Assessing the nitrate content in livestock drinking water of Namakkal
district in Tamil Nadu

Introduction

                    Nitrate in itself is not toxic to animals, but at the elevated level incidence of nitrate poisoning in livestock. Water may be source of toxic levels of nitrate for livestock [1]. Water may become contaminated by fertilizer, animal wastes or decaying organic matter. Shallow wells with poor casings are susceptible to contamination. Marginally toxic levels of nitrate in water and feed together may cause nitrate toxicity in animals. Areas where the fertilizer spreader turns or areas where filling take place may have excessive quantities of nitrate freely available to animals and grazing result in acute nitrate poisoning [2]. Animals can be treated by intravenous injections of methylene blue. Commercial preparations intended for the treatment of prussic acid poisoning should not be used to treat nitrate poisoning. Prevention of nitrate poisoning is best achieved by controlling type and quality of forage offered to livestock. Analyzing the nitrate content in drinking water of livestock given as early warning system to forecast the nitrate toxicity in livestock. Hence the present study has been carried out to estimate the nitrate content of different sources of water offered to livestock in the Namakkal district.

Materials and Methods

All other chemicals used were of analytical grade and the highest purity available from commercial sources, and doubly distilled water was used in the preparation of all solutions in the experiments. Hydrochloric acid solution (0.1N Hcl) was prepared by 10 ml HCL in 1L Distilled water. Acetic acid (20%) was prepared by 20 ml Acetic acid in 80 ml distilled water. Bray’s indicator prepared by 100g barium sulfate (BaSo4), 10g manganese sulfate (MnSo4.H2O), 2g Zinc (metallic Zn), 75g citric acid, 4g sulfanilic acid, 2g 1-naphthylamine is mixed. The bray’s indicator is stored in a blackened bottle away from light.

Collection of water samples

                    The numbers of water samples were collected based on the propionate random sampling from the Namakkal districts area. The Namakkal district area was around 3363.00 Km² [3]. In Namakkal district, 1160 water samples were collected from different villages by using stratified random sampling/Multi-stage random sampling (Table-1). The source of water samples commonly from Bore Water, Well Water, River Water and Sewage Water were collected for the estimation of Nitrate. Nitrate content was estimated using the kit method.

Table.1 Collection of water samples at Namakkal District

Analysis of Nitrate

Nitrate content was estimated by colorimetric method and measured at a wave length of 520nm [4]. Cattle-fed water Samples were taken in 1ml test tube and add 1ml of (20%) acetic acid and 0.5g of Brays indicator for the determination of nitrate. The pink color was observed and compared with score card value. The pink color formation was due to the reduction of nitrate to nitrite by zinc and manganese sulfate. The reaction was then followed by the diazotization of a sulfonic acid with nitrate ion and subsequently coupled with 1-napthyl amine to form pink color.

Results and Discussion

Totally 1160 water samples were collected from different sources. Among them, 266 were from Well water samples, 258 from Bore Well samples, 206 from Bore/Well samples, 227 from River water samples and 203 from Sewage water samples. The different sources of water samples collected were listed in figure-1.

                               Fig.1 Collection of water samples in Namakkal District

Nitrate estimation of water samples

                    The nitrate content was estimated from different water samples Table-1. The result showed that nitrate concentration wasfound to be varying between samples. Among 1160 water samples in Namakkal district, 84.3% of samples had 10-50 ppm, 25.5% had 51-100 ppm, 4.1% had 101-300 ppm, 0.2% had above 300 ppm and 20.1% had traces of nitrate content. The results are summarized in Table -2.

Table-2 Nitrate estimation of water samples in Namakkal District

Fig.2 Nitrate estimation of water samples in Namakkal District

                    The water samples which had >100 ppm nitrate content has related to incidences of nitrate toxicity and death of dairy animal [5]. The water gets high- risk source of nitrates through water from deep wells fed by soil water from highly fertile soils, condensed water from ventilating shafts in piggeries due to higher ammonia levels in the air, fluids draining from silos containing materials which is rich in nitrates and water contaminated by fertilizer, animal wastes or decaying organic matter may also be a source of toxic levels of nitrate. Marginally toxic level of nitrate present in water and feed when combined to give cattle can also lead to poisoning. Livestock breeding could also affect consuming water samples above 100 ppm nitrate content [1].

                    In this present study, very few samples were recorded above 100 ppm nitrate content. This might be due to the source of water from ponds, shallow wells or streams that collect drainage from manure, highly fertilized fields or industrial waste. Deep wells are usually safe sources of water [6]. In this study bore well/well collected from different sites were found to be predominantly below 100 ppm which illustrates that bore well waters are usually safe sources of water [1].These waters should be safe for livestock and prevent nitrate poisoning [3].

Conclusion

                    Hence, it can be concluded that in general screening for nitrate content in different water samples where the farmer follows indiscriminate use of fertilizers or excess application of urea/poultry manure to the agricultural field, so that to prevent nitrate toxicity incidence in dairy cattle and extension work on managemental guidelines of nitrate toxicity in dairy animals also necessary to the farmers.

References

[1].Badiadka & Sunil.,K. (2009).  A Spectrophotometric Method for the Determination of Nitrate and Nitrate. Eurasian Journal of Analytical Chemistry.4 (2):204-214.

[2]. Bartholomew., B.A, & Hill, M.J. (1984). The pharmacology of dietary nitrate and the origin of urinary nitrate. Food Chemistry and Technology.22:789-795.

[3]. Charlie Stoltenow & Greg Lardy. (2015). Nitrate poisoning of Liveston. NDSU Extension Service, V839.

[4].Ensafi.,   A,  Rezaei.,  B & Nouroozi., S. (2004) Simultaneous spectrophotometric determination of nitrite and nitrate by flow injection analysis. Analytical Science. 20: 1749.

[5].Richard S. A., Thomas., R. M, Lawrence., J.& Hutchinson,K. (2012).  Prevention and control of Nitrate Toxicity in Cattle. Extension. PP-1-20. [6]. Provinand Pitt. (2012) Nitrates and Prussic Acid in Forages. The Texas A&M University System, E-543; PP 1-12.