Contaminant and

(TNRCC contaminant number)

Water quality parameter code(s)

Threshold concentration

Model comments

First logistic regression model

AIC

Somers’ D

Second logistic regression model

AIC

Somers’ D

2,4,5-T (21)

39742, 39740

0.01 mg/L

P=(exp(-6.44 + 0.085*p22 + 0.0001*TDA - 0.034*p51 + 1.77*hydgrp)/

(1+(exp(-6.44 + 0.085*p22 + 0.0001*TDA - 0.034*p51 + 1.77*hydgrp))

178.5

0.618

P=(exp(-6.28 + 0.031*p_urb + 0.0001*TDA - 0.033*p51 + 1.71*hydgrp)/

(1+(exp(-6.28 + 0.031*p_urb + 0.0001*TDA - 0.033*p51 + 1.71*hydgrp))

180.5

0.613

2,4,5-TP (SILVEX)(22)

39762, 39760

0.01 mg/L

P=(exp(-2.38 + 0.056*p_urb + 118.5*perm - 0.066*MCS + 0.122*p_wet)/

(1+(exp(-2.38 + 0.056*p_urb + 118.5*perm - 0.066*MCS + 0.122*p_wet))

148.6

0.631

P=(exp(-2.94 + 0.849*p85 + 74.0*perm + 0.000035*TDA + 0.388*p92)/

(1+(exp(-2.94 + 0.849*p85 + 74.0*perm + 0.000035*TDA + 0.388*p92))

145.3

0.607

2,4-D (24)

39732, 39730

0.01 mg/L

P=(exp(-3.42 + 0.151*p21 + 0.889*hydgrp + 0.00005*TDA + 0.325*p91)/

(1+(exp(-3.42 + 0.151*p21 + 0.889*hydgrp + 0.00005*TDA + 0.325*p91))

194.9

0.531

P=(exp(-3.35 + 0.055*p_urb + 0.852*hydgrp + 0.00006*TDA + 0.241*p_wet)/

(1+(exp(-3.35 + 0.055*p_urb + 0.852*hydgrp + 0.00006*TDA + 0.241*p_wet))

193.3

0.551

Alachlor (41)

46342, 77825

0.01 mg/L

P=(exp(-12.9 + 6.66*ala_use + 0.146*p22 + 0.059*p81 + 2.32*hydgrp + 0.066*p71)/

(1+(exp(-12.9 + 6.66*ala_use + 0.146*p22 + 0.059*p81 + 2.32*hydgrp + 0.066*p71))

88.2

0.754

P=(exp(-9.09 + 3.97*ala_use + 0.032*p_urban + 0.026*p_ag + 1.79*hydgrp)/

(1+(exp(-9.09 + 3.97*ala_use + 0.032*p_urban + 0.026*p_ag + 1.79*hydgrp))

91.9

0.705

Aldrin (45)

39330, 39331, 39332

0.01 mg/L

P=(exp(-3.52 + 0.166*P23 + 0.042*P81 + 0.491*welldn)/

(1+(exp(-3.52 + 0.166*P23 + 0.042*P81 + 0.491*welldn))

81.8

0.646

P=(exp(-3.51 + 0.043*p_urb + 0.025*p_ag + 0.487*welldn)/

(1+(exp(-3.51 + 0.043*p_urb + 0.025*p_ag + 0.487*welldn))

85.7

0.624

Alkalinity (46)

39036, 39086, 39087

250 mg/L

Poor models

P=(exp(-0.169 + 0.058*p41 - 0.224*p43 - 0.025*p81 – 0.0003*popdn – 0.0001*TDA)/

(1+(exp(-0.169 + 0.058*p41 - 0.224*p43 - 0.025*p81 – 0.0003*popdn – 0.0001*TDA))

247.0

0.515

P=(exp(0.811 - 0.045*p22 - 0.190*p43 - 0.026*p81 – 0.002*BS – 0.0001*TDA)/

(1+(exp(0.811 - 0.045*p22 - 0.190*p43 - 0.026*p81 – 0.002*BS – 0.0001*TDA))

247.9

0.491

Aluminium (47)

01106

100 mg/L

Poor models

P=(exp(-1.12 + 0.549*fert_n + 0.046*MCS + 0.304*p91 + 0.269*p85)/

(1+(exp(-1.12 + 0.549*fert_n + 0.046*MCS + 0.304*p91 + 0.269*p85))

154.4

0.427

P=(exp(-1.23 + 0.445*fert_n + 0.053*MCS + 0.199*p_wet + 0.513*welldn)/

(1+(exp(-1.23 + 0.445*fert_n + 0.053*MCS + 0.199*p_wet + 0.513*welldn))

