Environmental Chemistry in the Real World

Jace Hargis, PhD

Advance Organizer

• Hydro-Geo-Chemical Cycle• Field/Soil Technician • Field Chemist • Analytical Lab Chemist• Consulting Chemist• Task/Project Manager

© 2003 John Wiley and Sons Publishers

Geologic Cycle

Tectonic

Hydrologic

Rock

Biogeo-chemical

Subsurface Systems

Field Work

• Destinations• Drill• Purge• Collect Soil/Water Sample• Preserve• Ship to lab for analysis

• O - Organic layer – leaf litter & organic material.

• A – Topsoil layer – loose with varying amounts of organic matter.

• B – Subsoil - lighter in color, dense and low in organic matter.

• C – Transition - void of organic, made of partially weathered parent.

• D – below C is Bedrock

Field Chemist

• Perform basic analysis in the field typically to inform drillers – direction of contaminant, depth, etc.

• Screening for hazardous waste – water and air

Water Quality Indicators

• Alkalinity• Ammonia• Bacteria• Dissolved Oxygen• Conductivity• Hardness• Nitrate• Phosphate• Chemicals (Pesticides, VOCs, Metals)

Alkalinity & Ammonia (NH3)

• Alkalinity - water’s ability to neutralize acids. Produced by minerals (limestone, CaCO3).

• NH3 produced by decay of organic matter. Bacteria readily convert NH3 to NO3.

Nitrate (NO3)

• Primary plant nutrient. Water soluble and moves easily from surface to GW.

• Excess causes algal blooms that reduce water quality and DO.

• Excessive use of fertilizers & sewage creates surplus.

Dissolved Oxygen (DO)

• Product of photosynthesis and diffusion.

• Warmer the water, the less O2 it can hold.

• Organisms need at least 5 ppm O2.

Conductivity

• Water’s ability to conduct an electrical current.

• Pure H2O is poor conductor. Add dissolved solids (salts) increases conduct.

• Measured using conductivity meter.

• pH - measure of the hydrogen ion (H+) conc.

• Scale is 0-14. Neutral (7); Acidic (<7); Basic (>7).

• Aquatic organisms exist within range of 5-9.

Analytical Lab Chemistry

• Organic - SVOC, VOC, Pest• Inorganic - Cations, Anions• Wet Chemistry – WQ

Organic - Gas Chromatograph

Cations (Metals) Atomic Absorption Spectroscopy

Determines presence of cations such as Fe, Cu, Al, Pb, Ca, Zn, Cd in low mg/L (ppm).

Data Validation

Path

Plume Maps

Data Validation• Systematic review of env chemical data, where

qualifiers (U, J, UJ or R) are added. • Provides information on quality of the data.• Parameters reviewed

– initial and continuing calibration– Blanks– Surrogates– matrix spikes and duplicates– holding times; and – target compound identification.

Report Writing• Collect Data• Plume Maps• Interpret using GW flow, fate and transport

data• Recommend remedial action and monitoring

Remedial Actions

• Excavation & removal of contaminated soil• Recovery Wells and Slurry Walls • Groundwater pump & treat extraction systems

w/GAC• Soil-Vapor Extraction• Natural attenuation

Environmental Audits

(1) Compliance audits to ensure company is meeting regulations;

(2) Audits of property transfers; (3) "Treatment, storage, and disposal facility"

audits used to follow hazardous material throughout their life cycle;

(4) Preventative measures to reduce company’s risk.

Risk Assessment• Human Health

– Identifying pollution sources– Predicting contaminant fate and transport– Quantifying chemical exposures– Evaluating tox data

• Assumes 70kg individual exposed over a 70-yr life.• Ecological - define levels protective of environment and

to derive clean up criteria.

Task/Project Management Sum

• Proposal - RfP• Plans

– Work Plan– H&S Plan– Sampling Plan

• Staffing– PM, TM,

Engineers, Chemists, Hydrogeologists, Technicians, Editor

• Project– Permits– Well installations– Sample collection– Lab analysis– Data validation– Data interpretation– Risk assessment– Report writing– Technical editing– Reprographics– Deliverable

• On-time, budget, high-quality- $$$

Thank You

Jace Hargis, PhD