Introduction
Materials and methods
Study area
Sampling and analytical techniques
Statistical analysis
Results and discussion
Temperature and pH
Conductivity and DO
SAC and ORP
COD, BOD5 and TSS
Statistical analysis
Correlation analysis
T
| pH | COND | DO | TURB | SAC | ORP | COD | BOD5
| TSS | |
---|---|---|---|---|---|---|---|---|---|---|
Dry season (n = 22) | ||||||||||
T
| 1.00 | |||||||||
pH | 0.47* | 1.00 | ||||||||
COND | – | – | 1.00 | |||||||
DO | – | 0.44* | −0.42* | 1.00 | ||||||
TURB | – | – | 0.54* | – | 1.00 | |||||
SAC | 0.58*†
| 0.72*†‡
| 0.73*†‡
| – | – | 1.00 | ||||
ORP | – | – | −0.54*†
| – | – | – | 1.00 | |||
COD | – | 0.65*†‡
| 0.72*†‡
| – | 0.80*†‡
| 0.68*†‡
| −0.47* | 1.00 | ||
BOD5
| – | 0.59*†
| 0.73*†‡
| – | 0.83*†‡
| 0.64*†
| −0.47* | 0.99*†‡ | 1.00 | |
TSS | – | 0.48* | 0.79*†‡
| – | 0.75*†‡
| 0.57*†
| −0.69*†‡
| 0.87*†‡
| 0.88*†‡
| 1.00 |
Rainy season (n = 22) | ||||||||||
T
| 1.00 | |||||||||
pH | – | 1.00 | ||||||||
COND | 0.56*†
| – | 1.00 | |||||||
DO | – | 0.78*†‡
| – | 1.00 | ||||||
TURB | −0.58*†
| – | −0.56*†
| – | 1.00 | |||||
SAC | – | – | – | – | – | 1.00 | ||||
ORP | – | −0.49* | 0.43* | −0.58*†
| – | – | 1.00 | |||
COD | −0.47* | – | −0.53* | – | 0.94*†‡
| – | – | 1.00 | ||
BOD5
| −0.49* | – | −0.54*†
| – | – | – | – | – | 1.00 | |
TSS | −0.47* | – | −0.50* | – | 0.96*†‡
| – | – | 0.94*†‡
| – | 1.00 |
Winter season (n = 22) | ||||||||||
T
| 1.00 | |||||||||
pH | – | 1.00 | ||||||||
COND | – | – | 1.00 | |||||||
DO | – | 0.83*†‡
| −0.46* | 1.00 | ||||||
TURB | – | – | – | −0.42* | 1.00 | |||||
SAC | – | – | 0.82*†‡
| – | 0.61*†
| 1.00 | ||||
ORP | – | – | – | – | – | – | 1.00 | |||
COD | – | – | 0.77*†‡
| – | 0.72*†‡
| 0.95*†‡
| – | 1.00 | ||
BOD5
| – | – | 0.57*†
| – | 0.88*†‡
| 0.82*†‡
| – | 0.89*†‡
| 1.00 | |
TSS | – | – | 0.76*†‡
| – | 0.46* | 0.81*†‡
| – | 0.68*†‡
| 0.59*†
| 1.00 |
Factor analysis
Cluster analysis
Algorithms for evaluation of water quality in Atoyac River basin
Varifactor 1 | Varifactor 2 | Varifactor 3 | |
---|---|---|---|
Dry season | |||
>75 | -λ, -TURB, -SAC, -BOD5, -COD, -TSS | -DO |
–
|
75–50 | -pH, -ORP, | -T, -pH |
–
|
50–30 | -T
| -ORP, -SAC |
–
|
Eigen value | 5.58 | 1.93 |
–
|
Total variance % | 55.78 | 19.26 |
–
|
Rainy season | |||
>75 |
T, λ, -TURB, -COD, -TSS | -pH, -DO | – |
75–50 | -SAC, -BOD5
| ORP | -COD |
50–30 | ORP | -T | -λ, TURB, SAC, -pH |
Eigen value | 4.20 | 2.31 | 1.11 |
Total variance % | 42.01 | 23.13 | 11.08 |
Winter season | |||
>75 | -λ, -TURB, -SAC, -BOD5, -COD, -TSS | -pH, -DO | -ORP |
75–50 | DO | -T | – |
50–30 | ORP | – | SAC, -TSS |