155.6

0.435

Antimony (49)

01095, 01097, 99897

0.01 mg/L

P=(exp(-2.16 - 0.349*P41 + 0.376*P81 + 0.00006*TDA)/

(1+(exp(-2.16 - 0.349*P41 + 0.376*P81 + 0.00006*TDA))

43.8

0.879

P=(exp(3.40 - 0.172*P22 - 0.123*P71 - 0.079*p42)/

(1+(exp(3.40 - 0.172*P22 - 0.123*P71 - 0.079*p42))

50.5

0.812

Arsenic (51)

01000

5.0 mg/L

P=(exp(1.40 - 0.048*p_forest + 0.111*p_urb + 0.105*p_drain – 0.032*MCS)/

(1+(exp(1.40 - 0.048*p_forest + 0.111*p_urb + 0.105*p_drain – 0.032*MCS))

202.9

0.634

P=(exp(-0.193 - 0.049*p_forest + 0.098*p_urb + 0.624*hydgrp – 0.038*MCS)/

(1+(exp(-0.193 - 0.049*p_forest + 0.098*p_urb + 0.624*hydgrp – 0.038*MCS))

209.3

0.599

Atrazine (53)

39632, 39630

0.1 mg/L

P=(exp(-5.02 + 0.135*atr_use + 0.250*P21 + 0.193*p_clay)/

(1+(exp(-5.02 + 0.135*atr_use + 0.250*P21 + 0.193*p_clay))

132.9

0.746

P=(exp(-8.77 + 0.057*p_ag + 0.119*p_urban + 0.035*p71 + 1.75*hydgrp)/

(1+(exp(-8.77 + 0.057*p_ag + 0.119*p_urban + 0.035*p71 + 1.75*hydgrp))

132.6

0.740

Barium (54)

01005

200 mg/L

P=(exp(6.76 + 0.244*P22 + 0.921*P92 - 0.061*p43 – 2.30*hydgrp)/

(1+(exp(6.76 + 0.244*P22 + 0.921*P92 - 0.061*P43 – 2.30*hydgrp))

219.7

0.596

P=(exp(3.33 + 0.269*P22 + 1.03*P92 + 0.040*p71 – 1.53*hydgrp)/

(1+(exp(3.33 + 0.269*P22 + 1.03*P92 + 0.040*P71 – 1.53*hydgrp))

220.9

0.579

Benzene (56)

34030

0.01 mg/L

P=(exp(-4.33 + 0.125*p21 – 3.18*fert_n + 0.282*p_clay + 184*p61)/

(1+(exp(-4.33 + 0.125*p21 – 3.18*fert_n + 0.282*p_clay + 184*p61))

48.6

0.657

P=(exp(-3.14 + 0.027*p_urban – 1.86*fert_n + 0.178*p_clay)/

(1+(exp(-3.14 + 0.027*p_urban – 1.86*fert_n + 0.178*p_clay))

51.0

0.585

Beryllium (62)

01010

1.0 mg/L

P=(exp(-2.61 - 0.209*p22 + 5.05*bulk_d + 0.650*p85 - 0.096*p_clay)/

(1+(exp(-2.61 - 0.209*p22 + 5.05*bulk_d + 0.650*p85 - 0.096*p_clay))

165.2

0.505

P=(exp(-3.23 - 0.061*p22 + 6.20*bulk_d - 0.430*fert_n - 0.078*p_clay)/

(1+(exp(-3.23 - 0.061*p22 + 6.20*bulk_d - 0.430*fert_n - 0.078*p_clay))

167.3

0.505

Bicarbonate (63)

00453

200 mg/L

P=(exp(-4.39 + 0.038*p_forest – 2.11*p_wet + 0.053*p51 + 0.186*p_clay)/

(1+(exp(-4.39 + 0.038*p_forest – 2.11*p_wet + 0.053*p51 + 0.186*p_clay))

96.3

0.635

P=(exp(-2.22 + 0.127*p41 – 3.22*p92 + 0.057*p51 + 0.872*fert_n)/

(1+(exp(-2.22 + 0.127*p41 – 3.22*p92 + 0.057*p51 + 0.872*fert_n))

100.8

0.632

Boron (64)

01020

200 mg/L

P=(exp(2.61 - 0.056*p_forest - 0.045*MCS - 0.253*welldn)/

(1+(exp(2.61 - 0.056*p_forest - 0.045*MCS - 0.253*welldn))

95.2

0.675

P=(exp(1.84 - 0.021*p42 - 0.437*p91 - 0.005*BS)/

(1+(exp(1.84 - 0.021*p42 - 0.437*p91 - 0.005*BS))

