Table 3. Statistical correlations between the decrease in doxycycline therapeutic concentration and different water parameters in different water sources.
| Water parameters | Tap water | Ground water | ||
|---|---|---|---|---|
| R | p-value | R | p-value | |
| pH | 0.772 | 0.025* | 0.685 | 0.05* |
| Electrical conductivity (EC) (dc/m) | 0.312 | 0.451 | 0.180 | 0.699 |
| Total dissolved solids (TDS) (μg/l) | 0.309 | 0.457 | 0.523 | 0.229 |
| Total Hardness (TH) (μg/l) | 0.495 | 0.213 | −0.064 | 0.892 |
| Calcium ions (Ca+2) (μg/l) | −0.234 | 0.576 | −0.389 | 0.388 |
| Magnesium ions (Mg+2) (μg/l) | 0.828 | 0.011* | −0.110 | 0.814 |
| Sodium ions (Na+) (μg/l) | 0.309 | 0.457 | 0.227 | 0.624 |
| Chloride (Cl−) (μg/l) | 0.207 | 0.623 | 0.064 | 0.891 |
| Nickle (Ni) (μg/l) | – | – | – | – |
| Iron (Fe) (μg/l) | −0.206 | 0.625 | −0.378 | 0.403 |
| Copper (Cu) (μg/l) | −0.051 | 0.904 | −0.018 | 0.969 |
| Zinc (μg/l) | 0.077 | 0.856 | 0.234 | 0.613 |
*
p-value < 0.05 is statistically significant.