Eigen value | 4.98 | 1.96 | 1.04 |
Total variance % | 49.85 | 19.64 | 10.46 |
Comparison studies
Location | Temperature (°C) | pH | Conductivity (μS/cm) | DO (mg/L) | SAC | ORP (mV) | Turbidity (NTU) | BOD5 (mg/L) | COD (mg/L) | TSS (mg/L) | References |
---|---|---|---|---|---|---|---|---|---|---|---|
Worldwide rivers | |||||||||||
Nakdong River, South Korea | 14.4–17.7 | 7.7–8.1 | 126.9–773.6 | 10.1–11.2 | – | – | – | 0.7–3.4 | 3.3–8.8 | 7.3–35.5 | Jung et al. (2016) |
Guayas River, Ecuador | 26.0 | 7.7 | 200.0 | 7.5 | – | – | 9.8 | – | 18.0 | – | Damanik-Ambarita et al. (2016) |
Karnaphuli River, Bangladesh | 21.2–31.0 | 7.9–8.2 | – | 8.07–9.92 | – | – | – | – | – | – | Ali et al. (2016) |
Dez River, Iran | 8.2–29.8 | 7.3–7.6 | – | – | – | – | 7.86–8.96 | – | – | – | Ramavandi et al. (2015) |
Upper Manyame River, Zimbabwe | 19.0–25.6 | 6.82–6.83 | 98.8–198.6 | 3.60–4.81 | – | – | – | 84.5–50.2 | 72.78–135.39 | 11.55–33.01 | Kibena et al. (2014) |
U-tapao River, Thailand | 27.0–28.0 | 6.76–6.88 | 129.0–4304.0 | 2.86–4.30 | – | – | – | 1.93–2.74 | – | 18.47–37.69 | Gyawali et al. (2013) |
Ismailia Canal, Nile River, Egypt | 24.0 | 8.12 | 423.4 | 7.85 | – | – | – | 3.77 | 6.29 | 100.7 | Goher et al. (2014) |
Songhua River, China | 9.85–14.76 | 7.48–7.60 | – | – | – | – | – | 2.64–22.70 | 15.29–73.18 | – | Wang et al. (2013) |
Mahanadi River, India | – | 6.7–7.6 | – | 7.34 | – | – | – | 7.45 | – | – | Sundaray et al. (2006) |
Present study | |||||||||||
Atoyac River basin, Mexico (R.Atoyac, R.Zahuapan and Valsequillo dam) | |||||||||||
Dry season | 13–27.3 | 7.36–10.24 | 684–1870 | 0.4–3.8 | 11.09–114.54 | −370.1 to 25.5 | 1.5–381.7 | 10–480 | 46–1055 | 0–240 | |
Rainy season | 16.90–28.50 | 7.23–8.55 | 138–1185 | 1.72–7.76 | 0.09–189.26 | 18.60–173.80 | 0.41–148.74 | 10–55 | 20.90–449.70 | 20–2996 | |
Winter season | 13.8–22.7 | 7.27–9.06 | 573–1672 | 0.58–21 | 15.2–94.5 | −42.6 to 270.6 | 3–346 | 6–340 | 18–612 | 14–200 | |
Water quality standards | |||||||||||
Drinking water quality | – | 8.5 | – | – | – | – | – | – | 10 | – | WHO (2011) |
Irrigation water quality | – | 8.5 | 3000 | – | – | – | – | – | – | – | FAO (1994) |
CONAGUA acceptable limits | – | – | – | – | – | – | – | 6 < BOD5 ≤ 30 | 20 < COD ≤ 40 | 75 < TSS ≤ 150 | |
SEMANART maximum permissible limits | |||||||||||
Irrigation | – | – | – | – | – | – | – | 150 | – | 150 | NOM-001-SEMARNAT- (1996) |
Public urban use | 40 | – | – | – | – | – | – | 75 | – | 75 | NOM-001-SEMARNAT- (1996) |
Protection of aquatic life | 40 | – | – | – | – | – | – | 30 | – | 40 | NOM-001-SEMARNAT- (1996) |