100.4

0.591

Cadmium (74)

01025

5.0 mg/L

Poor models

P=(exp(-0.424 - 0.025*p51 + 0.027*p71 + 0.455*fert_n + 0.002*BS)/

(1+(exp(-0.424 - 0.025*p51 + 0.027*p71 + 0.455*fert_n + 0.002*BS))

245.3

0.371

P=(exp(2.03 - 0.052*p21 - 0.053*p41 - 0.034*p43 - 0.043*p51)/

(1+(exp(2.03 - 0.052*p21 - 0.053*p41 - 0.034*p43 - 0.043*p51))

244.1

0.360

Calcium (75)

00915

100 mg/L

P=(exp(0.642 - 0.055*p42 + 0.059*p82 - 0.032*p81 – 0.401*p91)/

(1+(exp(0.642 - 0.055*p42 + 0.059*p82 - 0.032*p81 – 0.401*p91))

299.7

0.650

P=(exp(-1.33 - 0.040*p_forest - 0.431*p_wet + 2.71*bulk_d)/

(1+(exp(-1.33 - 0.040*p_forest - 0.431*p_wet + 2.71*bulk_d))

312.3

0.627

Carbaryl (76)

39750, 49310, 82680

0.01 mg/L

P=(exp(-1.18 + 0.118*p23 + 21.6*p61 - 0.061*MCS)/

(1+(exp(-1.18 + 0.118*p23 + 21.6*p61 - 0.061*MCS))

119.4

0.600

P=(exp(-1.46 + 0.032*p_urban + 0.030*p51 - 0.065*MCS)/

(1+(exp(-1.46 + 0.032*p_urban + 0.030*p51 - 0.065*MCS))

120.8

0.570

Carbonate (80)

00452

1.0 mg/L

P=(exp(1.16 – 0.140*p41 + 0.078*p51 + 0.072*p21 – 0.064*MCS)/

(1+(exp(1.16 - 0.140*p41 + 0.078*p51 + 0.072*p21 – 0.064*MCS))

92.9

0.714

P=(exp(6.00 – 0.089*p_forest – 0.060*p_ag - 0.070*MCS – 1.16*welldn)/

(1+(exp(6.00 - 0.089*p_forest – 0.060*p_ag - 0.070*MCS – 1.16*welldn))

92.3

0.699

Chlordane (81)

39350, 39352

0.01 mg/L

P=(exp(12.3 + 0.49*p21 – 49.7*Kfact + 0.00004*TDA)/

(1+(exp(12.3 + 0.49*p21 – 49.7*Kfact + 0.00004*TDA))

85.7

0.848

P=(exp(9.19 + 0.148*p_urban – 38.1*Kfact + 0.00003*TDA)/

(1+(exp(9.19 + 0.148*p_urban – 38.1*Kfact + 0.00003*TDA))

88.8

0.820

Chloride (85)

00940

125 mg/L

P=(exp(-6.42 + 0.066*p51 - 0.034*p_forest + 6.63*bulk_d + 0.646*welldn)/

(1+(exp(-6.42 + 0.066*p51 - 0.034*p_forest + 6.63*bulk_d + 0.646*welldn))

262.8

0.766

P=(exp(-7.85 + 0.067*p51 + 0.034*p71 + 6.75*bulk_d + 0.048*p82)/

(1+(exp(-7.85 + 0.067*p51 + 0.034*p71 + 6.75*bulk_d + 0.048*p82))

273.1

0.728

Chromium (90)

01030, 01032

15.0 mg/L

Poor models

P=(exp(-0.979 - 0.062*p51 - 0.042*p81 + 0.845*hydgrp + 0.00007*TDA)/

(1+(exp(-0.979 - 0.062*p51 - 0.042*p81 + 0.845*hydgrp + 0.00007*TDA))

240.0

0.514

P=(exp(-2.01 + 0.038*p_urban + 0.032*p_forest + 0.693*fert_n + 0.00006*TDA)/

(1+(exp(-2.01 + 0.038*p_urban + 0.032*p_forest + 0.693*fert_n + 0.00006*TDA))

246.0

0.456

Copper (94)

01040

20 mg/L

Poor models

P=(exp(-1.71 - 0.028*p_forest + 0.160*p_wet + 0.020*p51 + 2.20*bulk_d)/

(1+(exp(-1.71 - 0.028*p_forest + 0.160*p_wet - 0.020*p51 + 2.20*bulk_d))

