metals analysis, if the mean plus two standard deviations calculated using the last twelve samples or using the last year's worth of samples, whichever is the greater number of samples, is less than the allowable limits for all metals, then the sampling frequencies above may be reduced by half.

For E. coli, if the running four-sample geometric mean of the last twelve samples or of the last year's worth of samples, whichever is the greater number of samples, always meets the criteria of less than 2 x 10⁶CFU/g, then the sampling frequencies above may be reduced by half.

For nutrient analysis, if the coefficient of variation calculated using the last twelve samples or using the last year's worth of samples, whichever is the greater number of samples, is less than twenty per cent, then the sampling frequencies above may be reduced by half.

When any of the above three conditions are violated, sampling frequencies must return to the original frequencies.

If this requirement is met, then the most recent sample results from the generating facility may be used. If the material is in temporary storage for a longer period of time, if the material is mixed with any materials from other sources, or if the material is managed in such a way that the nutrient or contaminant concentrations could be expected to have changed, then samples must be collected for analysis from the material in the temporary storage in accordance with Table 1.3.

1.4 Averaging of Results

Where a material is required to be analyzed for regulated metals or E. coli, the concentration of metals or E. coli in the material is considered to be the average of the concentrations in the four most recent samples. This allows for any variation that may occur in sampling or analysis of the materials, while maintaining protection of the environment. Metal concentrations are calculated as a simple arithmetic mean, where the concentrations of each of the metals in the previous four samples are added together and the resulting total is divided by four. E. coli concentrations are calculated as the geometric mean where the concentrations of E. coli in each of the previous four samples are multiplied together and the fourth root of the resulting product is calculated.

Where the mean concentration of any parameter exceeds the allowable level, and the generator still intends to land apply the material, the generator has the option of re-sampling the material. This is done by continuing to take representative samples with an interval between samplings of at least two days. The analytical results are then used to calculate the mean value. Sampling can continue on this basis until the mean value of the four most recent samples is within allowable limits for all parameters. This method is for use where a large value is skewing the mean, and that value may be due to a spurious analytical result.

1.5 Sampling Locations

Samples for nutrient analysis must be taken at a location or locations from which the material is being transported to land application sites. This is to provide the farmer with the best possible estimates of concentrations of total N, available N, and total P.

Samples that are being collected for total solids, volatile solids and regulated metals analysis must be collected from both the storage location from which the material is being taken to land application sites and from the location (i.e. the generation facility) from which the material is being taken to the centralized storage facility if materials from different sources are being mixed.

Samples of material that are to be analyzed for E. coli must be collected at a generating facility or a storage location immediately after the treatment process as outlined below.

In situations where materials are transferred from storage at the generating site to a temporary storage facility, for sampling purposes, the temporary storage facility can be regarded as being part of the plant if and only if the material is in temporary storage for less than four weeks prior to land application. If this requirement is met, then the most recent sample results from the generating facility may be used. If the material is in temporary storage for a longer period of time, if the material is mixed with any materials from other sources, or if the material is managed in such a way that the nutrient or contaminant concentrations could be expected to have changed, then samples must be collected for analysis from the material in the temporary storage.

For more information:
Toll Free: 1-866-242-4460
E-mail: nman.omafra@ontario.ca