220.7

0.461

P=(exp(-1.18 - 0.041*p42 - 0.302*p85 + 0.021*p82 + 0.019*p71)/

(1+(exp(-1.18 - 0.041*p42 - 0.302*p85 + 0.021*p82 + 0.019*p71))

219.0

0.468

DCPA di-acid degradate (99)

82682

0.001 mg/L

P=(exp(-4.03 + 0.197*p21 + 0.043*p71 + 2.48*DCPA_use + 0.004*BS + 0.0001*TDA)/

(1+(exp(-4.03 + 0.197*p21 + 0.043*p71 + 2.48*DCPA_use + 0.004*BS + 0.0001*TDA))

91.5

0.713

P=(exp(-0.837 + 0.040*p_urban – 1.10*p_wet - 0.070*MCS + 0.0001*TDA)/

(1+(exp(-0.837 + 0.040*p_urban – 1.10*p_wet - 0.070*MCS + 0.0001*TDA))

87.0

0.666

DDE (101)

346853, 39366

0.001 mg/L

P=(exp(-4.30 + 0.035*p_urban + 0.055*p_drain + 0.00008*TDA + 0.008*BS)/

(1+(exp(-4.30 + 0.035*p_urban + 0.055*p_drain + 0.00008*TDA + 0.008*BS))

75.6

0.663

P=(exp(-12.0 + 0.954*p85 + 0.008*BS + 25.1*Kfact + 0.00008*TDA)/

(1+(exp(-12.0 + 0.954*p85 + 0.008*BS + 25.1*Kfact + 0.00008*TDA))

71.4

0.665

Diazinon (104)

39570, 39572, 39573

0.01 mg/L

P=(exp(-1.24 + 0.402*p21 + 0.00007*TDA + 0.027*p81)/

(1+(exp(-1.24 + 0.402*p21 + 0.00007*TDA + 0.027*p81))

188.3

0.664

P=(exp(-0.866 + 0.078*p_urban + 0.00008*TDA + 1.60*p_org – 0.027*p51)/

(1+(exp(-0.866 + 0.078*p_urban + 0.00008*TDA + 1.60*p_org – 0.027*p51))

202.5

0.599

Dieldrin (112)

39380, 39381

0.01 mg/L

P=(exp(-8.02 + 0.048*p_urban - 0.080*p51 + 2.02*hydgrp + 0.0001*TDA)/

(1+(exp(-8.02 + 0.048*p_urban - 0.080*p51 + 2.02*hydgrp + 0.0001*TDA))

141.0

0.745

P=(exp(-7.59 + 0.313*p23 + 0.499*p92 + 1.52*hydgrp + 0.00005*TDA)/

(1+(exp(-7.59 + 0.313*p23 + 0.499*p92 + 1.52*hydgrp + 0.00005*TDA))

140.5

0.705

Diuron (119)

49300

0.01 mg/L

P=(exp(-1.81 + 0.980*diuron_use + 0.127*p21 + 0.544*welldn)/

(1+(exp(-1.81 + 0.980*diuron_use + 0.127*p21 + 0.544*welldn))

95.3

0.543

P=(exp(-1.75 + 0.868*diuron_use + 0.051*p_urban + 0.542*welldn)/

(1+(exp(-1.75 + 0.868*diuron_use + 0.051*p_urban + 0.542*welldn))

96.8

0.536

Fluoride (129)

00950, 00951

1.0 mg/L

P=(exp(-1.68 - 0.018*p_ag - 0.044*p_forest + 80.3*perm + 0.096*p_clay)/

(1+(exp(-1.68 - 0.018*p_ag - 0.044*p_forest + 80.3*perm + 0.096*p_clay))

335.5

0.507

P=(exp(-1.10 - 0.024*p81 - 0.040*p42 – 0.079*p43 + 1.86*bulk_d)/

(1+(exp(-1.10 - 0.024*p81 - 0.040*p42 – 0.079*p43 + 1.86*bulk_d))

335.3

0.506

Hardness (135)

00900

300 mg/L

P=(exp(-4.39 + 0.111*p22 + 0.046*p51 + 0.034*p71 + 0.073*p82 + 2.66*bulk_d)/

(1+(exp(-4.39 - 0.111*p22 – 0.046*p51 + 0.034*p71 + 0.073*p82 + 2.66*bulk_d))

305.7

0.642

P=(exp(-3.75 - 0.014*p_ag – 0.055*p_forest + 206*perm + 1.23*hydgrp + 0.139*welldn)/

(1+(exp(-3.75 - 0.014*p_ag – 0.055*p_forest + 206*perm + 1.23*hydgrp + 1.39*welldn))

323.9

0.575

Heptachlor (136)

39410, 39411

0.01 mg/L

P=(exp(-4.01 + 0.031*p_ag + 0.058*p_urban + 0.045*p_drain)/

(1+(exp(-4.01 + 0.031*p_ag + 0.058*p_urban + 0.045*p_drain))

69.6

0.772

P=(exp(-3.87 + 0.029*p_ag + 0.0012*popdn + 0.043*p_drain)/

(1+(exp(-3.87 + 0.029*p_ag + 0.0012*popdn + 0.043*p_drain))

68.9

0.769

Heptachlor epoxide(137)

39420, 39421

0.01 mg/L

P=(exp(-3.75 + 0.027*p_ag + 0.071*p_urban + 0.375*welldn)/

(1+(exp(-3.75 + 0.028*p_ag + 0.071*p_urban + 0.375*welldn))

77.1

0.820

P=(exp(-3.39 + 0.088*p81 + 0.198*p21 – 1.39*p91)/

(1+(exp(-3.39 + 0.088*p81 + 0.198*p21 – 1.39*p91))

71.2

0.818

Iron (144)

01046

150 mg/L

Poor models

P=(exp(2.42 – 0.048*p42 - 0.031*p51 – 0.020*p71 - 0.030*P82)/

(1+(exp(2.42 – 0.048*p42 - 0.031*p51 – 0.020*p71 – 0.030*p82))

269.3

0.504

P=(exp(-1.54 - 0.019*p51 + 2.31*bulk_d + 0.509*manure_n)/

(1+(exp(-1.54 - 0.019*p51 + 2.31*bulk_d + 0.509*manure_n))

275.0

0.472

Lead (147)

01049

25 mg/L

Poor models

P=(exp(0.185 – 0.050*p43 – 0.026*p51 + 0.155*p85 + 0.002*BS)/

(1+(exp(0.185 – 0.050*p43 - 0.026*p51 + 0.155*p85 + 0.002*BS))

260.7

0.318

P=(exp(-0.315 + 0.029*p22 – 0.028*p51 + 0.027*p71 + 0.002*BS)/

(1+(exp(-0.315 + 0.029*p22 - 0.028*p51 + 0.021*p71 + 0.002*BS))

266.2

0.282

Lindane (148)

39340, 39341

0.01 mg/L

P=(exp(-5.03 + 0.199*p23 – 0.040*p51 + 1.11*hydgrp + 0.0001*TDA)/

(1+(exp(-5.03 + 0.199*p23 - 0.040*p51 + 1.11*hydgrp + 0.0001*TDA))

175.4

0.645

P=(exp(-4.80 + 0.043*p_urban – 0.039*p51 + 1.06*hydgrp + 0.0001*TDA)/

(1+(exp(-4.80 + 0.043*p_urban - 0.039*p51 + 1.06*hydgrp + 0.0001*TDA))

179.1

0.641

M+P xylene (150)

85795

0.1 mg/L

Poor models

P=(exp(-3.79 + 0.047*p_urban + 0.005*BS + 171.5*perm)/

(1+(exp(-3.79 + 0.047*p_urban + 0.005*BS + 171.5*perm))

47.3

0.475

P=(exp(-3.19 + 0.100*p22 + 0.052*p42 + 157.2*perm)/

(1+(exp(-3.19 + 0.100*p22 + 0.052*p42 + 157.2*perm))

46.7

0.496

Magnesium (151)

00925

20.0 mg/L

P=(exp(-3.04 - 0.068*p22 - 0.132*p43 - 0.089*p81 + 6.49*bulk_d)/

(1+(exp(-3.04 - 0.068*p22 - 0.132*p43 - 0.089*p81 + 6.49*bulk_d))

267.8

0.747

P=(exp(-2.23 + 0.067*p51 + 0.040*p71 + 0.068*p82 + 0.0006*popdn)/

(1+(exp(-2.23 + 0.067*p51 + 0.040*p71 + 0.068*p82 + 0.0006*popdn))

284.0

0.680

Manganese (152)

01056

75 mg/L

P=(exp(5.35 - 0.069*p42 + 0.058*p43 - 0.020*p51 – 11.3*kfact)/

(1+(exp(5.35 - 0.069*p42 + 0.058*p43 - 0.020*p51 – 11.3*kfact))

225.1

0.613

P=(exp(7.59 + 0.013*p_ag – 1.81*hydgrp - 0.007*BS – 0.00004*TDA)/

(1+(exp(7.59 + 0.013*p_ag – 1.81*hydgrp - 0.007*BS – 0.00004*TDA))

233.8

0.559

Mercury (153)

71890

0.5 mg/L

Poor models

P=(exp(-4.11 + 0.121*p23 + 0.026*p82 + 1.29*hydgrp + 0.00004*TDA)/

(1+(exp(-4.11 + 0.121*p23 + 0.026*p82 + 1.29*hydgrp + 0.00004*TDA))

230.3

0.391

P=(exp(-3.20 + 0.017*p_urban + 0.225*atr_use + 0.967*hydgrp + 0.00004*TDA)/

(1+(exp(-3.20 + 0.017*p_urban + 0.225*atr_use + 0.967*hydgrp + 0.00004*TDA))

228.6

0.418

Methyl-t-butyle ether (MTBE)(159)

78032

0.2 mg/L

Poor models

P=(exp(-1.48 + 0.041*p81 – 2.01*p91 + 0.106*p43 + 1.69*manure_n)/

(1+(exp(-1.48 + 0.041*p81 – 2.01*p91 + 0.106*p43 + 1.69*manure_n))

62.2

0.568

P=(exp(2.75 + 0.037*p_ag – 5.77*bulk_d + 1.06*manure_n)/

(1+(exp(2.75 + 0.037*p_ag – 5.77*bulk_d + 1.06*manure_n))

66.3

0.421

Metolachlor (160)

39415, 82612

0.01 mg/L

P=(exp(-4.17 + 0.048*p82 + 0.032*p81 + 6.20*p_org + 70.0*p61)/

(1+(exp(-4.17 + 0.048*p82 + 0.032*p81 + 6.20*p_org + 70.0*p61))

122.6

0.660

P=(exp(-2.58 + 0.028*p_ag - 0.066*MCS + 5.29*p_org + 0.00007*TDA)/

(1+(exp(-2.58 + 0.028*p_ag - 0.066*MCS + 5.29*p_org + 0.00007*TDA))

119.7

0.655

Metribuzin (161)

82611, 82612

0.01 mg/L

P=(exp(-1.61 + 0.040*p21 - 0.057*p42 + 12.4*p61)/

(1+(exp(-1.61 + 0.040*p21 - 0.057*p42 + 12.4*p61))

87.2

0.533

P=(exp(-0.541 + 0.013*p_urban - 0.033*p_forest – 0.075*MCS)/

(1+(exp(-0.541 + 0.013*p_urban - 0.033*p_forest – 0.075*MCS))

87.8

0.474

M-xylene (164)

No codes

 0.1 mg/L

Same models as for M+P xylene

P=(exp(-3.79 + 0.047*p_urban + 0.005*BS + 171.5*perm)/

(1+(exp(-3.79 + 0.047*p_urban + 0.005*BS + 171.5*perm))

47.3

0.475

P=(exp(-3.19 + 0.100*p22 + 0.052*p42 + 157.2*perm)/

(1+(exp(-3.19 + 0.100*p22 + 0.052*p42 + 157.2*perm))

46.7

0.496

Nickel (167)

01065

10 mg/L

Poor models

P=(exp(-4.17 + 0.077*p22 + 0.023*p71 + 0.238*p83 + 0.539*p91 + 1.00*hydgrp)/

(1+(exp(-4.17 + 0.077*p22 + 0.023*p71 + 0.238*p83 + 0.539*p91 + 1.00*hydgrp))

205.5

0.434

P=(exp(-0.185 + 0.056*p22 - 0.022*p82 + 0.253*p83 + 0.377*p91)/

(1+(exp(-0.185 + 0.056*p22 - 0.022*p82 + 0.253*p83 + 0.377*p91))

206.0

0.414

Nitrate (168, 169)

00630, 00631, 00618, 00620

2.0 mg/L

Poor models

P=(exp(-6.10 + 0.078*p82 + 0.244*p85 + 1.75*hydgrp – 0.018*MCS))/

(1+(exp(-6.10 + 0.078*p82 + 0.244*p85 + 1.75*hydgrp – 0.018*MCS))

336.3

0.494

P=(exp(-6.02 + 0.079*p82 + 0.046*p22 + 1.74*hydgrp – 0.021*MCS)/

(1+(exp(-6.02 + 0.079*p82 + 0.046*p22 + 1.74*hydgrp – 0.021*MCS))

336.8

0.496

Nitrite (170)

00613, 00615

0.1 mg/L

Poor models

P=(exp(-2.56 + 0.020*p_ag + 0.019*p_urban + 0.608*hydgrp – 0.036*p_drain)/

(1+(exp(-2.56 + 0.020*p_ag + 0.019*p_urban + 0.608*hydgrp – 0.036*p_drain))

316.1

0.394

P=(exp(-2.51 + 0.692*fert_n + 0.077*p22 + 0.487*hydgrp – 0.039*p_drain)/

(1+(exp(-2.51 + 0.692*fert_n + 0.077*p22 + 0.487*hydgrp – 0.039*p_drain))

306.4

0.424

O-xylene (176)

77135

0.01 mg/L

P=(exp(-6.24 + 0.492*p23 + 0.051*p71 + 0.014*BS)/

(1+(exp(-6.24 + 0.492*p23 + 0.051*p71 + 0.014*BS))

29.4

0.764

P=(exp(-4.49 + 0.104*p_urban + 0.012*BS)/

(1+(exp(-4.49 + 0.104*p_urban + 0.012*BS))

29.3

0.694

PCBs (179)

39516, 39517

0.01 mg/L

P=(exp(-1.14 + 0.059*p_urban - 0.088*MCS + 0.393*welldn)/

(1+(exp(-1.14 + 0.059*p_urban - 0.088*MCS + 0.393*welldn))

85.8

0.653

P=(exp(-0.900 + 0.178*p22 - 0.128*MCS + 0.034*p82)/

(1+(exp(-0.900 + 0.178*p22 - 0.128*MCS + 0.034*p82))

82.7

0.638

Prometon (185)

04037, 39056

0.01 mg/L

P=(exp(0.870 + 0.080*p_urban - 0.043*p_forest)/

(1+(exp(0.870 + 0.080*p_urban - 0.043*p_forest))

139.1

0.611

P=(exp(0.762 + 0.139*p22 - 0.075*p43 - 0.003*BS)/

(1+(exp(0.762 + 0.139*p22 - 0.075*p43 - 0.003*BS))

150.1

0.509

P-xylene (188)

No codes or data

0.1 mg/L

Same models as for M+P xylene

P=(exp(-3.79 + 0.047*p_urban + 0.005*BS + 171.5*perm)/

(1+(exp(-3.79 + 0.047*p_urban + 0.005*BS + 171.5*perm))

47.3

0.475

P=(exp(-3.19 + 0.100*p22 + 0.052*p42 + 157.2*perm)/

(1+(exp(-3.19 + 0.100*p22 + 0.052*p42 + 157.2*perm))

46.7

0.496

Selenium (195)

01145

2.0 mg/L

P=(exp(-1.58 - 0.061*p43 + 0.028*p82 + 0.259*p85 + 146*perm)/

(1+(exp(-1.58 - 0.061*p43 + 0.028*p82 + 0.259*p85 + 146*perm))

245.9

0.426

P=(exp(-2.49 - 0.076*p43 - 0.027*p81 + 3.58*bulk_d)/

(1+(exp(-2.49 - 0.076*p43 - 0.027*p81 + 3.58*bulk_d))

247.1

0.411

Silver (196)

01075 

2.0 mg/L

Poor models

P=(exp(0.703 + 0.107*p83 + 0.230*p91 + 0.338*welldn - 122*perm)/

(1+(exp(0.703 + 0.107*p83 + 0.230*p91 + 0.338*welldn – 122*perm))

258.6

0.298

P=(exp(1.67 + 0.016*p_ag + 0.342*welldn – 2.06*p_org - 130*perm)/

(1+(exp(1.67 + 0.016*p_ag + 0.342*welldn – 2.06*p_org - 130*perm))

260.7

0.259

Simazine (197)

04035, 39055

0.01 mg/L

P=(exp(-0.719 + 0.098*p21 + 0.052*p81 – 0.028*p42 - 0.463*p91)/

(1+(exp(-0.719 + 0.098*p21 + 0.052*p81 – 0.028*p42 - 0.463*p91))

146.8

0.640

P=(exp(-2.97 + 0.045*p_urban + 0.038*p_ag + 2.61*p_org + 0.00004*TDA)/

(1+(exp(-2.97 + 0.045*p_urban + 0.038*p_ag + 2.61*p_org + 0.00004*TDA))

147.8

0.615

Sodium (198)

00930

75 mg/L

P=(exp(-3.65 - 0.043*p_forest + 0.037*p51 + 4.76*bulk_d + 0.821*welldn) /

(1+(exp(-3.65 - 0.043*p_forest + 0.037*p51 + 4.76*bulk_d + 0.821*welldn))

254.4

0.773

P=(exp(-6.13 - 0.074*p43 + 0.041*p51 + 6.48*bulk_d + 0.790*welldn + 0.872*sod-chl_use) /

(1+(exp(-6.13 - 0.074*p43 + 0.041*p51 + 6.48*bulk_d + 0.790*welldn + 0.872*sod-chl_use))

253.1

0.771

Specific conductance (199)

00095

1,500 Us/cm

P=(exp(-2.02 – 0.066*p42 + 0.090*p82 + 0.048*p51 + 0.208*welldn)/

(1+(exp(-2.02 - 0.066*p42 + 0.090*p82 + 0.048*p51 + 0.208*welldn))

253.2

0.757

P=(exp(-0.871 – 0.067*p_forest – 0.018*p_urban + 173*perm + 0.187*welldn)/

(1+(exp(-0.871 - 0.067*p_forest – 0.018*p_urban + 173*perm + 0.187*welldn))

266.6

0.720

Sulfate (203)

00945

100 mg/L

P=(exp(-3.47 - 0.089*p41 + 5.76*bulk_d – 0.182*p43 - 0.053*p_drain) /

(1+(exp(-3.47 - 0.089*p41 + 5.76*bulk_d – 0.182*p43 - 0.053*p_drain))

293.4

0.676

P=(exp(0.575 – 0.065*p_forest + 124*perm + 0.015*p_urban – 0.035*p_drain)/

(1+(exp(0.575 – 0.065*p_forest + 124*perm + 0.015*p_urban – 0.035*p_drain))

292.9

0.681

Total dissolved solids (TDS)(205)

70301

500 mg/L

P=(exp(1.11 - 0.061*p42 – 0.051*p43 - 0.033*p81 + 0.048*p82 + 0.75*welldn)/

(1+(exp(1.11 - 0.061*p42 – 0.051*p43 - 0.033*p81 + 0.048*p82 + 0.75*welldn))

273.1

0.717

P=(exp(-0.532 - 0.063*p_forest - 0.024*p_ag + 3.28*bulk_d + 0.653*welldn)/

(1+(exp(-0.532 - 0.063*p_forest - 0.024*p_ag + 3.28*bulk_d + 0.653*welldn))

273.8

0.710

Toluene (211)

34010

0.01 mg/L

P=(exp(-1.58 + 0.120*p21 – 0.222*p43 - 0.079*MCS + 301*perm) /

(1+(exp(-1.58 + 0.120*p21 – 0.222*p43 - 0.079*MCS + 301*perm))

66.5

0.615

P=(exp(9.69 - 0.269*p43 – 0.050*p71 – 2.73*hydgrp – 0.048*MCS) /

(1+(exp(9.69 - 0.269*p43 – 0.050*p71 – 2.73*hydgrp – 0.048*MCS))

69.0

0.607

Total coliform (213)

31501

20,000 counts/100 ml

P=(exp(-0.266 + 0.085*p_urban – 0.028*p_forest + 4.09*manure_p) /

(1+(exp(-0.266 + 0.085*p_urban – 0.028*p_forest + 4.09*manure_p))

54.5

0.801

P=(exp(-1.77 + 1.09*p21 – 0.057*p42 + 7.54*p_org) /

(1+(exp(-1.77 + 1.09*p21 – 0.057*p42 + 7.54*p_org))

52.1

0.786

Uranium (223)

22703, 75990, 80020

2.0 mg/L

P=(exp(-8.84 + 0.117*p81 + 0.122*p82 + 1.11*p85 + 0.138*p51) /

(1+(exp(-8.84 + 0.117*p81 + 0.122*p82 + 1.11*p85 + 0.138*p51))

44.1

0.856

P=(exp(-13.1 + 0.157*p_ag + 0.114*p_urban + 185*perm + 0.162*p51) /

(1+(exp(-13.1 + 0.157*p_ag + 0.114*p_urban + 185*perm + 0.162*p51))

45.0

0.877

Xylenes (total) (226)

81551

0.1 mg/L

P=(exp(-2.43 + 0.00013*TDA – 1.88*welldn + 0.625*p92 + 127*perm) /

(1+(exp(-2.43 + 0.00013*TDA – 1.88*welldn + 0.625*p92 + 127*perm))

51.6

0.533

P=(exp(1.56 + 0.00011*TDA – 1.34*welldn - 0.934*hydgrp) /

(1+(exp(1.56 + 0.00011*TDA – 1.34*welldn - 0.934*hydgrp))

52.1

0.563

Zinc (227)

01090

50 mg/L

P=(exp(-0.401 + 0.0005*popdn + 0.146*p83 + 0.384*p92) /

(1+(exp(-0.401 + 0.0005*popdn + 0.146*p83 + 0.384*p92))

262.4

0.342

P=(exp(-0.446 + 0.075*p22 + 0.152*p83 + 0.410*p92) /

(1+(exp(-0.446 + 0.075*p22 + 0.152*p83 + 0.410*p92))

259.7

0.373